Microsoft Word - AbstractsGAC-MAC2012.doc

On behalf of the St. John’s 2012 local organizing committee,

we welcome delegates to North America’s oldest city, St.

John’s, for the joint annual meeting of the Geological Asso-

ciation of Canada (GAC

) and the Mineralogical Association

of Canada (MAC). Returning once again to Newfoundland

and Labrador, delegates and guests will enjoy not only an ex-

ceptional technical program of outstanding geoscience, but

also the rich-culture, friendly faces and rugged landscapes

that this historic city has to offer.

The meeting is being held at the Delta St. John’s Hotel and

Conference Centre. The location provides delegates with the

convenience of a compact conference venue, located in the

heart of downtown and with a spectacular view of the Nar-

rows. We hope you will take the opportunity to explore the

history, culture, unique architecture, culinary pleasures and

colourful characters that the city has to offer.

The meeting’s motto, Geoscience at the Edge, alludes not

only to the geographic location of the host city, St. John's, sit-

uated at the eastern edge of the North American craton, but

also to the leading geoscience research and ideas being pre-

sented at the meeting. Whether your focus is on petroleum,

base or precious metals, geophysics, bedrock or seafloor map-

ping, climate change, or geotourism, St. John's 2012 will pres-

ent the latest research and technical developments in the Earth

Sciences. The technical program contains three symposia and

twenty one special sessions featuring a cross section of geo-

science research from Economic Geology to soft rock ses-

sions including shale gas, facies models, provenance

determination, geohazard assessment and oil spill prevention.

The program has a short course and a diverse offering of

twelve field trips. The meeting contains an expansive out-

reach program that features events and activities that aim to

raise awareness of the Earth Sciences to the general public,

as well as to students and teachers.

St. John’s 2012 not only has an excellent technical program,

but also a diverse special events program. Join us for the Gala

Banquet, which features fine dining and memorable New-

foundland entertainment. Other social events include: a lob-

ster dinner, a chance for lobster lovers to enjoy the finest that

the North Atlantic has to offer; and a Pub Night, an opportu-

nity to savour local microbrew while enjoying the sights and

sounds of historic downtown St. John’s.

We hope you enjoy the rich culture and breathtaking beauty

that the City of Legends has to offer.

Alana Hinchey, GAC

Chair

Steve Piercey, MAC Co-Chair

Au nom du comité organisateur de St. John’s 2012, nous

souhaitons aux participants la bienvenue à la plus ancienne

ville d’Amérique du Nord, St. John’s, à l’occasion de la réu-

nion annuelle conjointe de l'Association géologique du

Canada (AGC

) et l'Association minéralogique du Canada

(AMC). En revenant une fois de plus à Terre-Neuve-et-

Labrador les participants et leurs invités pourront encore prof-

iter non seulement d’un programme d’activités professionn-

elles géoscientifique exceptionnel, mais aussi de la riche cul-

ture, de l’accueil de gens sympathiques et des paysages

sauvages particuliers à cette ville historique.

La réunion se tiendra à l'hôtel Delta de St. John’s et à son cen-

tre de conférence. L'emplacement offre aux délégués l’avan-

tage d’un lieu de conférence compact situé au cœur du

centre-ville avec une vue spectaculaire sur le Narrows. Nous

espérons que vous profiterez de l'occasion pour vous enquérir

de l'histoire, de la culture, de l'architecture unique, et que vous

goûterez les plaisirs culinaires uniques et les personnages

hauts en couleur de la ville.

Le thème de la réunion, Géosciences de pointe, fait allusion

non seulement à l'emplacement géographique de la ville hôte,

St. John’s, situé à l'extrémité orientale du craton de

l'Amérique du Nord, mais également à la recherche géosci-

entifiques et aux idées de pointe présentées à de la réunion.

Que vous vous intéressiez au pétrole, aux métaux de base ou

précieux, à la géophysique, à la cartographie des affleure-

ments ou des fonds marins, au changement climatique, ou au

géotourisme, St. John’s 2012 présentera les dernières

recherches et développements techniques en sciences de la

Terre. Le programme d’activités professionnelles comprend

trois symposiums et vingt-et-une séances spécialisées don-

neront un aperçu des recherches géoscientifiques en cours, en

géologie économique, sur les roches non-consolidées, les gaz

de schiste, les modèles de faciès, la détermination des matéri-

aux d’origine, l'évaluation des géorisques et la prévention des

déversements de pétrole. Le programme d’activités comprend

un cours intensif ainsi qu’une fourchette diversifiée de douze

excursions de terrain. La réunion comprend un ambitieux pro-

gramme de sensibilisation qui propose des événements et des

activités qui visent à sensibiliser aux sciences de la Terre le

grand public, les étudiants et les enseignants.

St. John’s 2012 a non seulement un excellent programme

d’activités professionnelles, mais aussi un programme

d’événements spéciaux diversifié. Soyez des nôtres à la soirée

gala, qui propose un dîner raffiné et un divertissement terre-

neuvien mémorable. Les autres activités sociales compren-

nent entre autre: un dîner de homard, et une soirée au pub.

Nous espérons que vous apprécierez la richesse culturelle et la

beauté à couper le souffle de St. John’s, cette ville de légendes.

Alana Hinchey, AGC

Président

Steve Piercey, AMC Co-président

WELCOME TO ST. JOHN’S 2012 / BIENVENUE À ST. JOHN’S 2012

LOCAL ORGANIZING COMMITTEE

COMITÉ ORGANISATEUR LOCAL

GAC Chair / Présidente Alana Hinchey GSNL

MAC Co-Chair / Co-président Steve Piercey MUN

General Secretary / Secrétaire général Tim van Nostrand GSNL

Finance / Finance Greg Sparkes GSNL

Fund Raising / Financement Annie Parrell Chair/responsible ENERGY

James Conliffe Co-chair/co-responsible GSNL

Registration / Inscription Kelly Batten-Hender Chair/responsible CNLOPB

Stephanie Johnson Co-chair/co-responsible CNLOPB

Gerry Kilfoil Co-chair/co-responsible GSNL

Promotion / Promotion Lori Cook Chair/responsible ENERGY

Amanda McCallum Co-chair/co-responsible GSNL

Accommodations / Hébergement Dawn Evans-Lamswood Chair/responsible VALE

Derek Wilton Co-chair/co-responsible MUN

Exhibits / Expositions Greg Stapleton Chair/responsible GSNL

Publications / Publications Chris Pereira Chair/responsible GSNL

Andrea Mills Co-chair/co-responsible MINES

Field Trips / Excursions Andy Kerr Chair/responsible GSNL

Eric Albrechtsons Co-chair/co-responsible SE

Short Courses / Cours intensifs Graham Layne Chair/responsible MUN

Paul Sylvester Co-chair/responsible MUN

Social Events / Activités récréatives Jennifer Smith Chair/responsible GSNL

Technical Program / Joe MacQuaker Chair/responsible EM

Programmes scientifique Hamish Sandeman Co-chair/co-responsible GSNL

Technical Services / Larry Nolan Chair/responsible GSNL

Services techniques Colin Farquharson Co-chair/co-responsible MUN

Outreach / Amanda McCallum Chair/responsible GSNL

Sensibilisation et formation Dianne Noseworthy Co-chair/co-responsible CNLOPB

Website/Email / Steve Amor Chair/responsible GSNL

Site Internet, adrélee, webmestre

Volunteer Coordinator Monica Squires Chair/responsible GSNL

Accompanying guest / Tony Burgess Chair/responsible MINES

Programme d’activités des invités Brad Way Co-chair/co-responsible MINES

GSNL Geological Survey of Newfoundland and Labrador, Department of Natural Resources

MUN Memorial University of Newfoundland

MINES Mines Branch, Newfoundland and Labrador Department of Natural Resources

CNLOBP Canada-Newfoundland and Labrador Offshore Petroleum Board

ENERGY Energy Branch, Newfoundland and Labrador Department of Natural Resources

EM ExxonMobil

SE Suncor Energy

VALE VALE

TABLE OF CONTENTS

TABLE DES MATIÈRES

ABSTRACTS / RÉSUMÉS............................................................................................................... 1

AUTHOR INDEX / INDEX DES AUTEURS.................................................................................. 157

Abstracts can also be searched using this link /

Les résumés peuvent aussi être consultes sur le site suivant :

http://gac.esd.mun.ca/gac_2012/search_abs/program.asp

Graphic design / Graphisme:

Beth Oberholtzer and Charles Newhook

Layout / Mise en page:

Joanne Rooney

Database management /

Gestion de banque de données

Gerry Kilfoil

THERMAL HISTORY OF THE KAPOETA METEORITE: A

STUDY OF Fe

-Mg ORDERING IN ORTHOPYROXENE BY

SINGLE-CRYSTAL XRD AND MÖSSBAUER SPECTROSCOPY

Abdu, Y.A. and Hawthorne, F.C., Department of Geological

Sciences, University of Manitoba, Winnipeg, MB R3T 2N2,

[email protected]

Kapoeta is an achondrite meteorite that belongs to the howardite group.

Howardites, eucrites, and diogenites meteorites (HED) are believed to

originate from igneous processes on the asteroid 4 Vesta. Kapoeta is

characterized as a polymict breccia with a light-dark structure, and the

rock consists almost entirely of pyroxene. The study of intracrystalline

distribution of Fe

and Mg between the nonequivalent octahedral sites M1

and M2 in pyroxenes is very useful in tracing the thermal history of a rock.

In unshocked and slowly cooled pyroxenes to ~ 500 °C and below, Fe

orders at the M2 site whereas Mg occurs predominately at the M1 site. In

crystals that have been rapidly cooled from high temperatures, a more

disordered Fe

-Mg distribution over the M1 and M2 sites is observed.

Single-crystal X-ray diffraction was used to determine Fe

-Mg

degree of ordering on orthopyroxene crystals from the Kapoeta meteorite,

through the intracrystalline distribution parameter, p, defined as: p =

(Fe

(M1).Mg(M2))/(Fe

(M2).Mg(M1)), which is then used to calculate

the Fe

-Mg ordering closure temperature (Tc). The distribution of Fe

and Mg over the M1 and M2 sites determined by the structure refinement

gives Tc values in the range 350-450°C, in agreement with those

previously obtained on some orthopyroxene crystals from Kapoeta having

similar compositions to our orthopyroxenes (Mg/(Mg+Fe) range: 70-80%),

all are within the Tc values reported on orthopyroxenes from diogenites.

These closure temperatures indicate a slow cooling rate for these Kapoeta

orthopyroxenes, and the similarities of Tc and composition to those of

diogenites may suggest a diogenitic origin deep within the parent body of

the HED meteorites.

Mössbauer spectra collected on powdered samples from both the

light and dark structures of Kapoeta are characteristic of orthopyroxene.

The light and dark structures have almost identical Mössbauer spectra. The

spectra are fitted with two doublets due to Fe

at the M1 and M2 sites in

orthopyroxene. In contrast to the low Tc values determined by structure

refinement, the distribution of Fe

between the M1 and M2 sites

determined by Mössbauer spectroscopy suggests a Tc value of ~ 900 °C,

indicating a fast cooling. The results are discussed in relation to the

thermal and shock histories of the HED parent body.

ROPER-LIKE MICROFOSSILS FROM THE MESOPROTERO-

ZOIC HELENA EMBAYMENT, BELT SUPERGROUP

Adam, Z.R., Montana State University, Department of Earth

Sciences, Bozeman, MT, zachary.ada[email protected], and

Butterfield, N.J., University of Cambridge, Department of Earth

Sciences, Cambridge, UK, [email protected]

Shale samples from the Helena Embayment of the Lower Belt Supergroup

(> 1.45 Ga), Montana have yielded well-preserved acritarch assemblages,

including a range of taxa characteristic of the broadly contemporaneous

Roper Group, northern Australia. Sampled horizons are in the vicinity of

White Sulfur Springs, Montana, and include drillcore (Cominco American,

#SCC-34) of the Chamberlain Shale and outcrop of the stratigraphically

younger Greyson Shale.

The Chamberlain consists of dark siliciclastic/calcareous shales, and

has been interpreted as representing a low-oxygen, low-energy shoreward

transgressive facies that was eventually replaced by regressive Greyson

Shale-like facies. The Greyson Shale appears to represent a shallow water

setting, and is gradationally overlain by the conspicuously red and

mudcracked Spokane Formation. In addition to simple spheroidal

(Leiosphaeridia spp.) and filamentous (Siphonophycus spp., Tortunema

sp., Rugosoopsis sp.) microfossils, one drillcore Chamberlain sample

yielded four Valeria specimens associated with large, striated tubular

sheaths. Each Valeria has been compressed at different relative angles to

the poles of their concentric striations, supporting an interpretation that the

striations express physical attributes of the vesicle ultrastructure. Greyson

samples have yielded an intriguing range of morphologically differentiated

acritarch taxa. There are two Tappania specimens, four small

Gemmuloides specimens (each with distinct, sub-rounded buds ranging

from 9-25% of parent vesicle size) and numerous specimens resembling

Caudosphaera, though these specimens possess dark, globose spheroidal

vesicles that are not distinguished in Caudosphaera descriptions from

Russia.

Spheroids and filaments are found throughout the entire microfossil

record, but this assemblage has a typical Mesoproterozoic aspect. Tappania

is known from the Mesoproterozoic Roper, Ruyang (China), Vindhyan

(India), and Kamo (Russia) Groups, but is conspicuous in the Roper.

Roper is also noted for the presence of Satka, which has been previously

documented in the Chamberlain, and for fused filaments which may

correspond to those recovered in this study. Overall, this preliminary study

of Belt Supergroup microfossils reveals an assemblage strikingly similar to

that found in the Roper Group and points to an early Mesoproterozoic

establishment of a modestly diversified eukaryotic biota, followed by

pronounced macroevolutionary stasis with very limited, if any,

bioprovinciality. Such patterns have important implications for

understanding the macroevolutoionary expression of the Mesoproterozoic

biosphere.

FORENSIC PALYNOLOGY: CONSIDERING EVIDENCE FROM

FOOTWEAR

Adekanmbi, O.H. and Ogundipe, O.T., Department of Botany,

University of Lagos, Akoka, Lagos, Nigeria, sholaadekanmbi2000@

yahoo.com

Five forensic samples were collected from five (5) different locations in

University of Lagos campus including the Faculty of Science, the

Botanical Garden, the faculty of Business Administrations, Distance

Learning Institute and University of Lagos Gate. Samples were collected

from the pair of shoes of individual students and members of staff who

cooperated using brushes in succession (a brush for a pair of shoes) for

pollen collection. The dusts were carefully brushed into white envelopes

shading them from the direction of the wind. The white envelope were

sealed up and labeled. The collected samples were taken into the

laboratory and subjected to standard palynological sample preparation to

isolate the palynomorphs. The aim of this research was to assess the

forensic value of soil samples from footwear in linking suspects to crime

scenes. The recovered pollen assemblage were compared with the present

vegetation at the vicinity within which the students walked to determine

the degree to which pollen assemblages from footwear represent

vegetation within the same localized area, and the degree to which the

retrieved pollen assemblage differ from distant localized areas. Retrieved

palynomorphs assemblage showed a high degree of similarity with

vegetation within the sampled locality, the relative abundance of

palynomorphs being proportional to vegetation. The recovered

palynomorphs also revealed the various locations the people sampled have

visited before getting to sampled locations suggesting that forensic

palynology should always be incorporated as a vital tool in criminal

investigations in countries where this is yet to be accepted. One must

however stress the importance of strong background in plant ecology and

palynology and necessity of carrying out detailed vegetation surveys of all

relevant places, after this can forensic palynology be used to their fullest

potentials.

BIOLOGICAL AND ECOLOGICAL FACTORS CONTROLLING

CARBONATE BUILD-UPS AND PRODUCING A PRECISION

ARCTIC/SUBARCTIC MARINE CLIMATE ARCHIVE: THE

CALCIFIED ALGA CLATHROMORPHUM COMPACTUM

Adey, W., Natl. Museum of Natural History, Smithsonian Institution,

Washington, DC 20560, adeyw@si.edu, Halfar, J., University of

Toronto at Mississauga, ON L5L 1C6, and Williams, B., Keck

Science Center, Claremont Colleges, Claremont, CA 9171-5916

Numerous studies have demonstrated that the coralline alga C. compactum

can yield high-resolution precision paleoenvironmental records in regions

where other archival records are unavailable. However, at present

information on C. compactum biology and ecology is limited. Using an

extensive collection of samples from the northwestern Atlantic Coast from

northern Labrador to the Gulf of Maine, this study provides an

understanding of the complex interaction between reproduction, cellular

anatomy and temperature-regulated growth. At mid-photic depths of 10-

25m, C. compactum can cover large areas of rocky bottom, forming

clathrostromes (carbonate build-ups). Ultimate crustal thickness is

primarily limited by geomorphological stability, very high levels of wave

energy and mollusk boring. The thickest specimens found to date

(>100mm), in northern Labrador, exhibit more than 800 years of growth.

C. compactum reaches maximum coverage and clathrostrome formation in

island complexes at moderate wave exposures. In protected bays and

fjords, lower salinities, sedimentation and competition by the branching

coralline Lithothamnion glaciale prevents significant clathrostrome

formation.

Reproductive/anatomical investigation, using mosaic images taken

with SEM, have demonstrated how metabolically-emplaced inner wall

calcite, integral with growth, is regulated by temperature, while carbonate

density is controlled by the addition of secondary inter-filament calcite,

deposited primarily in summer, likely by photosynthesis-driven CO

removal. Winter crustal accretion (growth), at 10-15 µm/month in

Labrador, continues, under sea ice and snow, during short winter days; the

available evidence suggests that growth is likely in the high Arctic in

complete winter darkness. In Labrador, summer accretion rates are roughly

20-25 µm/month. In the Gulf of Maine, the southern limit of C.

compactum, where the species is considerably less abundant than in the

Labrador Sea, accretion rates are about 400 µm/year; in northern Labrador,

they are about 120 µm/year. C. compactum occurs throughout the Arctic

and into the North Pacific, but it is unknown at this time whether or not it

is a dominant crust in the Arctic, producing significant carbonate buildups.

It is possible that this species can provide a pan-Arctic climate archive of

considerable significance.

LATERAL FLUID FLOW UNDERNEATH AND INTO CARLIN-

TYPE GOLD DEPOSITS: ISOTOPIC CONSTRAINTS ON THE

PATH OF HYDROTHERMAL FLUID FLOW

Ahmed, A.D., Hickey, K.A., [email protected], Barker, S.L.L.,

Dept Earth & Ocean Sciences, The University of British Columbia,

Vancouver, BC V6T 1Z4, and Leonardson, R.W., Barrick Gold

Corporation, Elko, NV, USA

In the shallow crust, fluid flow responsible for the formation of many

bedrock-hosted hydrothermal ore deposits is commonly conceptualized as

occurring in a dominantly vertical direction controlled by high angle fault

structures. In this study we use carbon and oxygen stable isotopes in

conjunction with a pre-existing trace element database to investigate

pathways taken by ore-forming fluids into the Pipeline deposit, a giant

Carlin-type sedimentary rock-hosted disseminated gold deposit located in

north central Nevada. We sampled deep drill holes within, below and to

the side of the main orebodies and this enabled us to assess the extent of

lateral verses vertical fluid flow up to 600m below mineralization.

A lack of pervasive δ

O depletion and low concentrations of trace

elements in the rocks beneath the main ore zone at Pipeline demonstrate

that mineralization was not the product of any large scale vertical

upwelling of ore stage hydrothermal fluid. There is, however, evidence of

extensive lateral fluid flow along a major lithological contact between the

Roberts Mountains and Weban Formations and along a thrust stack below

the regionally extensive Roberts Mountains Thrust. A second thrust, the

Abyss Fault, ~100-200m below the Pipeline deposit has minor isotopic

depletion but overall no evidence of major fluid rock interaction. Genesis

of the Pipeline deposit involved direct lateral flow of hydrothermal fluid

on at least a 103m scale and suggests “deeper” might not always be

“better” in brownfields exploration for Carlin-type deposits.

TESTING THE OROGENIC COLLAPSE MODEL FOR THE

MESOPROTEROZOIC GRENVILLE PROVINCE

Ahmed, M. and Rivers, T., Memorial University of Newfoundland,

St. John's, NL A1B 3X5, madeeha.ahme[email protected]

A new tectonic model for the hinterland of the Grenville Province has been

proposed that interprets the crustal-scale architecture in terms of pervasive

collapse of an orogenic plateau following its construction during the

Ottawan orogenic phase. Collapse led to the formation of exhumed mid-

crustal core complexes juxtaposed against down-dropped higher crustal

levels, including the orogenic upper crust and the cool orogenic lid. This

model integrates crustal-scale seismic sections with structural,

isotopic/geochronological and petrological data for the Ottawan phase to

define the orogenic style, peak P-T conditions, and timing of

metamorphism at each crustal level. Specifically, it contrasts the Ottawan

tectonic evolution of the three crustal levels: (i) mid-crustal migmatitic

gneiss terranes, characterized by sub-horizontal L-S fabrics that formed at

peak P-T conditions of 800-1100 MPa and 750-850 °C from 1090-1050

Ma, (ii) upper crustal schist terranes with steep to vertical structures that

formed at peak P-T of 300-600 MPa and 600-750 °C from 1050-1020 Ma,

and (iii) an orogenic lid that escaped penetrative deformation and in which

the peak temperature was < 500 °C. These levels are currently juxtaposed

in a crustal-scale horst and graben architecture, the arrangement implying

there was an important episode of extension after peak metamorphism in

the mid crust. In detail, exhumation of the mid crust was coeval with peak

metamorphism in the upper crust, suggesting that heating of upper crust

occurred by conduction after it was juxtaposed against the exhumed, hot

mid crust.

A test of this tectonic model for the Grenville Province is currently in

progress as an MSc project by the first author. The study is based on a

transect in the western Grenville Province in Ontario, which incorporates

the exhumed mid crust, upper crust and the orogenic lid. At each level of

the orogenic crust, representative structures have been recorded and low

variance samples collected for the determination of P-T data. In situ dating

of peak and retrograde metamorphic assemblages will be carried out using

monazite chronology where feasible. The aim is to more precisely define

the details of the collapse process in adjacent crustal levels, and integrate

the results into a more refined tectonic model.

REDUCTANTS INVOLVED IN THE FORMATION OF THE

ATHABASCA BASIN UNCONFORMITY-RELATED URANIUM

DEPOSITS

Alexandre, P. and Kyser, K., Queen's University, Kingston ON K7L

3N6, [email protected]

Several possible reductants involved in the formation of unconformity-

related U deposits in the Athabasca Basin have been considered from the

point of view of their standard reduction potential (E0, V) when reducing

to U

to form uraninite, by far the most abundant U mineral in these

deposits. The reductants can be endogenous (e.g., graphite), produced in-

situ by a pre- or syn-ore alteration (e.g., Fe

), or exogenous (e.g., CH

The two most commonly suggested reductants are graphite and Fe

which are relatively weak ones, with E0 of 0.52 and 0.77V, respectively.

Graphite is important for the development of structures with which

unconformity-related U deposits are often associated, but is inert and must

be converted into a more reactive form (CO: E0 of –0.11V) to be an

effective reductant. Methane is a weak reductant as well but its oxidation

produces several intermediate products (methanol, formaldehyde, and

formic acid), which have increasingly stronger standard reduction

potentials, down to –0.11V. Several metals, including iron, are very strong

reductants (E0 down to ca. –0.4V), but were not available at the deposition

sites in any significant amounts.

Pyrite, FeS

(and possibly other sulfides), can also be considered as

possible reductant for unconformity-type uranium deposits, as suggested

for the Camie River deposit (Otish Basin, Quebec). The break up of pyrite

would provide Fe

, a weak reductant, but most significantly S

, which is a

strong reductant with standard reduction potential of –0.48V. In the acid

conditions necessary to break up pyrite, S will be oxidized through a series

of compounds from S

to S

, some of which are also strong reductants.

An important corollary of these results is that the stronger reductants,

such as CO and the oxidation products of methane and S are all highly

mobile, meaning that a significant U deposit can be formed away from the

source of these reductants, as has been suggested for the Centennial

deposit in the south-central portion of the basin. This indicates that

unconformity-type uranium deposits can be found off-conductor and

possibly explains the formation of “perched” ore-bodies. Finally, an

important consideration about the formation of an unconformity-type

uranium deposit is not only the relative reduction potential of a particular

reductant, but also its abundance, the reduction potential of its oxidation

products, and the possible participation of more than one reductant.

MODELING OF THE FLUID FLOW INVOLVED IN THE

FORMATION OF THE ATHABASCA BASIN UNCONFORMITY-

RELATED URANIUM DEPOSITS

Alexandre, P. and Kyser, K., Queen's University, Kingston, ON K7L

3N6, [email protected]

The fluid flow necessary for the formation of a typical unconformity-

related uranium deposit in the Athabasca Basin, Canada, has been modeled

using a derivation of Darcy’s law. As a simplification, it is considered that

the sandstone was the only source of U for these deposits, even though the

basement probably contributed a limited amount of U to the system. Of the

three possible fluid flow regimes (gravity, convection, overpressure),

gravity under pure hydrostatic conditions is most effective considering the

vast volumes of fluids needed to form the deposits, even though it is

possible that convection may have played a limited role; the role of

overpressure has been demonstrated to be limited.

Assuming U concentration of fluid=1 ppm, deposit size=75 million

pounds U

, time to make a deposit=1 My, deposition efficiency=70%,

sandstone permeability=10

-14

, effective length of fluid flow=450 km

(size of the basin projected at the time when these deposits formed, at ca.

1.6 Ga), cross section of fluid flow for one deposit=1 by 10 km, and

temperature=200°C.

The fluid flow necessary to form a typical Athabasca Basin deposit

in 1 My is 1.3×10

-3

/s. The pressure necessary to mobilize this amount

of fluid flow would be 1.46×10

Pa, corresponding to a height difference

of ca. 150 m over the E-W length of the basin. Such a height difference

between distant points could readily occur during a tectonic event affecting

the continental crust at the time the deposit formed.

Thus, a typical unconformity-related uranium deposit in the

Athabasca Basin can form under pure gravity-driven hydrostatic regime,

and only basinal fluids are necessary. The critical fluid circulation factors

are be the amount of U in the ore-related fluid, deposition time, and

deposition efficiency. Large, world-class deposits can form by increasing

all of these parameters and possibly introducing a certain, though limited,

proportion of lithostatic regime.

PORPHYRY-STYLE ALTERATION AND MINERALIZATION

ASSOCIATED WITH HIGH-LEVEL TONALITE-GRANO-

DIORITE INTRUSIONS AT THE DARALOO AND SARMESHK

COPPER DEPOSITS, SOUTH IRAN

Alimohammadi, M., Alirezaei, S., Faculty of Earth Sciences, Shahid

Beheshti University, Tehran, Iran, M_Alimoha[email protected], PO

Box 15875-4731, and Kontak, D.J., Department of Earth Sciences,

Laurentian University, Sudbury, ON P3E 2C6

The Daraloo and Sarmeshk copper deposits occur in a NW-SE trending

fault zone in the southern section of the Cenozoic Urumieh-Dokhtar

Magmatic Belt, Iran. Alteration and mineralization cover a 10 km long,

NW-SE trending zone, 500 m wide, with the Daraloo and Sarmeshk

deposits located at the NW and SE ends, respectively. Geological mapping

and drilling (about 100, 200-500 m deep drill holes) indicate the area is

characterized by a series of Miocene (?) age, porphyritic tonalite-

granodiorite plutons which intrude Eocene andesitic volcanic and

pyroclastic rocks. Alteration assemblages are comparable to those in

porphyry Cu±Mo systems and are well developed in both deposits, with

phyllic and silicic alteration types dominant. Potassic alteration, identified

in the deeper part of the system, occurs as secondary biotite replacing

original mafic minerals, and subordinate K-feldspar replacing plagioclases.

Chloritic alteration, manifested by a greenish to greenish-gray color, is

widespread, particularly to the east of the Sarmeshk deposit. This

alteration overprints the earlier biotite alteration, as evidenced by relict

hydrothermal biotite and locally abundant biotite in the chlorite alteration.

Propylitic alteration, developed mostly in the host volcanic rocks, is

distinguished by the presence of epidote, carbonates, and chlorite. A

supergene argillic alteration has affected both deposits. Mineralization

occurs as quartz-sulfide stockworks and disseminated sulfides in both

porphyritic intrusions and adjacent volcanic rocks. This hypogene

mineralization is characterized by abundant pyrite and magnetite, minor

chalcopyrite, and trace bornite and molybdenite. Magnetite, common in

both deposits, occurs both in quartz-sulphide veinlets as well as discrete

magnetite veinlets and disseminations. Supergene enrichment is poorly

developed at Sarmeshk; however an enriched blanket, 5 to 40 m thick, is

developed at Daraloo. This lack of supergene enrichment at Sarmeshk

might be attributed to a less efficient leaching, due to the intense silicic

alteration, or lower copper assays in the original mineralization. Whole

rock chemistry, fluid inclusion studies, and stable and radiogenic isotope

analyses are in progress to characterize the source and nature of the

magmas and fluids responsible for the alteration and mineralization.

MAPPING OF HYDROTHERMAL ALTERATIONS ASSOCIATED

WITH PORPHYRY-STYLE MINERALIZATION IN DARALOO-

HANZA AREA, CENTRAL PART OF THE DEHAJ-SARDOEIEH

BELT, SOUTH IRAN, USING SPECTRAL ANALYSIS OF ASTER

DATA

Alimohammadi, M., Alirezaei, S., Faculty of Earth Sciences, Shahid

Beheshti University, Tehran, Iran.m_alimohammadi@sbu.ac.ir

The Cenozoic Urumieh-Dokhtar Magmatic Belt (UDMB) of Iran is a

major host to porphyry Cu±Mo±Au deposits (PCDs). Most known PCDs

in the UDMB occur in the southern section of the belt, also known as the

“Dehaj-Sardoeieh belt”, or “Kerman Copper belt”. The PCDs are

commonly associated with well-developed potassic, phyllic, silicic,

propylitic, and in some cases, argillic alterations, with phyllic alteration

being dominant in most cases. Mineralization occurs as quartz-sulfide

stockworks, as well as sulfide disseminations in the parent porphyritic

bodies and in the host volcanic-pyroclastic rocks.

To investigate suitable approaches for ASTER data pre-processing

and analysis to identify the distribution of the alteration minerals

(assemblages) associated with copper mineralization, a case study was

carried out on the "Daraloo-Hanza area" in the central part of the KCB.

The area is characterized by extensive hydrothermal alteration, covering an

area 15 km

in extent in NW-SE direction, developed mainly over three

porphyry copper systems, known as Daraloo, Sarmeshk, and Bondar-

Hanza, lying to the north, center and south of the area, respectively.

The research includes ASTER data pre-processing, processing and

field and petrographic studies. Various image processing techniques

including different ratio images, relative band depth, minimum noise

fraction, pixel purity index, and matched filter processing were used to

delineate and generate a hydrothermal alteration map. The analysis of 14-

bands ASTER data for mapping hydrothermal alterations was found to

provide satisfactory results. VNIR+SWIR relative reflectance spectral

analysis was appropriate and helpful for detecting and mapping sericitic,

argillic and propylitic alterations. Fe-oxides/hydroxides were successfully

mapped by using ASTER VNIR as well as landsat ETM+ data. TIR

emissivity analysis proved to be useful for mapping silicified, and quartz-

rich rocks. The most promising results were obtained by matched-filter

processing that helped revealing extensive phyllic and silicic alterations

with Fe-oxides/hydroxides, as well as local areas of kaolinite alteration.

The analysis of ASTER data and follow-up field and petrographic

studies suggest that sericitic- silicic alterations and Fe-oxides/hydroxides

tend to be associated with copper mineralization at current exposures in the

Daraloo-Hanza area. Considering the common association of the PCDs

with sericitic and silicic alterations and widespread occurrence of Fe-

oxides/hydroxides at surface, the results from this study can be used for

exploration for PCDs in other parts of the Kerman Copper belt and likely

in other areas.

A FILTERING TECHNIQUE FOR IDENTIFYING LOCAL

MAXIMA IN REGIONAL GEOCHEMICAL DATA SETS

Amor, S.D., Geological Survey of Newfoundland and Labrador, St.

John's, NL, stephenam[email protected]

The use of “global” percentiles is effective for identifying very strong,

large geochemical anomalies, of which the lake-sediment and water

databases from Newfoundland and Labrador contain several. However,

such features have the effect of setting the threshold so high that attention

is drawn away from potentially significant local maxima in regions where

background is lower. An example from Labrador can be seen in the strong,

extensive anomalies of fluoride in lake water that characterize the Flowers

River Complex, and the dispersion train from the Strange Lake Complex.

The influence of these features on the Labrador data set is such that

fluoride values from almost all of southern Labrador are classed as

background, despite the presence of several local maxima, one of which is

associated with the Popes Hill REE discovery. A similar effect is noted in

the case of nickel in Labrador, where strong anomalies in northern

Labrador, and over the Labrador Trough in the west, cause a local

maximum in the vicinity of the Voisey’s Bay deposit to be overlooked.

A filtering method for identifying such local maxima is proposed

whereby a percentile value, for a particular element, is assigned to each

sample not with respect to the data set as a whole, but with respect to its

near neighbours only. The latter are defined by drawing a circle of

specified search radius around the sample and identifying all the samples

that fall within it. The sample is ranked with respect to this population of

neighbours, and its rank converted to a percentile; the procedure is

repeated for every sample in the data set. The process is computer-

intensive although the algorithm is uncomplicated. Some experimentation

is necessary to determine an optimal search radius; this varies from

element to element but ranges typically between 40 and 80 km, with the

lower radii being more appropriate in the Newfoundland data set where the

sampling density is greater.

This approach seems to be most effective in regional data sets that

include a few localized features of very strong response, such as fluoride

and nickel in Labrador, and bromine in Newfoundland (of which the

highest values tend to concentrate in coastal regions). For elements whose

values are more evenly-distributed, such as zinc and cobalt, filtering the

data provides no significant advantage in anomaly identification.

HISTORY OF REACTIVATED FAULT SYSTEMS IN THE

NORTHEAST THELON BASIN REGION: REGIONAL TO LOCAL

CONTROLS ON BASIN DEVELOPMENT AND HYDRO-

THERMAL FLUID FLOW FOR URANIUM

Anand, A., Jefferson, C.W., Pehrsson, S.J., Geological Survey of

Canada, 601 Booth Street, Ottawa, ON K1A 0E8, White, J.C.,

Department of Earth Sciences, University of New Brunswick,

Fredericton, NB E3B 5A3, McEwan, B.J., Bethune, K., University of

Regina, 3737 Wascana Pkwy., Regina, SK S4S 0A2, and Tschirhart,

V., MAGGIC, School of Geography & Earth Sciences, McMaster

University, 1280 Main St. W., Hamilton, ON L8S 4K1

Reactivated ENE-WSW-trending dextral fault arrays in the northeast

Thelon Basin region have been investigated under the Geomapping for

Energy and Minerals Program through detailed outcrop and sample

analysis. The sub-vertical fault arrays have dominantly sub-horizontal

mineral lineation from strike-slip displacement and steeply raking

slickensides from late dip-slip offsets of gently dipping strata against

basement. The reactivated, segmented fault zones discordantly transect the

main basement foliation, and comprise zones of sub-parallel brittle and

ductile fractures. They are ~50 m wide and preferentially localized along

the south sides of ~1 km wide deep structures interpreted from broad linear

demagnetized zones. Some discontinuities interpreted as related to D

thrusting and isoclinal folding also appear to have been reactivated.

We test three fractal methods for synthesizing the fracture, quartz

vein and shear zone data: fragment size-frequency distributions, box-

counting (geometry, length and spatial distributions), and Cantor-dust

analysis (pattern anisotropies and inhomogeneities). Textural data and

fractal geometries are consistent with three deformation mechanisms: 1)

Brittle dextral shear by attrition, distributed and implosion brecciation, 2)

Linkage of pre-existing or precursor structures by oblique structures, as

strain was propagated across a laterally expanding fault zone, and 3)

Extension resulting in dip-slip movement across metre-wide zones. These

observations highlight the importance of the modes and orientations of

fracturing, and the orientations of pre-existing fabrics and rock

architecture.

Fractal analysis of clast shapes and clast size distributions

distinguishes three breccia styles and indicate that fluid pressure

fluctuations were important in the brecciation process. Approximate

palaeostress orientations during brecciation and their relationship to the

deformational history of the terrane have been reconstructed by combining

the orientations of microfractures (crack-seal, stylolites, branch cracks)

with field data. Results from this study allow brecciation to be placed

within a regional framework and constrain relationships with hydrothermal

alteration/fluid flow systems, shear zone formation, lithological contrasts

within the supracrustal rocks of early –mid Palaeoproterozoic age, and

domainal variations in regional deformational phases such as D

and D

These methods and findings provide templates for detailed studies of

fractures, brecciation and mineralization processes in less well exposed

strands of the Thelon, Turqavik and Amer faults, as well as in other

terranes where fluid-induced brittle deformation and seismic pumping may

have contributed to the generation and localization of uranium deposits.

Very late stage fractures and high-dilation breccias are particularly

favourable sites for hydrothermal mineral deposition, forming transitory

low-pressure channels for repeated rapid passage of hydrothermal fluids.

EFFECTS OF THRUSTING DURING EARLY THIN-SKINNED

TECTONICS RECORDED BY INTERCALATED 2.6 Ga FELSIC

EXTRUSIVE ROCKS AND EARLY PALEOPROTEROZOIC

QUARTZARENITE IN THE NE THELON AREA

Anand, A., Jefferson, C.W., Pehrsson, S.J., Hunt, P., Geological Survey

of Canada, 601 Booth Street, Ottawa, ON K1A 0E81; White, J.C.,

Calhoun, L., Department of Earth Sciences, University of New

Brunswick, Fredericton, NB E3B 5A3; Bethune, K.M. and McEwan,

B.J., University of Regina, 3737 Wascana Pkwy., Regina, SK S4S 0A2

Regional to detailed structural studies under the Geomapping for Energy

and Minerals Program have defined four deformation events, with the first

) involving dramatic compressive translation and intercalation of

Neoarchean with early Paleoproterozoic strata by multiple thrusts and

recumbent isoclinal folds. D

significantly changed stratigraphic

thicknesses, affecting reconstructions of original units (Ps1, Ps2 and Ps3)

within the early Paleoproterozoic Amer and Ketyet River groups. For

example the extensive basal quartzarenite (Ps1, hereafter “quartzite”),

originally ~100-200 m thick, now ranges from 400 to 1000+ m thick in

some places but forms slivers only 10s of metres thick in this study. This

study examines the nature of intercalation between the quartzite and a

highly foliated 2.58–2.62Ga felsic extrusive unit (hereafter “rhyolite”) that

directly underlies the quartzite in many places.

In the area of the Kiggavik uranium camp the rhyolite overlies

Neoarchean feldspathic metagreywacke (hereafter “wacke”) of the

Woodburn Lake group. A zone of multiply repeated wacke – rhyolite –

quartzite panels forms a key structural complex that lies along the north

flank of the uranium camp. Within this complex, the rhyolite and quartzite

are thin sheets that record various states of internal plastic deformation

along their mutual contact (mylonitic shears, foliation boudinage,

imbricated boudins, intrafolial folds, C/S fabric) and multiply refolded

foliated gouge materials. Meso- and microstructural observations

document alternating brittle and crystal-plastic deformation processes and

pervasive dissolution-recrystallization. Even zircon grains are extensively

altered and crushed. It is advocated that fluids expelled along multiple

thrusts were responsible for hydrofracturing and cataclastic deformation.

Periods of brittle fracturing alternated with ductile deformation during the

thin-skinned tectonic event. In this interpretation, deformation of the

wacke – rhyolite – quartzite assemblage was progressively accommodated

by numerous short-lived and strongly localized cataclastic events at the

bases of multiple thrusts rather than along a permanently weak

décollement unit.

The wacke, rhyolite and quartzite were structurally intercalated

during D

, interpreted as after ~2.15Ga (metagabbro sills tentatively

correlated elsewhere with Ps2 basalt) but before 1.9 Ga (detrital zircons in

Ps4 that elsewhere unconformably overlies the D1-deformed Ps1-3

assemblage). This took place long before Thelon Basin developed by

strike-slip and extensional faulting. However the alternating structural

panels of wacke, rhyolite and quartzite may have channeled much later

hydrothermal fluid flow that formed basement-hosted uranium deposits

during and/or after development of Thelon Basin (1.75 to 1.5Ga). This is

one example of applying relevant knowledge from basement deformation

history to the uranium metallogeny of Paleoproterozoic basins.

GEOCHEMICAL SIGNATURES OF CARBONATE IMPACT

MELTS FROM THE STEINHEIM IMPACT CRATER, GERMANY

Anders, D., dander53@uwo.ca, Osinski, G.R., Department of Earth

Sciences, University of Western Ontario, 1151 Richmond Street,

London, ON, N6A 5B7, Grieve, R.A.F., Earth Sciences Sector,

Natural Resources Canada, 601 Booth Street, Ottawa, ON, K1A 0E8,

Schmieder M., The University of Western Australia, 35 Stirling

Highway, Crawley, 6009 WA - Perth, Australia, Kegler, P.,

Christian-Albrechts-Universität zu Kiel, Ludewig-Meyn-Str. 10,

Kiel, 24118, Germany, and Buchner, E., Universität Stuttgart,

Herdweg 51, Stuttgart, 70174, Germany

The 3.8 km in diameter Steinheim impact crater counts among the best-

preserved complex impact structures with a central uplift on Earth. It lies

within a sequence of flat-lying Triassic to Upper Jurassic sediments of the

Swabian Alb plateau (SW Germany). Previous studies revealed the

existence of silicate and carbonate melt lithologies within rocks of the B-

26 core drilled in the western central basin of the Steinheim structure. Here

we present a reinvestigation of these results to further evaluate

geochemical features and signatures of the carbonate melt.

At a depth of 78-79 m, closely beneath the structural crater floor of

the Steinheim Basin, the B-26 drill core consists of Upper Jurassic

limestone containing macroscopic fractures that are filled with veins of

Ca-Mg-carbonates. These carbonates exhibit an MgO content of up to ~20

wt% and were previously described as “impact-induced dolomitic melt”

generated from the Steinheim target rocks and subsequently injected into

host limestone fractures. The incorporation of detectable amounts of Si, Al

and K into the Ca-Mg-carbonate groundmass is consistent with carbonate

melt from other terrestrial impact craters such as Haughton crater, Canada.

In general, the major elemental compositions of impact carbonate melts

resemble those of carbonatite igneous rocks. The accumulation of Si, Al

and Na in carbonatites is assumed to be attributed to chemical exchange

with their wall rocks. Geochemical plots of the Steinheim carbonate melt

show direct correlations of (Ca

, Mg

, Fe

, Mn

) and Al

+ (K

, Na

)

as well as (Ca

, Mg

, Fe

, Mn

) and (K

, Na

) + Si

suggesting a

chemical exchange of cations.

So far, the following substitution processes can be determined that

might lead to the accumulation of Si, Al and K within the dolomitic melt

assemblage:

2 (Ca

, Mg

, Fe

, Mn

) ↔ Al

+ (K

, Na

)

(Ca

, Mg

, Fe

, Mn

) + Al

↔ (K

, Na

) + Si

↔ Si

Further investigation and bulk composition analyses of the dolomite

melt assemblage are required to confirm this assumption and to explain the

incorporation of Si, Al, and K into the dolomitic melt, their source and

possible scenarios of the origin of the Steinheim carbonate melt.

CONTRASTING TECTONOMETAMORPHIC EVOLUTIONS IN

THE EASTERN PART OF THE SVECONORWEGIAN OROGEN

Andersson, J.

, jenny.ander[email protected], Möller, C.

and Stephens,

M.B.

Geological Survey of Sweden, Box 670, SE-751 28, Uppsala,

Sweden;

Department of Geology, Sölvegatan 12, SE-223 62 Lund,

Sweden

The eastern part of the Sveconorwegian orogen consists of two, crustal-

scale orogenic segments: (I) the parautochthonous to allochthonous

Eastern Segment, adjoining the pre-Sveconorwegian craton in the east, and

(II) the allochthonous Idefjorden terrane overlying the Eastern Segment in

the west. The lithotectonic boundary between the Eastern Segment and the

Idefjorden terrane is a west-dipping or sub-vertical, major ductile shear

belt. These two orogenic segments show fundamentally different igneous,

structural and metamorphic evolutions in Sveconorwegian and pre-

Sveconorwegian time.

In the Eastern Segment, extensive high-P metamorphism at around

990-980 Ma, in discrete tectonic units reaching the eclogite facies, was

followed by penetrative, regional-scale ductile deformation and partial

melting under upper amphibolites facies conditions at around 970-960 Ma.

Ductile deformation fabrics are cut by c. 960-950 Ma old, undeformed,

granite and pegmatite dykes. Records of earlier Sveconorwegian

metamorphism are lacking. The high-grade deformation fabrics were

folded and stretched along E-W-trending axes and reoriented by regional-

scale, open folding along N-S-trending axes. Protoliths to metamorphic

rocks in the Eastern Segment are mainly 1.8 Ga and 1.7 Ga old intrusive

rocks, equivalent in age and origin to rocks in the foreland east of the

orogen. Pre-Sveconorwegian, high-grade metamorphism and deformation

is constrained in two discrete intervals at 1.44-1.42 Ga and 1.41-1.38 Ga

(Hallandian orogenesis).

In the overlying Idefjorden terrane, high-P metamorphism followed

by high-grade ductile deformation and partial melting occurred in the

1040-1020 Ma interval, overlapping in age with cross-cutting, undeformed

pegmatite dykes. Records of late-Sveconorwegian metamorphism at 990-

960 Ma are only present inside the southern part of the boundary ductile

shear belt, close to the contact to the exhumed, high-grade, lower crustal

levels of the Eastern Segment. The regional Sveconorwegian structural

grain of the Idefjorden terrane is characterised by N-S-trending structures,

including ductile deformation fabrics, fold axes of large-scale folds,

regional deformation zones, and tectonic contacts between elongated,

metamorphic sub-domains. The Idefjorden terrane also hosts tectonic

domains that show little or no imprint of Sveconorwegian metamorphism

and deformation. The pre-Sveconorwegian evolution of the Idefjorden

terrane is dominated by igneous activity, metamorphism and deformation

at 1.64-1.52 Ga (Gothian orogenesis). Imprints of 1.4 Ga Hallandian

reworking are absent.

The striking differences in age and character of the tectono-

metamorphic build up in the eastern part of the Sveconorwegian orogen

suggests a polyphase orogenic evolution that possibly included both a

significant hiatus and shifts in style and character of plate convergence.

PRECAMBRIAN BASEMENT ROCKS IN THE VICINITY OF THE

CHIDLIAK KIMBERLITES: INITIAL MAPPING ON THE HALL

PENINSULA, BAFFIN ISLAND

Ansdell, K.M., Department of Geological Sciences, University of

Saskatchewan, Saskatoon, SK S7N 5E2, kevi[email protected],

Hunchak, A. and Pell, J., Peregrine Diamonds Ltd., 201-1250 Homer

Street, Vancouver, BC V6B 1C6

The Precambrian rocks on the Hall Peninsula, southeastern Baffin Island,

are very poorly understood as they have only been mapped at

reconnaissance scale. However, unravelling the origin and evolution of

these rocks is vital as they should provide important constraints on the

assembly of the northeastern margin of the Canadian Shield. At present, it

is unclear whether the peninsula is underlain by Archean rocks of the Rae

or North Atlantic cratons, or microcontinents, such as Metaincognita, that

accreted during Paleoproterozoic collisional events. The western part is

intruded by the Paleoproterozoic Cumberland batholith, whereas the north-

central part is cut by the Chidliak diamondiferous kimberlites. Regional

scale airborne geophysics has emphasized the likely complexity of the

geological relationships in the basement rocks to the kimberlites, and so

the aim of this project was to determine the field relationships,

mineralogical, geochemical and age characteristics of a small 20 km

swath of basement rocks in the vicinity of the discovery kimberlites.

All the basement rocks in the area have been metamorphosed to

amphibolite grade, and the dominant fabric is a gneissosity that strikes

broadly east-west and is parallel to primary compositional variations.

Outcrops are scattered and so the character of contacts between units is not

known as they are typically not exposed. The most common rock units are

garnet-biotite-sillimanite/cordierite faserkiesel-bearing psammitic and

pelitic gneisses, the latter containing evidence for melt generation, with

rare quartzite layers. The pelitic and psammitic gneisses are sometimes

interbedded at the tens of centimetres to metre scale, although there is no

convincing evidence for the stratigraphic younging direction. In the north

of the study area are amphibolites, up to tens of metres thick, which locally

contain stretched centimetre-scale pyroxene phenocrysts. These are

interpreted as mafic volcanic flows. The southern end of the mapping area

consists of a gneiss dome dominated by and cored by tonalitic gneiss,

which is rimmed by less voluminous granodioritic and K-feldspar

porphyritic gneisses. These rocks are also intruded by coarse-grained

peridotite, which appears to have been boudinaged during the main

deformation event. Geochemical and geochronological analysis of these

rocks is ongoing, although it is interpreted, based on extrapolation of

regional geological relationships, that the deformation and metamorphism

is Paleoproterozoic in age. The presence of diamondiferous kimberlites

suggest the presence of Archean crust, although the supracrustal rocks may

also be Paleoproterozoic and have been deposited or structurally emplaced

on older basement, possibly preserved in the gneiss domes.

FIELD RELATIONS, PETROLOGY, AND TECTONIC SETTING

OF THE ORDOVICIAN WEST BARNEYS RIVER PLUTONIC

SUITE, SOUTHERN ANTIGONISH HIGHLANDS, NOVA SCOTIA,

CANADA

Archibald, D.B.

, [email protected], Barr, S.M.

, Murphy, J.B.

White, C.E.

, Escarraga, E.A.

, Hamilton, M.A.

, MacFarlane,

C.R.M.

and MacHattie, T.G.

Dept. of Earth and Environmental

Science, Acadia University, Wolfville, NS B4P 2R6;

Dept. of Earth

Sciences, St. Francis Xavier University, Antigonish, NS B2G 2W5;

Nova Scotia Department of Natural Resources, PO Box 698,

Halifax, NS B3J 2T9;

Dept. of Geology, University of Toronto,

Toronto, ON M5S 3B1;

Dept. of Earth Sciences, University of New

Brunswick, Fredericton, NB E3B 5A3

The West Barneys River plutonic suite consists of gabbro, syenite, quartz

syenite, and alkali-feldspar granite outcropping over an area of

approximately 100 km

in the central part of the southern Antigonish

Highlands. Based on mapping and petrological studies, the suite is

subdivided into five separate intermediate to felsic plutons (Laggan, Brora

Lake, Mount Adam, Leadbetter Road, and Haggarts Lake), two mafic

plutons (Garden River and Duck Ponds), and a large, heterogeneous

composite pluton (Poor Farm Brook). The Poor Farm Brook pluton is

dominantly (65%) gabbroic but also includes syenitic and granitic rocks

similar to those in the other plutons. Magma mixing and mingling textures

indicate a co-magmatic relationship between the mafic and intermediate-

felsic lithologies, although U-Pb (zircon) ages of 484.8 ± 2.5 Ma from a

gabbroic sample and 469.4 ± 0.5 Ma from a quartz syenite sample show

that emplacement occurred over a significant span of time. Many of the

rocks in the suite have high magnetic susceptibilities consistent with

abundant modal magnetite, titanomagnetite, and/or ilmenite, and the suite

is associated with a large positive magnetic anomaly. Intermediate to felsic

rocks are hypersolvus and consist mainly of perthitic K-feldspar and

variable amounts of quartz; interstitial granophyre is present in some

samples, consistent with shallow emplacement. Mafic phases are Fe-rich

amphibole and clinopyroxene, and in some units, fayalite. Gabbroic rocks

consist of plagioclase (oligoclase-labradorite) and augite/diopside with less

abundant orthopyroxene, olivine, biotite, and ilmenite/magnetite. They are

mainly medium-grained and intergranular but locally porphyritic with

plagioclase phenocrysts. Their chemical compositions are transitional from

tholeiitic to alkalic and characteristic of continental within-plate mafic

rocks. Intermediate and felsic samples have chemical characteristics of

within-plate A-type granitoid rocks. Epsilon Nd values at 480 Ma are

between 0.9 and 4.9 with similar ranges in both mafic and

intermediate/felsic samples. These values are typical for rocks derived

from Avalonian subcontinental lithospheric mantle and consistent with a

co-genetic origin for the mafic and intermediate/felsic components of the

suite. Emplacement of the plutonic suite may have been related to long-

lived ensialic back-arc extension associated with subduction of Tornquist

Sea oceanic lithosphere beneath Avalonia throughout the Ordovician. The

West Barneys River plutonic suite represents an important and previously

unrecognized magmatic episode during the evolution of Avalonia.

LATE CRETACEOUS MIDDLE FORK CALDERA AND ITS

RESURGENT INTRUSION, EAST-CENTRAL ALASKA

Bacon, C.R., [email protected], Dusel-Bacon, Cynthia, USGS,

Menlo Park, CA 94025, USA, Aleinikoff, J.N., USGS, Denver, CO

80225, USA, and Slack, J.F., USGS, Reston, VA 20192, USA

The Middle Fork caldera comprises a 10 × 20 km area of rhyolite welded

tuff and granite porphyry ~100 km west of the Yukon border. Intracaldera

tuff has quartz and feldspar phenocrysts ≤4 mm, cm-sized fiamme, and a

maximum exposed thickness of 850 m. Less densely welded tuff near the

caldera margins locally contains 1–2 cm K-feldspar megacrysts and

pumice clasts to 6 cm. Zircon from intracaldera tuff yields a SHRIMP-RG

U–Pb age of 68.7 ± 1.1 Ma (all ages 95% confidence). Granite porphyry

occupies much of an 8 × 12 km area having 650 m of relief within the

western part of the caldera fill. Zircon from the porphyry gives a SHRIMP-

RG U–Pb age of 68.4 ± 1.0 Ma. These ages agree with a previous

Ar/

Ar biotite age of 69.1 ± 0.5 Ma for proximal outflow tuff. The

crystal-rich intracaldera tuff contains embayed quartz, plagioclase>K-

feldspar, biotite, and Fe–Ti oxide phenocrysts in a very fine-grained

crystalline groundmass. The porphyry carries 40–50% larger phenocrysts

of the same phases (K-feldspar to 2 cm, rarely to 4 cm) in a fine-grained

groundmass characterized by abundant 50–100 µm quartz. Compositions

of 3 tuff and 3 porphyry samples overlap, form a limited differentiation

series at 69–72% SiO

, have arc geochemical signatures, and yield

subparallel chondrite-normalized rare earth element patterns with light

REE enrichment, concave-upward heavy REE, and small negative Eu

anomalies. Although their phenocrysts differ in size and abundance, the

similar mineralogy, composition (in spite of crystal concentration in the

tuff), and indistinguishable ages of the tuff and porphyry indicate that the

magmas were closely related. A rare magmatic enclave (54% SiO

, arc

geochemical signature) in the porphyry may be similar to parental magma

and indicates thermal and mafic magma input. The porphyry is interpreted

to have been exposed by erosion of thick intracaldera tuff from an

asymmetric resurgent dome; proximal outflow tuff, and thus the 69 Ma

land surface, remains at the west margin of the caldera structure. The

Middle Fork caldera lies within a region of Paleozoic metamorphic rocks

and Mesozoic plutons bounded by NE-trending faults. To the NW,

Cretaceous plutonic rocks are widely exposed, indicating greater

exhumation. The Middle Fork is a relatively well preserved caldera within

a broad region of Alaska and adjacent Yukon that contains Late

Cretaceous plutons and, in the less deeply exhumed blocks, silicic volcanic

rocks.

EXPERIENCING SCIENCE ON THE LAND AT THE TUNDRA

SCIENCE CAMP, DARING LAKE, NORTHWEST TERRITORIES

Baldwin, D.

, [email protected], Andrews, T.

, Clark, K.

Hans, B.

, Stephenson, T.

and Yuill, S.

NWT Geoscience Office,

4601-B 52 Ave, Yellowknife, NT X1A 2R3;

Prince of Wales

Northern Heritage Centre, PO Box 1320 PWNHC, Yellowknife, NT

X1A 2L9;

Wek'eezhii Renewable Resources Board, 102 A 4504 49

Ave, Yellowknife, NT X1A 1A7;

Environment and Natural

Resources, Government of the Northwest Territories, Box 1320,

Yellowknife, NT, X1A 2L9

For ten days each summer, since 1995, the Tundra Ecological Research

Station, at Daring Lake, NWT becomes the focus of land-based learning

and educational activities for a group of high school students, teachers,

researchers, Aboriginal Dene elders and science mentors. The group comes

together to learn about plant and animal biology, ecology, geology,

archaeology, traditional and cultural knowledge, and climate change

studies.

Half-day sessions on each topic begin in a research-tent classroom.

Instructors cover basic vocabulary and concepts of each discipline using

hands-on props and visual aids. An excursion on the tundra landscape

follows every class, to actively engage participants in field work. This is

done by observing, recording, collecting information and samples and

becoming familiar with instruments and tools used by researchers.

Aboriginal elders teach about the land through story-telling and

demonstrations. An all-day hike along a sinuous esker provides an

opportunity to process the formal learning into a connected synthesis in the

overall scope of the landscape. While students are engaged in the multi-

disciplinary instruction sessions, they begin a collection of objects which

they later research and identify using the resource materials back in camp.

A Collections Fair allows each student to display and share their individual

collection with their peers.

For the second part of the camp, students choose a discipline and

develop a project that interests them, working in small groups or

individually, along with a mentor to guide their research. Data collection

takes many forms: recording, measuring, mapping, graphing, sketching,

counting, interviewing, photo-documenting and describing observations on

the land. Projects are presented to peers and mentors through

demonstrations, skits, songs and displays, followed by a question period.

Throughout the camp, cultural activities and games play an integral part

tying in the human history and a Dene cultural perspective to the present

day. Communal chores, as well as free time for journaling and recreation,

complete the busy days. This program brings students and educators onto

the land to experience a wide variety of science disciplines, traditional

knowledge and hands-on learning to help them develop an interest in

science-related careers and to integrate information about our past, present

and future on the land.

PALEOGEOGRAPHIC CONTROLS ON THE DISTRIBUTION

AND CHARACTER OF THE NEOPROTEROZOIC RAPITAN

IRON FORMATION, NWT

Baldwin, G.J., gj_baldwin@laurentian.ca, Turner, E.C., Department

of Earth Sciences, Laurentian University, Sudbury, ON P3E 2C6,

and Kamber, B.S., Department of Geology, Trinity College Dublin,

Dublin, Ireland

The Neoproterozoic Rapitan iron formation is one of the largest

undeveloped iron deposits in Canada. Like most other Neoproterozoic iron

formations, it is stratigraphically associated with glacioclastic rocks of the

Sturtian glaciation, the first of three ‘snowball Earth’ events. Iron

formation is distributed unevenly along the exposure belt: iron formation

thickness exceeds 100 m in the Snake River (SR) area, but is less than 20

m in the Mountain-Keele-Redstone River (MKRR) area, and the Rapitan

Group is absent between these two areas. Although previous study of the

iron formation resulted in several different depositional models, relatively

little focus has been placed on explaining its distribution, which is quite

distinct from that of older iron formations, in which individual layers can

be traced for hundreds of kilometres. Numerous stratigraphic,

sedimentological, and geochemical differences in both the Rapitan iron

formation and the associated glacioclastic rocks in the two areas

containing iron formation indicate that localised sub-basins exerted a

strong control on iron formation deposition. This control is expressed as

three distinct but related effects: (1) the relative age of each sub-basin; (2)

each basin’s accommodation space or depth; and (3) the volume of clastic

sediment supplied. Iron formation is underlain by rift deposits of the

Coates Lake Group and glacioclastic turbidites of the Sayunei Formation

in the MKRR area, whereas these units are absent in the SR area; this

indicates that the MKRR sub-basin was more evolved. The SR sub-basin

had ample accommodation space during iron formation deposition, and the

deep basin was isolated from significant clastic input, allowing true iron

formation to form. Basin depth influenced the character of the sediments

overlying the iron formation: thick iron formation in the deeper parts of the

basin is capped by granular iron formation (GIF) and hematitic

glacioclastic rocks, whereas thin iron formation in shallower inboard areas

is overlain by hematite-poor glacioclastics and no GIF. This distribution of

lithofacies indicates that deep areas that were the most favourable for iron

formation deposition filled all accommodation space well before the iron

supply was exhausted, which resulted in terminal deposition of shallow-

water GIF and hematite-rich clastics; whereas areas with thinner iron

formation exhausted their iron supply prior to deposition of hematite-poor

pebble to boulder diamictites. The assembled evidence indicates that

geographic position in the basin and the extent of pre-existing fill were the

primary controlling factors in initiation and termination of iron formation

deposition.

DEPOSITIONAL AGE OF THE RAPITAN GROUP, NWT AND YT:

IMPLICATIONS FOR THE ONSET OF THE STURTIAN

GLACIATION

Baldwin, G.J., gj_baldwin@laurentian.ca, Turner, E.C., Department

of Earth Sciences, Laurentian University, Sudbury, ON P3E 2C6,

and Kamber, B.S., Department of Geology, Trinity College Dublin,

Dublin, Ireland

The timing and causes of the glacial events associated with the ‘Snowball

Earth’ hypothesis remain contentious. The earliest of these events, the

Sturtian glaciation, is best typified by the glaciomarine diamictites,

turbidites, and iron formation of the Rapitan Group, Canada. Sediments

associated with the Sturtian glaciation worldwide have returned U-Pb

zircon and Re-Os black shale ages from 740 Ma to as young as 660 Ma,

suggesting a either a significant glacial duration, or poor overall age

constraints. One of the best publicized mechanisms for the initiation of the

Sturtian glaciation is the so-called ‘fire and ice’ model, in which rapid

weathering of a freshly emplaced large igneous province (LIP) would

cause sufficient atmospheric CO

draw-down to trigger a global glaciation.

This model is contingent on the near-simultaneous emplacement of the

LIP, its weathering, and glacial onset- all at low latitudes. Consequently, it

cannot be tested without age constraints relating Neoproterozoic glacial

deposits with known LIPs of sufficient area and volume. Recently, strata

correlated with the Rapitan Group have been dated at 716.47±0.24 Ma.

This age is within error of that of the Franklin LIP (Canada), and has been

touted as evidence that ‘fire and ice’ involving the Franklin LIP triggered

the Sturtian glaciation.

Here we present a new detrital zircon age from the Rapitan Group

itself. The sample was extracted from cross-bedded sandstone underlying

the Rapitan iron formation by 75 m. A large number of zircon were pilot

dated by LA-ICP-MS on double-sided tape and the youngest were then

dated by high-precision ID-TIMS. A coherent population of 8 grains

defines a concordia age of 711.34±0.25 Ma. This is the new maximum

depositional age of the Rapitan Group and for the Sturtian glaciation in the

region, and is broadly consistent with both U-Pb zircon dates from ash

beds interleaved with Sturtian glacioclastic rocks, and Re-Os dates from

shales overlying other Sturtian glacial deposits. Significantly, it is a full 5

million years younger than the Franklin LIP, a span of time that is too long

to support the ‘fire and ice’ model. Furthermore, this suggests that

previous correlations between the Rapitan Group and other strata in the

region may be erroneous, and that the Sturtian glaciation may have been a

diachronous event worldwide.

CONSTRAINING THE AGE OF LOW-TEMPERATURE

METASOMATISM OF A CARLIN-TYPE GOLD DEPOSIT,

NEVADA

Barker, S.L.L., sbarker@eos.ubc.ca, Vaughan, J., Hickey, K.A.,

Cruickshanks, M., Mineral Deposit Research Unit, University of

British Columbia, Vancouver, BC V6T 1Z4, and Zwingmann, H.,

CSIRO Earth Science and Resource Engineering, Australian

Resources Research Centre, Technology Park 26 Dick Perry Avenue,

Kensington, Perth WA 6151, Australia

The Carlin-type gold deposits of NE Nevada have a prolonged history of

hydrothermal alteration and gold mineralization, with debate over when

the main endowment of gold mineralization occurred. In this study, we use

Rb-Sr isotope analysis of variably altered and gold-mineralized

lamprophyre dyke from the Banshee deposit, in the northern Carlin Trend

to constrain the age of potassic metasomatism. In addition, we use K-Ar

dating of illite from altered dykes, and apatite fission track from

lamprophyre to reveal a complex history of hydrothermal alteration and

metasomatism.

EARLY PALEOZOIC EVENTS AND DEVELOPMENTS

DETERMINED FROM CONODONT BIOSTRATIGRAPHIC,

PALEOECOLOGIC AND ISOTOPIC STUDIES, CANADIAN

NORTH ATLANTIC LAURENTIAN BORDERLAND

Barnes, C.R., School of Earth and Ocean Sciences, University of

Victoria, PO Box 3065, Victoria, BC V8W 3P6, crbar[email protected],

and Zhang, S., Canada - Nunavut Geoscience Office, PO Box 2319,

626 Tumit Plaza, Suite 202, Iqaluit, NT X0A 0H0, Shunxin.Zhang

@NRCan-RNCan.gc.ca

The North Atlantic Laurentian margin in Canada preserves some

remarkably complete Lower Paleozoic stratigraphic sequences that have

remained relatively unaltered by thermal and tectonic events. This part of

Laurentia was positioned about 20° south of the paleoequator through the

Ordovician-Silurian and, together with the largely peneplaned Canadian

Shield, resulted in extensive epeiric seas that were characterized by

carbonate and periodic organic-rich shale deposition. Changes in sea level,

epeirogeny and climate are reflected in the stratigraphic, sedimentologic

and biotic records of these shallow shelf and deeper offshore basin and

slope facies. Five decades of intense, systematic collecting in selected key

areas has yielded several hundred thousand conodont microfossils from

their origin in the Late Cambrian through the Early Silurian. These areas

include: western Newfoundland (Port au Port, Cow Head and Great

Northern peninsulas; Late Cambrian through Early Ordovician); Anticosti

Island and the St Lawrence Lowlands of Quebec (mid Ordovician through

Early Silurian); eastern and southern Ontario (mid-Late Ordovician); some

Precambrian Shield outliers; and the Hudson Bay region (outcrop and

offshore wells; Late Ordovician through Early Silurian). Following

painstaking taxonomic studies, faunal identifications, some cladistics

work, and elucidation of evolutionary lineages, the detailed conodont

biostratigraphy has been established for these areas. The extensive regional

sampling coverage has allowed determination of paleobiogeographic

patterns such as the interplay of provincial faunas, while the intensive

stratigraphic studies and sampling with subsequent statistical analyses of

the faunas have established the nature and evolution of conodont

communities though time. Recent isotopic studies (Sr, Nd, O) on

conodonts with other colleagues have provided valuable additional data to

help interpret paleoceanographic and paleoclimatic events and trends.

Integration of most of these data sets from the Canadian North Atlantic

borderland of Laurentia has the potential to contribute significantly to

resolving some of the most important issues in the Early Paleozoic (mainly

Ordovician-Silurian) including for example: the rapid five-fold increase in

biodiversity that characterizes the mid-Ordovician; the nature of ocean

circulation and stratification during the extreme greenhouse states; the

paleoclimatic switch to an icehouse state with the uncertainties of the

duration and sequential biotic effects of the terminal Ordovician glaciation;

and the effects of eustasy and climate/ocean change on biotas within

epeiric seas.

REMOTE PREDICTIVE MAPPING OF SURFICIAL MATERIALS

IN THE FAR NORTH OF ONTARIO IN AID OF LAND USE

PLANNING

Barnett, P.J., peter.barnett@ontario.ca, and Yeung, K.H., Ontario

Geological Survey, Sudbury, ON P3E 6B5

In 2008, the Ontario government announced plans to permanently protect

half of the Far North region of Ontario and launched a planning process to

support this goal. During the initial stages of planning the need for primary

landscape data became apparent. A project to remotely predict surficial

materials was initiated by the Ontario Geological Survey in response to

this information need.

SPOT imagery (4 colour bands and the panchromatic band), a digital

elevation model and its derivatives and the Ontario Hydro Network vector

drainage shape files are the primary data sources for this remote predictive

mapping exercise. Multiresolution segmentation algorithm, using different

image layer weights, scale parameters and homogeneity criterion, within

an object-based image analysis software is used to achieve meaningful

objects representing various surficial material types. Objects are then

classified based on digital signature, internal variability of signature and

proximity to certain vector layers and certain adjacent material types.

Limited helicopter-supported field work combined with the

examination of archival information provides the ground control on the

classification of objects. In addition, information from other Far North

Information Knowledge Management Program projects, such as base data

and land cover information has been used in the interpretation and

classification of the surficial materials.

MESOPROTEROZOIC-NEOPROTEROZOIC INFRASTRUCTURE

OF GANDERIA: DETRITAL ZIRCON AGES FROM THE

BROOKVILLE TERRANE, SOUTHERN NEW BRUNSWICK,

CANADA

Barr, S.M., Department of Earth and Environmental Science, Acadia

University, Wolfville, NS B4P 2R6, sandra.barr@acadiau.ca, White,

C.E., NS Department of Natural Resources, PO Box 698, Halifax,

NS B3J 2T9, Davis, D.W., Dept. of Geology, University of Toronto,

22 Russell St., Toronto, ON M5S 3B1, McClelland, W.C.,

Department of Geoscience, 121 Trowbridge Hall, University of

Iowa, Iowa City, IA 52242 USA, and van Staal, C.R., Geological

Survey of Canada, 625 Robson Street, Vancouver, BC V6B 5J3

The Brookville terrane in southern New Brunswick is the oldest known

component of the Ganderian microcontinent of the northern Appalachian

orogen. Hence, its composition, tectonic evolution, and provenance are

keys to understanding the origin and travels of Ganderia. The Brookville

terrane includes metasedimentary rocks of the Green Head Group, in

mylonitic contact with the Brookville Gneiss, an assemblage of low-

pressure/high-temperature paragneiss and tonalitic orthogneiss. The Green

Head Group consists of the locally stromatolitic metacarbonate- and

quartzite-dominated Ashburn Formation and metasiltstone-dominated

Martinon Formation. Based on previously published detrital zircon ages,

the maximum age for the Ashburn Formation is ca. 1230 Ma, whereas the

Martinon Formation contains detrital zircon as young as ca. 600 Ma. Both

the Green Head Group and the Brookville Gneiss are intruded by ca. 555-

525 Ma subduction-related Golden Grove Plutonic Suite, providing a

minimum age for the host rocks.

Additional detrital zircon studies reported here were aimed at

resolving the original stratigraphic relationship between the Ashburn and

Martinon formations, as well as their relationship to the Brookville

paragneiss. Analysis by ICP-MS of 72 additional grains from the Ashburn

Formation quartzite sample analyzed previously by TIMS similarly

yielded no grains younger than ca. 1200 Ma, a predominance of Meso- and

Paleoproterozoic ages back to ca. 2100 Ma, and a few Neoarchean ages. A

sample from the metasiltstone matrix of a carbonate olistostrome in the

Martinon Formation contains rounded grains with ages mainly between ca.

1000 Ma - 2200 Ma, indicating provenance similar to that of the Ashburn

Formation quartzite. However, the sample also contains euhedral grains

with ages clustered around 650 Ma. A calcareous metasiltstone sample

from the Brookville paragneiss also yielded detrital zircon grains with

mainly ages between 1150 Ma and 2000 Ma, indicating provenance similar

to that of the Ashburn and Martinon formations. An orthogneiss sample

yielded euhedral (igneous) zircon grains with a concordia age of 616 ± 4

Ma, slightly older than previously reported ages of ca. 605 Ma and

indicating an interval of continental margin subduction at least 60 Ma

older than that represented by the Golden Grove suite.

Similar detrital zircon age spectra showing a dominance of

Proterozoic ages strongly support a link among the Ashburn Formation,

Martinon Formation, and Brookville paragneiss in terms of provenance,

but do not resolve the question of the original stratigraphic relationship

among these units or the age of the passive margin sequence represented

by the Green Head Group.

LANTHANUM DISPERSION IN SOIL-PLANT SYSTEM IN A

TROPICAL AREA: THE CAMUTANGA Pb-Ba MINERALIZA-

TION, PERNAMBUCO, BRAZIL

Barros, J.S.M.

, [email protected], Silva, P.R.P.B.

, Souza

Neto, J.A.

1,2

and Garlipp, A.B.

1,2,3

Programa de Pós-Graduação em

Geociências, UFPE;

Departamento de Geologia, UFPE;

Bolsista do

Programa Nacional de Pós-Doutoramento da FACEPE

The study area is located in northeastern Brazil in the city of Camutanga

about 120 km northwest of Recife where there is a Pb-Ba mineralization

explored in the 1930s. Soil and vegetation samples (Musa spp.) were

collected at five stations over (E1 and E3) and outside (E2, E4 and E5) of

the mineralized body. Were done soil profiles at each station and collected

samples from each horizon identified. For the Musa spp. were collected

roots, leaves, bark and fruit. The results of the soil analysis (multi-acid

digestion and ICP-MS/AES measurement) showed concentrations of La

between 10.9 and 56.5 mg.kg

-1

at stations outside of the mineralized corps

and 44.7 and 77.6 mg.kg

-1

over the mineralization. The evaluation of the

vertical distribution of the La soil profile shows an concentration increase

with depth, except in E4 where the highest concentration is in the surface

horizon. At the samples of Musa spp. concentrations (aqua regia digestion

and ICP-MS/AES measurement) ranged from 0.03 to 2.54 mg.kg

-1

and

0.03 to 6.03 mg.kg

-1

, over and outside of the mineralized corps,

respectively. The highest concentrations were identified in the roots (2.49

to 6.03 mg.kg

-1

), followed by leaves (0.22 to 0.70 mg.kg

-1

). The fruit and

the bark had the lowest concentrations, ranging from 0.03 to 0.07 mg.kg

-1

and 0.04 to 0.06 mg.kg

-1

, respectively. The transfer factor calculation

between the concentrations of soil and vegetation show that about 5 to

17% of La in the soil is absorbed and retained by the plant root, while only

about 0.1 to 2% of La in the soil is absorbed by the plant and set in the

aerial part (leaf, bark and fruit). The fruit had the lowest transfer rates of

the concentrations of soil La (0.1%) and the leaves had a transfer rate from

0.4 to 2%. The results of the La concentrations in the soil when compared

with reference values (50 to 20 mg.kg

-1

) for similar soils, show that the

concentrations obtained not represent a significant La anomaly in the study

area. Additionally, the analysis plants show that the main La accumulator

organ of Musa spp. is the root. In modern physicochemical conditions

presents in the studied area, this organ is effective in protecting the

retention of the La in the aerial parts, mainly the fruit.

ARCHITECTURE OF A MASS TRANSPORT DEPOSIT AT THE

BASE OF TERTIARY IN THE JEANNE D’ARC BASIN, OFF-

SHORE NEWFOUNDLAND

Bartlett, C.L. and Hall, J., Memorial University of Newfoundland,

PO Box 4200, Suite 3003 Bruneau Centre, St. John's, NL A1C 5S7,

[email protected]

Mass transport deposits form a significant component of deep marine

sediments. Knowledge of the architecture of such deposits is relevant to

assessment of them as potential geohazards for drilling rigs. The

architecture of a mass transport deposit at the Base of Tertiary in the

Jeanne d’Arc Basin, offshore Newfoundland displays features that indicate

direction of flow, and internal structure. The strata patterns and the internal

structure of the studied mass transport deposit jointly indicate zones of

extension, compression, and lateral transfer. The intricate distribution of

the thrust faults, back thrusts, lateral transfers and extensional faults

signifies the forces present upon the failure. This distribution can be

mapped in the Thorvald Mass Transport Deposit (MTD), offshore

Newfoundland. The MTD is defined by conventional seismic mapping and

enhanced by seismic attributes within the Flying Foam 3-D dataset from

the Jeanne d’Arc Basin.

The Thorvald Mass Transport Deposit, consisting of semi-chaotic

and coherent sediments, underwent contractional and extensional faulting

and lateral transfers during failure. The downslope transport, initiated by

sliding and slumping, created a thick cap of remoulded debris. The

architecture of the remoulded debris includes features such as compression

ridges, thrust faults, back thrusts, layered coherent strata, and mounds,

which were studied using 3D seismic tools.

PROVENANCE DISCRIMINATION IN SURFACE SEDIMENTS

AND CORE RECORDS FROM THE AMERASIAN BASIN

(ARCTIC OCEAN) CONSTRAINED BY QUANTITATIVE

MINERALOGICAL ANALYSES

Bazhenova, E., Zou, H., Stein, R., Matthiessen, J., Alfred Wegener

Institute for Polar and Marine Research, Am Alten Hafen 26, 27568

Bremerhaven, Germany, Evgenia.[email protected], and Vogt, C.,

University of Bremen, Klagenfurter Str. 2, 28359 Bremen, Germany

This study focuses on the determination of potential source areas for the

terrigenous material derived from Eurasia and North America to

reconstruct the late Quaternary sedimentary environments in the

Amerasian Basin of the Arctic Ocean. When compared to the potential

source areas in the Arctic Ocean hinterland, spatial and temporal variations

in bulk mineralogy may provide important information on the trajectories

of sea-ice drift, iceberg transport and oceanic currents.

Investigations are carried out on surface samples recovered from the

Mendeleev Ridge and shelves of the East Siberian and the Chukchi seas.

Mineralogical analysis was performed on bulk sediments by the X-ray

diffraction (XRD) method. Dry powder samples were mixed together with

corundum for further quantification of mineral contents. Raw XRD data

were processed using the RockJock and QUAX software to test the

consistency of both methods. Additionally, composition of artificial

mixtures was determined to test the accuracy of mineral standards.

Obtained results are used to identify mineralogical provinces in the

surface sediments of the Amerasian Basin. This geographical distribution

is also compared to the previously published studies, including the

numerous research activities carried out in the Siberian shelf seas in the

middle of the 20

century.

Bulk mineral composition of surface sediments is further used for

unmixing of the downcore mineralogical records for sediment cores

recovered along two transects across the Mendeleev Ridge during the

ARK-XXIII/3 Expedition of RV “Polarstern”. Trends in mineralogical

composition are also compared to the grain-size distribution in order to

attribute the provenance changes to different transportation mechanisms in

variable sedimentary environments.

Re-Os ISOCHRON AGE OF CARBONACEOUS SHALES IN THE

UPPER MISTASSINI BASIN, QUEBEC, SUPPORTS CORREL-

ATION OF PALEOPROTEROZOIC BASINS AROUND THE

MARGINS OF THE SUPERIOR CRATON

Bekker, A., Department of Geological Sciences, University of

Manitoba, Winnipeg, MB R3T 2N2, [email protected],

Rainbird, R., Geological Survey of Canada, Ottawa, ON K1A 0E8,

and Creaser, R.A., Department of Earth & Atmsopheric Sciences,

University of Alberta, Edmonton, AB T6G 2R3

Recent geochronologic data constrain the age of Paleoproterozoic granular

iron formations (GIF) in the Animikie basin, located on the southern

margin of the Superior craton, and in the Labrador Trough, on the eastern

margin of the Superior craton, to ca. 1878 Ma. Between these basins is the

Mistassini basin, which contains, in its upper part, the Temiscamie

Formation GIF and overlying shales and wackes of the Kallio Formation.

The Temiscamie Formation unconformably overlies shallow-marine

carbonate rocks of the Albanel Formation, which record the end of the ca.

2.22-2.1 Ga Lomagundi carbon isotope excursion and thereby provide an

indirect age constraint for the lower part of the Mistassini basin. In all

three basins, shallow-water GIFs are overlain by a transgressive succession

of wacke and shale, interpreted to have been deposited in a foreland basin

setting. Tuffs in the basal part of this succession in the Animikie basin

were dated by U-Pb method at ca. 1832-1827 Ma, indicating a possible

hiatus at the base of the shale-wacke succession. Closely-spaced hand

specimens of thinly-laminated, carbonaceous shale from the Kallio

Formation were collected from a recently exposed roadside outcrop for

Re-Os dating to constrain the age for the upper part of the Mistassini basin.

The samples yielded 1826 ± 15 Ma isochron (2σ, Model 3, n=7,

MSWD=2.3) with the initial Os isotope ratio of 0.15 ± 0.08, which we

interpret as the depositional age. The initial Os isotope ratio indicates

limited radiogenic Os flux from weathering of continental crust. Our data

provide the first age constraint for deposition in the upper part of the

Mistassini basin and further support correlation of the Temiscamie GIF

with GIFs in the Animikie basin and in the Labrador Trough. It also

supports possible correlation with deeper-water carbonaceous shales and

wackes from the Sudbury basin, which lies along the southern margin of

the Superior craton between the Mistassini and Animikie basins. Ca. 1.88

Ga GIFs were deposited along the southern and eastern margins of the

Superior craton and as far onto the craton as the Belchers Islands and

Sutton Inlier over a relatively short time span. Furthermore, our data

emphasize the regional extent of hiatuses within the transgressive

succession deposited in the foreland basin that likely reflects protracted

and multi-stage accretion of the Laurentia.

CHARACTERIZATION OF URANIUM MINERALOGY FROM THE

LORADO TAILINGS SITE, URANIUM CITY, SASKATCHEWAN,

CANADA

Bergen, L.L., umb[email protected]ba.ca, and Fayek, M., Depart-

ment of Geological Sciences, University of Manitoba, 125 Dysart

Rd., Winnipeg, MB R3T 2N2

The study of uranium in mine tailings can be used to develop a better

understanding of uranium transport in the environment and its affect on the

ecosystem. The main objective of this research is to characterize the

uranium mineralogy and uranium transport at the Lorado Mill historical

tailings site, Uranium City, Saskatchewan. The Lorado mill operated

between 1957 and 1960 and treated ore from the Lorado mine and a

number of smaller satellite mines. There is an estimated 177,000 m

tailings on land and an additional 50,000 m

within the adjacent Nero

Lake, resulting in a total of 227,000 m

of tailings at the Lorado mill site.

These tailings are highly stratified, comprise of up to four meters of silt

and sand overlying peat, and provide a unique opportunity to study

uranium transport in a stratigraphically heterogeneous environment.

In 2010 and 2011 the Lorado tailings were sampled using PVC pipes

to obtain one 1 m and eleven 0.5 m deep cores to characterize the tailings

both vertically and laterally. Cores generally consist of an orange sandy

horizon that varies in thickness from <1cm up to 0.5m, which overlies a

fine-grained silty horizon with fine layers of grey and red/purple clay

located near the water table. Petrography indicates uraninite (<20 ìm) is

the dominant uranium mineral and is generally encapsulated within quartz.

Salt crusts, not present in 2010, which covered large areas of the tailings in

2011, were sampled. The salt crust was heterogeneous exhibiting various

colours including: white, yellow-green, yellow, orange, brown, black and

grey. The salts are a mixture of various sulphate minerals including:

gypsum (CaSO

•2H

O), hexahydrite (MgSO

•6H

O) and bianchite

(ZnSO

•6H

O).

Bulk chemical analyses of core sediment samples by ICP-MS show

uranium concentrations range up to 200 ppm. Uranium concentrations vary

with depth. The highest uranium concentrations occur at surface, just

below the salt crust and in lower grey-purple silt horizon. Bulk ICP-MS

analysis of the salt crust indicates they have high uranium concentrations

ranging between 74 and 3,230 ppm. The highest uranium concentrations

are associated with orange and yellow salts while the lowest

concentrations are associated with the brown, black and grey salts.

Uranium concentration profiles at the Lorado tailings site suggest that

during dry climatic conditions (summer 2011) uranium is drawn upwards

and concentrated in the salt crusts, whereas in wet climatic conditions

(summer 2010) uranium is mainly concentrated in the clay-rich layers.

X-RAY DIFFRACTION (XRD) AND X-RAY FLUORESCENCE

(XRF) ANALYSIS OF CREMATED HUMAN REMAINS

Bergslien, E.T., Buffalo State College, 1300 Elmwood Ave. 271

Science Building, Buffalo, NY 14222 USA, bergslet@buffalostate. edu

In early 2002, people across the United States were appalled as the story of

the Tri-State Crematory unfold on national television. After a woman

walking her dog discovered a skull, responding authorities kept finding

more and more bodies. Rather than performing the contracted cremations

at Tri-State, the bodies were simply dumped unceremoniously around the

property. More than 330 bodies were eventually recovered, setting off a

vast exercise in forensic anthropology. More baffling, most bodies

received prior to a certain date were actually cremated, and later on, while

most of the bodies were dumped on-site, some were sent to other facilities

for proper cremation. Hundreds of families were uncertain as to the

contents of the urns in their possession and regional crime laboratories

were overwhelmed with questioned remains. Many families had received

cement dust, wood ash or other materials instead of the cremated remains

of their loved ones.

In such investigations powder x-ray diffraction (XRD) can be a

powerful forensic tool. XRD is used for identification of crystalline

materials, including differentiating components of mixtures. The major

mineral component of bone is calcium phosphate, which is similar in

structure and composition to inorganic apatite group. XRD analysis allows

investigators to quickly distinguish bioapatite from filler materials such as

cement dust and wood ash with little to no sample preparation. More

complex is distinguishing bioapatite from mineral apatite. Geologically,

trace amounts of around half the elements on the periodic table can be

incorporated into geoapatite. Substitution into living organisms is much

more limited, thus trace element analysis (XRF), can be used to distinguish

organic from inorganic apatite. For example, fluoride substitutes so readily

into apatite, occurring even at body temperature, that fluorapatite quickly

develops in humans that have been using fluoridated water or toothpaste.

Conversely, high levels of arsenic, sulfur, vanadium or antimony are

indicative of geoapatite.

The elevated temperatures achieved under burning, or cremation,

cause recrystallization of bioapatite, actually simplifying its analysis. The

resultant material is clearly distinguishable from the materials reportedly

used as fill in the urns from Tri-State and can also be differentiated from

geologic apatite. In a study of samples of leg bones and dentin that were

collected from a human cremated at 1010°C for 2.5 hours, XRD results

clearly show distinctive differences between bone apatite, dentin apatite,

and geological apatite. Bone apatite shows a significant component of

carbonate while dentin appears to be virtually pure apatite.

UNRAVELLING THE TECTONIC EVOLUTION OF HIGH-

GRADE GNEISSES OF THE BEAVERLODGE DOMAIN,

SOUTHWESTERN RAE PROVINCE, SASKATCHEWAN, USING

A MULTIDISCIPLINARY APPROACH

Bethune, K.M., Dept. of Geology, University of Regina, 3737

Wascana Parkway, Regina, SK S4S 0A2, Berman, R.G., Rayner, N.,

Geological Survey of Canada, 601 Booth Street, Ottawa, ON K1A

0E8, and Ashton, K.E., Saskatchewan Geological Survey, 2101

Scarth Street, Regina, SK S4P 2H9

The Rae Province, a principal building block of the Canadian Shield, has a

remarkably protracted tectonic history, extending from the Archean to late

Paleoproterozoic. This longevity is nowhere more evident than in the

southwestern Rae Province in Saskatchewan, where, aside from Archean

tectonism, Precambrian rocks variably record the effects of four major

Paleoproterozoic tectonic events – the 2.45-2.3 Ga Arrowsmith, 2.1-1.93

Ga Thelon-Taltson, 1.9 Ga Snowbird and 1.9-1.8 Ga Hudsonian orogenies.

In the past decade, a combination of geological mapping, structural

analysis and geochronology has been used to decipher the tectonic

complexity of the Beaverlodge domain, one of the largest lithotectonic

elements in this region. This high-grade terrain is now known to consist of

two main structural levels: a lower level comprising mainly high-grade

Archean (3.0 and 2.7-2.6 Ga) gneisses and a higher level comprising

mainly 2.33 to <2.17 Ga supracrustal rocks of the Murmac Bay Group, at

more variable metamorphic grade. Whereas the older/deeper package

underwent tectonothermal events in the Archean (~2.57 Ga) and early

Paleoproterozoic (~2.34 Ga) rocks at higher structural levels bear no

record of these events, recording only younger (1.94-1.90 Ga)

metamorphism. In metapelitic gneisses, an older (1940-1930 Ma)

generation of monazite is linked to development of the dominant ESE-

trending composite (S

) transposition foliation, whereas younger

monazite (1910-1900 Ma) is ascribed to resetting during refolding of this

foliation about NE-trending (F

) axes. Two principal tectonic stages are

inferred. The first stage (1940-1930 Ma), attributed to Taltson orogeny,

involved tight to isoclinal folding (D

1/2

) and development of the main

) foliation, followed by more open folding (D

). The absence of

Taltson-age plutonic rocks, except for low-volume crustal melts, suggests

that this stage involved crustal thickening along a clockwise P-T-t path.

High strain along the contact between Archean rocks and the Murmac Bay

Group indicates some degree of translation of cover rocks over basement.

Pelitic rocks at higher structural levels underwent metamorphism to middle

amphibolite facies, whereas deeper crustal rocks attained granulite-facies

conditions. The second stage, correlated with Snowbird tectonism at 1.91-

1.90 Ga, involved refolding of D

to D

structures about NE-trending axes

in a dextral transpressive regime. Upper crustal rocks remained at the same

crustal level whereas deeper crustal rocks were uplifted, instigating

decompression reactions. Additional post-1.9 Ga (Hudsonian) shortening

and exhumation of this terrain was accommodated by subsequent ductile-

brittle thrust reactivation of domain-bounding shear zones, with further

brittle extensional reactivation approaching the time of Athabasca Basin

development.

CHARACTER AND TECTONIC SETTING OF THE MIDDLE

PALEOPROTEROZOIC THLUICHO LAKE GROUP, SOUTHERN

RAE PROVINCE, CANADIAN SHIELD: ALLUVIAL-FLUVIAL

BASIN DEVELOPMENT IN THE HINTERLAND OF THE

TALTSON OROGEN

Bethune, K.M., Dept. of Geology, University of Regina, 3737

Wascana Parkway, Regina, SK S4S OA2, and Hunter, R.C.,

Exploration Division, Cameco Corporation, 2121 - 11

Street West,

Saskatoon, SK S7M 1J3

In addition to Archean orogenesis, the Rae Province of the central

Canadian Shield records the effects of multiple, staggered Paleo-

proterozoic orogenic events along both its western and eastern margins. In

the Athabasca region of Saskatchewan the legacy of this activity is a

complex record of deformation, metamorphism, and intervening periods of

uplift and erosion. This record is preserved in the form of four major

Proterozoic successions, each bounded by an unconformity and each

relatively less deformed than immediately underlying rocks. The second

oldest of these successions, the middle Paleoproterozoic Thluicho Lake

Group, is a valuable monitor of tectonic activity in this region. This ~1.5

km thick sequence of continental alluvial-fluvial rocks was deposited on

an uplifted Archean to early Paleoproterozoic basement complex, and

subsequently deformed and metamorphosed to greenschist facies. Detrital

zircon geochronology has established a maximum depositional age of 1.92

Ga, consistent with regional geological relationships indicating deposition

after high-grade Taltson (ca. 1.93 Ga) metamorphism in the basement

complex but before development of 1.91-1.90 Ga northeast-trending

structures affiliated with the Snowbird tectonic zone. Isotopic provenance

indicates that detritus was derived exclusively from local sources, namely

Archean (ca. 2.6 Ga) to early Paleoproterozoic (2.5-2.3 Ga) basement

rocks of the underlying Zemlak and adjacent Nolan, Taltson, Ena and

Beaverlodge domains. These provenance characteristics, coupled with the

close spatial relationship to basement mylonites, suggests that the Thluicho

Lake Group was deposited in east-southeast-trending, fault-controlled

basins in the hinterland of the Taltson orogen, and paralleling a major

ca.1.93 Ga tectonic front. Similarities in lithology, age and provenance

suggest that the Thluicho Lake Group correlates with the more extensive

Nonacho Group to the north, although there are differences in primary

basin orientation that are not well understood. Both groups are proposed to

be part of the youngest of four craton-wide early to middle

Paleoproterozoic sequence stratigraphic assemblages, the fourth and

youngest assemblage being characterized by immature siliciclastic rocks

ascribed to intracratonic basin inversion and/or foreland basin

development during the early stages (1.92-1.90 Ga) of the amalgamation

of Laurentia/Nuna. However, while the Thluicho and Nonacho Groups

may represent proximal foreland basin deposits of the Taltson orogen,

certain characteristics are more diagnostic of an intermontane and/or

strike-slip pull-apart setting. This paper will examine similarities and

differences between the two groups, and explore the question of

depositional setting in relation to tectonics and the wider sequence

stratigraphic framework established for the Rae Province.

A POSSIBLE CORRELATION OF MANGANESE-RICH SEDI-

MENTARY ROCKS FROM THE HARLECH DOME AND THE

MEGUMA TERRAIN

Bevins, R.E., richar[email protected], Cotterell, T.F.

and Horak, J.M., Department of Geology, National Museum of

Wales, Cardiff, Wales, UK, CF10 3NP

It has recently been proposed that the Cambrian successions of the

Meguma Terrain of Nova Scotia and the Harlech Dome region of North

Wales show a much greater similarity to each other than the adjacent

successions on Avalonia. They both contain thick successions of turbiditic

sandstones of early Cambrian age, succeeded by alternating mudstones and

sandstones of early to middle Cambrian age within which are manganese-

rich horizons. It is likely that the two terranes were in close proximity in

Cambrian times on the margin of Gondwana, and the term ‘Megumia’ has

been adopted for this proposed tectonic entity.

In the Harlech Dome area the ore bed is typically 30-40 cm thick and

is laterally extensive across the region, over an area of around 190 km

The ore bed is banded on the cm scale and consists of a mixed carbonate

and silicate assemblage. Individual bands are variably red, yellow, dark

brown and black. Early studies reported the bed to be dominated by

rhodochrosite and rhodonite, although subsequently it was suggested that

spessartine was the main silicate component, rather than rhodonite.

Kutnohorite was also recognised amongst the carbonates present.

A detailed study of a 16 cm thick section of the ore bed at Llyn du

bach mine in the Harlech Dome has confirmed the presence of spessartine,

rhodochrosite, kutnohorite and quartz, as well as identifying sonolite,

tephroite, dolomite and either titanomagnetite or jacobsite. Spessartine is

dominant in the red horizons, whilst the carbonates show a predominance

of kutnohorite towards the base of the bed and rhodochrosite higher in the

bed; dolomite occurs typically as concretions. Other samples show the

presence of alleghanyite. The three silicate phases sonolite, tephroite and

alleghanyite have been recorded from other manganese deposits world-

wide present in low-grade metamorphic sequences. We suggest that these

phases are characteristic of such chemical systems in low-grade

metamorphic rocks and might prove to be equivalent to the calc-silicate

phases present in low-grade metabasites, such as pumpellyite and prehnite.

The current project aims to investigate and compare the mineralogy

of the manganese-rich horizons in the two regions, which are now

geographically separated, to determine whether the manganese mineralogy

can be used to: (i) further support the correlation proposed between the

two regions; and (ii) to confirm the validity of the manganese mineral

assemblage as a grade indicator in low-grade metamorphic rocks.

GOLD MINERALIZATION IN THE ARCHEAN BEATTIE

SYENITE, DUPARQUET, ABITIBI BELT, QUÉBEC, CANADA

Bigot, L., [email protected], and Jébrak, M., Département des

sciences de la Terre et de l'Atmosphère - Université du Québec à

Montréal(UQAM), CP 8888 Suc Centre-ville, Montréal, QC H3C 3P8

The standard orogenic gold model characterizes the majority of gold

deposits within the Abitibi belt. However, several examples of late-

Archean gold mineralization are disseminated and associated with alkaline

intrusions, thus differing from the standard orogenic gold model. The

Beattie Syenite is an Archean porphyry intrusion emplaced along the

major Porcupine-Destor Fault Zone in the Abitibi belt. It was mined from

1933 to 1956, with a total production of about 33 tonnes of gold in 9.2 Mt

of ore. The syenite is aligned along an east-west axis; it is hosted by mafic

and intermediate volcanic rocks of the Kinojevis Group and is

penecontemporaneous with the Timiskaming sedimentary rocks

deposition.

The structural evolution of the syenite consists of an early ductile-

brittle flattening phase followed by two more shallow stress episodes

marked by two different regimes, one north-south with conjugated dextral

and sinistral faults, and the other east-west shearing. The obliquity of the

two stress tensors, the regional distribution of mineralization, and the 3D

geological model suggest a regional tilting event.

Gold mineralization appears as disseminated ore, within the

intrusion, and controlled in shear zones in its core and along its contact

with the volcanic country rocks. Gold is hosted in arsenopyrite and

arsenian pyrite. Gold grains are less than micron-sized. The association

with arsenian minerals and the very small size suggests that gold was

incorporated into the crystalline structure of arsenopyrite and arsenian

pyrite in solid solution (Au1+) or as nanoparticles (Au0).

The metallic assemblage in the Beattie syenite is polyphased: (1) a

primary phase enriched in iron-titanium appears to have produced martite

in a more oxidizing environment; (2) Several subsequent sulfidation

phases were marked by the presence of pyrites and arsenopyrites, some

rich in gold, suggesting crystallization under more reducing conditions and

at lower temperatures. During the sulfidation phases, three generations of

pyrite are identified; the first generation is arsenian and gold-bearing,

whereas the second and third are arsenic-poor and gold free. (3) A late

silica-enriched hydrothermal phase remobilized the gold and is marked by

cataclasis. Gold migrated into the fractures developed in the cataclazed

pyrite, where it recrystallized with silver in the form of electrum.

Several petrological characteristics in the Beattie gold deposit,

including gold appearances, metallic mineralogy, type of alterations, and

ore control, suggest a shallow magmatic deposit.

Keynote THE HOT LONG-LIVED SVECONORWEGIAN COL-

LISIONAL OROGEN: A REVIEW AND NEW CONSTRAINTS

FROM SE NORWAY

Bingen, B.

, bernard.bingen@ngu.no, Viola, G.

1,2

, Engvik, A.K.

, and

Yi, K.

Geological Survey of Norway, 7491 Trondheim, Norway;

Norwegian University of Science and Technology, 7491 Trondheim,

Norway;

Korea Basic Science Institute, 363-883 Chungbuk, South

Korea

Recently published and new structural, petrological and SIMS U-Pb zircon

data refine substantially our understanding of the 500 km wide

Sveconorwegian orogen as the product of a hot, long-lived, polyphase,

bivergent collisional orogeny developed at the margin of Baltica at the end

of the Mesoproterozoic. The Sveconorwegian orogeny followed a 1200-

1130 Ma bimodal, within-plate magmatism in Telemark, Kongsberg and

Bamble, more extensive than previously assumed. The earliest

documented Sveconorwegian ca. 1144 Ma patchy MP granulite-facies

metamorphism in Bamble is probably genetically related to this

magmatism. So is the classical MP granulite-facies metamorphism around

Arendal, redated at ca. 1132 Ma. Evidence for Gothian 1550 Ma protoliths

question previous interpretations that the Arendal granulites correspond to

the root of a Sveconorwegian volcanic arc tracing an early-

Sveconorwegian suture zone. Bamble and Kongsberg were subsequently

thrusted westwards on top of Telemark around 1080 Ma marking the onset

of collisional tectonics. To the east, in the Idefjorden terrane, an HP, 1.3

GPa, granulite-facies event is locally recorded and was dated at ca 1050

Ma. This was followed by widespread amphibolite-facies partial melting.

Seven leucosomes associated with top-to-the-west regional kinematics and

resulting from muscovite-, biotite- and amphibole dehydration melting,

range in age from ca. 1039 to 997 Ma. This partial melting is coeval with

widespread syn-collisional granitic plutonism and LP amphibolite- to

granulite-facies metamorphism in the west of the orogen in Rogaland-Vest

Agder. The reported long-lived high grade conditions suggest development

of a mid-crustal west-directed (?) channel flow with flow after ca. 1030

Ma and a slowly eroding orogenic plateau. In this model, the low-grade

Telemark supracrustals may belong to a shallow orogenic lid,

characterized by deposition of immature sediments in grabens (Eidsborg

Fm, <1118 Ma, Kalhovde Fm <1065 Ma). At ca. 980 Ma, the

Sveconorwegian orogeny propagated eastwards in the footwall of the

arcuate, southeast-verging, “Mylonite Zone” thrust, leading to eclogite-

facies metamorphism in the Eastern Segment. Convergence was followed

by gravitational collapse after ca. 970 Ma. High-grade LP conditions were

maintained in Rogaland-Vest Agder until ca. 930 Ma and were associated

with post-collisional plutonism, including anorthosites. The Putumayo

orogen and Oaxaquia Terrane at the margin of Amazonia are characterized

by granulite-facies metamorphism at ca. 990 Ma and possibly represent

conjugate margins correlatives during continental collision.

MAFIC IGNEOUS EVENTS AS CONSTRAINTS FOR DEVELOP-

MENT AND URANIUM MINERALIZATION OF THE PALEO-

PROTEROZOIC ATHABASCA, THELON AND DESSERT LAKE

BASINS

Bleeker, W., Geological Survey of Canada, 601 Booth Street,

Ottawa, ON K1A 0E8, wbleeker@nrcan.gc.ca

Mafic igneous rocks, either as extrusive horizons or as intrusive sills and

dykes, provide critical time markers in studies of sedimentary basins and

mineralized systems. In some systems they also provide the heat engine

that drives hydrothermal fluid circulation.

Despite their critical importance, the dating of these rocks has long

presented a challenge in terms of obtaining precise and accurate isotopic

ages. The initial application of K-Ar whole rock and mineral ages, Rb-Sr

whole-rock isochrons, and Sm-Nd whole-rock or internal mineral

isochrons have had a checkered history, with ages being plagued by either

loss of radiogenic daughters or mixing processes.

This situation changed with the realization that mafic rocks in many

cases do contain accessory minerals that are amenable to U-Pb dating:

zircon, baddeleyite, zirconolite, titanite, rutile and apatite. Without any

doubt baddeleyite (ZrO

) is the star performer in this line-up because it

typically has a sufficiently high U content, low common Pb, is relatively

robust, and essentially unknown as an inherited phase. Zircon, if present, is

equally valuable but may be plagued by more severe Pb loss and

inheritance. Chemical abrasion techniques may partly circumvent the Pb

loss problem.

Routine crushing and mineral separation of mafic rocks, however,

commonly fails to recover baddeleyite (and/or zircon), resulting in the

common perception, often incorrect, that the rocks in question do not

contain these phases. Several important developments have changed this

situation: 1) better mineral separation, tuned to recovery of fine, platy,

baddeleyite crystals; 2) modern SEM imaging in electron backscattered

mode allowing efficient identification of all Zr-bearing phases in a thin

section, or even in just a quickly polished rock slab; and 3) availability of

different analytical strategies for dating the identified phases, e.g. in situ

ionprobe.

Systematic SEM imaging has shown that baddeleyite, zircon, and

zirconolite are more common than appreciated. However, even in some

medium-grained mafic rocks, baddeleyite may be less than 20 µm in size

and below the physical limit of effective mineral separation. In situ

ionprobe dating provides the solution in such cases. With further

incremental advances in mineral separation and microbeam techniques,

more and more mafic rocks will finally yield their ages. In nearly all cases,

the initial investment of SEM imaging, to define the mineralogy,

abundance, and size distribution of accessory phases, is highly worthwhile,

forming the basis on which to decide the analytical strategy. Some case

studies relevant to this session will be discussed.

THE 2193 Ma DOGRIB GIANT DYKE SWARM OF THE SLAVE

CRATON: PRECISE AGE AND SETTING

Bleeker, W.

, [email protected], van Breemen, O.

, Mitchell,

, Nilsson, M.

, Hunt, P.

, Peng, P.

, LeCheminant, A.N.

(retired)

and Buchan, K.

(emeritus),

Geological Survey of Canada, 601

Booth Street, Ottawa, ON K1A 0E8;

Yale University;

Lund

University;

Chinese Academy of Sciences

Dogrib dykes of the southern Slave craton (McGlynn & Irving, 1975)

represent one of the classic, Paleoproterozoic, giant dyke swarms of the

Slave crustal fragment. Recognized early as an important target for

paleomagnetic investigations (assessing the coherency of the Canadian

shield prior to the Hudsonian orogeny), the utility of the paleomagnetic

data has long been hindered by absence of precise isotopic ages. Early age

dating efforts (K-Ar and Rb-Sr) yielded scattered results from 0.90 Ga to

as old 2.69 Ga, compromising any interpretation of APW paths. Recent U-

Pb studies by van Breemen et al. on several Slave craton dykes also

produced the first baddeleyite age for the Dogrib dykes, showing that this

swarm is ca. 2190 Ma.

Since then, we have collected more optimum material from 1) the

central gabbroic phase of the largest Dogrib dyke (~80 m wide), and 2)

late-stage residual melt veins with pegmatoidal textures. Using the

technique of Söderlund, we separated larger baddeleyites from both

samples, yielding a precise and reliable age of 2193±2 Ma (upper

intercept; Mitchell et al., 2012). Carefully comparing separation results

from the different samples, the pegmatoidal veins perhaps yielded slightly

more and larger baddeleyites, but only one fraction, from the central

gabbro, is fully concordant. The new samples also contain zircon and

zirconolite, but SEM imaging shows neither phase to be simple. As seems

common in mafic rocks, the zircons look more complex, mottled, and

altered, generally showing small bright specks of thorianite (ThO

In the broader Yellowknife area, the swarm consists of half a dozen

large dykes, trending ENE and defining a swath ~100 km wide. The major

dykes show a subtle but distinct fanning, with trends varying from ~075°

in the north to ~060° further south, indicating a magmatic centre for the

Dogrib swarm along the eastern (burried) margin of the Slave craton, not

along its southwestern corner. This is in agreement with the small number

of large, linear dykes, which is typical for the intermediate to distal zone of

a giant dyke swarm.

Dogrib magmatism was associated either with uplift and rifting along

the southeastern craton margin or was a precursor to such events. The

coeval “SW Slave Magmatic Province” is therefore best interpreted as an

alkaline province along a magmatic rift arm projecting deep into the craton

interior, in perfect analogy to how the Lake Nipissing magmatic province

and slightly older Grenville dyke swarm relate to the Iapetan rift margin of

eastern Laurentia.

DEPOSITIONAL CONTROLS ON HORIZONTAL WELLBORE

PLACEMENT IN THE MARCELLUS SHALE, APPALACHIAN

BASIN: INSIGHTS FROM CHEMO- AND SEQUENCE STRATI-

GRAPHY

Blood, D.R.

, [email protected]m, Lash, G.G.

and

Bridges, L.C.

Pure Earth Resources, 168 Jameson Way, Seven

Fields, PA 16046;

SUNY Fredonia, Fredonia, NY 14063

Placement of a lateral in the Marcellus shale necessitates consideration of

two properties of the reservoir: location of the hydrocarbon within the

reservoir and pre- and post-stimulation deliverability of the formation.

Core calibrated petrophysical analysis of Marcellus logs is conducted to

determine total organic carbon (TOC) content, gas-filled porosity, clay

volume, and both free and adsorbed gas-in-place volumes. The distri-

bution of in-place hydrocarbons is controlled by the sequence stratigraphic

framework of the Marcellus, which comprises two third-order

transgressive-regressive cycles. Within a particular T-R cycle, the shale

becomes progressively more organic and quartz rich through the

transgressive systems tract and progressively diluted by clay through the

overlying regressive systems tract. Organic richness throughout much of

the Marcellus basin appears to have been controlled principally by a

combination of bottom water conditions conducive to preservation of

organic macerals and dilution by clastic detritus. Indeed, enrichment of

authigenic uranium and molybdenum in tandem with observed size

distributions of pyrite framboids suggest a depositional environment

dominated by a strongly suboxic to intermittently euxinic water column

through Union Springs and locally Oatka Creek deposition. Elsewhere,

regional covariance trends of authigenic molybdenum and uranium and

their respective enrichment factors define a uniform (Mo/U)auth ratio of ±

2 — 3 times the Mo/U molar ratio of seawater. Mo is enriched relative to

U by a factor of 5:1 to 10:1 suggesting accelerated transport of Mo to the

seafloor by a particulate (Mn) transport mechanism that would have

required frequent fluctuations between suboxic and moderately sulfidic

water column conditions. Deposits of the Union Springs Member illustrate

the best reservoir development. The importance of TOC to Marcellus gas

production goes beyond its ability to adsorb gas; it also appears to host

porosity development within the Marcellus shale. Given that the Marcellus

accumulated rapidly (~1.5my), condensed intervals are dominated by TOC

that is largely unoxidized. Inferred condensed intervals are defined by

minimal clay and especially abundant quartz, principally diagenetic. The

siliceous horizons serve as higher modulus, brittle intervals necessary for

the initiation of hydraulic fracture stimulation. Further, minimal clay

within the condensed intervals may be expected to diminish the degree of

proppant embedment.

BIOGEOCHEMICAL SIGNATURES AND RELATIONSHIPS TO

RARE EARTH ELEMENT AND ZIRCONIUM MINERALIZATION

AT THE NORRA KÄRR DEPOSIT, SOUTHERN SWEDEN

Bluemel, B.

, britt.blueme[email protected], Dunn, C.

, Hart, C.

Saxon, M.

;

UBC - Mineral Deposit Research Unit, Vancouver, BC;

Colin Dunn Consulting Inc., North Saanich, BC;

Tasman Metals

Ltd., Vancouver, BC

The Norra Kärr rare metal deposit is located in southern Sweden,

approximately 300km southwest of Stockholm. It is a peralkaline

nepheline syenite complex, enriched in heavy rare earth elements

(HREEs). The deposit ranges from 200m to 400m in width, is

approximately 1300m long, and has been well defined by ongoing

diamond drilling. The HREE mineralization is dominantly found in the

pegmatitic “grennaite” unit, a eudialyte-catapleiite-aegerine nepheline

syenite.

Biogeochemical exploration can be more useful than traditional soil

surveys, particularly at the grassroots scale, because tree and plant root

systems interact with large volumes of soil over an extensive region and

therefore provide a broader, more composite signal than a single soil

sample collected at one site from one specific horizon. Sampling trees and

shrubs provides an integrated signal from a much wider area; more ground

can be covered with a single biogeochemical sample than with other

grassroots exploration methods.

In June 2011 a total of 181 vegetation samples and 14 soil samples

were collected from 88 sites along 4 east-west transects located above the

deposit and continuing well into the unmineralized granitic country rock.

All samples were first completely dried, then digested in a modified Aqua

Regia solution, and then analysed by ICP-MS at Acme Analytical

Laboratories in Vancouver. The soils sieved to –80 mesh, and analysed by

a similar method.

The dominant sample media were Norway spruce, three types of

common fern, and Ah and B horizon podzols where available. Earlier work

suggests that Zr, as well as REEs, accumulate in higher concentrations in

ferns than other organic material.

The results of the analytical work from two particular fern species,

Dryopteris filix-mas and Athyrium filix-femina, clearly show a strong

signal to background ratio (in the case of ytterbium up to 20× higher) over

the deposit compared to the surrounding barren granitic country rock. The

findings from this study confirm the efficacy of ferns as a suitable

sampling tool for peralkaline nepheline syenite Rare Earth Element

exploration.

POSSIBLE OCCURRENCE OF THE SHURAM-WONOKA

NEGATIVE C-ISOTOPE EXCURSION IN THE CLOUDINA-

BEARING CORUMBÁ GROUP (EDIACARAN, BRAZIL)

Boggiani, P.C., Universidade de São Paulo, Instituto de Geociências,

Brasil, [email protected], Gaucher, C., Departamento de Geología,

Facultad de Ciencias, Montevideo, Uruguay, [email protected],

Sial, A.N., NEG-LABISE, Department of Geology, Federal

University of Pernambuco, Recife, PE, Brazil, [email protected]

The genesis of one the largest negative C-isotope excursion - the Ediacaran

Shuram-Wonoka – is still the subject of debate. It occurs just below of the

appearance skeletal fossils and it could be a primary marine signal or

diagenetic. At the base of the Tamengo Formation (Corumbá Group) there

are negative C-isotope values, and the correlation of this anomaly with the

Shuram-Wonoka excursion is the subject of this study. The Corumbá

Group crop out in the southern Paraguay Belt and as cratonic cover

comprising a typical Neoproterozoic succession characterized by

diamictite, thick banded iron formation, cap carbonate, stromatolitic

dolomite, phosphorite and black limestone with carbon isotope data

showing negative and positive excursions (δ

PDB

from – 3 to + 5 ‰)

related with the first occurrence of Cloudina and Corumbella (Tamengo

Formation). Five sections of Tamengo Formation were studied, the only

one showing the entire unit being the Laginha Quarry Section. There, a

negative C-isotope excursion occurs at the base, with a nadir value of – 3.6

‰ with subsequent values around – 1 ‰, by 20 m, with drastically shift to

+ 5 ‰, associated with the first Cloudina. A plateau around + 3 ‰

follows, which is a characteristical of the upper Tamengo Formation. In

the Laginha Quarry section, the negative excursion is recorded in a black

limestone overlying the carbonatic polymitic breccia, that mark the base of

the Tamengo Formation. This breccia is interpreted as result of an eustatic

sea-level fall followed by renewed transgression characterized by organic

limestones and rithmites (black shales alternating with black mudstone).

The negative excursion is probably related to the beginning of the

transgression and its aftermath maximum flooding is related to the highest

C-isotope value (+ 5 ‰). Despite the fact that geochemical proxies suggest

a primary isotopic signal, we cannot rule out completely a secondary

origin for the negative C-isotope excursion at the base of Tamengo

Formation, mainly because was not possibly to identify it in different

sections. Furthermore it is not so large (only – 3 ‰ and around – 1 ‰ over

20 m) as reported from Oman and the Death Valley (USA). This highlights

the need for continued research, may be in other sections showing the

same interval, since the Corumbá Group has been showed as an Ediacaran

unit of interest for the study of the Shuram Excursion which, if it is

primary, has a profound bearing on the cause of early animal evolution.

THE WOLLASTON SUPERGROUP IN MANITOBA: TECTONO-

STRATIGRAPHY AND URANIUM-RARE METAL MINERALI-

ZATION

Böhm, C.O., Kremer, P.D., Manitoba Geological Survey, Winnipeg,

MB R3G 3P2, christian.bohm@gov.mb.ca, and Rayner, N.,

Geological Survey of Canada, Ottawa, ON K1A 0E8

The Wollaston Supergroup, a Paleoproterozoic rift, passive margin and

foreland sequence that overlies and is infolded with Archean basement

rocks of the southeastern Hearne craton, extends over hundreds of

kilometers from northeastern Saskatchewan through northern Manitoba

into Nunavut. The Wollaston metasedimentary sequence consists of

psammitic, semi-pelitic, pelitic, and lesser amounts of calcsilicate and

marble, all of which are variably injected by leucogranite and were

strongly tectonized and metamorphosed to granulite grade during the

Trans-Hudsonian orogeny. Regionally, the Wollaston Supergroup rocks

are flanked by largely plutonic Archean basement rocks of the Hearne

craton. In northwestern Manitoba, exposures of the Wollaston Supergroup

appear to be most similar to the early foreland-basin sequence of the Daly

Lake Group in Saskatchewan.

U-Pb zircon results from seven Wollaston domain metasedimentary rocks

in northwest Manitoba, ranging from quartzite, to psammite to calc-silicate

paragneiss, record up to five geologically distinct detrital sources : 1) >2.5 Ga

(mostly ~2.58 and 2.70 Ga), representing detritus eroded from Archean

basement rocks of the Hearne craton; 2) rare ~2.4-2.2 Ga, thought to correspond

to cryptic cratonic fragments exotic to the Hearne craton; 3) minor 2.1 Ga,

interpreted to be derived from reworking of a locally underlying syn-rift

succession equivalent to the lowermost Wollaston Supergroup in

Saskatchewan; 4) ~2.0-1.90 Ga, interpreted as detritus shed from the advancing

volcanic terranes related to either the opening of the Manikewan ocean

(Southern Indian and Rottenstone domains) or a Rae-Hearne internal zone; and

5) variable ~1.86-1.85 Ga, inferred as injected melt, contemporaneous and

possibly related to the continental-arc Chipewyan (Wathaman) batholith, which

intrudes Wollaston Supergroup rocks.

Formation of the Wollaston Supergroup was influenced by the ~2.2

Ga global onset of oxygenation of atmosphere and oceans, which likely led

to intense erosion of the exposed Hearne craton, solution of uranium in

seawater and precipitation/accumulation in reducing siliciclastic and

calcareous sediments. Subsequent high-grade metamorphism led to partial

assimilation of the thick sedimentary sequence and in-situ generation of S-

type granitic melts, with late-stage enrichment of uranium, thorium and/or

rare metals in zones of pervasive metasomatism, alteration and fracture-

veining, particularly in the calcsilicate gneiss and marble horizons.

Consequently, this presents a different mineralization environment and

process compared to the main, unconformity-type uranium deposits in the

Athabasca Basin, to which Wollaston Supergroup rocks form part of its

basement.

RECORD OF EARLY METABOLISMS AND BIOLOGICAL

EVOLUTION IN ARCHEAN STROMATOLITES

Bosak, T., Petroff, A.P. and Rothman, D.H., Massachusetts Institute

of Technology, Cambridge, MA 02139, USA, [email protected]

Stromatolites, laminated and lithified sedimentary structures, record

microbial interactions with the flowing water and carbonate sediments

throughout recorded Earth history and have the potential to illuminate long

term trends in biological and environmental evolution. In particular, the

stromatolite record older than ~2.5 billion years may contain morpho-

logical evidence of the earliest microbial interactions with sediments, early

photosynthetic communities, and early oxygenic photosynthesis.

Because fabrics of many Archean stromatolites are obscured by

extensive diagenesis, interpretations of Archean stromatolites require

quantitative models that consider realistic morphogenetic processes and

are able to explain stromatolite scales, macroscopic organization and

macroscopic shapes. On the other hand, the reconstruction of microbial

metabolisms from Archean stromatolite textures requires a better

understanding of fabrics and the preservation potential of anoxygenic

microbial communities under chemical conditions relevant for the Archean

carbonate depositing environments. Conical, pinnacled and tufted

structures are thought to offer some of the most unambiguous evidence for

biological processes in the Archean stromatolite record. A recent model

attributes the shape of conical stromatolites to the precipitation of minerals

under a diffusive boundary, rather than the presence of light-seeking

microbes. However, the stabilization of the conical shape may require

strong and currently poorly understood biological mechanisms and

warrants further experimental work. Light-driven processes may have

directly influenced the organization of fields of some mm- and cm-scale

stromatolites, whereas dm- and larger scale columns may arise from scale-

dependent interactions between microbial stabilization of sediments, flow

and scour. Small conical stromatolites as old as 2.9 billion years may also

preserve evidence of photosynthetic communities growing around gas

bubbles, suggesting that oxygenic phototrophs contributed to stromatolite

growth much before the rise of atmospheric oxygen. Because the

stromatolite-building potential of anoxygenic photosynthetic communities

under conditions relevant for the Archean is poorly constrained, we

established anaerobic enrichment cultures of photosynthetic organisms in

the presence of low sulfate. Our preliminary results show that these

conditions can support the growth of robust anoxygenic photosynthetic

mats that are able to withstand similar shear and scour as some modern

cyanobacterial mats and form tufted, draped and filmy structures. These

systems can be used to investigate the morphogenesis of Archean

stromatolites that currently lack clear modern analogs.

THREE DIMENSIONAL GEOLOGICAL MODELS AS TOOLS TO

BETTER UNDERSTAND ORE-SYSTEM PROCESSES RESPON-

SIBLE FOR SOME OF SASKATCHEWAN’S MINERAL

RESOURCES

Bosman, S.A.

, [email protected], Card, C.D.

, Gouthas, G.

Zmetana, D.

, Yang, C.

, Music, T.

, Berenyi, J.

and Morelli, R.

Saskatchewan Geological Survey, Saskatchewan Ministry of Energy

and Resources, 200-2101 Scarth St., Regina, SK S4P 2H9;

Geological Survey of South Australia, Minerals and Energy and

Resources Division, Manufacturing, Innovation, Trade, Resources

and Energy, 4

Floor, 101 Grenfell Street Adelaide, South Australia

5001, Australia

Over the past several years the Saskatchewan Geological Survey has

developed internal expertise in 3D modelling, with the greatest advances

occurring during 2010 and 2011. Part of this expertise was gained through

collaboration with, and personnel exchanges between, the Geological

Survey of South Australia, which was already advanced in the usage of 3D

modelling as a geoscience tool.

Using Paradigm’s™ GOCAD® software, four 3D models have been

produced including: the uranium-rich Athabasca Basin of northern

Saskatchewan; potash-rich southern Saskatchewan; the coal deposits in the

Pasquia Hills area of eastern Saskatchewan; and the sub-Phanerozoic base

metals district west of the Flin Flon camp. Of these, the Athabasca Basin

model is the most advanced and includes a number of integrated data types

including lithostratigraphic, Quaternary, geophysical, geochemical,

structural and mineralogical. Initial work involved modelling of the

geological framework, including the Athabasca Group stratigraphy, the

unconformity with underlying basement rocks and various structural

features. Subsequently, regional outcrop and downhole geochemical, and

clay mineralogy information were added.

The ultimate goal of importing the relevant information into the

model is to facilitate our understanding of ore-systems, the underlying

theme in all the models, within the Athabasca Basin. Current research

indicates that the Athabasca Group/basement unconformity, structural

corridors and fluids from both the Athabasca Group and its basement, all

play key roles in forming unconformity-related uranium deposits. Using

3D software, we can begin to identify locations at which these important

ingredients are spatially coincident, and analyze whether or not they might

have been interacting at the time of mineralization. Moreover, prospective

regions distal to known uranium occurrences could be identified, thus

generating new exploration potential. Additional information such as

geochemistry and the location of alteration systems, commonly determined

by clay mineralogy, can be added which may help further refine these

areas of potential. Statistical analysis of geochemical data can be

performed quickly and allows the user to generate subsets of anomalous

geochemical data. These data can be compared spatially against, for

example, the lithostratigraphy or structural features to identify background

signatures and potential controls for regions with anomalous

characteristics. The purpose of each Saskatchewan 3D model is to advance

our geological knowledge in areas of interest to the mineral exploration

industry, with the ultimate goal of helping to simplify resource potential

evaluation.

MULTI-SENSOR CORE LOGGING IN THE MATAGAMI VMS

DISTRICT, ABITIBI GREENSTONE BELT, QUEBEC: CONTEXT

AND METHODOLOGY

Bourke, A., Ross, P-S. and Fresia, B., Institut national de la

recherche scientifique, centre Eau Terre Environnement, 490 rue de

la Couronne, Québec, QC G1K 9A9

Measurements of physical, geochemical, and mineralogical properties on

exploration drill cores can be used for various applications in geosciences,

namely in 3D geological modeling, to improve geophysical models, to

characterize hydrothermal alteration, for mineral resource calculations, or

chemo-stratigraphy. Traditionally, these measurements were taken one at a

time, often using destructive methods. Consequently, few base metal

mining camps across Canada have access to extensive public databases of

physical properties, and high-resolution geochemical or mineralogical

measurements are generally not available.

The mobile laboratory for the physical, mineralogical, and chemical

characterization of rocks at INRS makes it possible to measure on drill

cores, almost simultaneously and in a non-destructive manner, density

based on gamma-ray attenuation, magnetic susceptibility, up to 25

chemical elements by energy-dispersive XRF, as well as infrared/visible

light spectrometry for alteration minerals. All the measurements can be

done at a spatial resolution down to few centimeters, if needed. The multi-

sensor core logger also acquires a continuous image of the drill core,

making it possible to compare measurements with the visual appearance of

the rock in order to better understand variations in the different parameters,

and to build a complete digital archive of the drill hole. The results are

submitted to a quality control and corrected, when possible, to more

realistic values, based on measurements with conventional methods. Each

parameter is valuable on its own, but the entire database can also be used

in multivariate statistical analysis.

Initial logging was performed in 2010-2011 in the Matagami mining

camp, Abitibi Greenstone Belt, Quebec. This district hosts numerous

Archean zinc-rich volcanogenic massive sulphide deposits and shows good

potential for new discoveries. Ore deposits are clustered in three areas: the

North Flank, the South Flank, and the West Camp. Drill holes

characterized by the mobile laboratory are located in the three areas. The

project was subsidized by Ministère des Ressources naturelles et de la

Faune du Québec (MRNF) and logistical support was offered by Xstrata

Zinc Canada. We also acknowledge the collaboration of Breakwater

Resources, Donner Metals, and SOQUEM. These measurements will be

useful for university research projects currently underway in the Matagami

area (volcanology, geochemistry, metallogeny, geophysics), for 2D and 3D

geological mapping, and for mineral exploration. Detailed scientific

reports and a database are available for downloading (sigeom.mrnf.

gouv.qc.ca).

LOW-MAGNETIC PRIMORDIAL CRUST OF MARS

Boutin, D., Mcgill University, 3450 University Street, Montreal, QC

H3A 2A7, dboutin003@sympatico.ca, and Arkani-Hamed, J.,

University of Toronto, Toronto, ON M5S 1A7

The absence of a global core field at present indicates that the magnetic

anomalies of Mars detected by Mars Global Survey over the heavily

cratered southern hemisphere arise from remanant magnetization. There

are some vast areas on Mars devoid of appreciable magnetic anomalies:

the northern lowland and the Tharsis bulge. The lowland formation process

has likely demagnetized the crust, and the Tharsis bulge has mainly

formed in the absence of a strong core dynamo in the late Noachian. The

heavily cratered primordial crust in the southern hemisphere has likely

been created during the differentiation of the magma ocean in the later

stages of the planet’s accretion. It is expected that the crust has been

strongly magnetized in case there was a strong core dynamo. However,

Arkani-Hamed and Boutin[1] showed that a large area of the southern

hemisphere, south of 30S and extending from west of Hellas basin to east

of Argyre basin, is also very low-magnetic, which led the authors to

propose that there was no strong core field during the first ~120 Myr of the

planet’s history, when the newly formed crust was cooling below its

magnetic blocking temperatures. Here we re-examine the proposal in

detail, by studying the magnetic field detected by MGS over impact-

related Quasi-Circular Depressions (QCD), 239 in total, and impact crater,

28 in total, on the entire surface of Mars with diameters greater than 250

km. The impacts that have produced these features are capable of

demagnetizing the entire crust and creating a distinct magnetic edge effect

at the satellite altitudes in case the surrounding crust is magnetized. Two

other areas of the primordial crust is now found nonmagnetic, which

supports the proposal. We also examined the magnetic signature of 16

giant basins on Mars and concluded that the core dynamo likely ceased

within about 200 Myr at ~4Ga, as previously suggested by Lillis et al.[2].

Accordingly, the observed strong magnetic anomalies are likely due to

magnetic source bodies in the crust which are formed and have been

magnetized within the first ~400 Myr of the planet’s history, but ~120 Myr

after the accretion.

References:

[1]Arkani-Hamed, J. and Boutin, D. (2012) Icarus, 217, 209–230.

[2]Lillis et al., Geophysical Research Letters, 35, L14203, doi:10.1029/

2008GL034338, 2008

MINOR AND TRACE ELEMENT COMPOSITION OF

MAGNETITE FROM Ni-Cu DEPOSITS WORLDWIDE AND ITS

APPLICATION TO MINERAL EXPLORATION

Boutroy, E.

, emilie.boutroy.[email protected], Dare, S.

, sasdare@

hotmail.com, Beaudoin, G.

, Georges.Beaudoin@ggl. ulaval.ca, and

Barnes, S.J.

, [email protected],

Université Laval,

Québec, QC G1V 0A6;

Université du Québec à Chicoutimi

(UQAC), Chicoutimi, QC G7H 2B1

Iron oxides are common minerals in different types of ore deposits and

geologic environments. There are significant variations in the

concentration of trace elements in magnetite and hematite depending on

the metallogenic environment at the time of formation of the deposit. This

makes iron oxides useful as indicator minerals for mineral exploration.

Magnetite is a common accessory mineral in Ni-Cu-PGE deposits and it

can be either primary, formed by direct crystallization from the sulfide

liquid at ~ 1000ºC, or secondary, e.g., replacement of the sulfides during

alteration or metamorphism.

Magnetite in sulfide samples (n = 120), representative of 15

worldwide, major Ni-Cu-PGE deposits with a range of geological

environments and ages, were analyzed by electron microprobe analysis

(EMPA) and a subset (n = 20) by laser ablation-ICP-MS (LA-ICP-MS).

The samples are divided into 6 different types according to the

composition of the parental host magma: (1) Komatiite (n = 38), (2) Flood

basalt (n = 18), (3) Ferropicrite (n =16), (4) Anorthosite (n = 18), (5)

Picrite-Tholeiite (n = 36) and (6) Impact melt (n = 23).

Most of primary magnetite (95%) has high Ni+Cr and plot in the Ni-

Cu sulfide deposit field on the Ni+Cr vs. Si+Mg diagram. When classified

by magma type, the compositions of all the primary magnetite plot on the

same trend which indicates that variation in magma composition between

mafic and ultramafic does not exert important control on magnetite

composition except for Ga and Ge. Instead, magnetite trace element

composition is mainly controlled by sulfide liquid differentiation. The

composition of primary magnetite records the evolution of the sulfide

liquid from early-forming Fe-rich monosulfide solid solution (MSS) and

later-forming magnetite hosted in the Cu-rich intermediate solid solution

(ISS).

A petrographic study on sulfide samples from the komatiite-hosted

Thompson Ni-deposit (Manitoba, Canada) distinguished two types of

secondary magnetites in addition to rare primary magnetite: (1) secondary

magnetite formed by replacement of pyrrhotite and (2) secondary

magnetite formed during the serpentinization of ultramafic rocks or

alteration of chromite. In contrast to primary magnetite, both types of

secondary magnetite have low Ni+Cr and plot outside of the Ni-Cu sulfide

deposit field. There is a clear compositional difference between primary

magnetite formed during sulfide mineralization and later secondary

magnetites which are depleted in most trace elements (Ni, Mn, V, Ti, V,

Al, Cr), with the exception of Si and Mg which are sometimes enriched.

QUESTING THE EVIDENCE FROM EARTH’S OLDEST

‘ANIMALS’

Brasier, M.D.

1,2

, [email protected], Antcliffe, J.B.

and Liu,

A.G.

Department of Earth Sciences, Oxford University, South

Parks Road, Oxford, OX1 3AN, UK;

Department of Earth Sciences,

Memorial University of Newfoundland, St John’s, NL A1B 3X5;

Department of Earth Sciences, University of Bristol, Wills

Memorial Building, Queen’s Road, Bristol, BS8 1RJ, UK;

Department of Earth Sciences, University of Cambridge, Downing

Street, Cambridge, CB2 3EQ, UK

Rangeomorph fossils are among the most abundant and arguably

successful groups of Ediacaran soft-bodied organisms. They thrived in

deep to shallow water settings for ~40 million years. Over the last decade,

our group has been undertaking comparative analyses of bedding planes

from SE Newfoundland and England (~585Ma – 555Ma) germane to the

decoding of rangeomorph architecture, ecology and evolution. This has

revealed new and remarkably well-preserved bedding planes with

specimens of frondose fossils allied to Charnia, including very large

Bradgatia preserved down to submillimetric level, and impressive

populations of the iconic Newfoundland fossil Beothukis, named in

respectful memory of that extinct aboriginal peoples called the Beothuk.

We will here present a coherent and comprehensive scheme for the

analysis of rangeomorph morphology, in which Beothukis is central. This

scheme provides a robust framework for comparative studies of

rangeomorph ontogeny and evolution during this critical time in Earth

history.

SULFIDE-SILICATE PARTITIONING OF PGEs (AND Au):

IMPLICATIONS FOR NOBLE METAL BEHAVIOUR IN

MAGMATIC SYSTEMS

Brenan, J.M., University of Toronto, br[email protected]

There is considerable variation in sulfide-silicate melt partition coefficients

for the noble metals (PGEs and Au), with most direct measurements

(analysed by bulk methods) yielding values of 10

or less. More recent

estimates, which combine separate metal solubility measurements in

sulfide and silicate, have suggested partition coefficients exceeding 10

Resolving this discrepancy is essential for developing accurate models of

noble metal behaviour during melting, and validating metal concentration

mechanisms in magmatic systems. In this study, sulfide and silicate were

equilibrated at known ƒ

-ƒ

conditions, with run-products analysed by

LA-ICPMS to ensure exclusion of sulfide contamination from the silicate

melt analysis. Experiments were done at 1200°C and 1 atm with ƒ

controlled using the Pt-PtS buffer and ƒ

estimated to be FMQ-1 using the

Cr content of run-product silicate melts. Three different synthetic basalts

were employed, differing in their FeO content (5-15 wt%), with initial

sulfide melt composition having FeS stoichiometry + 1 wt% each of Cu

and Ni. Two separate sulfide melt compositions were synthesized, with

different suites of metals doped at the 1 wt% level for each. Mixtures of

powdered sulfide and silicate glass were contained in crucibles made from

natural chromite, then loaded, along with the sulfide buffer, in silica

ampoules, which were evacuated, then sealed. Samples were held for 1 to

4 days at temperature, then quenched in cold water. Run-product glasses

were free of obvious sulfide contamination, as evidenced by uniform, and

low time-resolved signals for the PGE and Au. Concentrations of Ru and

Os in run-product glasses were always below detection (approx 20 and 5

ppb, respectively), yielding minimum sulfide/silicate partition coefficients

of >10

(Ru) and >10

(Os). Measurable, but low, abundances for other

PGE and Au were determined, with calculated sulfide/silicate partition

coefficients of >10

(Pd, Rh, Ir, Pt) and 4000-11000 (Au). Partition

coefficients for Pd, Rh, Ir and Pt were found to increase with increasing

concentrations of these elements in the sulfide melt, with little or no

change in the silicate melt concentration. This is interpreted to reflect a

low level of sulfide contamination in the silicate melt, and argues for even

higher partition coefficients for these elements. Thus, results are more in

line with the large partition coefficients estimated from combined sulfide

and silicate PGE solubility data. This indicates that the concentration of

PGEs into magmatic sulfide is likely to depend only on the sulfide to

silicate mass ratio.

THE STRUCTURE AND KINEMATICS OF THE CENTRAL

TAIWAN MOUNTAIN BELT DERIVED FROM GEOLOGICAL,

GPS, AND SEISMICITY DATA

Brown, D., Alvarez-Marron, J., Schimmel, M., Camanni, G.,

Instituto de Ciencias de la Tierra “Jaume Almera”, CSIC, Barcelona,

Spain, [email protected], Wu, Y-M., Department of Geosciences,

National Taiwan University, Taipei, 106, Taiwan, and Yu, S-B.,

Institute of Earth Sciences, Academica Sinica, Nankang, Taipei,

Taiwan

The structure of the Taiwan mountain belt is thought to be that of an

imbricate thrust and fold belt developed above a shallowly dipping basal

detachment. In recent years, however, a growing amount of seismicity data

from the internal part of the mountain belt indicates the existence of

widespread fault activity in the middle and lower crust, suggesting that

deeper levels of the crust must be involved in the deformation than is

predicted by the imbricate thrust belt model. To address this issue, we

present new geological mapping, long-term GPS, earthquake focal

mechanism, and seismic energy release data from the central part of

Taiwan. We suggest that the foreland basin part of the Western Foothills

comprises an imbricate thrust system that is structurally and kinematically

linked to a basal detachment at between 7 and 10 km depth. To the east of

the foreland basin, in the Hsuehshan Range, our data show the presence of

major faults that are steeply dipping and which penetrate 25 to 30 km

depth, or more. This indicates that much deeper levels of the crust are

involved in the deformation, and that a structural and kinematic model in

which this part of the mountain belt forms a zone of transpression with a

structural architecture similar to that of a crustal-scale positive flower

structure better fits the available data. Eastward, in the Central Range,

deep water sediments appear to form an allochthon that is being overthrust

by Mesozoic basement rocks. The involvement of such deep crustal levels

and Mesozoic basement in the deformation if suggestive of the reactivation

of pre-existing basin-bounding faults that where located on the Eurasian

continental margin.

TECTONIC PROCESSES DURING THE BUILDING OF THE

URALIDES

Brown, D., Instituto de Ciencias de la Tierra "Jaume Almera", CSIC,

Barcelona, Spain, [email protected]

The Uralides, together with the Appalachian-Caledonide-Variscan

orogenic system, was one of the main orogens that developed during the

building of Pangea. The large scale tectonic processes that formed the

Uralides include an arc-continent collision that began in the Middle

Devonian and ended in the Early Carboniferous, followed by continent-

continent collision that began in the Late Carboniferous and lasted until the

Early Triassic. In the Southern Urals of Russia, the Laurussia margin

involved in the arc-continent collision consisted of a basement that was

composed predominantly of rocks of Archean and Proterozoic age that, by

the time of arc-continent collision, was overlain by Cambrian, Ordovician,

Silurian, and Devonian sediments interpreted to have been deposited in

rift-related grabens on the continental slope and rise, and on the shallow

marine platform. The Magnitogorsk Arc consists of Early to Late

Devonian island arc volcanic rocks and overlying volcaniclastic sediments.

Arc-continent collision led to the development of an accretionary complex

that includes shallowly and deeply subducted continental margin rocks,

ophiolite fragments, and sediments that were deposited in a foreland-basin

setting.

The Late Paleozoic continent-continent collision that took place

between Laurussia and Kazakhstania reveal a number of tectothermal

processes. Reflection and wide-angle seismic profiles demonstrate that the

Uralides has an overall bivergent structural architecture, but with

significantly different characteristics from one tectonic zone to another.

The integration of other types of data sets with the seismic data allows us

to interpret that the changes in the crustal-scale structural architecture

indicate that there was significant partitioning of tectonothermal conditions

and deformation from zone to zone across major fault systems, and

between the lower and upper crust. Also, a number of the structural

features revealed in the bivergent architecture of the orogen formed either

in the Neoproterozoic or in the Paleozoic, prior to continent-continent

collision. From the end of continent-continent collision to the present, low

temperature thermochronology suggests that the evolution of the Uralides

has been dominated by erosion and slow exhumation. Despite some

evidence for more recent topographic uplift, it has so far proven difficult to

quantify it.

Keynote COLLISION TECTONICS ACROSS THE PROTEROZOIC

–PALEOZOIC TRANSITION: SECULAR CHANGE IN UPPER

MANTLE TEMPERATURE AND HOT VS COLD OROGENESIS

Brown, M., Laboratory for Crustal Petrology, Department of

Geology, University of Maryland, College Park, MD 20742-4211,

USA, [email protected]

Convergent plate boundaries characterized by one-sided subduction create

asymmetry in the thermal structure with lower dT/dP in the subduction

zone and by higher dT/dP in the backarc/orogenic hinterland. During

orogenesis these thermal environments are imprinted in the rock record as

contrasting types of metamorphism with different apparent thermal

gradients: blueschists–low-T eclogites record oceanic subduction;

ultrahigh-pressure metamorphism (UHPM) records continental subduction;

medium-T eclogite–high-pressure granulite metamorphism (E-HPGM)

records terminal collision; and, granulite–ultrahigh temperature

metamorphism (G-UHTM) is generated in backarcs/orogenic hinterlands.

On a plot of apparent thermal gradient vs age there is a dramatic change in

the late Neoproterozoic. During the Proterozoic, the geological record

preserves two contrasting types of metamorphism: E-HPGM, with

gradients of 350–750°C/GPa, and G-UHTM, with gradients of 750–

1500°C/GPa. Blueschists and UHPM, with gradients of 150–350°C/GPa,

first appear in the Cryogenian–Ediacaran, whereas G-UHTM virtually

disappears from the rock record during the Cambrian. The decrease in

upper mantle temperature during the Mesoarchean–Neoarchean allowed

one-sided subduction to become established globally by the Proterozoic.

The appearance of blueschists and UHPM in the rock record could have

been due to continued decrease in upper mantle temperature, which was

~100°C warmer than at present in the Neoproterozoic. This postulate may

be tested using a 2-D petrological–thermomechanical numerical model of

collision. For present conditions, strong lower crust results in coupled

collision forming narrow orogenic belts with UHPM rocks, whereas weak

lower crust results in decoupled collision with wide orogenic belts and

low-to-medium grade metamorphism. Increasing the upper mantle

temperature to >100°C above the present value promotes development of

hot and narrow convergence zones bounded by regions of lithospheric

extension and decompression melting. Strong lower crust results in

formation of magmatic belts above hot continental subduction zones,

whereas weak lower crust results in narrow two-sided orogens with a deep

hot crustal roots. A comparison between geological observations and

model results suggests the transition from a hot to cold collision regime

occurred during the Neoproterozoic. Furthermore, at the dawn of the

Phanerozoic there was a change in the mechanism of breakup and

formation of supercontinents from fragmentation, dispersal and reassembly

by elimination of the complementary superocean, with suture zones

characterized by E-HPGM and backarcs/orogenic hinterlands by G-

UHTM, to one in which internally-generated ocean basins opened and

closed by terrane transfer, with suture zones characterized by early

blueschists and UHPM followed by E-HPGM during terminal collision,

but G-UHTM is rare.

SYNGENETIC PRECIOUS METAL ENRICHMENT IN A DE-

FORMED VOLCANOGENIC MASSIVE SULFIDE (VMS)

SYSTEM: THE MING MINE, BAIE VERTE PENINSULA,

NEWFOUNDLAND APPALACHIANS, CANADA

Brueckner, S.M., Piercey, S.J., Sylvester, P.J., Memorial University,

300 Prince Philip Dr., St. John's, NL A1B 3X5, s.brueckner@

mun.ca, Maloney, S. and Pilgrim, L., Rambler Metals & Mining

Canada Ltd., PO Box 610, Baie Verte, NL A0K 1B0

The early Ordovician Ming Mine (487 Ma; total resource 12.5 Mt ore @

1.52 wt% Cu, 1.69 ppm Au, 8.11 ppm Ag, and 0.45 wt% Zn), Baie Verte

Peninsula, Newfoundland, represents a type example of a precious metal-

enriched VMS deposit within the Appalachian Orogen. Despite past

production, and a history of research, the origin of precious metal

enrichment remains uncertain. New, high-grade Cu-Au±Ag zones were

discovered at the moderately metamorphosed and deformed Ming Mine in

the early 2000s and have provided considerable new insight into the cause

of precious metal enrichment in the deposit, particularly information from

the 1806 and 1807 zones, Ming S up and down plunge, Ming N and an

upper and lower footwall zone. Rhyolitic tuffs, flows and breccias host

massive to stringer mineralization and are altered to quartz–sericite ± green

mica ± chlorite ± biotite. Alteration in the rhyolites changes to a more

quartz–chlorite–biotite–magnetite assemblage in the lower footwall zone.

The hanging wall consists of mixed mafic-felsic volcaniclastic turbidites.

The sulfide mineral assemblage varies in the deposit. The lower footwall

zone is dominated by a uniform chalcopyrite–pyrrhotite assemblage. In

contrast, metal zoning occurs in the stringer to massive sulfide

mineralization and is especially well documented from the 1806 zone. The

down plunge of this zone is dominated by a pyrite–chalcopyrite

assemblage, whereas the up plunge shows a gradual change from a pyrite–

chalcopyrite–sphalerite–metamorphic pyrrhotite assemblage to a pyrite–

sphalerite–chalcopyrite–galena assemblage vertically upwards. In addition,

various sulfosalts rich in magmatic suite elements (e.g., arsenopyrite,

tetrahedrite-tennantite, stannite, boulangerite, loellingite), Te-bearing

phases (e.g., BiTe, coloradoite), Ag-phases (e.g., miargyrite, unnamed

AgCuFeS phase, argentotetrahedrite, AgHg alloy), and electrum occur

throughout the 1806 zone. The abundance of these sulfosalts and precious

metal-rich minerals increases slightly from down to up plunge in the 1806

zone. Furthermore, microprobe analysis reveal (1) no invisble gold in

recrystallized pyrite, arsenopyrite or any other sulfide phase; (2) high Hg-

contents in electrum (12 – 17 wt%); and (3) a varying Fe-content in

sphalerite (2 – 9 wt%). The abundance of magmatic suite sulfosalts, Hg-

rich electrum, and absence of orogenic-gold deposit features (e.g., quartz-

carbonate alteration, simple sulfide mineralogy), are consistent with a

syngenetic origin for Au-Ag-(Sb-As-Bi-Sn-Te-Hg)-enrichment via

magmatic fluids. Internal remobilization due to later deformation and

metamorphism was also important in remobilizing Au–Ag, as evidenced

by Au-Ag phases along recrystallized pyrite and arsenopyrite grain

boundaries and along cracks in these phases.

RELICT ECOSYSTEMS, MATGROUND RESTRICTION AND

THE CHANGING FACE OF THE DEEP

Buatois, L.A. and Mángano, M.G., Department of Geological

Sciences, University of Saskatchewan, 114 Science Place, Saskatoon,

SK S7N 5E2

Trace- and body-fossil evidence indicates that the colonization of the deep

sea started in Ediacaran times. In fact, the oldest trace fossils are known

from deep-marine deposits rather than shallow-water deposits. Ediacaran

deep-marine ichnofaunas are poorly diverse, and consists of very simple

trails and burrows, essentially representing two main architectural designs

(simple horizontal trails and passively filled horizontal burrows). Both

ichnodiversity (global and alpha) and ichnodisparity were extremely low.

In particular, nonspecialized grazing trails (e.g. Helminthopsis,

Helminthoidichnites) are associated with the exploitation of microbial

mats, a strategy that was also dominant in Ediacaran shallow-marine

environments. However, while matgrounds underwent environmental

restriction in shallow, fully marine settings after the agronomic revolution,

exploitation of microbial mats persisted during most if not all the

Cambrian in the deep sea. Cambrian deep-marine ichnofaunas are of

“Ediacaran aspect” and the deep sea can be regarded as a relict ecosystem.

However, the Cambrian radiation is expressed in the deep sea by the

addition of a number of architectural designs, such as surface-coverage

branching burrows (e.g. Oldhamia), horizontal to oblique branching

burrows (e.g. Saerichnites), trackways and scratch marks (e.g.

Diplichnites), plug-shaped burrows (e.g. Bergaueria) and smooth bilobate

trails and burrows (e.g. Didymaulichnus). As a result, Cambrian deep-

marine ichnofaunas display a remarkable increase in ichnodisparity, as

well as in global and alpha ichnodiversity. Deep-marine ecosystems

undertook significant changes by the end of the Cambrian, reflecting the

seaward expansion of the agronomic revolution and the demise of

matground-dominated ecosystems. The main architectural designs of deep-

marine trace fossils were established in deep-sea environments by the

Early Ordovician, recording the first appearance of the Nereites

Ichnofacies. Lower to Middle Ordovician deep-marine ichnofaunas seem

to be moderately diverse, and fodinichnia commonly dominates rather than

graphoglyptids. A significant ichnodiversity and ichnodisparity increase

occurred in the Late Ordovician-Early Silurian, with ichnofaunas recording

higher proportions of graphoglyptids. In the common absence of body

fossils, trace fossils represent an important source of information to

address the early evolution of deep-sea ecosystems.

LOCATING MANTLE PLUME CENTRES FOR MAFIC DYKE

SWARMS OF LARGE IGNEOUS PROVINCES (LIPs) IN

NORTHERN CANADA BASED ON NEW MAPPING

Buchan, K.L., Geological Survey of Canada, 601 Booth Street,

Ottawa, ON K1A 0E8, [email protected], and Ernst, R.E.,

Department of Earth Sciences, Carleton University, and Ernst

Geosciences, 43 Margrave Avenue, Ottawa, ON K1T 3Y2

Based largely on a digital map of the mafic dyke swarms of northern

Canada, recently completed as a component of the GEM (Geo-mapping for

Energy and Minerals) Tri-Territorial Bedrock Compilation Synthesis, we

identify or refine the location of mantle plume centres for a number of

swarms thought to belong to Large Igneous Provinces (LIPs). Of particular

interest are swarms whose radiating geometry or other characteristics, such

as dyke density and geographic relationship to cratonic margins, can be

used to locate plume centres. On the Queen Elizabeth Islands, five

Phanerozoic dyke swarms are now recognized. Two of these, the well

known Cretaceous (0.13-0.08 Ga) Queen Elizabeth Islands swarm (a

component of the High Arctic LIP) and a smaller newly identified

Paleozoic Henson Bay swarm, radiate from foci close to the northwest

coast of Ellesmere Island. Dykes associated with the widespread

Neoproterozoic (0.72 Ga) Franklin LIP event are mapped in greater detail

then previously, especially on Victoria Island and the adjacent mainland.

New mapping provides a more accurate location for the swarm’s focus

near Banks Island on Laurentia’s northern margin. The Neoproterozoic

(0.78 Ga) Hottah swarm of the Gunbarrel LIP, previously mapped in the

Wopmay Orogen and Mackenzie Mountains, is interpreted to extend in a

broad fanning pattern beneath Paleozoic cover rocks west of the Canadian

Shield, with a focus off Laurentia’s western margin. New mapping of the

Paleoproterozoic (ca. 2.11 Ga) Indin swarm of the southwestern Slave

craton confirms and augments earlier interpretations of a radiating pattern

with a focus off the western margin of the craton, and shows an increase in

dyke density towards the focus. The Paleoproterozoic (2.23 Ga) Malley

swarm of the southeastern Slave craton has recently been interpreted to

extend to northeastern as the poorly dated Britchta swarm, having been

offset along the prominent Bathurst fault. The reconstructed and remapped

swarm appears to show a slight radiating pattern with the dykes dying out

to the southwest in the cratonic interior, suggesting a focus off the eastern

margin of the craton. Finally, the unusual high density of dykes in a

number of swarms, such as the Mesoproterozoic (1.74 Ga) Cleaver swarm

of the Wopmay Orogen, Paleoproterozoic (ca 2.19 Ga) MacQuoid swarm

of the Western Churchill Province and Paleoproterozoic (1.88 Ga) Ghost

swarm of the Slave craton, likely indicates relatively close proximity to

their source region (e.g. mantle plume), although the direction to the

source is often unclear.

TRACKING HYDROTHERMAL ALTERATION AND MINERAL-

IZATION IN ROCK-FORMING AND ACCESSORY MINERALS

FROM THE LYON MOUNTAIN GRANITE AND RELATED IRON

OXIDE APATITE (IOA) ORES FROM THE ADIRONDACK

MOUNTAINS, NEW YORK STATE

Buchanan, A.

, Hanchar, J.M.

, Steele-MacInnis, M.

, Crowley, J.

Valley, P.M.

, Fisher, C.M.

, Piccoli, P.M.

and Fournelle, J.

Department of Earth Sciences, Memorial University of

Newfoundland, St. John’s, NL;

Department of Geosciences,

Virginia Tech, Blacksburg VA 24061 USA;

Department of

Geosciences, Boise State University, Boise, ID 83725 USA;

United

States Geological Survey, 87 State Street, Montpelier VT 05602

USA;

Department of Geology, University of Maryland, College

Park, MD 20742 USA;

Department of Geoscience, University of

Wisconsin-Madison, Madison, WI 53706 USA

The Lyon Mountain granite (LMG) is located in the northeastern

Adirondack Mountains in New York State and hosts several economic-

grade low-titanium iron oxide apatite (IOA) ore deposits. The ores are

hosted by perthite granite which has been extensively altered to albite and

microcline granite by Na and K metasomatism. Previously dated host

rocks of the magnetite-apatite ores from the Adirondacks have zircon core

ages ~1150 Ma and rims of zircon crystals and single age zircon from

these same rocks have been dated between 1060-1050 Ma.

This study aims to determine the relative timing of LMG

emplacement and subsequent hydrothermal alteration and Fe mineral-

ization. For example, the host rocks yield zircon ages of ~1150 Ma and

~1050 Ma yet it is not clear whether these ages represent hydrothermal

alteration or pluton emplacement.

Zircon crystals separated from several of these magnetite-apatite ores

reveal at least two periods of mineralization; one event at ~1039 Ma and

another between ~1015-1000 Ma documenting protracted events that post-

date the 1060-1050 Ma LMG magmatism. To better understand the timing

of these post ~1050 Ma events U-Pb isotope dilution thermal ionization

mass spectrometry (ID-TIMS) of apatite was done on the ore and host rock

samples, yielding ages ranging from 1050 to 850 Ma, with large variations

within samples and within grains. Two of the ore-apatite samples have

homogenous Sm/Nd and elemental ratios, precluding calculation of Sm-Nd

ages. However a third ore sample shows a large spread in Sm/Nd and

yields a Sm-Nd isochron age of ~850 Ma, in close agreement of U-Pb ages

by ID-TIMS of this ore apatite. Initial Nd isotopic composition of both ore

and host rocks are identical and consistent with published Adirondack

whole rock data, suggesting a local source for rare earth elements (REE) in

these ores.

These younger isochron and ID-TIMS ages may reflect cooling

recorded in those minerals, or a younger hydrothermal event. Apatite from

the LMG also shows varying degrees of oxidation (recorded in Fe and As),

which may indicate pulses of hydrothermal fluids over time. The apatites

have unusually high REE and Y concentrations (some total REEs > 20wt.

% and up to 8 wt. % Y

). In contrast, the minor and trace element

compositions of the major rock-forming minerals (e.g., plagioclase and

microcline feldspar, clinopyroxene, fayalite) and the zircon and fluorite in

the LMG have generally average igneous granitic trace and minor element

compositions.

USING OLIVINE TRACE ELEMENT DATA TO UNRAVEL THE

CONUNDRUMS OF THE VOISEY’S BAY INTRUSION AND

RELATED Ni-Cu MINERALIZATION, LABRADOR

Bulle, F., [email protected], and Layne, G.D., Department of Earth

Sciences, Memorial University, St. John’s, NL A1B 3X5

The mafic Voisey’s Bay (VB) intrusion transgresses the 1.85 Ga

collisional contact between the Archean Nain Province and the

Paleoproterozoic Churchill Province in Eastern Labrador. It is part of the

Mesoproterozoic Nain Plutonic Suite, an anorogenic igneous suite largely

dominated by granitic and anorthositic plutons. The VB intrusion

comprises a group of troctolitic to olivine gabbroic bodies (Reid Brook and

Eastern Deeps) linked by olivine gabbro dikes, and is associated with a

world-class Ni-Cu-Co sulfide deposit. Massive and disseminated zones of

mineralization are spatially and genetically related to a breccia sequence

(BBS) at the base of the dike and at the entry line of this dike into the

larger Eastern Deeps intrusion [1]. Upward from this sulfide-laden,

brecciated and country rock-contaminated sequence, the troctolitic rocks

progressively decrease in sulfide content, contain fewer gneissic fragments

and grade into an effectively barren, homogeneous plagioclase and olivine

cumulate, collectively termed normal troctolite (NT) [1]. In an attempt to

quantify the ore-forming potential and the episodicity of the varied host

gabbroic rocks, we performed trace element analyses of olivine from the

BBS and troctolite sequences using Secondary Ion Mass Spectrometry. We

observe systematic variations in Cr, Mn, Fe, Co, Ni and Zn contents in

olivines for both sulfide-free and sulfide-bearing zones. Olivines from the

BBS gradually increase in Mn (up to 11,000 ppm) and Zn (up to 550 ppm)

closer to massive sulfide and are in general Cr, Co and Ni depleted

compared to those from nominally barren troctolites. Olivine compositions

from NT samples, on the other hand, reveal the presence of high Ni (up to

2,500 ppm) olivine “reefs”, which are bracketed by horizons with olivine

Ni contents of ≤ 1,500 ppm. These excursions also show excellent

correlation with deflections in whole-rock trace element content. Our data

imply that: (1) olivines from the homogenous NT display a “cryptic-

layering”, indicating crystallization from episodically intruding pulses of

fresh mafic magma; (2) the high Mn and Zn concentrations are a result of

crystallization from a country rock-contaminated mafic magma, and hence,

might act as a geochemical indicator for the assimilation of upper crustal

material. These observations can therefore assist in identifying

characteristic trace element signatures of olivines that formed in

contaminated (and thus potentially sulfide saturated) magmas.

[1] Lightfoot and Naldrett (1999) GAC Vol. 13, 1-30.

USING SMALL CARBONACEOUS FOSSILS (SCFS) TO RESOLVE

THE NEOPROTEROZOIC-PALAEOZOIC TRANSI-TION

Butterfield, N.J., njb1005@cam.ac.uk, and Harvey, T.H.P.,

University of Cambridge, Cambridge, UK CB2 3EQ

The transition from a pre-Ediacaran ‘microbial world’ to the profusely

macroscopic condition of the Phanerozoic revolutionized the course of

planetary history. Unfortunately, the fossil record of the critical interval is

biased by 1) the over-representation of biomineralized forms accompanying

the Cambrian explosion, 2) secular shifts in taphonomic pathways, including

an early Cambrian switch from “Ediacara-type” to “Burgess Shale-type”

macrofossil preservation, 3) the “exceptional” nature of non-biomineralizing

Cambrian macrofossils and phosphatized microbiotas, and 4) laboratory

procedures that overlook or eliminate key data.

Shale-hosted organic-walled microfossils have long been used to

recover a record of non-biomineralizing fossil organisms, but standard

palynological processing tends to destroy larger and/or more delicate

material. In order to recover this key fraction, we advocate the use of a low

manipulation HF-dissolution procedure, combined with hand-picking of

individual microfossils. Such processing recovers a substantially larger

range of carbonaceous fossils, most notably those too small to be easily

detected on bedding surfaces, but too large to survive the rigors of boiling

acids, vacuum-assisted sieving and/or heavy liquid separation.

Significantly, this record of small carbonaceous fossils (SCFs) is proving

sufficiently common to illuminate key aspects of the Neoproterozoic-

Palaeozoic transition.

Like their shelly (SSF) counterparts, SCFs constitute a polyphyletic

assemblage of mostly disarticulated fossil remains that nonetheless provide

important stratigraphic, biogeographic, phylogenetic and palaeo-

environmental resolution. In addition to documenting global occurrences

of a wide range of Cambrian SCFs, we have identified a previously

unrecognized radiation of crustaceans limited to shallow-water epicratonic

seas (which fail to preserve Burgess Shale-type macroscopic counterparts);

a wide range of carbonaceous fossils derived from originally

biomineralized sclerites (including conodonts, sponges, palaeoscolecids,

hyoliths and chancelloriids); and a record of unambiguously metazoan

SCFs extending back to the earliest Cambrian.

Probable metazoan SCFs have also been recovered from terminal

Ediacaran deposits, but have yet to be identified in earlier Ediacaran or

Cryogenian acritarch biotas. It is also true, however, that the potential for

high-quality carbonaceous preservation was relatively limited through

most of this interval. On the other hand, older, pre-Cryogenian SCF

assemblages exhibit the same degree of exquisite preservation as found in

the Cambrian, and the absence of any recognizably metazoan remains in

these biotas, despite decades of both conventional and low-manipulation

processing, points convincingly to the genuine absence animals at this

time. As such, the search for the first metazoans should be centred on the

Ediacaran, with possible roots into the preceding Cryogenian.

SHEAR ZONE INFLUENCE ON THE EMPLACEMENT OF A

GIANT PEGMATITE: THE WHABOUCHI LITHIUM PEGMA-

TITE, QUEBEC, CANADA

Bynoe, L., [email protected], Linnen, R., [email protected], and Jiang,

D., [email protected], The University of Western Ontario, Depart-

ment of Earth Sciences, 1151 Richmond St., London, ON N6A 5B7

This project addresses the factors responsible for the emplacement of the

albite-spodumene type Whabouchi pegmatite, located approximately 250

km north-northwest of Chibougamau and 40 km east of the community of

Nemaska within the James Bay region, Quebec. The Whabouchi pegmatite

is a 1.4 km by 130 m dyke of over 25 Mt with an average grade of 1.54

%Li

O. The dyke was emplaced into a metamorphosed volcano-

sedimentary belt, which is surrounded by granitoids. Preliminary mapping

of the Whabouchi property has revealed several rock types including 4

types of pegmatites differentiated by their mineral components: biotite-

garnet, muscovite-biotite-garnet, muscovite-garnet and the Whabouchi

albite-spodumene pegmatite. In this respective order, there is a progression

from the biotite-garnet type in the north, toward the albite-spodumene

pegmatite over a distance of approximately 3 km. This progression is

interrupted where pegmatites are in contact with deformed granites, which

acted as sources for the biotite occurring within the muscovite-garnet

pegmatites. Muscovite-garnet pegmatites occur southwest of the

Whabouchi pegmatite and grade into biotite-bearing granites that display

well-defined foliations. Other rock types identified on the property are

deformed granites, brecciated granites, pegmatitic granites, orthogneisses

and metabasites. The Whabouchi pegmatite is within a high-strain zone

developed in upper greenschist to amphibolite facies metabasites. The

metabasite host rocks in the shear zone are thoroughly transposed and the

transposition foliation is ubiquitously developed and dips steeply at an

average of 60°. Stretching lineations are also well developed and

subvertical inside the shear zone. Small branching pegmatite veins from

the main mineralized body are strongly folded with subvertical fold

hingelines. Shear-sense indicators in outcrops consistently suggest a

dextral sense of shear, indicative of a dextral transpressional shear zone.

Cross-cutting relationships between the albite-spodumene pegmatite and

transposed metabasites suggest a late syn- to post-kinematic emplacement

of the Whabouchi pegmatite. These preliminary observations support

either a pre-existing shear influence on the emplacement of the Whabouchi

pegmatite or fracture-controlled emplacement affected significantly by

pre- and post-ductile deformation.

A GEOHERITAGE STRATEGY FOR NOVA SCOTIA

Calder, J.H., jhcalder@gov.ns.ca, Nova Scotia Department of

Natural Resources, PO Box 698, Halifax, NS B3J 2T9

Long recognized by some of the world’s great scientific minds, including

Lyell, Darwin and Dawson, the geological heritage of Nova Scotia has

been commemorated by local communities, in provincial and federal

parks, by private sponsors, and by the ultimate recognition of UNESCO

World Heritage. None of this, however, has been achieved from a

systematic vision, and the desire for new commemoration requires a

systematic approach, both to take inventory of our geoheritage and to

provide a clear vision of sites that should be recognized, and in some cases

promoted or protected. Geoheritage is defined most succinctly as

geological features that inform humanity of its relationship with the Earth.

Like UNESCO World Heritage, geoheritage can be divided into two

categories: cultural/social geoheritage, where value is tied to human

interaction with the site (comprising spiritual sites, mine sites,

stoneworks), and physical geoheritage, where value lies in the aesthetic

qualities of landscape, or in informing us of Earth history and Earth

processes. Geotourism refers to the marketing of visitation to geoheritage

sites and its economic benefits. Although there is great potential in

geotourism for community-based economic development, not all

geoheritage sites are appropriate candidates, for reasons of integrity, visitor

safety, or even scientific obscurity (type sections being one example). The

geoscience community will help to establish the geoheritage list using a

rubric that considers: i) level of significance; ii) interpretive potential; and

iii) appropriateness as a geotourism site. The development of a systematic

geoheritage list will assist government agencies in making informed

decisions and in fulfilling their mandates with wise allocation of resources.

Perhaps most importantly, the formal recognition of geoheritage has

potential to bring scientists and communities together at a time when we

need more than ever to heed the lessons of Earth history as we face very

real challenges to our shared future on this Earth.

INTEGRATED GEODATABASE STUDY OF THE COMPLEXLY-

DEFORMED U-HOSTING PALEOPROTEROZOIC AMER

GROUP, NUNAVUT

Calhoun, L.J., lydia.c@gmx.com, White, J.C., Department of Earth

Sciences, University of New Brunswick, Fredericton, NB E3B 5A3,

Jefferson, C.W., Geological Survey of Canada, 601 Booth Street,

Ottawa, ON K1A 0E8, Tschirhart, V., School of Geography and

Earth Sciences, McMaster University, Hamilton, ON L8S 4L8, and

Patterson, J.G., Fellow, Science College, Concordia University,

Montreal, QC H3G 1M8

The uranium-hosting Paleoproterozoic Amer Group, central Nunavut,

comprises four dominantly sedimentary sequences (Ps1 through Ps4)

deposited unconformably on Archean basement of the Rae sub-province.

Ps1 is characterized by Ayagaq Fm. quartzites formed in a stable cratonic

and/or marine setting, with minor conglomerate and/or a distinctive schist

at its base. Ps2 is a sharply transgressive sequence of graphitic siltstone

(Resort Lake Fm.) shallowing up to dolostone (Aluminium River Fm.) and

intercalated to overlying porphyritic basalt (Five Mile Lake Fm.). Ps3

comprises three units recording an overall coarsening- then shallowing-

upward sequence involving siltstone to feldspathic arenite (Three Lakes,

Oora Lake and Showing Lake formations). Ps3 is the primary host of U-

mineralization in this region. Ps4 arkose (Itza Lake Fm) is preserved as

isolated occurrences above a profound unconformity. The Amer Group is

intensely deformed. D

produced multiple transposition (three fold

generations) and displacement along discrete detachments resulting in sub-

horizontal axial surfaces and tectono-stratigraphy. D

generated the

regional, generally upright synclinoria, and is separated from D

by the

Ps3-Ps4 unconformity. Late D

folds with sub-horizontal axial surfaces are

rare. The region is transected by arrays of ENE- and NW- trending faults.

Elucidation of the structure of Ps3 units is central to determining the

distribution of U-mineralization in the Amer Group. The difficulties of

dealing with a polydeformed terrane are exacerbated by the absence of

exposure in critical areas. This problem has been overcome by integrating

detailed outcrop examination with high-resolution aeromagnetic data, and

legacy drill hole data. The analysis is dependent on the strong, but distinct

magnetic responses of the euhedral disseminated magnetite-bearing fine

siliciclastic Three Lakes and Showing Lakes formations that, in preserved

stratigraphic sequences are separated by the Oora Lake Fm. The aforesaid

approach has enabled identification of a consistent, yet distinctly different

geometry for the Amer Group “basins”. In contrast to the apparent

straightforward structure of the regional D

synclinoria, it is demonstrated

that the D

tectono-stratigraphy forms large, regional recumbent structures

masked by the lack of outcrop, but for which evidence occurs at all scales

and within separate data sets i.e. field, geophysics, drill hole. The

occurrence in some areas of elongate “cigar-shaped” mineralized zones

reflects U-concentration within D

hinge zones coaxially overprinted by

. The success of this study in integrating diverse data bases, especially

high-resolution geophysics and detailed outcrop mapping, argues for the

future extension of such approaches.

THE ANATOMY OF A SUBMARINE SLIDE COMPLEX IN

NORTHEAST FLEMISH PASS

Cameron, G.

, gocamero@nrcan.gc.ca, Campbell, C.

, Saint-Ange,

, Jiménez García, P.

, Piper, D.J.W.

and MacKillop, K.

Natural

Resources Canada, Bedford Institute of Oceanography, 1 Challenger

Drive (PO Box 1006), Dartmouth, NS B2Y 4A2;

Tragsatec S.A.,

Gerencia de Asuntos Pesqueros y Acuícolas C/ Nuñez de Balboa,

116 2ª planta 28006, Madrid

Flemish Pass is a north-south trending, saddle-shaped, mid-slope basin

located between Grand Bank and Flemish Cap on the eastern Canadian

continental margin. This basin has trapped thick sequences of Quaternary

sediment, consisting of hemipelagic and proglacial muds, mass-transport

deposits, and turbidites. A sediment slide complex in northern Flemish

Pass near the Mizzen prospect, first identified on multibeam data collected

in 2009, was investigated in August 2011 using high resolution seismic

reflection systems and shallow piston coring.

This multiple failure complex extends about 80 km along the

northwest flank of Flemish Cap and about 20 km downslope with three

large arcuate slide scars found at its center. These arcuate failures are up to

10 km wide and 9 km long downslope, with scarps over 120 m high. These

failures appear to be among the most recent in the complex. Unfailed

sediments in the slide area have continuous coherent internal reflectors on

seismic profiles. Failed sediments have run out as far as 20 km onto the

floor of the pass, forming a mass transport deposit (MTD) up to 130

meters thick. The MTD appears acoustically transparent and massive on

seismic profiles, with a hummocky upper surface in some locations, and an

erosional base overlying well stratified sediments. Several cores taken

along a series of terraces formed by the multiple failure events provide a

composite stratigraphy of the upper 150 m below the seabed. Preliminary

geotechnical results from a piston core taken in an area of undisturbed

seabed adjacent to the failure complex show under-consolidated sediments

exist at depth, and may indicate that the sediments are inherently unstable.

An existing chronostratigraphic framework in Flemish Pass suggests that

this failure complex developed after deposition of the base of Holocene

seismic marker, giving it an age of less than 12 ka. Additional age control

from recently acquired cores taken within this slide complex may yield a

more precise estimate of the age of these slide events.

GEOPHYSICAL EVIDENCE FOR BOTTOM CURRENT

ACTIVITY THROUGHOUT THE CENOZOIC FROM THE

CONTINENTAL MARGIN OFF NOVA SCOTIA, CANADA

Campbell, D.C., [email protected], and Mosher, D.C.,

Geological Survey of Canada-Atlantic, Bedford Institute of

Oceanography, Dartmouth, NS B2Y 4A2

The widespread sediment drifts that flank the continental margins of the

North Atlantic provide geological evidence for bottom current activity

throughout the Cenozoic. Prior to this study, sediment drifts and other

features indicative of active bottom currents were thought to be of limited

extent along the continental margin off Nova Scotia (the Scotian margin),

making the Scotian margin anomalous compared to the adjacent margins

to the north and south. In this study, we demonstrate that sediment drifts

are a common feature in the Cenozoic succession along the Scotian

margin. Analysis of recently acquired 2D and 3D multichannel seismic

reflection data combined with published biostratigraphic results suggest

that large sediment drifts developed in the Late Miocene to Pliocene, and

possibly as early as the Late Eocene. These large drifts represent more than

50% of the preserved Cenozoic succession along parts of the western

Scotian margin and exceed 1.4 km in thickness. Small sediment drifts

developed locally throughout the late Paleogene and Neogene, either

southwest and down current of seafloor obstacles or within channels.

Increased bottom current intensity contributed to the formation of regional

seismic markers, first along the continental rise in the Early Oligocene,

then along the continental slope during the Late Miocene and Pliocene.

The timing of bottom current intensification appears to be similar to the

record from the U.S. Atlantic margin. 3D seismic data show localized

erosion surfaces that preserve along-slope seismic amplitude anomalies,

barchan bedforms, and possible evidence of helical scour. 3D seismic data

also allow determination of paleo bottom-current direction using multiple

criteria. All bottom current evidence suggests a northeast-to-southwest,

along-slope flowing Western Boundary Undercurrent (WBUC) during the

Cenozoic. There is no preserved evidence of northward encroachment of

the Gulf Stream or Gulf Stream Rings. Increased intensity of the WBUC in

shallower water depths is interpreted to have occurred during the Miocene

to Pliocene and possibly represents increased contribution from Labrador

Sea water masses. It is clear that along-slope sedimentary processes were

far more important in shaping the Scotian margin than previously

understood.

PRELIMINARY RESULTS OF RECENT FIELD INVESTI-

GATIONS OF THE SURFICIAL GEOLOGY AND SEAFLOOR

PROCESSES IN FLEMISH PASS

Campbell, D.C.

, [email protected], Saint-Ange, F.

, Cameron,

, Jiménez García, P.

and Piper, D.J.W.

Geological Survey of

Canada-Atlantic, Bedford Institute of Oceanography, PO Box 1006

Dartmouth, NS B2Y 4A2;

Tragsatec S.A., Madrid, Spain

Flemish Pass is a perched basin in over 1000 m water depth bound to the

west by the Grand Banks and to the east by Flemish Cap. It is an area of

active hydrocarbon exploration with the completion of 4 exploration wells

since 2003. Quaternary and modern geological processes affect seabed

stability and shallow drilling conditions in the area. In an effort to augment

the regional understanding of these processes and the surficial geology of

Flemish Pass, the Geological Survey of Canada conducted a 3 week

marine geological expedition to the area in August 2011. Data were

acquired using high resolution seismic reflection systems, a large piston

corer, an instrumented seafloor lander, and a towed camera system.

Expedition planning was guided by regional multibeam bathymetry and

sub-bottom profiler data collected during the Nereida Program*.

In northern Flemish Pass, detailed surveying of a widespread mass

transport complex shows that the feature formed through multiple phases

of seabed failure. Strategic sampling was undertaken to determine the

timing of failure events and geotechnical properties of the failed and

unfailed seabed. Preliminary laboratory data indicate unexpectedly low

sediment strength for the undisturbed interval. New seismic reflection data

over enigmatic mounds on Sackville Spur do not support an interpretation

of failure blocks for these features. Video and core data collected over one

mound shows abundant gravel near its top, probably due to winnowing of

ice-rafted detritus, and suggest the mounds are relict features of uncertain

origin. Data from southern Flemish Pass reveal a previously unrecognized

contouritic moat and drift system near Beothuk Knoll. A core from the

floor of the moat recovered 3 m of very fine sand indicating that bottom

current strengths in the area are sufficient to hinder deposition of finer

sediment. A large canyon and sedimentary ridge immediately south of

Flemish Pass appears to be partially fed by this contourite system. The

results show that the Labrador Current has played, and possibly still plays,

a significant role in redistributing sediment along Flemish Pass. Ongoing

processing of data and samples from the 2011 expedition will provide

important new information about the surficial processes and geotechnical

properties of the seabed in Flemish Pass.

* A North Atlantic Fisheries Organization vulnerable marine

ecosystems mapping project carried out by Spain, with partners from the

Geological Survey of Canada, Fisheries and Oceans Canada, and the

Centre for Environment, Fisheries and Aquaculture Studies in the UK.

THE BLACK BIRCH LAKE ASSEMBLAGE: A CONTINENTAL

SUPRACRUSTAL SUCCESSION IN THE SOUTHERN HEARNE

PROVINCE WITH IMPLICATIONS FOR THE SOUTHERN

EXTENT OF THE CENTRAL HEARNE PROVINCE

Card, C.D.

, [email protected], Bethune, K.

, Bosman, S.A.

and

McEwan, B.

Saskatchewan Geological Survey, 200-2101 Scarth

St., Regina, SK S4P 2H9;

Department of Geology, University of

Regina, CW 230, 3737 Wascana Parkway, Regina, SK S4S 0A2

The upper amphibolite- to granulite-facies Black Birch Lake Assemblage

(BBLA) is a supracrustal succession exposed south of the Athabasca Basin

in the southern Hearne Province of Saskatchewan. The BBLA is

characterised by quartzite and amphibolite near its base, overlain by

psammite, semi-pelite to pelite, silicate-facies iron formation and rare

dolomitic marble. Quartzite contains rare trough cross beds and

amphibolite rare, relict pillows indicating a volcanic origin for some of the

unit with mafic plutons constituting the balance. Mafic rocks with

amphibolitic texture but where hornblende has been replaced by biotite are

common, as are mafic rocks containing garnet-anthophyllite± cordierite

that are indicative of Mg-metasomatism. What is striking about the BBLA

is the preservation of metamorphosed saprolitic rocks at its base. In most

cases meta-saprolites are characterised by blebby white leucosome,

sillimanite along foliation planes, and magnetite. These were interpreted as

pelitic units by previous mappers but their stratigraphic position between

unaltered orthogneiss and plutonic rocks and quartzite of the BBLA is

conspicuous. In addition, a zoned, metamorphosed, saprolite is preserved

at Black Birch Lake that includes an upper aluminous zone, underlain by

iron-rich and “rotten” and rusty zones before finally grading into granitoid

gneisses. The relationships suggest an unconformable relationship between

the BBLA and Archean granitoid rocks and derived gneissic equivalents,

including ca. 2.6 Ga granites. Therefore, the BBLA is likely a continental

supracrustal succession.

Previous workers suggested that the BBLA and equivalents might

represent the western extension of the ca. 2.1-1.86 Ga Wollaston

Supergroup, whereas others proposed correlation with the ca. 2.71-2.68 Ga

Ennadai group in the extreme northeastern part of Saskatchewan. Our field

observations, however, indicate that the BBLA is younger than 2.6 Ga and

therefore not correlative with the Ennadai group. Equivalence with the ca.

2.1 Ga Courtenay Lake group, the basal strata of the Wollaston

Supergroup, remains possible and requires further testing.

In conclusion, the BBLA appears to represent a continental

supracrustal succession, contrasting the Rankin-Ennadai greenstone belt,

which is oceanic in origin and was composed solely of juvenile material

before 2.68 Ga. This implies a break between the southern and central

Hearne in the vicinity of the Athabasca Basin. Coincident negative Bouger

gravity and aeromagnetic anomalies that terminate just to the northeast of

the Athabasca Basin and underlie the Ennadai group in northeastern

Saskatchewan may represent an expression of this boundary.

THE VIRTUAL MUSEUM OF CANADA BURGESS SHALE

WEBSITE – REACHING OUT TO A GLOBAL AUDIENCE

Caron, J-B., Department of Natural History (Palaeobiology), Royal

Ontario Museum, 100 Queen’s Park, Toronto, ON M5S 2C6,

[email protected]

The Burgess Shale in Yoho National Park (British Columbia) is famous for

its spectacular soft-bodied organisms dating from the Cambrian Period.

Designated a UNESCO World Heritage Site in 1980, it is now part of the

Canadian Rocky Mountain Parks World Heritage Site. The Burgess Shale

is located in a protected area, but Parks Canada allows a limited number of

visitors to access this site each summer and only through licensed guided

hikes. While hiking to the site offers a unique learning experience for

visitors to the Parks, it is not for everyone (the hike is long and strenuous)

and the number of participants remains small to minimize environmental

disturbance. In order to expand public education and awareness, the Royal

Ontario Museum and Parks Canada have launched a new bilingual

(English and French) website entirely dedicated to the Burgess Shale

(http://burgess-shale.rom.on.ca/). The website was funded by Canadian

Heritage through the Virtual Museum of Canada Program. Visitors can

access a wealth of information about the fossils, the geology, and the

history of discoveries in ways not available before, from anywhere in the

world. Presentation of our diverse geological heritage through the

development of websites of this kind will facilitate protection of sensitive

environmental areas where, for example, visitation is an issue, while at the

same time expand opportunities for education.

PIKAIA GRACILENS FROM THE BURGESS SHALE:

REVISITING WALCOTT’S MOST FAMOUS WORM

Caron, J-B., Department of Natural History (Palaeobiology), Royal

Ontario Museum, 100 Queen’s Park, Toronto, ON M5S 2C6,

[email protected], and Conway Morris, S., Department of Earth

Sciences, University of Cambridge, Downing Street, Cambridge,

CB2 3EQ, UK

Pikaia gracilens is one of the most iconic fossils from the 505 million year

old Burgess Shale. Originally described in 1911 by Walcott as a possible

polychaete worm, Pikaia has also been regarded as a primitive chordate, a

possible stem group craniate, and a cephalochordate – but its status has

remained controversial. A modern restudy of this animal was long

overdue. For the first time, we present a detailed description of all 114

specimens, including 60 newly collected by the Royal Ontario Museum.

Specimens range from 1.5 to 6 cm and comprise up to 100 sigmoidal

myomeres. A small bilobed head bears a pair of slender, flexible tentacles.

There is no evidence of eyes. Below the head are up to nine bilaterally

arranged appendages that are potentially connected to pharyngeal pores.

Internally, portions of the notochord and nerve chord, a dorsal organ and a

vascular system are preserved. Its sigmoidal myomeres and notochord

mark Pikaia as a chordate, but it differs from all other primitive chordates

known in the Cambrian fossil record. We regard this animal as the most

basal stem group chordate, with potential affinities to yunnanozoans.

ANATOMY AND STRUCTURAL EVOLUTION OF THE

RETROWEDGE OF THE SOUTHERN CANADIAN CORDILLERA

Carr, S.D., Ottawa-Carleton Geoscience Centre, Department of Earth

Sciences, Carleton University, 1125 Colonel By Drive, Ottawa, ON

K1S 5B6, [email protected], and Simony, P.S., Department

of Geoscience, University of Calgary, 2500 University Drive NW,

Calgary, AB T2N 1N4

In the southern Canadian segment of the Cordillera, a doubly verging,

“warm medium-sized” orogen formed in the Cretaceous to Eocene in a

plate tectonic setting of oblique convergence. We document the internal

geometry and structural evolution of the ~400 km wide, east-verging,

retrowedge side of the orogen. The External Rocky Mountains and

Foothills comprise three major east-verging, Late Cretaceous to Eocene,

thin-skinned, piggyback thrust and fold systems. They root westward into

a basal décollement and accommodated ~180 km of shortening. The

Western Internal zone is characterized by tracts of metamorphic rocks and

metamorphic core complexes (e.g. Kettle, Okanagan, Priest River and

Valhalla), some of which are basement-cored domes (e.g. Frenchman Cap,

Thor-Odin, and Spokane). They have a downward-younging progression

of Late Cretaceous to Eocene metamorphism and deformation in

infrastructural flow zones characterized by transposition foliation,

migmatites, flow folds and 1-7 km thick shear zones. Nested between the

External and Western Internal zones is a relict ~100-200 km wide Early

Cretaceous orogen that predated emplacement of ca. 100 Ma plutons. The

geology and architecture of the Western Internal and External zones can be

explained by progressive development of major Late Cretaceous to Eocene

shear zone systems in the Internal zone that can be directly linked with

coeval thrust and fold systems in the External zone. The linkage was via

Late Cretaceous activation and Late Cretaceous to Early Eocene

reactivation of the 150-200 km-wide central portion of the Rocky

Mountain basal décollement that lies beneath and translated the

intervening Early Cretaceous orogen. Thickening in the retrowedge

insulated the underlying rocks of the incipient Internal zone leading to

progressive heating, weakening and localization of the basal shear zone. At

the base of the wedge, cooler stiffer rocks lay to the east of the Internal

zone, at each stage, acting as an indentor. Thus, the development of a basal

shear zone was coupled with flow of the hot mass of the Internal zone up

and over an indentor, strain softening of it, and incorporation of it into the

wedge in successive stages. During Early Eocene shortening, extensional

shear zone systems were localized on the margins of tectonothermal

culminations. Motion of deep-seated décollements beneath some of these

culminations may have contributed to their doming. Crustal shortening

ended at ca. 52 Ma in a transtensional tectonic regime, coinciding with

crustal-scale extension in the Western Internal zone.

TESTING JOINT INVERSION CODE WITH GEOLOGICALLY

REALISTIC MODELS

Carter-McAuslan, A., acarter[email protected], Lelievre, P.,

Blades, G. and Farquharson, C.G., Memorial University of

Newfoundland, St. John's, A1B 3X5

Joint inversion is a type of inversion carried out for two different physical

properties simultaneously. When a single Earth model is derived which fits

different, complementary survey data that are sensitive to two physical

properties it is more likely to be closer to the true subsurface structure than

a single property inversion. A number of synthetic Earth models based on

the geology of the Eastern Deeps zone of the Voisey's Bay deposit in

Labrador have been constructed in order to test recently developed joint

inversion modelling code. This code performs a joint inversion of seismic

tomography and gravity data. The code uses unstructured triangular and

tetrahedral meshes which are more easily comparable to the wireframe

meshes commonly used to describe the geometry of ore deposits. Several

triangular (2D) and tetrahedral (3D) unstructured mesh test models have

been developed. The 2D models were based on conceptualized models of

the Eastern Deeps and are varied in complexity. The 3D tetrahedral model

was built based on Datamine wireframe models. The Datamine models had

to be simplified to remove small scale features, and to improve mesh

quality in order to be appropriate for geophysical numerical modelling. A

method for creating geophysically suitable meshes was devised, and from

this method software was developed to partially automate the creation of

meshes. Single property and joint inversions were carried out to evaluate

the ability of the inversion code to reproduce the models and to determine

which inversion parameters were most crucial in generating the best

inversion results. Inversions included a number of different gravity station

distributions in order to determine the effect of employing borehole

gravity, a relatively new technique. Through these tests it has been shown

that the joint inversion code was able to locate a buried high contrast target

in 2D tests with a variety of gravity distributions. Adjusting the sensitivity

weighting improved the results of inversions where only borehole gravity

stations were used. During 3D tests it has been concluded that a balance

between the noise levels, maximum cell size of the inversion mesh,

number of cells in a mesh, memory usage and CPU time has to be attained

in order to apply this joint inversion code in practice.

EASTERN BAIE VERTE PENINSULA REVISITED: FROM

EARLY PALEOZOIC SUPRASUBDUCTION ZONE OPHIOLITE,

THROUGH SYN-OROGENIC CONTINENTAL VOLCANISM, TO

LATER PALEOZOIC EXTENSIONAL COLLAPSE

Castonguay, S., Geological Survey of Canada, Québec, QC G1K

9A9, [email protected], Skulski, T., McNicoll, V., Geological

Survey of Canada, Ottawa, ON K1A 0E8, Moussallam, Y., Dept. of

Geography, Cambridge University, UK, CB2 3EN, and van Staal, C.,

Geological Survey of Canada, Vancouver, BC V6B 5J3

Baie Verte Peninsula in the Newfoundland Appalachians records a

complex Paleozoic history of plate interaction between Laurentia and

outboard terranes. A geological map of the eastern half of the peninsula

combines published government, academic and industry data with new

bedrock mapping, geophysics, lithogeochemistry and geochronology. In

this area, a tectonic window exposes late Precambrian to early Paleozoic

continental margin rocks of the Ming’s Bight Group. The eastern half of

Baie Verte Peninsula is more notable for its well-preserved supracrustal

and plutonic rocks of the tectonic upper plate and younger continental

cover. During the Taconic Orogeny, the Laurentian margin was overthrust

by a 489 Ma suprasubduction ophiolite and 487 Ma juvenile island arc that

host VMS copper and late gold mineralization in the Betts Cove and

Pacquet complexes. A syn- to post obduction, >470-467 Ma submarine

ophiolite cover sequence is represented by the Snooks Arm Group in the

Betts Cove and Pacquet complexes. In eastern Baie Verte, this basinal

facies, volcano-sedimentary cover disconformably overlies the ophiolite

and island arc sequence, and is separated by the Nugget Pond iron

formation and host to younger gold mineralization. Emergence of this

marine succession in eastern Baie Verte is linked to voluminous, episodic

arc- and later granite magmatism represented by 457 Ma felsic dykes and

the voluminous 445-433 Ma Burlington Plutonic Complex. Bimodal, post-

arc magmatism in the Cape St. John Group (428-426 Ma) and synvolcanic

plutons including the 429 Ma Cape Brule porphyry and 427 Ma

Dunamagon granite are the vestiges of a large, continental caldera complex

and its satellite plutons that are broadly contemporaneous with the Salinic

Orogeny. Rocks of the eastern Baie Verte Peninsula have been affected by

at least four phases of deformation. An early, NW-directed fault in the

Betts Cove ophiolite, is the sole evidence of early D

deformation related

to Taconic obduction of the Baie Verte oceanic tract. Penetrative D

deformation involved S-SE overturned folds, and later, SSE-directed

ductile to brittle-ductile shear zones that affect both Ordovician and

Silurian units. Open, upright F

cross folds are interpreted as

penecontemporaneous with D

and resulting from an overall Salinic

transpressional regime. In the northern part of the map area, recumbent F

folds are cogenetic with southeast-dipping, ductile-brittle extensional shear

zones. These structures are responsible for local unroofing of continental

margin units causing a metamorphic overprint (405-370 Ma) and reflect

transtensional deformation between the NE-striking, dextral Baie Verte

Road and Green Bay faults.

CHARACTERIZATION AND EMPLACEMENT CONDITIONS OF

THE GOLD MINERALIZATION OF THE DAISY-MILANO GOLD

MINE, MOUNT MONGER DISTRICT, WESTERN AUSTRALIA

Caté, A.

1,2

, [email protected], Dubois, M.

, Tuduri, J.

2,4

Doucere, M.

and Squire, R.

INRS centre ETE, 490 Rue de la

Couronne, Québec, QC G1K 9A9;

Institut Polytechnique LaSalle

Beauvais, rue Pierre Waguet - BP 30313, F-60026 BEAUVAIS,

France;

Laboratoire LGCgE, Université Lille1, F-59655 Villeneuve

d'Aacq, France;

Current address: ENAG-BRGM, 3 avenue Claude

Guillemain, BP 36009, F-46060 Orleans CEDEX 2, France;

Silverlake Resources, PO Box 750, Kalgoorlie WA 6430, Australia;

School of Geosciences, Monash University, Melbourne, Victoria

3800, Australia

The Daisy-Milano gold mine is located in the Eastern Goldfields Archean

superprovince, Yilgarn Craton, Australia. It is owned and exploited by

Silverlake Resources since 2007 and the total resources are currently

inferred at 1,069,700 t at 18 g/t gold.

The deposit is considered to belong to a gold lode vein orogenic type

and is hosted in dacitic porphyries, andesites, komatiites and volcaniclastic

rocks in a greenstone belt.

The mineralized vein network is generally oriented 020°/80° and is

controlled by N150° sinistral shear zones. Gold is located in quartz

carbonate veins and is generally associated with pyrite.

Two stages of mineralization have been defined:

• Stage 1: pyrite, chalcopyrite, galena, electrum, and gold-silver tellurides;

• Stage 2: no economical mineralization

Gold remobilization creates zones with extremely high grades

(>1000 g/t) and induces a high nugget effect. Pervasive sericite, chlorite

and pyrite haloes due to the hydrothermal alteration surround the

mineralized areas.

A microthermometric and RAMAN spectroscopic study of fluid

inclusions has been performed in quartz grains. The most common type

includes CO

-dominated inclusions. They are spatially related to two-

phase or three-phase H

O-CO

inclusions including a muscovite daughter

crystal. Extremely rare CH

-bearing inclusions can be found with either

O or CO

. Analyses reveal that CO

is extremely pure. Homogenization

temperatures vary from -21.2 to 29.7°C, indicating highly variable

densities (0.572 to 0.938 g/cm

). Detailed study of the distribution amongst

fluid inclusions assemblages suggests that the variable composition and

densities of fluid inclusions is due to post-trapping perturbations.

O-CO

inclusions, which represent the initial fluid composition

and physical properties, show emplacement conditions at 480±100°C and

4.5±1 kbar. CH

inclusions indicate a late hydrothermal stage with a

significant pressure drop.

DIRECT DATING AND CHARACTERIZATION OF THE POPE'S

HILL REE DEPOSIT, LABRADOR

Chafe, A.N., Hanchar, J.M., Fisher, C.M., Department of Earth

Sciences, Memorial University of Newfoundland, St. John's, NL

A1B 3X5, [email protected], Crowley, J., Department of

Geosciences, Boise State University, Boise, ID 83725 USA,

Dimmell, P.M., Silver Spruce Resources Inc., Suite 312 - 197

Dufferin St., Bridgewater, NS A1B 4J9, and Piccoli, P.M.,

Department of Geology, University of Maryland, College Park, MD

20742 USA

The Pope’s Hill rare earth element (REE) deposit is located approximately

80 km southwest of Happy Valley-Goose Bay, Labrador, along the Trans

Labrador Highway. Exploration done by Silver Spruce Resources, Inc. in

2010 led to the discovery of a highly prospective REE-bearing unit with

total REE plus yttrium (TREE+Y) as high as 25 wt.% along an open-ended

northeast trend approximately 2.8 km in length. Ore, host rock, and

country rock samples were collected to 1) quantify which phases contain

the REE and their abundances and distribution in the ore; and 2) use in situ

U-Pb geochronology and in situ Sm-Nd isotopes in monazite from the ore

and host rock to constrain the timing of mineralization and determine the

source of the REE. These data will help develop predictive models for this

type of mineral deposit elsewhere.

The Pope’s Hill REE deposit host rock is syenitic to monzonitic in

composition containing up to 90% Na- and K-feldspar with minor amounts

of hedenbergite, hornblende, and biotite and pervasive Na and K

hydrothermal alteration. Trace mineral phases include monazite, zircon,

and allanite. The REE ore occurs in millimeter- to centimeter-scale

segregations and pods that are locally discontinuous. EMPA results

demonstrate that apatite-britholite, allanite, and titantite contain the

majority of REE+Y in the Pope’s Hill deposit. A minor amount of the REE

are contained in monazite, fergusonite and an unidentified REE-carbonate.

Apatite and titanite are present in both high-REE and low-REE types,

where the minerals either conform to their stoichiometric composition or

contain chemical substitutions incorporating major quantities of REE and

Si, where Si

+ REE

substitute for Ca

+ P

. In some REE-rich ore

samples high-REE apatite and britholite co-exist.

Monazite in the host rock yields a U-Pb age of ~1060 Ma, while

monazite in the ore is ~1000 Ma. A Sm-Nd isochron age obtained from the

major REE phases in the ore agrees well with the monazite U-Pb age of

the ore, and therefore provides excellent constraints on the timing of REE

mineralization. The initial Nd isotopic composition of the REE phases is

nearly identical to that of the host rock, permissive of a locally derived

source for the REE elements.

REMOBILIZATION AND FRACTIONATION OF RARE-EARTH

ELEMENTS DURING POSTEMPLACEMENT EVOLUTION OF

CARBONATITES: IMPLICATIONS FOR EXPLORATION

Chakhmouradian, A.R., chakhmou@cc.umanitoba.ca, Reguir, E.P.,

Yang, P., University of Manitoba, Winnipeg, MB R3T 2N2,

Demény, A., Hungarian Academy of Sciences, Budapest, Hungary,

Mumin, A.H., Department of Geology, Brandon University,

Brandon, MB, and Couëslan, C., Manitoba Geological Survey,

Winnipeg, MB

Carbonatites in orogenic terranes host some the world’s most spectacular

rare-earth deposits, where rare-earth elements (REE) are concentrated in

such primary minerals as bastnäsite (REECO

F) and monazite (REEPO

Carbonatites found in Precambrian orogenic settings commonly show

evidence of post-emplacement deformation involving ductile flow, grain-

boundary migration, grain deformation and comminution, and post-

deformational recovery. These processes are accompanied by mineral

reactions involving primary calcite and accessory REE-host phases. Some

of these mineralogical changes (for example, remobilization of REE and

their redeposition as a new, syn-deformational mineral assemblage) have

profound implications for REE exploration. Our data show that primary

calcite and fluorapatite undergoing postemplacement deformation are

strongly susceptible to the removal of light REE (leading to LREE

concentrations up to 20 times lower than the original levels), whereas

heavy REE remain essentially immobile. The remobilization of light REE

is not accompanied by any changes in isotopic composition or Y/Ho ratio

(i.e. the primary "mantle" geochemical signature of carbonatites is

retained), suggesting that the deformation processes under consideration

involve a fluid isotopically equilibrated with the primary igneous

paragenesis. The remobilized lanthanides are deposited as a late-stage

paragenesis of minerals (commonly, monazite, Ca-REE carbonates and

allanite), whose composition is largely controlled by the fluid chemistry

and local depositional environment. These data imply that

postemplacement deformation has a dual effect: on the one hand, it may

result in significant dispersal of REE, but on the other, it may lead to the

development of an economically viable late-stage light-REE

mineralization (e.g., monazite).

PRELIMINARY PETROGRAPHIC CHARACTERIZATION OF

IMPACTITES FROM THE POPIGAI IMPACT STRUCTURE

Chanou, A., [email protected], Osinski, G.R., University of Western

Ontario, 1151 Richmond St., London, ON N6A 5B7, Ames D.E. and

Grieve, R.A.F., Geological Survey of Canada, Natural Resources

Canada, 601 Booth St., Ottawa, ON K1A 0E8

This study presents the preliminary petrographic results of a suite of

impact melt-bearing breccias from the Popigai impact structure, Russia.

This petrographic characterization is part of a broader comparative study

of impact-induced breccias. The study aims to elucidate the formation and

deposition mechanisms of melt-bearing breccias also known in the

literature as ‘suevites’. The suite of samples presented here is from beneath

the coherent impact melt sheet at Popigai and has been classified by others

as ‘suevite’ breccia. The relative “textures” of these samples were semi-

automatically and quantitatively analyzed by means of digital image

analysis on a macroscopic (hand sample) scale, using ImageJ software.

The petrographic investigation was conducted using traditional optical

microscopy, Scanning Electron Microscopy (SEM), and Electron

Microprobe Analysis (EMPA). Petrographic microscopic investigation

agrees with textural macroscopic observations in terms of “textures”. At

both scales, impact melt particles exhibit complex deformation textures

and interaction with both the groundmass and the mineral fragments of the

breccia. The glass fragments vary from strongly vesiculated to almost non-

vesicular and from “light-coloured” to “dark-coloured”. In addition, these

glass fragments occasionally exhibit an internal fabric with preferentially

oriented mineral clast inclusions that appear to have deformed along with

the glass fragment. Most fragments mineral/glass have obvious reaction

rims. In addition, present are lithic fragment that appear as angular to

subrounded fragments. Of interest are 100µm wide features of mantled

recrystallized melt that appears in the form of sheaf-like laths, “coated”

with clinopyroxene rims. Preliminary chemical results suggest a mostly

anhydrous aluminosilicate melt. The compositions are mainly quartzo-

feldspathic with the presence of Ca-rich pyroxenes. It has been observed

that the clinopyroxenes have an extensively more Ca-rich composition

compared to that of the melt. In addition, pyroxene aluminum content

varies greatly an observation that may reflect crystallization temperature.

Generally, however, both impact melt rock and glass fragments have a

similar chemical composition. Finally, the groundmass is broadly

consisted by similar (but finer) phases as the clastic population of the

breccia. Composed mainly by crystallites of plagioclase, quartz, pyroxene

and some carbonate.

LATE PALEOZOIC FRACTURE-ZONE OPHIOLITIC BELT IN

WEST JUNGGAR, NW CHINA

Chen, S., chenshi4714@gmail.com, Pe-Piper, G., Department of

Geology, Saint Mary's University, Halifax, NS B3H 3C3, Piper,

D.J.W., Geological Survey of Canada (Atlantic), Bedford Institute of

Oceanography, Dartmouth, NS B2Y 4A2, and Guo, Z.J., Key

Laboratory of Orogenic Belts and Crustal Evolution, Ministry of

Education, School of Earth and Space Sciences, Peking University,

Beijing, China, 100871

West Junggar is located at the east end of the Kazakhstan orocline, in the

collisional triple junction where the Siberian, Tarim and Kazakhstan plates

are sutured. Two parallel subvertical belts of ophiolitic rocks, principally

serpentinite, outcrop in West Junggar: the Darbut and Baijiantan ophiolitic

belts. Late Devonian (363.6 Ma) peperitic basalts form the base of a 2 km

thick Lower Cretaceous basin fill that occurs in continuous stratigraphic

sections distributed regionally over a distance of 100 km on both sides of

the Darbut and Baijiantan ophiolitic belts.

The Baijiantan ophiolitic belt (outcrops ca. 5 km long, 1.5 km wide)

comprises ultramafic rocks, with lesser gabbro, sandstone, basalt, and tuff,

which show block-in-matrix structures and high-angle fault contact with

the surrounding basin fill. Nearly all the peridotite is serpentinized and

foliated, but some small blocks retain their original mantle lithology of

dunite, harzburgite and lherzolite. Detailed field mapping and analysis of

stretching lineations, rotation of sheared lenses, S-C foliation and shear

fissures show that emplacement of the Baijiantan ophiolitic belt was

related to a NE-trending sinistral strike-slip system. The Darbut ophiolitic

belt (ca. 105 km long, <5 km wide), 40 km to the northwest, has similar

rock assemblages and structural features to the Baijiantan ophiolitic belt.

Detrital zircon U-Pb (LA-ICP-MS) dating of three samples from

sandstone blocks in the Baijiantan ophiolitic belt and one sample from

Lower Carboniferous basin fill sandstone shows that the four samples have

similar age distributions. The sandstone blocks in the ophiolite thus came

from the adjacent coeval basin fill; they are not exotic blocks transported

by obducting oceanic crust, distinguishing them from conventional

ophiolitic belts. The peperitic basalts form the upper crust of a continuous

small ocean basin, in which the Darbut and Baijiantan ophiolites originated

as oceanic fracture zones, similar to those interpreted from the Troodos

(Cyprus) and Bela (Pakistan) ophiolites. They should not be interpreted as

evidence of a plate boundary or of subduction or obduction of oceanic

crust.

TRACE FOSSIL EVIDENCE FOR EDIACARAN BILATERIAN

ANIMALS WITH COMPLEX BEHAVIORS

Chen, Z.

, Zhou, C-M.

, Yuan, X-L.

and Xiao, S.

1,2

State Key

Laboratory of Paleobiology and Stratigraphy, Nanjing Institute of

Geology and Paleontology, Chinese Academy of Sciences, Nanjing

210008, China;

Department of Geosciences, Virginia Polytechnic

Institute and State University, Blacksburg, VA 24061 USA

Trace fossils provide an important source of information about the

behavioral ecology of early soft-bodied animals in the Ediacaran Period

(635–542 Ma). We report a group of trace fossils from the Ediacaran

Dengying Formation in the Yangtze Gorges area, South China. The

Dengying Formation is constrained between 551 Ma and 542 Ma and

contains Ediacaran fossils, macroalgal fossil Vendotaenia and the tubular

fossil Sinotubulites.

Here we focus on three types of traces that are often connected with

one another: millimeter-sized horizontal tunnels, surface tracks, and

vertical burrows. The horizontal tunnels are preserved as full reliefs. They

are about 4–7 mm in width, which remains constant along the length of

individual tunnels. They typically consist of two raised lateral lobes

separated by a central furrow, although the bi-lobed nature is sometimes

apparent only along part of burrow length. In transverse cross sections, the

tunnels have a bi-lobed and biconvex profile. The surface tracks are

comparable in width to the horizontal tunnels, but they are always

preserved as negative epireliefs or positive hyporeliefs. They consist of

two parallel sets of sharp scratch marks. The vertical burrows are

cylindrical, about 5 mm in depth, and 5 mm in diameter. They are always

connected to the horizontal tunnels.

Trace fossils are often preserved in a facies characterized by thin-

bedded limestone closely associated with microbial mat. The extensive

development of biomats may separate two layers of similar lithology and

server a plane of splitting, and let to trace fossils can be preserved close to

the sediment-water interface. These three types of trace represent animal

activities related to under-mat feeding, epibenthic locomotion, and

temporary dwelling. Because these three types of traces are connected,

indicate these traces were made by the same bilaterian animals that had

complex behaviors, lived in association with microbial mats to exploit

nutrient and O

resources. These animals heralded a new age in ecosystem

engineering, animal-sediment interaction, and biogeochemical cycling.

COLLOID-FACILITATED TRANSPORT OF CESIUM-137 IN

PARTIALLY SATURATED MEDIA: THE INFLUENCE OF

NATURAL ORGANIC MATTER

Cheng, T., Memorial University of Newfoundland, St. John’s, NL

A1B 3X5, [email protected], and Saiers, J.E., Yale University, New

Haven, CT 06511, USA

Colloid-facilitated transport of contaminants through the vadose zone has

important implications to groundwater quality, and has received

considerable attention over the last decade. Natural organic matter (NOM)

is ubiquitous in the vadose zone, and its influence on mineral colloids and

solute transport has been well documented. NOM sorption to colloids and

sediment grains increases the mobility of colloids. Meanwhile, NOM

either decrease or increase solute contaminant adsorption to colloids and

sediment grains, and therefore could increase or decrease contaminant

mobility. The overall effect of NOM on colloid-facilitated transport

depends on the relatively importance of these mechanisms. The objective

of this work is to elucidate the effects of NOM on colloid-facilitated

transport of a radionuclide contaminant (

137

Cs) within partially saturated

sediments. Measurements made onto re-packed laboratory columns reveal

that either in the presence or absence of NOM, the mobility of

137

Cs was

limited when colloids were not present. The addition of mineral colloids in

the influent slightly increased

137

Cs mobility, and effluent

137

Cs was

dominated by colloid-associated form, indicative of colloid-facilitated

transport. When NOM were added to an influent that contained both

mineral colloids and

137

Cs, the mobility of both mineral colloids and

137

significantly increased, although the presence of NOM slightly decreased

137

Cs adsorption to colloids. Our experimental results further show that the

influence of NOM on colloid-facilitated transport is controlled by the type

of transport media and the type of mineral colloids. However, the influence

of moisture content of the media on colloid and

137

Cs transport seems

negligibly small. A mathematical model, which accounts for (i) advective-

dispersive transport of colloid and

137

Cs, (ii) rate-limited colloid

deposition, and (iii) rate-limited

137

Cs desorption from colloids and

adsorption to sediment grains, was applied to describe our colloid and

137

Cs transport data. The model successfully simulated the transport of

colloids and

137

Cs both in the presence and absence of NOM. Our

modeling results show that NOM (i) reduces colloid deposition rate, (ii)

reduces the total number of sites available for colloid deposition in the

transport media, and (iii) reduces the rate of

137

Cs adsorption to sediment

grains. The overall effect of NOM is therefore an increase in both colloid

and

137

Cs transport. Findings from this work demonstrate the importance of

NOM in controlling colloid and solute contaminant transport and provide a

method to quantify the influence of NOM.

TIMING OF OPHIOLITE OBDUCTION AND REGIONAL

METAMORPHISM IN THE GRAMPIAN OROGEN

Chew, D.M., Department of Geology, School of Natural Sciences,

Trinity College Dublin, Dublin 2, Ireland, [email protected], Daly, J.S.,

UCD School of Geological Sciences, University College Dublin,

Dublin 4, Ireland, Page, L.M., Department of Geology,

GeoBiosphere Science Centre, Sölvegatan 12, 223 62 Lund

University, Sweden, and Whitehouse, M.J., Laboratory for Isotope

Geology, Swedish Museum of Natural History, Stockholm, Box 50

007, SE-104 05 Stockholm, Sweden

The Grampian terrane in the Caledonides of Scotland and NW Ireland is

the type locality for Barrovian (regional) metamorphism. It is thought to

have resulted from the collision of the Laurentian margin with an oceanic

arc and suprasubduction ophiolite during the Early Ordovician. Here we

address the timing and P-T conditions of Grampian ophiolite obduction

and re-evaluate the link with regional metamorphism.

Magmatic zircons from the Highland Border Ophiolite, Scotland

define a 499 ± 8 Ma U-Pb Concordia age. Its metamorphism is dated by a

490 ± 4 Ma 40Ar-

Ar hornblende age, and a 488 ± 1 Ma

Ar-

muscovite age from a metasedimentary xenolith within it, from which P-T

estimates of 5.3 kbar and 580°C relate to ophiolite obduction.

Metamorphism of the Irish correlative of the Highland Border Ophiolite is

constrained by a 514 ± 3 Ma

Ar-

Ar hornblende age, while mica schist

slivers within it yield detrital zircon U-Pb ages consistent with Laurentian

provenance and Rb-Sr and

Ar-

Ar muscovite ages of ca. 482 Ma. P-T

values of 3.3 kbar and 580°C constrain the conditions of ophiolite

obduction.

Peak Grampian metamorphism on the Laurentian margin (Dalradian

Supergroup) is constrained to c. 475 – 465 Ma. This includes U-Pb zircon

ages from Grampian syn-orogenic intrusives and metamorphic mineral

ages from Dalradian regions devoid of syn-orogenic intrusive rocks. There

is therefore a pronounced time gap between c. 470 Ma mineral ages in the

Laurentian margin (Dalradian Supergroup) and c. 490 Ma mineral ages in

the Grampian ophiolitic rocks. P-T conditions also differ markedly, with

high T - low P metamorphism in the Grampian ophiolitic rocks and high P

- low T (blueschist-facies) metamorphic conditions in the subducted

Laurentian margin sediments of the Dalradian Supergroup.

It is envisaged that subduction of the leading edge of the

Laurentian plate initiated at c. 490 Ma, contemporaneous with the start

of ophiolite obduction and resulted in high-pressure metamorphism of

the Laurentian margin. The high-pressure rocks were transferred to the

hanging-wall plate and thrust back onto the margin, and exhumed by

extensional collapse preserving mineral cooling ages as old as ca. 475

Ma close to the margin. Away from the Laurentian margin, collisional

thickening created the thick Dalradian nappe stack and associated

Barrovian metamorphism, with possibly minimal involvement of

obducted oceanic lithosphere. Collisional thickening may have initiated

shortly after ophiolite obduction in order to generate the ca. 470 Ma

Grampian peak metamorphism in the Dalradian.

VARISCAN INTRA-OROGENIC EXTENSION IN SW IBERIA:

INJECTION OF ANATETIC LEUCOGRANITES AND RELATED

GOLD-MINERALISATIONS

Chichorro, M.A., CICEGE - DCT - FCT - , ma.chicho[email protected]

In SW Iberia, after a phase of crustal shortening and building of the

Appalachian and Variscan Mountains (when the Rheic Ocean between

Laurussia and Gondwana close), continental extension and onset of high-

medium-grade metamorphic terrains occurred. The high-medium-grade

metamorphic terrains in the Ossa-Morena Zone consist of strongly sheared

Ediacaran, Cambrian and Ordovician (c. 590–480 Ma) protoliths. The

dominant structure is a widespread steeply-dipping foliation with a gently-

plunging stretching lineation generally oriented parallel to the fold axes.

Despite of the wrench nature of this collisional orogen, kinematic

indicators of left-lateral shearing are locally compatible with an oblique

component of extension. U-Pb and

Ar-

Ar geochronology and structural

data constrain the Variscan wrenching in the Ossa-Morena Zone.

Wrenching is responsible for the developed of ductile extensional shear

zones, rapid exhumation of deep crust, metamorphic rocks, partial melting

and magma production in the interval c. 356-321 Ma. In the Boa Fé shear

zone of the Évora Massif, gneisses were exhumed from a depth of 11–15

km to 6-8 km, indicating a minimum vertical displacement of c. 4-6 km

and exhumation rates of 1 to 2-3 mm a

-1

. In the Évora Massif, the cooling

history was complex, with a first stage in the Tournaisian, a second stage

in the Visean (lasting 2 to 5 Ma), with a cooling rate of 60-80 to 150-

200ºC Ma

-1

, and a final stage in the Serpukhovian. The spatial distribution

of anatectic leucogranites veins/dykes running through a footwall

migmatite system, and reaching the Boa Fé extensional shear zone

operated under amphibolite to greenschist facies metamorphic conditions.

Statistical results show that frequency of thickness and spacing of the

leucogranitoid veins/dykes conform to power-law distributions comparable

to what is observed in volcanic systems. The fractal geometry of the

distribution of leucogranites stress the development of a dense framework

of thinner weakly or non-mineralised veins and dykes formed at higher

nucleation/growth ratios in the footwall migmatite system that contrast

with the emplacement of wider dykes and associated gold-mineralized

veins within the shear zone. The volume of injected leucogranites

veins/dykes into the Boa Fé shear zone is lower (15-20%) when compared

with the footwall (35-45%), and is comparable to an expanding footwall

shear zone with non-coaxial flow and volume increase.

CONSTRAINTS TO BASEMENT-INVOLVED FOLDING OF

UPPER-CRUSTAL ROCKS IN THE EAST RANGE OF THE

SUDBURY BASIN, ONTARIO

Clark, M.D., Riller, U. and Morris, W.A., McMaster University,

1280 Main Street West, Hamilton, ON L8S 4L8, clarkm8@

mcmaster.ca

Tilting of crystalline basement rocks associated with folding strain at

uppermost crustal levels is difficult to recognize if basement rocks are

devoid of traceable marker planes. Here we use the orientation of

Paleoproterozoic Matachewan dyke segments complemented by compiled

paleomagnetic data to identify tilting in Archean basement rocks

associated with kilometer-scale folds of the eastern Sudbury Basin,

Ontario. Spatial analysis of the strike of dyke segments is consistent with

generation of the NE-lobe and a newly identified anticline, referred to as

the West Bay Anticline, in the layered Sudbury Igneous Complex (SIC).

This anticline accounts better for the structural characteristics of the

eastern Sudbury Basin than a previously proposed anticline with west-

plunging hinge line. The West Bay Anticline is characterized by abrupt

plan-view thickness variations in the lower SIC and curved faults

displaying significant strike separations of SIC contacts. These structural

characteristics are consistent with folding strain imparted to the SIC and

adjacent Archean rocks during formation of the West Bay Anticline.

Sublayer embayments and associated quartz-diorite dykes served likely as

zones of mechanical weaknesses, at which the higher-order folds localized.

Unfolding magnitudes of the NE-lobe based on primary paleomagnetic

remanence directions are significantly smaller than inferred magnitudes

that are based on the assumption that the basal SIC contact was initially

planar. Thus, the basal SIC contact in the NE-lobe must have had a trough-

like geometry at the time of remanence acquisition. We advocate a

scenario for the formation of the NE-lobe, in which the trough geometry of

the SIC is primary rather than a consequence of tilting prior to

solidification of, and remanence acquisition in, the SIC. Finally, we

caution the interpretation of photo lineaments in eroded basement terranes

purely as a consequence of planar structural elements.

A GEOLOGIST RESIDENCY PROGRAM AT THE EDGE: FOGO

AND CHANGE ISLANDS, NEWFOUNDLAND

Cobb, Z., (President, Shorefast Foundation, Fogo Island, NL),

Shorefast Foundation, PO Box 102, Joe Batt’s Arm, NL A0G 2X0,

[email protected]

Shorefast Foundation is a private, non-for-profit organization based on

Fogo Island and Change Islands, off the northeast coast of Newfoundland.

With the people of Fogo Island and Change Islands, we are working

to establish a leading geotourism destination built upon the intrinsic

physical, creative and cultural assets of this elemental, powerfully remote

place. We want to and we will bring together the spirit and energy of

visitors and the local community to unleash the creative and economic

potential of this special place.

Shorefast Foundation is supporting economic diversification through

the development of world renowned geotourism products by creating a

unique destination for artistic, cultural, ecological and culinary pursuits at

“the edge of the earth”. Our projects build on the people, culture and

ecology of the islands to create a leading destination for geotourism and to

build another leg to the economy of the islands.

On Fogo Island we know that the rocks watched us arrive and we

don't forget that they will watch us leave – they know what came before us

and they connect us to the people who came before. There are stories in the

rocks. We take comfort in the knowledge that these old hills and these old

rocks underlie everything.

As part of its Guest Programming, Shorefast is developing a

geological outreach and education program for its guests, staff and the

residents of Fogo Island and Change Islands. The principal objectives of

the program are: (1) To explore the relationships between geology,

landscape, culture and art; (2) To provide geological education and

outreach through a series of lectures and guided tours on selected trails and

shorelines; and (3) To enhance the geological knowledge of the islands and

integrate that knowledge with other aspects of our natural and cultural

heritage. A key component of the Shorefast Geology Program will be the

establishment of a “Geologist in Residence” on Fogo Island, supported by

Shorefast in partnership with geologists and professional organizations.

We believe geologists can reveal these untold stories in the rocks,

through a residency program anchored on the rocks at “the edge of the

earth” and we invite the geological community to partner with us in this

program.

GEOLOGICAL HERITAGE, EDUCATION & ECONOMIC

DEVELOPMENT

Collier, L., Thompson, G. and Macleod, L., Fortune Head

Interpretation Center, PO Box 159, Fortune, NL A0E 1P0,

fhef@townoffortune.ca

Fortune Head ECO Friends, a not-for-profit organization, became

incorporated in May of 2007 to provide advice and direction pertaining to

the ongoing operations of the Fortune Head Interpretation Center located

in the town of Fortune, in this Province.

Their mandate is educate and preserve the significance of the Fortune

Head Ecological Reserve (located 1.6 km west of the town), which

contains the Global Stratotype Section and Point from the Precambrian Era

and the Cambrian period. This fossil find has been referred to as the

golden spike - making it unique to the entire world because it’s accessible,

easy to relate to other similar sedimentary rock formations elsewhere in the

world, and shows a thick, unbroken sequence of trace fossil types.

The aim of the organization is to develop and implement a strategy to

ensure sustainability of the Interpretation Center that will also provide

economic benefit to the region by utilizing the Reserve as a resource - an

anchor! We have come to the realization in a small area of our small, yet

beautiful Province that our unique and geological history can reap

benefits! Its preservation and promotion through educating our youth

through programs and activities, and of course engaging the general

public/tourists, creates an interest to visit - extending facts in the field of

geology, extending a stay in the area!

Fortune’s proximity to the French Islands of Saint Pierre and

Miquelon is a competitive advantage for us - with a steady stream of

tourism traffic waiting to board a ferry. Many of these tourists explore the

area, and acquire points of interest from the Visitor Information Desk

housed in the Center.

The Town of Fortune is investing in providing wages for a full-time

Business Development Officer for the Board (Center), whereby

professional development opportunities are provided. These opportunities

are an asset to developing quality educational programs for school groups

as well as interpretation for the general public. This position also is

responsible for other initiatives - package market developments, gift shop

and coffee bar operations.

As we continue to support information and education programs to

promote action in the field of geological heritage conservation we are

encouraging an interest for visitation to these sites and are able to

capitalize on lengthening the visit in the area, increasing economic

development for many small businesses.

STRANGE LAKE: GEOLOGY, MINERALIZATION AND

ALTERATION OF QUEST RARE MINERALS' B ZONE

Collins, P., patrick.collins@questrareminerals.com, Quest Rare

Minerals Ltd., 30 Poplar Avenue, St. John's, NL A1B 1C8

The Strange Lake alkalic complex, located along the Newfoundland and

Labrador and Quebec border, hosts abundant rare earth showings, one

historic non NI 43-101 resource (IOC; 52 Mt @ 1.3% TREO) and one NI

43-101 compliant resource (B Zone: @ 0.579% TREO cut-off, 140.6 Mt

@ 0.933% TREO indicated; 0.579% TREO cut-off, 89.6 Mt @ 0.882%

TREO inferred). The complex is compositionally zoned, with grossly

concentrically distributed, progressively REE—enriched phases of granite

and localized pegmatite-aplite. The B Zone, controlled 100% by Quest

Rare Minerals, is located along the north western contact between the

Complex and Proterozoic quartz monzonite and Archean gneiss and occurs

in the carapace of the intrusion. REE mineralization is hosted in sheeted

pegmatites that vary from several centimeters to over 30 metres of

vertically continuous pegmatite. Interpretation suggests that the thicker

sheets are continuous over more than 1000 m along strike. Within these

sheets, REE-bearing minerals are commonly concentrated in late volatile-

rich zones. An important aspect of mineralization at the B Zone is the high

proportion of heavy REE, a feature not common to many other REE

deposits. B Zone alteration is complex: major Na, Ca and Fe metasomatic

events are documented overlapping each other and affecting granite and

pegmatite mineralization both destructively and constructively.

Hf ISOTOPE EVOLUTION ARRAYS REVEAL THE LIMITS OF

UNIFORMITARIAN PLATE TECTONIC STYLE THROUGH

TIME

Collins, W.J., University of Newcastle, Newcastle, NSW, 2308,

Australia, bill.collins@newcastle.edu.au, and Murphy, J.B., St.

Francis Xavier University, PO Box 5000, Antigonish, NS

Hf isotope evolution arrays revealed from zircons provide a new way to

evaluate orogenic- and global-scale geodynamics, and in doing so, provide

information on how far back in time “Uniformitarian Plate Tectonic

Principles” can be applied. The accretionary Paleozoic Tasmanides

Orogenic Zone of eastern Australia is an orogen-scale example. Two

features are critical: (1) the complicated sequence of repeated extension-

contraction events recorded in the tectono-stratigraphy are mimicked by

the Hf isotopic (ε

) arrays: Short periods of crustal thickening are

associated with strong – ε

excursions, and alternate with much longer

periods of extension involving reversals to +ε

values; (2) the outboard

and successively younger orogens become progressively more juvenile

with time, which is also reflected in the wholerock Nd isotopic evolution,

and is consistent with the interpreted tectonic setting of a protracted

retreating accretionary orogenic system.

The long-term (500-250 Ma) progression to more juvenile (+ε

)

values for the Tasmanides forms part of a larger dataset that encompasses

the entire circumPacific orogenic system throughout the Phanerozoic (550-

0Ma). Data from the Andes, New Zealand, Japan, and the former

Gondwanan margin, all show a remarkably systematic contraction of the

Hf isotopic array with time. It indicates the circumPacific orogenic system

had Precambrian crust and subcontinental lithospheric mantle (SCLM)

permanently removed from beneath nascent active plate margins that

formed around the newly formed supercontinent (Gondwana) at ~500 Ma,

and that the old crust was progressively replaced with juvenile crust.

By contrast, the collage of sequential Eurasian collisional orogens

that young southward through Asia during the Mesozoic have a Hf isotopic

array that “fans” with time, so that the ε

range increases from ~35 epsilon

units at 500 Ma to ~55 units by the Neogene. The array suggests that

Precambrian SCLM was successively removed at the active margin of

each orogen (during subduction), but was then replaced by similar SCLM

during continental collision, as old continental crust was underthrust and

remelted at the termination of each Wilson cycle.

The two contrasting Hf isotopic arrays reflect contrasting protracted

(500 Ma duration) global-scale, orogenic systems that can be tracked

through the Precambrian. They suggest that circumPacific-style tectonics

were operating back to 2 Ga, possibly to ~ 3Ga, and that supercontinental

assembly associated with Wilson-style tectonics began at least 2.2 Ga ago.

HOW DID TERRANES OF TIMANIAN, CALEDONIAN AND

URALIAN AFFINITIES END UP IN THE NORTH AMERICAN

CORDILLERA?

Colpron, M., Yukon Geological Survey, Whitehorse, YT Y1A 2C6,

Maurice.Colpron@gov.yk.ca, and Nelson, J.L., BC Geological

Survey, Victoria, BC V8W 9N3

Exotic terranes of inferred Arctic affinity form an outer belt within the

North American Cordillera extending from Alaska to northern California.

These include Arctic Alaska-Chukotka, Farewell, Alexander, and the

Eastern Klamath and Northern Sierra terranes. The geological history,

fossil and detrital zircon data for these terranes show strong correlations

and linkages among them, and many features in common with the northern

Caledonides, the Timanide orogen, and the Urals.

Neoproterozoic successions from a number of these terranes include

early Neoproterozoic (ca. 980-920 Ma and ca. 870-850 Ma) magmatism

and late Neoproterozoic arc magmatism (ca. 700-540 Ma). These contrast

with the western Laurentian margin at that time, which was characterized

by epeirogenic basinal sedimentation and rifting related to breakup of

Rodinia, but are similar to magmatism in the north Atlantic (Valhalla) and

in the Timanides of NE Baltica. In the Alexander terrane, the late

Neoproterozoic arc succession is overlain by Ordovician-Silurian arc

volcanics and related plutons, and Silurian-Devonian conglomerate and

sandstone that are compared with Old Red Sandstone. In northern

California, Ordovician-Early Devonian mélanges contain blocks of both

Neoproterozoic and early Paleozoic arc magmatic rocks, Ordovician

blueschist, and are associated with late Neoproterozoic and Silurian

ophiolites. These features have more in common with the Caledonian-

Appalachian orogen than with the early Paleozoic passive margin of

western Laurentia.

Early Paleozoic faunas from most of these terranes have strong

affinities to either Siberia and/or Baltica. Detrital zircon populations from

early Paleozoic sandstones in these terranes commonly show a nearly

continuous spread of ages between 2.0-1.0 Ga, a pattern characteristic of

Baltica. Some samples display healthy populations of late Neoproterozoic

(ca. 700-550 Ma) and/or Ordovician-Silurian (ca. 450-420 Ma) zircons;

patterns ascribed to Timanian and Caledonian sources, respectively.

Together, these features suggest that Cordilleran terranes of inferred

Arctic affinity probably occupied an intermediate position between

Baltica, Laurentia and Siberia, in proximity to the northern Caledonides in

Neoproterozoic-early Paleozoic time. Westward dispersion of these

terranes is interpreted to result from development of a Scotia-style

subduction system between Laurussia and Siberia in mid-Paleozoic time –

the NW Passage – following closure of the Iapetus ocean. Diachronous

Late Silurian to Early Devonian orogenic activity across Arctic Canada

records passage of some of these terranes. Westward propagation of a

narrow subduction zone coupled with a global change in plate motion,

linked to closure of the Rheic ocean, are proposed to have led to initiation

of subduction along the western margin of Laurentia.

LAKE SUPERIOR-TYPE IRON FORMATIONS IN THE

LABRADOR TROUGH – AN OVERVIEW

Conliffe, J. and Kerr, A., Mineral Deposits Section, Geological

Survey of Newfoundland and Labrador, PO Box 8700, St. John's, NL

A1B 4J6

The Labrador Trough in western Labrador and northeastern Quebec hosts

numerous world-class iron ore deposits within Paleoproterozoic (2.17 to

1.87 Ga) supacrustal rocks. These deposits have been mined since 1954,

with five currently producing mines in Labrador and Quebec and a number

of further projects under development. Iron ore deposits are hosted in the

Sokoman Formation, a 30-170m thick sequence of cherty iron rich

sediments which outcrop continuously for more than 1100km. They are

classified as Lake Superior-type iron formations, which formed as a

chemical sediment in shallow to deep-water environments. The Sokoman

Formation is variably altered and metamorphosed, which has important

implications for the economic viability of iron ore deposits.

Four main types of iron ore deposits exist within the Sokoman

Formation. The most widespread are weakly metamorphosed sedimentary

iron formations (~30% Fe), termed taconites. Although not presently

exploited, these deposits represent very large resources of low-grade

material. Metamorphosed iron formations (metataconites) are present in

the southern part of the region, which was affected by Grenvillian

metamorphism and deformation. Recrystallization to coarser-grained

magnetite and specular hematite produces material that is higher in grade

than the taconites (up to 40% Fe), and considerably easier to beneficiate.

Most current iron production in the Labrador Trough comes from

metataconite deposits (Carol Lake and Scully Mine in Labrador, Mont

Wright and Bloom Lake in Quebec). Soft, friable, fine-grained secondary

iron ores with >55% Fe, termed direct shipping ores, are found mostly in

the Schefferville District. Enrichment of primary taconites is believed to be

related to groundwater circulation and supergene enrichment associated

with deep Mesozoic tropical weathering. Direct shipping ores mined in the

Schefferville area between 1954 and 1982 amounted to 250 million tonnes,

and mining operations have recently restarted. Finally, hard high-grade

(~60% Fe) hematite ores have been described from several locations.

These deposits are economically unimportant at present, but their origins

may be important in the context of genetic models for high-grade iron ore

mineralization elsewhere in the Labrador Trough.

Current research is focused on developing genetic models of iron ore

deposits in the Labrador Trough, combining detailed fieldwork with

geochemical techniques such as fluid inclusion microthermometry and

stable isotopes. Combined hypogene-supergene models for the origins of

high-grade iron ore deposits in other parts of the world such as Australia

and Brazil require further investigation in the context of the Labrador

Trough, and may have implication for future exploration.

TOWARDS A NEW ABSOLUTE CHRONOLOGY FOR THE

EARLY SOLAR SYSTEM

Connelly, J.N., Bizzarro, M., Centre for Star and Planet Formation,

Geological Museum, Copenhagen University, Øster Voldgade 5-7,

1350, Copenhagen K, Denmark, connelly@snm.ku.dk, Ivanova, M.,

Vernadsky Institute, 19 Kosygin Str., 119991 Moscow, Russia, and

Krot, A.N., Hawai‘i Institute of Geophysics and Planetology, 1680

East-West Rd, Honolulu, HI 96822, USA

The ages of calcium-aluminum inclusions (CAIs) and chondrules underpin

our understanding of the timing and nature of critical events in the first ca.

5 million years of solar system formation. We have undertaken a study to

determine the Pb and U isotopic compositions of a set of CAIs and

chondrules to construct a suite of robust absolute ages for the formation of

these inclusions from CV meteorites. Measuring U isotopic compositions

of small amount of U (<5 ng) from these inclusions has become necessary

due to the recent recognition that the

238

235

U is not invariant in all

meteoritic materials. Pb from each inclusion is parsed into 10 to 15

aliquots via strategic stepwise dissolution using progressively stronger

acids.

One of the CAIs (22E from Efremovka) is mineralogically similar to

fine-grained spinel-rich CV CAIs formed by gas-solid condensation from a

gas depleted in refractory rare earth elements. As such, it is an ideal

candidate to provide a benchmark age of CAI formation and, by inference,

the solar system. This inclusion yields an age of 4567.34±0.27 Ma, an age

that overlaps 2 other CAIs we have dated from this same meteorite. The

concordance of these Pb ages for CAIs is consistent with Al-Mg data that

suggest a brief episode of CAI formation. Relative to this benchmark age

for our solar system (T0), we find that chondrules from the CV chondrite

Allende range from as old as T0 to as young as 4564.8±0.2 Ma. The

youngest chondrule age requires that the CV chondrite parent body did not

accrete until 2.5 Myr after T0, consistent with the insufficient amount of

Al to cause widespread melting of the parent body by this time.

The development of U isotopic analyses for sample limited materials

was the last technical step required to erect the first assumption free

absolute chronometric framework for the first 5 Myr of the solar system.

The emerging picture is one of discordance between ages from the U-Pb

and Al-Mg systems, an observation that we attribute to an inhomogeneous

distribution of

Al within the inner solar system. There is a better

agreement for the Hf-W short-lived chronometer implying homogeneity of

182

Hf in the precursor materials to planets and planetesimals within the

inner solar system.

KEEPING THE LID ON: THERMOCHRONOLOGY FROM THE

MONT LAURIER TERRANE, GRENVILLE PROVINCE, QC

Cope, N.

, Schneider, D.A.

and Holm, D.K.

Kent State University,

Kent, OH 44242 USA;

University of Ottawa, Ottawa, ON, K1N 6N5

Convergence during the Grenvillian accretion led to crustal thickening and

juxtaposition of the currently shallow southeast-dipping imbricated

terranes of the Central Metasedimentary Belt (CMB) in eastern Canada.

The Mont Laurier terrane of the CMB (Quebec) is composed of a

Mesoproterozoic back-arc sequence metamorphosed to upper amphibolite /

granulite facies (at conditions of 6 ± 1 kbar and 650-700°C). Notable peak

assemblages include Fo-bearing marbles and Sil + Kfs migmatites, with

little to no retrogression. The terrane is further divided into the Marble

(west) and Quartzite (east) domains, separated by the easterly dipping

Heney deformation zone (HDZ). LA-ICPMS U-Pb geochronology on

select migmatites from both domains yielded bimodal U-Pb zircon and

monazite age populations at ca. 1230 Ma and ca. 1160 Ma, with mineral

ages from the leucosomal portion of the migmatite populating the younger

age population. Ar-Ar mineral analyses yielded generally well-behaved

age spectra with antithetic Ca/K spectra exhibiting full or near plateaux. In

proximity to the HDZ, hornblende and phlogopite ages are ca. 1145 Ma

and ca. 1150 Ma, respectively, whereas to the west in the Marble Domain

hornblende ages are markedly younger (ca. 970-950 Ma). Biotite ages of

905-885 Ma are similar to the majority of biotite Ar-Ar ages reported

across the southern Grenville Province. The Marble and Quartzite domains

record similar higher temperature U-Pb mineral ages indicating initial

Elzevirian (ca. 1245-1225 Ma) metamorphism followed by Shawinigan

(ca. 1190-1140 Ma) high-grade metamorphism with attendant partial

melting. Rapid cooling of the Quartzite Domain at the end of the

Shawinigan Orogeny together with the complete lack of evidence for any

metamorphic overprinting in the Otter Lake region during the long-lived

Grenville Orogeny (1095-980 Ma) is consistent with this region residing in

the mid-crust, and possibly part of an "orogenic lid" (Rivers 2008, 2009).

Cooling of Marble Domain rocks through 500°C nearly 200 m.y. after

cooling of the Quartzite domain suggests considerable late normal

displacement across the HDZ analogous to that proposed for terrane

bounding shear zones like the Robertson Lake and Bancroft shear zones in

Ontario, perhaps related to vertical collapse or lateral stretching of the

orogenic lid. S- and Z-fold pairs and kinematic indicators in the migmatite

packages are consistent with a vertical collapse model. Relatively uniform

biotite Ar-Ar ages across the province suggest orogen-wide thermal

stabilization at ca. 900 Ma.

THE SVECONORWEGIAN ACTIVITY IN CALEDONIAN NAPPES

OF THE MIDDLE ALLOCHTHON SOUTHERN NORWAY

Corfu, F. and Roffeis, C., University of Oslo, Department of

Geosciences, Postbox 1047 Blindern, N-0316 Oslo, Norway,

[email protected]

The nappe stack in the southern Scandinavian Caledonides comprises

thrust sheets of crystalline rocks formed predominantly between 1700 and

1500 Ma, with minor components at around 1450 and 1250-1200 Ma.

They were all pervasively affected by Sveconorwegian deformation and

metamorphism, and some parts also underwent Sveconorwegian

magmatism. The intensity of the metamorphism varies in different

segments: for example, it reached granulite facies and anatexis in the

central Jotun Nappe Complex but it attained a much lower grade in

peripheral trust sheets. The metamorphic activity was multiphase and in

the Jotun and Lindås nappes it occurred mainly between 950 and 900 Ma.

By contrast, in the Espedalen massif, and especially in parts of the

Hardanger-Ryfylke Nappe Complex, there is good evidence for an episode

of metamorphism at around 1000 Ma, which in the latter case also

corresponds to emplacement of a major pluton. Emplacement of

anorthosite in the Jotun and Lindås nappes occurred at about 970 Ma, in

the latter as a component of a 40 Ma suite that includes mangerites to

jotunites. Younger, ca. 960-950 Ma gabbro to tonalite occurs in the

Sognefjell complex undeneath the Jotun Nappe Complex. Some of these

nappes were only juxtaposed during the Caledonian events, and their

distinct features point to a derivation from different crustal domains.

However, their broadly similar Late Sveconorwegian history is consistent

with a provenance from parts of the Sveconorwegian orogen. Important

analogues in the Autochthon are the Rogaland anorthosite complex, the

suites of 980 to 930 Ma granites, and the late Sveconorwegian regional

metamorphism interpreted by Bingen et al. (2008, Norwegian Journal of

Geology) to reflect final convergence (Falkenberg phase) followed by

gravitational collapse (Dalane phase).

CONTRASTING STYLES BETWEEN THE TRANS-HUDSON AND

GRENVILLE OROGEN: SECULAR CHANGES IN TECTONIC

PROCESSES OR DIFFERENT EVOLUTIONARY PATHS?

Corrigan, D., Geological Survey of Canada, 601 Booth Street,

Ottawa, ON K1A 0E8

The Paleoproterozoic Trans-Hudson and Meso-Proterozoic Grenville

orogens present quite different parameters in terms of overall crustal

thickness attained, amount of crustal reactivation, levels of exhumation

achieved, exhumation mechanisms, as well as type of magmatism

involved. The Grenville Orogen, in particular, appears to have attained

overall greater crustal thicknesses, has more abundant occurrences of

exhumed eclogites and hosts large metamorphic core complexes and syn-

convergent extensional faults, the latter being quite rare in the Trans-

Hudson. From a magmatic perspective, the Grenville orogen hosts unique

anorthosite-mangerite-charnockite-granite (AMCG) complexes, which

have no know equivalents in the Trans-Hudson orogen except perhaps for

minor occurrences of anorthosite, gabbro and related anhydrous granitoid

rocks in the Snowbird Tectonic Zone. A valid question to ask is whether

these differences are the product of secular changes in tectonic processes

between ca 1.90 and 1.11 Ga or simply reflect different parameters

affecting both orogens such as duration of convergence, rate of

convergence, heat flow, lithosphere thickness, the size and shape of

colliding blocks, pre-collisional accretionary tectonics, etc. The similarities

observed in accretionary and tectonic processes between the Trans-Hudson

and more modern examples (e.g., parts of the Appalachian or Himalayan

systems) is striking, suggesting that tectonic processes 1.9 Ga ago were

likely more similar than different, to those observed today. This cast

doubts in explaining the broad contrasts observed between Trans-Hudson

and Grenville orogens in terms of significant changes in tectonic processes

through time, and points instead towards more mundane explanations such

as variations in specific parameters during orogenesis, with the most

important one perhaps being the duration of continent-continent

convergence.

SCANNING THE BARCODE USING GEOCHEMISTRY: SUPER-

CONTINENT RECONSTRUCTION BACK TO 2.7 Ga FROM

LARGE IGNEOUS PROVINCES

Cousens, B.L.

, [email protected], Hollings, P.

, Kerr,

A.C.

and Ernst, R.

Earth Sciences, Carleton University, Ottawa,

ON K1S 5B6;

Dept. Geology, Lakehead University, Thunder Bay,

ON P7B 5E1;

Earth and Ocean Sciences, Cardiff University, Wales,

UK, CF10 3YE

Over the past decade there have been advances in understanding of the

geochronological links between igneous rock units on various continents.

This “bar coding” of dyke swarms and other parts of large igneous

provinces (LIPs) has allowed greater precision in continental

reconstructions utilizing the model of mantle plumes and radiating dyke

swarms related to continental breakup. As part of the project

“Reconstruction of Supercontinents Back to 2.7 Ga Using the Large

Igneous Province Record” (industry, university, government consortium;

www.supercontinent.org) we are focusing on the geochemistry of LIPs

fragmented by plate tectonics. Magmatism from all parts of a single event

should be related petrologically, and may share similar mantle source

compositions, a differentiation history that varies with distance from

proposed plume centres, and a crustal interaction history that varies

depending on the age/composition of the intruded crustal block. Several

M.Sc. and Ph.D.-level projects are planned. First is the Gunbarrel event, a

ca. 780 Ma series of sills and dykes that are exposed from the Slave craton

south to the Wyoming craton and is associated with the breakup of Rodinia

(Sandeman et al., this meeting). A second project involves globally-

distributed magmatism at 1380 Ma recognized in western Laurentia,

northern Greenland, the Anabar Shield of Siberia, southeastern Baltica (the

southern Urals), Antarctica, the Congo and southern Kalahari craton.

These widespread 1380 Ma extensional magmatic events may mark the

final breakup of the Mesoproterozoic supercontinent Nuna (aka

Columbia). A third geochemical target is 1890-1870 Ma, mainly mafic

magmatism across the Slave craton and its marginal platformal sequences,

coeval with the final docking of the Hottah terrrane with the Slave craton.

An integrated geochemical and isotopic comparison of all these units with

respect to their position and distribution across the Slave craton will

investigate the number and distribution of magmatic sources, the extent of

lithospheric contamination, and the degree to which subduction related vs.

plume and asthenospheric sources were involved. In addition, we plan to

investigate the geochemical relationships between the ca. 1.1 Ga

magmatism of the Midcontinent Rift of North America (Hollings et al.,

this meeting) the Umkondo igneous province of the Kalahari craton and

other locations. Another focus will be ca. 1750 Ma LIP magmatism now

recognized in Canada, Siberia, Baltica and elsewhere. Ongoing projects

include circum-Superior province magmatism at 1880 Ma and

Matachewan (ca. 2.45-2.49 Ga) events in the Wyoming and Superior

cratons and comparison with other regions with matching LIP ages.

SULFUR ISOTOPES REVEAL THAT PEAK OF DECCAN

VOLCANISM POST-DATES THE CRETACEOUS-PALEOGENE

MASS EXTINCTION

Cousineau, M.L.

, [email protected], Therrien, F.

, Maruoka,

, Fortin, D.

and Wing, B.A.

University of Ottawa, Marion Hall,

Ottawa, ON K1N 6N5;

Royal Tyrell Museum of Palaeontology, PO

Box 7500, Drumheller, AB T0J 0Y0;

University of Tsukuba, 1-1-1

Tennodai, Tsukuba City, Ibaraki 305-8572, Japan;

McGill

University, 3450 University St., Montréal, QC H3A 2A7

The Cretaceous-Paleogene (KPg) boundary marks one of the most

significant mass extinctions in Earth history, leaving an evolutionary

imprint that can be still be seen in the modern biota. The leading

hypothesis attributes the extinctions to a bolide impact with sulfate-rich

rocks in the Yucatán Peninsula, Mexico. The major competing hypothesis

is the emplacement of the Deccan continental flood basalts in western

India. Both processes would have released massive amounts of sulfur in

the atmosphere. Absolute age measurements for the largest Deccan

eruptions and the KPg boundary suggest the two events were

contemporaneous, but measurement uncertainties have so far thwarted

attempts at resolving the relative timing of these two competing extinction

triggers.

We measured whole-rock sulfur content and isotopic composition

(δ

S) at a resolution of 2 cm or less across the KPg boundary at the

Knudsen’s Coulee Section (KCS), near Drumheller, Alberta, Canada. The

KCS is among the most complete and best-preserved terrestrial KPg

sections in the world and features many key markers, including the

boundary claystone, an iridium anomaly, and a fern-spore spike.

Our high-resolution study shows positively-correlated variations in

both signals, consistent with sulfur addition to an initially sulfur-poor

terrestrial environment. Profile modeling using simple Gaussian functions

shows that addition of

S enriched sulfur to the KCS occurred in three

pulses: a pair of overlapping pulses originating at the KPg boundary (one

intense pulse restricted to the first ≈2 cm above the boundary, and a

second, more moderate, extending over ≈9 cm), and a third pulse, ≈11 27

cm above the boundary. Mixing curves show the

S enriched sulfur is

derived from two distinct sources. Measurements associated with the brief

and intense pulse fall on a high δ

S (δ

S≈18‰) curve, comparable to

target rocks, while those associated with the broader pulses fall on a lower

S (δ

S≈8‰) curve, comparable to sulfate aerosols from oxidized

volcanogenic SO

The environmental scenario we propose places the onset – not the

end, or peak – of a major Deccan eruptive phase, lasting ≈90 kyrs, at the

KPg boundary, contemporaneous with a bolide impact. A subsequent

eruptive phase started ≈120 kyrs post-impact, and lasted for ≈90 kyrs. The

ratio of volcanogenic- to impact-derived sulfur at the KCS is ≈5:1,

consistent with independent published estimates of 3:1 to 88:1. Although

Deccan eruptions may have delayed the recovery of both marine and

terrestrial ecosystems after the KPg extinctions, our results highlight the

bolide impact as the primary extinction trigger.

DISTAL EXPRESSIONS OF MINERALIZING SYSTEMS:

MAPPING THE THERMAL FOOTPRINTS OF CARLIN-TYPE AU

SYSTEMS USING APATITE FISSION TRACK, APATITE (U-

Th)/He AND ZIRCON (U-Th)/He DATING

Cruickshanks, M., mcruickshanks@eos.ubc.ca, Hickey, K.A.,

Barker, S.L.L., Dept. Earth & Ocean Sciences, University of British

Columbia, Vancouver, BC, V6T 1Z4, Donelick, R.A., Apatite to

Zircon Inc., Viola, ID, USA, and Reiners, P.W., Department of

Geosciences, University of Arizona, Tucson, Arizona, USA

Targeting Carlin-type Au deposits in northern central Nevada is hindered

by a lack of extensive pervasive visual alteration and the disseminated

nature and submicron scale of Au mineralization. New methods for better

defining the expressions of these hydrothermal systems are needed to aid

future exploration for mineral deposits. Heat associated with hydrothermal

systems is transferred advectively within the fluid flow path as well as

conductively beyond the limit of hydrothermal fluid flow. The conductive

thermal halo should be the most distal expression of hydrothermal fluid

flow as it will extend beyond the front of fluid-rock interaction necessary

for mineralogical and geochemical alteration.

Low temperature thermochronology provides one possible means for

mapping out the thermal halo of hydrothermal fluid flow. Here we present

apatite fission track and apatite and zircon (U-Th)/He data used to map

low-temperature thermal anomalies associated with the mineralizing

hydrothermal fluid flow event, defining the limit of heat flow associated

with the formation of Carlin-type Au deposits in the northern Carlin Trend.

Thermal resetting of apatite fission track ages was observed up to 800 m

from mineralization in granodiorite. In surrounding host sediments,

however, the complexity of structural and stratigraphic controls and

resulting fluid flow network makes a distinct thermal footprint more

difficult to define, although a similar sized expression is inferred.

LATE CRETACEOUS EXHUMATION IN NORTHERN CENTRAL

NEVADA: EVIDENCE FROM LOW-TEMPERATURE APATITE

AND ZIRCON (U-Th)/He AND APATITE FISSION TRACK

THERMOCHRONOLOGY

Cruickshanks, M., [email protected]bc.ca, Hickey, K.A., Dept

Earth & Ocean Sciences, University of British Columbia, Vancouver,

BC, V6T 1Z4, Donelick, R.A., Apatite to Zircon Inc., Viola, ID,

USA, and Reiners, P.W., Department of Geosciences, University of

Arizona, Tucson, AZ, USA

The western Cordillera of North America at the latitude of northern

Nevada has a long history of contraction and crustal thickening through the

Late Paleozoic and Mesozoic, culminated in the Late Cretaceous Sevier

and Cretaceous to Eocene Laramide thrusting in Utah, Wyoming and

Colorado region. Mesozoic shortening was responsible for the thickened

crust that ultimately formed the Rocky Mountain ranges that run the length

of the North American Cordillera.

We present apatite fission track, apatite (U-Th)/He and zircon (U-

Th)/He thermochronology data from vertical deep drill holes in Jurassic

stocks from the northern Carlin Trend in north central Nevada. This data

shows unequivocal evidence for rapid cooling and exhumation of the this

region of the Sevier hinterland in the Late Cretaceous between 80-60 Ma.

Total exhumation since the emplacement of the stocks at 158 Ma is

estimated at 3-3.5 km. Calculated exhumation rates varied from ~0.01

km/Myr pre- and post- 80-60 Ma cooling to 0.1-0.2 km/Myr during the

main period of exhumation.

The Mesozoic evolution of the region influenced ongoing

development of topography through the Cenozoic in this part of the

Cordillera. Previous workers have proposed that the latest stage of the

Sevier thrusting was coincident with crustal thinning and collapse of an

overthickened hinterland in Nevada. They cite evidence for mid crustal

depressurization and cooling, but note little evidence for surface breaking

faults and erosional exhumation. No major low angle faults are known

within the study area, precluding tectonic exhumation as a likely cause of

the rapid cooling. Instead, erosion is considered most likely cause of

exhumation. Although there are no known sedimentary basins of that age

in north central Nevada, large drainage systems identified to the far west

and east of the hinterland may have transported sediments to more distal

depocentres. Evidence for Late Cretaceous sedimentary input into the

Cretaceous to Eocene Sheep Pass Formation in central east Nevada

suggests that there was also internal drainage within the Sevier hinterland.

MULTI-ELEMENT HISTOLOGICAL ANALYSIS OF AN

ORNITHOMIMID (DINOSAURIA) BONE BED FROM THE

UPPER CRETACEOUS HORSESHOE CANYON FORMATION

(MAASTRICHTIAN) OF ALBERTA

Cullen, T.M., Carleton University, 1125 Colonel By Dr., Ottawa, ON

K1S 5B6, [email protected]ton.ca, Ryan, M.J., Cleveland

Museum of Natural History, 1 Wade Oval Dr., Cleveland, OH

44106-1767, Evans, D.C., Royal Ontario Museum, 100 Queen’s

Park, Toronto, ON M5S 2C6, Currie, P.J., University of Alberta,

Edmonton, AB T6G 2E9, and Kobayashi, Y., Hokkaido University

Museum, Sapporo, Japan, 060-0810

Bone beds and bone microstructure can each provide important data from

which hypotheses regarding ontogeny, metabolism, ecology, and

behaviours of ancient vertebrates can be established. Ornithomimids (or

‘ostrich dinosaurs’) were a group of small, gracile theropods found

throughout the Cretaceous of North America and Asia. Multiple hind limb

elements (femora, fibulae, tibiae, metatarsals) from three individuals from

the first North American bone bed of late Cretaceous ornithomimids were

examined histologically. Each specimen showed fibrolamellar tissue, near-

equal spacing of lines of arrested growth (LAGs), and osteon development

at outer bone margins, indicating that they were experiencing rapid growth

at death. However, this rate was somewhat reduced in the largest

individual, possibly indicating the onset of maturation. The two smaller

individuals were determined to be two and three years of age at death,

while the approximately 10% larger individual was found to be four years

old at the time of death. This pattern is similar to that reported for other

theropods, but it is potentially different from Asian ornithomimids in

showing evidence of growth reduction at a much earlier age. These

differences could be related to predator-prey relationships, and could affect

our interpretations of the ecology of the late Cretaceous dinosaur

communities of western Canada.

Of note is that LAGs and other histological signals remain consistent

across the different hind limb elements examined within individuals. This

indicates that for at least some small theropods, age at death can reliably

be determined from various postcranial long bones. This has the potential

to significantly increase the database available for determining growth

patterns within various taxa, because isolated limb elements can be used as

long as body size at the time of death can be determined.

TECTONICS OF POLYCYCLIC GNEISS DOMAINS OF THE

CENTRAL GNEISS BELT (CGB), GRENVILLE PROVINCE,

ONTARIO

Culshaw, N.G., culshaw@dal.ca, Foster, J.F., Jamieson, R.A.,

Dalhousie University, Halifax, NS B3H 4R2, Gerbi, C., University of

Maine, Orono, ME 04469-5790 USA, and Slagstad, T., Geological

Survey of Norway, 7491 Trondheim, Norway

An extensive substrate of, thrust-stacked and polycyclic, Laurentian

margin domains underlies much of the CGB. In the northern CGB the Britt

and Powassan domains comprise polycyclic Paleo- and Mesoproterozoic

orthogneiss metamorphosed at ca 1450 Ma and intruded by monocyclic

plutons. In the eastern CGB, thrust contacts between polycyclic gneiss

sheets are widely exposed in the Algonquin domain but are obscured in the

western CGB by overlying monocyclic units.

At their northwestern boundary the imbricated polycyclic domains

(Britt and Powassan) overlie a belt of polycyclic but structurally distinct

units (Grenville Front Tectonic Zone and Nepewassi domain, GFTZ-ND)

which abut the Grenville Front. The south eastern boundary of the GFTZ-

ND is irregular with NNW and ENE stair-stepping segments separating the

Archean-cored ND from Britt. Late NW motion of the Britt domain across

and along this boundary has varied effects. Transpressive overprinting is

restricted to the margins of the GFTZ but Nepewassi domain response is

more widespread with formation of large scale refolds and shear zones

within its interior. NNW sectors of the ND-Britt boundary are strongly

sheared.

A current model of CGB tectonics invokes early thickening followed

by lower crustal nappe flow allowed by melt-softening in monocyclic

rocks. Historically, the structural, metamorphic and geochronological

evidence supporting this model is from the western CGB where

monocyclic domains dominate. New, and sparse older, geochronological

data from the Algonquin domain match key age groupings from the

western CGB and together with structural and metamorphic data support a

nappe flow model for the polycyclic substrate.

Several intriguing questions remain: are similar processes

responsible for producing retrograde eclogites, locally accompanied by

anorthosite gneiss, within the polyclic domains (and along polycyclic-

monocyclic boundaries) and early tectonic interleaving of monocyclic

upper crust (basal Parry Sound domain back-arc deposits) with lower crust

(anorthosite gneiss)? Is this process attempted subduction (of, respectively,

the Laurentian margin and back-arc lithosphere) or simply related to

Himalayan scale thickening?

ANOXIA IN THE TERRESTRIAL ENVIRONMENT DURING THE

LATE MESOPROTEROZOIC

Cumming, V.M.

, v.m.cumming@durham.ac.uk, Poulton, S.W.

and

Selby, D.

Earth Sciences Department, Durham University, South

Road, Durham, DH1 3LE, UK;

School of Civil Engineering and

Geosciences, Drummond Building, Newcastle University, Newcastle

upon Tyne, NE1 7RU, UK

The 1.1 Ga intracratonic Mid-Continent Rift System of central North

America reached >2000 km in length prior to rift failure due to the onset of

the Grenvillian orogeny. In the Lake Superior region up to 30 km of

volcanic and sedimentary rift-fill sequences make up the Keweenawan

Supergroup. This succession provides one of the few comprehensive

records of early rifting processes. It consists of 20 km of predominantly

flood basalts that are overlain by post-rift fluvial and alluvial red beds of

the Oronto and Bayfield Groups. The Oronto Group consists of fluvial and

alluvial volcaniclastics with one exception; the Nonesuch Formation, a 200

m thick lens of organic-rich grey to black siltstones and shales.

Depositional characteristics of the Nonesuch Formation suggest that it was

deposited in a restricted lacustrine setting; however, evidence from

biomarkers has also suggested that there may have been a marine incursion

during Nonesuch deposition.

Organic-rich rocks are important biogeochemical records of

surrounding geological and climatic processes, with lacustrine systems in

particular providing very high resolution archives. Geochronology of the

post-rift sedimentary units is poorly constrained. U-Pb zircon dates

constrain the rift-related volcanic units within the lower Copper Harbour

Conglomerate (underlying the Nonesuch Formation) at 1087 Ma, thus

marking the end of volcanic rift deposition. Here we present new Re-Os

geochronology that provides a depositional age for the Nonesuch

Formation which is in stratigraphic agreement with the underlying 1087

Ma volcanics of the Copper Harbour Conglomerate. Additionally, Os

isotope compositions provide a new line of evidence which strongly

suggests that these deposits are truly lacustrine in origin.

Continental paleoenvironmental conditions in the Late Mesopro-

terozoic are poorly understood. The geochemical signature recorded in the

Nonesuch Formation gives an insight into these conditions and the redox

chemistry of lake systems at this time. Iron speciation data for 45

Nonesuch Formation samples from core PI-1 show that anoxic ferruginous

conditions dominated in this lake system. This is contrary to previous

studies which suggested a euxinic depositional setting. These data have

implications for the habitats of early eukaryotes and suggest that the

terrestrial environment, similar to the oceans, was dominantly anoxic and

ferruginous at this time. This contrasts with a recent suggestion that

oxygenation of terrestrial aquatic environments preceded oxygenation of

the marine realm.

GEOLOGY AND GEOCHEMISTRY OF THE COUBRAN LAKE

BASALTS, A MIDCONTINENT RIFT-RELATED SEQUENCE

WITHIN THE CENTRAL COLDWELL COMPLEX, MARATHON,

ONTARIO

Cundari, R.

, Hollings, P.

, Scott, J. and Campbell, D.

Department

of Geology, Lakehead University, 955 Oliver Road, Thunder Bay,

ON P7B 5E1;

Ontario Geological Survey, Ministry of Northern

Development and Mines, Suite B002, 435 James St. South, Thunder

Bay, ON P7E 6S7

The Coubran Lake Basalts occur as part of a large, preserved roof pendant

of volcanic rocks in the center of the ~28 km diameter Mesoproterozoic

Midcontinent Rift-related, alkalic Coldwell intrusive complex near

Marathon, on the northern shore of Lake Superior. In one location, basalt

is exposed along a thin (3 to 5 m wide), ~350 m long stripped area. Thin

(~2 m), amygdaloidal flows appear to be draped over the side of a hill and

exhibit ropy flow tops, suggesting subaerial emplacement. The volcanic

pile is estimated to comprise five or six individual flows at this locality.

The basalts are locally hornfelsed, altered and are intruded by syenite

dykes. They likely predate the main phase of syenitic magmatism that

produced the central part of the intrusive complex.

Geochemically, the unit comprises two groups (types A and B)

distinguished by their incompatible element abundances. Basalt type A

dominates the succession and displays light rare-earth element (LREE)

enrichment (La/Sm

= 1.99 to 4.76) and heavy rare-earth element (HREE)

fractionation (Gd/Yb

= 1.96 to 2.30). Basalt type B lies towards the base

of the unit, forming the lowermost 10% of the exposed sequence and

displays strong LREE enrichment (La/Sm

= 7.44 to 9.32) with HREE

ratios comparable to that of type A (Gd/Yb

= 2.48 to 2.52). Major element

chemistry for both groups displays very little variation, with SiO

values

ranging from 49.33 to 51.98 wt%, TiO

values ranging from 0.78 to 0.99

wt%, and MgO ranging from 4.77 to 7.34 wt%.

Midcontinent Rift-related volcanic rocks have been classified and

correlated as five distinct groups (basalt types I through V) based on their

major element, trace element and Nd isotopic analyses. Basalt type II

represents a reversely polarized group of volcanic rocks deposited during

the first phase of magmatism (>1105 Ma). They are characterized by

LREE enrichment, HREE fractionation, as well as a negative niobium

anomaly. Primitive mantle-normalized diagrams show the Coubran Lake

Basalts to be similar to basalt type II, which includes the upper Siemens

Creek Volcanics, the central suite of the Osler Group and the recently

recognized Devon Volcanics. Further correlative work, including

radiogenic isotope analysis and paleomagnetism, is ongoing in order to

place the Coubran Lake Basalts in context with other Midcontinent Rift-

related volcanic units.

STRUCTURAL STYLE AND THERMAL HISTORY OF THE

EASTERN LANCASTER SOUND AND BYLOT ISLAND AREA, NU

Currie, L.D.

, [email protected], Coutand, I.

, Brent, T.A.

, Issler,

D.R.

, and Wielens, H.

(deceased),

Geological Survey of Canada,

Calgary, AB T2L 2A7;

Department of Earth Sciences, Dalhousie

University, Halifax, NS B3H 4J1;

Geological Survey of Canada

Atlantic, Dartmouth, NS B2Y 4A2

Understanding the structural style and thermal history of the Lancaster

Sound-Baffin Bay area is critical for assessing its hydrocarbon potential,

which is considered significant, and reducing exploration risk.

Contributions to the Baffin Bay Basins project of the GEM-Energy

program, including thermal modelling of new Apatite Fission Track data,

reinterpreted marine seismic data, primarily from the 1970’s, and

interpretation of more recent sub-bottom profile and bathymetry data,

indicate that crystalline basement in this area is dominantly affected by

northwest- and east-striking normal faults. These faults form the bounding

structures of an array of horsts and grabens, most of which lie beneath

Lancaster Sound and are inaccessible.

One graben, the Eclipse Trough, and its more mountainous bounding

horsts (Navy Board High to the southwest, Central Bylot High to the

northeast), together with another graben, the North Bylot Trough, and the

Liverpool High (farther northeast), are partially exposed on Bylot Island

and northeastern Baffin Island. The “Highs” currently form part of the

uplifted rim of northwestern Baffin Bay.

Apatite fission track results from the Archean crystalline basement

underlying Cretaceous to Tertiary sediments of the Eclipse Trough yielded

Early Paleozoic cooling ages suggesting that apatite fission tracks were not

completely re-set during the Mesozoic or Tertiary burial. This finding is

consistent with the low thermal maturity of the overlying sediments

(vitrinite reflectance <0.5% Ro). In contrast, thermal modelling of apatite

fission track data for crystalline basement rocks from the adjacent horsts

suggests Jurassic to early Cretaceous cooling, followed by Late Jurassic to

Early Cretaceous heating (likely due to burial) and Late Cretaceous to

Cenozoic cooling. This thermal history is consistent with the conclusion

from a provenance study that indicates that Central Bylot High separated

North Bylot Trough from Eclipse Trough as early as Maastrichtian time.

Latest Cretaceous to Paleocene cooling of the Central Bylot and Liverpool

highs was largely due to denudation, as evidenced by the predominantly

locally derived sediments found in North Bylot Trough.

PROVENANCE OF CRETACEOUS AND TERTIARY SEDI-

MENTS, BYLOT ISLAND, NU

Currie, L.D.

, [email protected], Sweet, A.R.

, McNicoll, V.

Smyth, H.

, Kellett, D.A.

and Haggart, J.W.

Geological Survey of

Canada, 3303-33

Street NW, Calgary, AB T2L 2A7;

Geological

Survey of Canada, 601 Booth Street, Ottawa, ON K1A 0E8;

CASP,

181A Huntingdon Road, Cambridge, UK;

Geological Survey of

Canada, 605 Robson Street, Vancouver, BC V6B 5J3

The undeveloped Lancaster Sound-Baffin Bay area is considered to have

significant petroleum potential, making it a focus of the Baffin Bay Basins

project of the Geological Survey of Canada’s GEM-Energy program.

Understanding its Mesozoic and Cenozoic depositional history is critical

for assessing hydrocarbon potential and reducing exploration risk.

Sedimentary rocks of Eclipse Trough (west Bylot Island, northern Baffin

Island) and North Bylot Trough (central northern Bylot Island) provide the

most complete accessible record of Late Cretaceous to Paleocene fluvial-

deltaic sedimentation in the western Baffin Bay area. New detrital zircon

U-Pb SHRIMP ages, palynology, and detrital rutile geochemistry for

Cretaceous and Paleocene samples from Bylot Island indicate a change in

provenance, and progression to distinct source areas for Eclipse and North

Bylot troughs as early as the Maastrichtian.

U-Pb detrital zircon age distributions for the Sirmilik formation of

Eclipse and North Bylot troughs (informal; Upper Cretaceous) are similar

to those of the Proterozoic of Borden Basin, middle Albian to possible

Turonian Hassel Formation-equivalent rocks of Eclipse Trough, and

Paleocene rocks of North Bylot Trough. These distributions contrast with

those of Paleocene strata of Eclipse Trough, which include Silurian to

Devonian zircons, indicating a change in provenance, and presumably

depositional patterns for Eclipse Trough.

The abundance of Proterozoic? Leiosphaeridia in the lower Upper

Maastrichtian and Paleocene of the North Bylot Trough contrasts with

their very limited occurrence in coeval strata of similar facies from the

Eclipse Trough.

Geochemistry for rutile grains from Hassel Formation-equivalent and

Sirmilik formation samples from Eclipse Trough indicates they were in

part derived from lower amphibolite- and greenschist-facies rocks, consis-

tent with a distant or recycled source, as rocks of this metamorphic grade

have not been exposed in this area since before Paleozoic (possibly

Mesoproterozoic) time. Rutile geochemistry for Paleocene rocks of North

Bylot Trough is indicative of upper amphibolite to granulite grade

source(s), and consistent with a local provenance.

STRATIGRAPHIC ORIGIN OF MARINE VERTEBRATES FROM

THE LOWER-MIDDLE TRIASSIC SULPHUR MOUNTAIN

FORMATION, BRITISH COLUMBIA

Cuthbertson, R.S.

and Cuthbertson, J.P.

Department of Biological

Sciences/

Department of Geoscience, University of Calgary, Calgary,

AB T2N 1N4, [email protected]

The Sulphur Mountain Formation (SMF) of east-central British Columbia

is highly significant in terms of its abundance and variety of Early Triassic

marine vertebrates. However, most strata of the SMF have been tilted to

near-vertical and typically weather to produce steep talus slopes.

Consequently, loss of stratigraphic context is a serious problem.

Two detailed stratigraphic sections were measured approximately 30

km southwest of Tumbler Ridge, B.C. Rock samples were collected from

the three members of the SMF that outcrop in this area: the Vega-Phroso

Siltstone Member (VPSM), the Whistler Member (WM), and the Llama

Member (LM). Based on field and laboratory observations, the VPSM is

dominated by siltstone, shale and silty shale; the fresh surface is nearly

always dark grey to greyish black, whereas the weathered surface is

dominantly moderate to dark yellowish brown; calcite ranges from 13-

30%, quartz from 5-15%, and muscovite from 1-5%; and most siltstone

samples have thinly spaced parallel laminations. The WM contains both

carbonate rocks and siltstones; the fresh surface colour is nearly always

greyish black, whereas the weathered surface may look mottled and can

range from yellowish brown to dark grey to olive black to brownish black;

calcite is dominant and typically makes up over 50% of the rock; wavy

laminations are characteristic; and several samples contain ammonite

impressions. The LM is dominated by siltstone, with subordinate shale and

sandstone; the fresh surface colour is variable, whereas weathered colour is

generally mottled light yellowish brown to olive grey; mineralogy is

highly variable, with calcite ranging from 17-30%, quartz from 6-25%, and

muscovite from 1-2%; samples are either non-laminated, or have thin,

indistinct parallel laminations.

The rock matrices of 20 marine vertebrate specimens previously

collected from the SMF were compared to the generalized geologic

characteristics noted above. Results indicate that 12 samples originate

from the VPSM, 3 from the WM, and 5 from the LM. Based on this

hypothesis of stratigraphic placement, early ichthyosaur taxa separate out

stratigraphically, with Utatsusaurus, Chaohusaurus, and Grippia cf.

longirostris restricted to the VPSM, and Phalarodon restricted to the LM.

The hypothesis presented here agrees with all instances in which the

known stratigraphic origin of these specimens had been previously

documented. However, in order to develop an understanding of the early

radiation patterns of the group, further work is necessary to achieve the

stratigraphic precision necessary to assess the relative ages of ichthyosaurs

collected from the SMF.

ORPHAN BASIN, OFFSHORE NORTHEAST NEWFOUNDLAND:

UNRAVELING THE DEPOSITIONAL HISTORY IN A FRONTIER

BASIN

Dafoe, L.T., Keen, C.E., Williams, G.L. and Dehler, S.A., Geological

Survey of Canada (Atlantic), Dartmouth, NS B2Y 4A2, ldafoe@

nrcan.gc.ca

Based on its proximity to the petroleum-rich Jeanne d’Arc Basin, the

minimally explored Orphan Basin to the northeast is becoming an enticing

area for oil companies focused on discovering oil and natural gas in

offshore eastern Canada. Growing interest in Orphan Basin stems from an

unusually attenuated continental crust, deep basin fill, and possible

correlations to the lithostratigraphy of neighboring basins. In our study, we

aim to unravel the depositional history of Orphan Basin and build linkages

to the source-rock-bearing Jeanne d’Arc and Flemish Pass basins by

integrating core and cuttings information with biostratigraphy,

lithostratigraphy, and seismic interpretations.

Our initial core analyses from the northern Jeanne d’Arc and Flemish

Pass basins, denote a depositional change from restricted marine in the

?Middle to Late Jurassic to open marine beginning in the latest Jurassic

and continuing through the Tertiary. During times of restricted marine

deposition, 100s of metres of sediment accumulated in nearshore settings

in the rapidly forming accommodation space. Conversely, open marine

units encompass heavily bioturbated strata, reflecting continuous outer

shelf to shoreface deposition. This prominent shift from restricted- to

open-marine deposition can be attributed to rifting and subsequent drifting

between the Grand Banks and Iberia, which opened the area to fully

marine conditions as rifting of the North Atlantic propagated northwards.

Well-log data from the neighboring basins suggests a similar

environmental shift occurred, at least in part, within Orphan Basin. Log

characteristics of the lower interval in the Great Barasway F-66 well

(located in central Orphan Basin) may indicate a similar Late Jurassic

restricted marine package, which we will attempt to confirm through

palynological analyses.

One of the major discrepancies between Orphan Basin and Jeanne

d’Arc Basin lithostratigraphy is the generally thin nature of Cretaceous and

lower Tertiary packages bounded by unconformities. Lack of accom-

modation space at this time suggests that the basin did not undergo major

subsidence to establish bathyal conditions until the middle Paleogene.

Nonetheless, the thin Cretaceous packages such as progradational

shoreface sands and distal shelf limestones are comparable to those of the

Jeanne d’Arc Basin. However, thicker shoreface sandstones are generally

confined to wells found in proximity to the Bonavista Platform (a

prominent sediment source), whereas the central Orphan Basin is typified

by shelfal shales. Our preliminary results above and our planned integrated

studies should provide a more comprehensive understanding of the

evolution and petroleum potential of Orphan Basin.

ALTERATION MINERALS AND ELEMENTAL ASSEMBLAGES

AROUND THE PHOENIX URANIUM DEPOSIT, ATHABASCA

BASIN, SASKATCHEWAN

Dann, J., Hattori, K., Dept. Earth Sciences, University of Ottawa,

Ottawa, ON K1N 6N5, and Sorba, C., Denison Mines Corp., 200-230

St East, Saskatoon, SK S7K 0E9

The Wheeler River Property, host of Denison Mine’s Phoenix Uranium

Deposit, is situated near the southeastern rim of the Athabasca Basin in

northern Saskatchewan. Discovered in 2008, the deposit currently has

resources of 39,449,000 million lbs. U

. The Phoenix Deposit occurs at

a depth of approximately 400 m. It occurs both along a shear zone and the

unconformity between Athabasca sandstones and the underlying Archaean

to Paleoproterzoic metamorphic rocks. The shear structure is named the

‘WS shear’, which occurs along the boundary between a graphitic pelite

and a garnetiferous pelite in the basement and cuts through the overlying

Athabasca sandstones. Rocks near the shear structure and the

unconformity are commonly altered to form disseminated, very fine-

grained secondary minerals.

Bulk rock compositions of drill core were determined at 10 m

intervals, comprising of a dataset of over 6700 rock samples. The

geostatistical analysis of the data was linked with the mineralogical-

petrological observations of samples using a petrographic microscope,

SEM, EPMA, XRD and TerraSpec

. The results of the rocks along the

shear zone show that the alteration in the basement is characterized by the

coeval formation of sulphide (pyrite and chalcopyrite) and dravitic

tourmaline. It is accompanied by intensive alteration of kaolinite and illite.

The alteration along the shear zone in the sandstones is represented by the

formation of kaolinite-group minerals, illite, and dravitic tourmaline. The

concentration of U is positively correlated with As, W and Mo but not with

S, K, Al, and B within the shear zone. Therefore the introduction of U into

the ‘graphitic conductor’ appears to have taken place as a separate event,

most likely after the pervasive alteration.

EXPERIMENTAL FORMATION OF A MICROBIAL DEATH

MASK

Darroch, S.A.F.

, Laflamme, M.

, Schiffbauer, J.D.

and Briggs,

D.E.G.

Yale University, New Haven, CT, USA;

Smithsonian

National Museum of Natural History, Washington, DC, USA;

Virginia Tech, Blacksburg, VA, USA

This study represents a first attempt to observe soft-tissue decay in

association with microbial mats, in order to recreate the ‘death mask’

model proposed for terminal Neoproterozoic lagerstätte. This model

explains the precipitation of authigenic iron sulfide minerals on, and

around, decaying carcasses in association with microbial mats, cementing

the sediment as a sole veneer and retaining the external morphology of the

organism in relief on the upper and lower surface of coarse-grained sandy

event beds. Although this model has been substantiated by the discovery of

abundant, microbially-induced sedimentary structures (MISS) and pyrite

veneers, in close association with Ediacaran fossils, it has not been tested

previously by experimental taphonomic studies under controlled laboratory

conditions. Arthropod larvae that decayed on top of a cyanobacterial mat

demonstrated higher quality preservation of fine-scale anatomy than larvae

that decayed in the absence of a mat. Decay experiments involving

bacterial mats and organic-rich sands generated a black ring extending

radially from the decaying carcasses. When this precipitate was analyzed

using XPS and ESEM-EDS it revealed the presence of likely iron sulfides,

or at least spatially associated Fe and S, and localized concentrations of

common aluminosilicate elements (Al, K, Fe and Mg) which is a

composition that has been documented in association with Ediacaran fossil

preservation.

APPLICATION OF NEW MULTI-RESOLUTION TRANSFORMS

APPLIED TO WELL LOG DATA ANALYSIS

Dashtian, H., [email protected]f.edu, Salahshoor, K., Petroleum

University of Technology, Tehran Petroleum Research Center,

Sattarkhan Ave, Khosrow Jonoobi St, Tehran, Iran, PO Box

1453953152, and Nekouie, H., Memorial University, Department of

Engineering, St. John's, NL

The aim of static reservoir characterization is to produce models in

particular of the spatial distribution of certain physical properties of rocks

and of the contained fluids, constituting a given reservoir. The

representative model is a product of multidisciplinary studies which are

related to different types of geological, geophysical data and new

mathematical methods. In this paper, we first present an overview of

emerging applications of wavelet transform in analyzing well log data and

it’s still active research topics employing wavelet transform framework.

Then, we present an overview of emerging signal processing techniques

which can be employed in reservoir characterization and well log data

analysis. It is shown that both discrete and continuous wavelet transform is

successfully implemented in analysis of spatial series of petrophysical well

logs. The engineering details of wavelet, cross-wavelet and curvelet

transform implementation for these data are provided for further studies.

We expect a flurry of new research and technology development activities

in the coming years utilizing still promising and almost untapped analog

wavelet transform and multi-resolution signal representation techniques.

Well logs of a large number of oil and gas wells in southern Iran

were used to demonstrate the applicability of wavelet and curvelet

transformations in denoising of well logs, identifying geological

boundaries, wellbore fractures and Milankovitch cycles. Correlation and

crass-correlations, fractality and multifractality of these data unrevealed

using these methods.

AGE OF DIAGENETIC APATITE CEMENTS FROM THE

UNCONFORMITY-TYPE BOOMERANG LAKE URANIUM

OCCURRENCE, PALEOPROTEROZOIC THELON BASIN,

NUNAVUT

Davis, W.J.

, [email protected], Gandhi, S.S.

, Enright, A.

Gall, Q.

, Hunt, P.

and Jefferson, C.W.

Geological Survey of

Canada, 601 Booth St., Ottawa, ON K1A 0E8;

Department of

Geology, University of Toronto, Toronto, ON;

1864 Rideau Garden

Drive, Ottawa, ON K1S 1G6

Fluorapatite is a locally common diagenetic mineral within siliciclastic

strata of the Paleoproterozoic Thelon Basin. It occurs both as pore-filling

cements and as fracture-filling veins. Boomerang Lake is an unconformity-

type uranium prospect at the southwestern margin of the Thelon Basin.

The uranium mineralization occurs in association with, but post-dates,

early pore-filling apatite cement within the host Thelon Formation

sandstone. The interstitial apatite cement at Boomerang Lake is

moderately enriched in U and has very low Th contents. In situ SHRIMP

U-Pb analyses yield a relatively imprecise age of 1688 ± 14 Ma (MSWD =

1.3; n=38) for interstitial apatite cement from a drill core sample

previously described by Davidson and Gandhi. Uranium mineralization at

Boomerang Lake is in the form of tristramite (Ca

0.6

0.3

0.1

(PO

)

0.75

(SO

)

0.25

-2(H

O), a rhabdophane group mineral. Crystallization of

tristramite post-dates, and involves partial resorption of the interstitial

apatite cement. The apatite age therefore provides a maximum age for the

uranium mineralization. The occurrence of tristramite at Boomerang Lake

may in part reflect reaction of uranium-bearing fluids with the earlier

diagenetic apatite cements. The age determined for apatite cement at

Boomerang Lake is slightly older than the 1667 ± 7 Ma age reported for

apatite from several localities in the northeastern part of the Thelon Basin,

approximately 300 km northeast of Boomerang Lake. This apparent

difference in age may suggest regional differences in the timing of apatite

cement formation within widely separated parts of the basin. Although

high in U, the diagenetic apatites in the northeastern part of the basin have

distinctively low concentrations of most other trace elements including

REE and Th. Total REE contents are one or two orders of magnitude lower

than is typical in crustal apatites. The very low REE and Th content of the

fluorapatite may reflect low concentrations of these elements in the

diagenetic fluids and/or their partitioning into other diagenetic phases such

as aluminum-phosphate-sulfate (APS) minerals.

MAGNETITE IN HYDROTHERMAL ALTERATION ASSOCI-

ATED TO IRON OXIDE-COPPER-GOLD SYSTEMS IN THE

GREAT BEAR MAGMATIC ZONE, CANADA

De Toni, A.F., Institut National de Recherche Scientifique, 490 rue de

la Couronne, Québec, QC G1K 9A9, Anthony_Franco.De_Toni@

ete.inrs.ca, Corriveau, L. and Montreuil, J-F., Commission géologique

du Canada, 490 rue de la Couronne, Québec, QC G1K 9A9

Magnetite is a minor to major constituent of veins, breccias and incipient

to intense alteration in iron oxide-copper gold systems of the Great Bear

magmatic zone, Northwest Territories. Prevalence of magnetite in most of

the known IOCG systems makes it a key mineral to understand and

monitor their evolution and development. Multiple magnetite paragenesis

associated with numerous textures are observed in these magmatic/

hydrothermal systems. The macroscopic and microscopic observation of

magnetite-bearing paragenesis is used to understand the processes that

have generated the spectrum of textures observed. Mineral assemblages

and associated textures can be used as exploration vectors to mineralized

zones so distinctions between different paragenesis are essential in the

comprehension of IOCG systems. To show the numerous aspects that can

exhibit magnetite-associated alteration, a protocol for regional to

megascopic description of replacements, veins and breccias has been

developed to facilitate the description of these rocks in the field and

subsequently on stained and unstained rock slabs and thin sections.

Prevailing paragenesis consists of 1) magnetite (Fe alteration), 2)

amphibole-magnetite ± apatite ± albite (high temperature Ca-Fe±Na

alteration), 3) K-feldspar-magnetite ± biotite or biotite-magnetite(high

temperature K-Fe alteration), with common overprint by hematite. Magnetite

replacement is preferentially formed around phenocrysts, within vesicules, in

groundmass, or replaces fragments in breccias. These habits suggest that

magnetite replacement forms where fluids circulate through porous and

permeable rocks and/or minerals. In bedded or layered rocks, magnetite

alteration can form selective stratabound replacements of specific horizons.

Magnetite also crystallize as breccia cement or fill veins. High temperature

K-Fe alteration crystallizes magnetite with K-feldspar in felsic and

intermediate igneous rocks, and biotite in siliciclastic sedimentary rocks and

mafic rocks. In potassic-altered porphyritic volcanic rocks, K-feldspar first

replaces the groundmass and then the phenocrysts with increasing alteration

intensity whereas biotite replaces selectively pre-existing amphiboles.

Replacements and veins of transitional high temperature Ca-K-Fe and

subsequent high temperature K-Fe alteration are commonly followed by the

mineralization stage, in which a wide variety of metal can be concentrated

(e.g. Cu, Au, Ag, Bi, Co, etc.). Each type of paragenesis and textures exert a

control on the aspect that will take subsequent alteration. As an example,

amphibole-magnetite veins preferentially cross-cut albitized zone at the

expense of the unaltered volcanic rocks. Ultimately, the main objective of the

project is to produce an atlas of alteration associated to IOCG that will

provide exploration tools and a framework for geologists during the

exploration of under-explored terranes.

GEOLOGICAL REVISION AND LITHO-STRATIGRAPHY OF

THE MATAGAMI (VMS) MINING CAMP

Debreil, J-A., INRS-ETE, 490 rue de la couronne, Québec City, QC

G1K 9A9 [email protected], Pilote, P., Williamson, K.,

Lacoste, P., Bureau de l'exploration géologique du Québec, Pavillon

Président-Kennedy, 201, avenue du Président-Kennedy, local PK-

6320, Montréal, QC, H2X 3Y7, Ross, P-S., INRS-ETE, 490 rue de la

couronne, Québec City, QC G1K 9A9

The Matagami mining camp is located in the north-western part of the

Archean Abitibi Greenstone Belt in Quebec, Canada. Some 19 zinc-rich

VMS deposits are currently recognized (production since 1960: 4.6 Mt Zn;

0.494 Mt Cu). Known mineralization occurs along three felsic bands: the

historical South Flank and North Flank of the stratified Bell River

Complex anorthositic intrusion, and the West Camp. The geology is

composed of a bimodal volcanic sequence and the stratigraphy is

subdivided in two major groups: the Watson Group, including mostly

felsic rocks, overlaid by the Wabassee Group, composed principally of

mafic rocks, with some localized felsic units. The groups are separated by

a marker horizon called the Key Tuffite, which has been a major

exploration tool, as most of the VMS deposits of the camp are found at this

stratigraphic level.

In 2008, a multi-disciplinary research program, including 3 PhD and

2 MSc projects, was undertaken in close collaboration with the mining

industry (Xstrata Zinc, Donner Metals, SOQUEM and Breakwater), the

GSC, and the MRNF, whose mandate was to provide new regional

geology insights.

The recent MRNF regional mapping campaign suggests a new

geological subdivision of the Matagami region into the North and South

Domains, delimited by the ENE-trending Rivière Allard shear-zone. This

shear zone passes north of the historical North Flank but truncates the

West Camp northwest of the Phelps Dodge VMS deposit. The North

Domain shows evidence of intense D2 north-south flattening. The South

Domain is affected by moderate to weak D2 flattening, but is mainly

characterized by open NE-trending D1 folds, visible in particular between

the West Camp and the South Flank. Superposition of D2 over D1 has

created a “dome and basin” geometry which has important impacts for

exploration.

The PhD project at INRS-ETE, which aims to define the volcanic

architecture of the Matagami mining camp using lithogeochemistry and

volcanic facies variations, had important impacts on this new regional

vision. On the basis of major and trace elements geochemistry, several

mafic volcanic units have been defined in certain areas of the camp using

primarily drill core information. The different felsic units have also shown

chemical differences not previously well constrained. This new knowledge

has been applied and extended more broadly during regional mapping.

This has lead to a better understanding of the architecture and stratigraphy

of the Matagami mining camp, and therefore will help exploration efforts.

(MRNF - Contribution 8439-2011-2012-8)

INSIGHT INTO RIFTING BETWEEN NOVA SCOTIA AND

MOROCCO FROM AN EXAMINATION OF MAGNETIC

ANOMALIES

Dehler, S.A., Geological Survey of Canada, Natural Resources

Canada, Dartmouth, NS B2Y 4A2, [email protected]

Positive magnetic anomalies characterize the rifted margins offshore Nova

Scotia and Morocco, and these anomalies were modelled to examine the

nature and style of rifting. The margins began forming during the Late

Triassic rifting and Middle Jurassic separation of the North American and

African plates, and deeper crustal structure, faulting style and basin

geometry vary considerably along the lengths of the margins. The margin

to the south of Nova Scotia has the clearly recognized characteristics of a

volcanic-style rifted margin, including seaward dipping reflector (SDR)

sequences that are interpreted as rift-related volcanic flows overlying

basement. These SDRs are coincident with a strong linear magnetic

anomaly, the East Coast Magnetic Anomaly (ECMA), which shares many

characteristics with the West African Coast Magnetic Anomaly

(WACMA). Seismic evidence for these reflector sequences is absent along

most of the Scotian margin, and the magnetic anomalies on the Nova

Scotia and Moroccan margins change character and fade in amplitude,

from south to north, midway along the margins. Several researchers have

proposed previously that this transition is associated with a change from a

volcanic to a non-volcanic style of rifting. New models of the magnetic

anomalies along the Scotian margin show good correlation of the ECMA

with the seaward edge of thinned continental crust. The observed

anomalies can be satisfied with modest amounts of igneous material,

emplaced at or near the edge of the thinned continental crust. Beneath the

central and northeastern sections of the margin, where the ECMA

amplitude is weak, there is a significant decrease in magnetic source

material. Margin segmentation may explain both the changes in magnetic

signature and the variability in predicted melt volume.

THE OCEANIC CRUSTAL STRUCTURE AT THE EXTINCT

LABRADOR SEA SPREADING CENTER

Delescluse, M., Ecole normale supérieure, 24 rue Lhomond, 75005

Paris, France, [email protected], Funck, T., Geological

Survey of Denmark and Greenland, Øster Voldgade 10, 1350

Copenhagen K, Denmark, Dehler, S.A., Geological Survey of

Canada, PO Box 1006, Dartmouth, NS B2Y 4A2, and Louden, K.E.,

Dalhousie University, Halifax, NS B3H 4R2

The SIGNAL cruise (Seismic Investigations off Greenland, Newfoundland

and Labrador) was carried out in 2009 to acquire marine refraction seismic

data in the area between southern Greenland and eastern Canada. Although

primarily focused on passive margins, the SIGNAL experiment also

included two refraction lines along and across a segment of the extinct

Labrador Sea spreading center. This extinct ridge represents a rare

opportunity to study the last stages of accretion of oceanic lithosphere,

with a full spreading rate < 1 cm/yr between Chron 20 (45 Ma) and the end

of spreading before Chron 13 (36 Ma). Dense airgun shots were recorded

by 18 ocean bottom seismometers (OBS) on the 230-km-long line 4 across

the spreading center, while 10 OBSs were deployed on the 145-km-long

line 5 within the axial valley. Both refraction lines follow multichannel

seismic (MCS) profiles. A previous study using fewer OBSs, immediately

northwest of the SIGNAL lines, shows a thin oceanic crust (5.5-km-thick

reducing to 4-km-thick within the axis), with a substantial decrease of P-

wave velocities at the axis. While confirming these first-order results, the

preliminary velocity models of SIGNAL lines 4 and 5 also show extreme

tectonic extension with evidence for mantle exhumation and

serpentinization (mantle velocities decrease to 7.5 km/s). On line 5 in the

axial valley, crustal thickness varies from 4 km to 1.5 km. Joint analysis of

the SIGNAL refraction velocity models and coincident MCS profiles show

evidence for an atypical basement at the extinct axis and around the area of

mantle exhumation. In these regions, the basement has a velocity of 4 km/s

and is characterized by a series of high-amplitude reflectors. These

reflective layers could be interpreted as volcanoclastic material emplaced

by a few volcanic centers in the axis that remained active when extension

became mainly tectonic. However, the reflectors are not significantly

tilted. Another possibility is that the last stages of ultra-slow spreading led

to an anomalous crustal structure characterized by a low velocity upper

crust and a thin lower-crust. Both situations raise the question of the

simultaneity and timing of extension during the termination of crustal

accretion.

ALKALINE ULTRAMAFIC DIATREMES OF THE MISSOURI

RIVER BREAKS AREA (MONTANA): A COMPARISON WITH

CLASSIC KIMBERLITE PIPES

Delpit, S., Ross, P-S., Institut national de la recherche scientifique,

centre Eau Terre Environnement, 490 rue de la Couronne, Québec,

QC G1K 9A9, [email protected], and Hearn, B.C., US

Geological Survey, 954 National Center, Reston, VA 20192 USA

We conducted fieldwork in the Missouri River Breaks (MRB) area of

north-central Montana (USA) where at least 25 diatremes are now exposed

due to erosion (Hearn 1968 Science 159:622-625). The diatremes and

associated alkaline ultramafic intrusions were emplaced at 52-47 Ma and

are part of the alkaline province of central Montana (69-27 Ma). The

volcanoes are hosted by a sequence of unconsolidated sediments (sands

and muds).

Detailed field and laboratory work were performed on pyroclastic

deposits from four diatremes during this study. These four diatremes

display more or less the same characteristics such as: the walls of the

diatremes are very steep at the level of exposure; there is strong evidence

of subsidence of the mostly bedded diatreme fill; the now bowl-shaped

beds locally feature indications of deposition by base surges; there are also

distinct non-bedded pyroclastic units separated from the bedded ones by

sharp contacts; huge slivers of sediments, from known formations, have

sunk along the margins of the diatremes. Moreover most pyroclastic rocks

contain a large proportion of spherical juvenile pyroclasts (ash to lapilli

size, and more rarely bomb size) and a large variety of them has been

identified.

The diatremes from the MRB share some characteristics with classic

kimberlite pipes of South Africa, known as class 1 kimberlites, including

formation from a low viscosity magma; deep, steep-sided cone-shaped

diatremes; the presence of “floating reefs” and mantle xenoliths; sharp

pipe margins; cross-cutting pyroclastic units; and spherical juvenile

pyroclasts named “pelletal lapilli” in kimberlites. Even though massive

volcaniclastic deposits often characterize kimberlite pipes, stratification

has also been observed. However, bedding of pyroclastic deposits is better

developed in the Montana examples, even at deep structural levels.

We propose an emplacement model for the Missouri River Breaks

diatremes. Some features such as bedded pyroclastic units, cross-cutting

non-bedded pyroclastic columns and bowl-shaped beds indicate an

emplacement by successive explosive pulses and a downward penetration

of the locus of phreatomagmatic explosions which leads to the growth of

the diatreme (diameter and depth). The pyroclastic material is deposited

bed by bed on the crater floor. During subsidence which occurs during the

volcanic activity and after, some slivers of soft rocks are detached from the

walls of the diatreme and move down. This emplacement model has

implications for the origin of class 1 kimberlite pipes, for which the

eruptive processes are still debated.

Keynote THE STRENGTH OF THE LITHOSPHERE AND ITS

ROLE IN TECTONICS

Dewey, J.F., [email protected], University College Oxford, High

Street, Oxford OX1 4BH, England, UK, Gueydan, F., Géosciences

Montpellier, UMR 5243- CC. 60, Université Montpellier 2, place E.

Bataillon, 34095 Montpellier cedex 5, France, and Tapponnier, P.,

Earth Observatory of Singapore, Nanyang Technological University

N2-01A-09, 50 Nanyang Avenue, Singapore 639798

A central and critical multi-stranded question of modern tectonics is “what

is the detailed rheology and strength of the continental lithosphere with

depth in the crust and mantle and how does this control bulk tectonic style

in continental extension and shortening. We address the controversy

between Watts and Burov who espouse the classic “peanut butter and jelly

sandwich” (strong upper crust and upper mantle, and weak lower crust)

model of Matthews, and the “crème brulee” (strong upper crust and weak

lower crust and mantle). We lean towards Watts and Burov-type models

with a strong upper mantle but show that both integrated and detailed

vertical strength is immensely varied and complicated in the continental

lithosphere. We illustrate this with a large range of “sailboard” diagrams.

A strong upper mantle is inconsistent with homogeneous extension/

thinning (McKenzie) and shortening/thickening (Dewey and Burke) of the

continental lithosphere and we discard such models in favour of the

observed asymmetry of low-angle extensional detachments (Boillot,

Manatschal) and thrusts (Snoke, Rutter) that involve mantle rocks. There

may be detachment of a weak crust from the mantle with mantle

shortening by thrusting. Olivine rheology demands a strong upper mantle.

It is inconceivable that plate tectonics could exist without mantle strength,

with very thin plates deriving their torsional strength from the upper crust

alone.

Old cratons are clearly strong “plums in the continental pudding” that

resist deformation. In our view, the mistake in the Jackson view of

lithospheric strength is the correlation of strength with earthquakes.

ND ISOTOPE MAPPING OF THE LAC DUMOINE THRUST

SHEET: IMPLICATIONS FOR THE LOCATION OF GREN-

VILLIAN BASEMENT EXHUMATION RAMPS IN THE SW

GRENVILLE PROVINCE

Dickin, A.P., Cooper, D., Guo, A., Hutton, C., Martin, C., Zelek, M.,

School of Geography & Earth Sciences, McMaster University,

Hamilton, ON L8S 4M1, and Sharma, K.N.M., Ministere des

Ressources Naturelles et Faune, 880, chemin Sainte-Foy, RC 120-C,

QC G1S 4X4

Nd isotope mapping has been performed in the Lac Dumoine region,

western Quebec, interpreted as a thrust sheet of the Grenvillian

Allochthonous Polycyclic Belt. The thrust sheet has an isotope signature

consistent with other terranes of the allochthonous belt, with TDM ages

<1.8 Ga in the main allochthon, but ages of 1.8 – 2.0 Ga in an underlying

duplex, itself thrust over parautochthonous Archean crust. However, the

new data also reveal a salient of Paleoproterozoic ages that bisect the main

thrust sheet into two lobes, showing them to be relatively thin-skinned

nappes. When combined with new Nd isotope mapping for Algonquin

Park, Ontario, these results suggest that the main ramp of the Allochthon

Boundary Thrust is located further to the SE than previously thought, with

a strong SW-NE linear trend that coincides with dipping reflectors imaged

on Lithoprobe seismic line 32 south of Algonquin Park.

OUTER-RAMP CARBONATE PRODUCTION, TRANSPORT, AND

DEPOSITION: UPPER ORDOVICIAN WINTERHOUSE FOR-

MATION, LONG POINT GROUP, WESTERN NEWFOUNDLAND

Dix, G.R., Ottawa-Carleton Geoscience Centre, and Department of

Earth Sciences, Carleton University, Ottawa, ON, gdix@connect.

carleton.ca, Burden, E. and Nwokeforo, B., Memorial University of

Newfoundland, St. John’s, NL

The Upper Ordovician Winterhouse Group lies exposed along Long Point,

Port au Port Peninsula, western Newfoundland, and represents outer ramp

deposition that forms the initial regression phase of a greater Caradocian

(Turinian-Edenian) T-R cycle within the remnants of a Taconic foreland

basin. The formation overlies the the Lourdes Formation that records an

overall deepening upward platform succession. The Winterhouse

Formation consists mostly of shale and laminated sandstone. However,

within the lower half of the succession are metre-scale intervals of skeletal

(brachiopod, echinoderm) quartzose limestones and pure limestone that

identify temporary reduction to shut-down of siliciclastic transport and

accumulation of graded to massive, medium to coarse-grained deposits,

often overlying irregular (scoured?) surfaces. These deposits appear to thin

upsection, but peculiar to each occurrence are angular to rounded cobble-

to block-size (up to 2 metres across) clasts similar in lithology to the host

carbonate matrix. Outcrop exposures suggest that these produce, locally,

overlapping laterally restricted sheet-like or podiform deposits. Locally,

skeletal grains are cemented by radiaxial fibrous to bladed low-Fe calcite,

which forms isopachous rims around allochems preserving an

uncompacted texture. Syntaxial calcite cement (on echinoderm grains) and

intergranular equant calcite form the more common cement types.

Previous work has been largely cursory in description, but often

emphasized that the carbonate clasts represented reworking of the

underlying carbonate platform (Lourdes Fm). Carbonates of these two

formations contain distinct facies. Preliminary field and petrographic

analyses indicate that lithification occurred in a cool-water marine or

modified marine environment at or very near the sediment-water interface;

and, that clasts represent marine reworking of a locally cemented seafloor.

Ongoing work is examining the geochemistry (trace elements, isotopic: C,

O, Sr) and fluid inclusion characteristics of the calcite cement to help

characterize the depositional and diagenetic setting of the Winterhouse

carbonates. At present, we suggest that the deposits represent sub-

thermocline production with local pervasive marine calcite cementation,

then reworking and transport.

THE OTTAWA-GATINEAU GEOHERITAGE COMMITTEE

ENTERS ITS SECOND DECADE

Donaldson, J.A., Carleton University, Colonel By Drive, Ottawa, ON

K1S 5B6, donaldson6427@rogers.com

The Ottawa-Gatineau Geoheritage Committee (OGGC) was initiated in

2002 to advance public understanding of the geosciences in relation to

enjoyment of, and respect for, the natural world. Our local committee

swiftly expanded from two members to 12, and has remained at this level,

with few changes in composition of the Committee, derived primarily from

the Geological Survey of Canada, Carleton University and The University

of Ottawa.

Because of imbalance in teaching of the natural sciences within our

school system, almost all citizens reach adulthood with a better

comprehension of things biological than things geological. Talks, field

excursions and displays organized by OGGC members continue to raise

awareness of this imbalance, and linkages with other nature-based groups

have significantly enhanced expansion of our outreach. Since our report

last year, we provided geoheritage guidance during a canoe trip organized

for high-school students by the Ottawa Riverkeeper, contributed to

upgrading of the James Wilson displays in the Matheson House Museum

in Perth, and prepared a brochure for an outdoor display of local rocks in

Perth that we hope to have designated as the second geoheritage park in

Ontario. In collaboration with Carleton University, the fifth annual

Geoheritage Day in October 2011 drew many new participants to eight key

sites where professional and student geoscientists provided educational

guidance throughout the day.

We had one minor setback last year. An outdoor display of 30 large

rocks in Metcalfe Geoheritage Park, Almonte, created entirely by

volunteer effort over several years and officially opened in 2010, was

disrupted by the need for sewer repair that required displacement of the

specimens. Stoic acceptance of this unexpected problem served to rally

considerable local support, and funds from several sources, including the

local Mississippi Mills Council, will usher in creation of a more elaborate

display in 2012.

OGGC maintains excellent support within the geological community,

strengthened by having had our geoheritage initiative adopted as a project

of the Canadian Geoscience Education Network; we continue to enjoy

widespread support among numerous nature-based groups; and launching

of our own website a few months ago will allow us to promote geoheritage

with greater impact. We see significant potential for creation of a geopark

in Eastern Ontario, and have encouraged several outdoor and tourism

groups to consider creation and submission of a geopark proposal. Above

all, we will continue to seek greater appreciation of geoheritage by

municipal, provincial and federal organizations.

DETERMINATION OF A FORENSIC GEOLOGY AND POLICE

SEARCH STRATEGY TO LOCATE SHALLOW BURIALS

ASSOCIATED WITH CRIME

Donnelly, L., Chair, International Union of Geological Sciences

(IUGS), Initiative on Forensic Geology, Wardell Armstrong, 2 The

Avenue, Leigh, Greater Manchester, WN7 1ES, UK, ldonnelly@

wardell-armstrong.com

Police searches to locate graves, firearms, weapons and items of value

that have been buried at a shallow depth beneath ground as part of a

criminal act, no longer need to rely on conventional line searches and

the use of cadaver dogs and air observations alone. Over the past 15

years or so geologists’ have been increasingly working closely with the

police by combining their expertise and resources and the result has

been the development of much improved and cost-effective, search

strategies. Although there has been a long association of forensic

geologists supporting police and law enforcement investigations, which

has been document for at least 150 years, only ‘recently’ have geological

methods and techniques been applied to some types of police searches.

The objective of this paper is to provide a general appreciation of how

forensic geology may enhance police ground searches. Often, this may

begin with the collation, review and analysis of geological data and

information and case intelligence. This enables the ground conditions,

hydrogeology, types and properties of rocks, soils and any ‘made

ground’ to be determined and the likely detectables associated with the

target to be estimated. The results of this initial phase may be

summarised in the form of a Conceptual Geological Model (CGM) for

the burial, which facilitates the communication of complex geological

information between the geologist and police officer. Based on this

ground-burial model the most suitable choice of search assets may then

be determined and a methodology devised to provide a high assurance

search, to confirm the presence or absence of the suspected buried

target. This paper also provides information on how organisation such as

the International Union of Geological Sciences (IUGS), Initiative on

Forensic Geology (IFG), has played a leading, pioneering role in the

promotion and development of forensic geology around the world, both

as a science and as part of some routine police and law enforcement

operations.

REGIONAL SEQUENCE STRATIGRAPHIC INTERPRETATION

OF THE MARCELLUS SHALE

Douds, A.S.B., [email protected], Willan, C.G., McCallum, S.D.,

EQT Production, EQT Plaza, 625 Liberty Ave, Pittsburgh, PA

15222, USA, and Blood, D.R., Pure Earth Resources, 168 Jameson

Way, Seven Fields, PA 16046 USA

The Middle Devonian Marcellus Shale was deposited in relatively shallow

water in the Acadian foredeep of the Appalachian Basin and is a proven

hydrocarbon source and reservoir. Several regional correlative surfaces

have been identified from standard triple combo well log data and

interpreted within the Marcellus. Regional correlations, incorporated with

core analysis, have led to the development of a sequence stratigraphic

framework for the Marcellus.

The Marcellus rests disconformably on the Onondaga Limestone and

contains a minimum of two third order sequences and several higher-order,

sub-regional sequences. Accommodation space for the sequences is

created by subsidence in the foreland basin. The base of each sequence is

represented by black, laminated shale with large amounts of detrital shell

material, which, in turn, is overlain by transgressive black, organic-rich

shale. The black shales grade both upward, and in a proximal direction,

into gray shale which is occasionally capped by a shallow water limestone.

This sequence is repeated through the deposition of the Tully Limestone,

after which Acadian clastics replace the carbonates.

Identification of the systems tracts and mapping their regional

distribution has highlighted differences in the nature of the grey and black

shales and allowed for the creation of a depositional model. The sequence

stratigraphic framework, wireline log data, core data, and petrophysical

and geochemical analyses have been integrated to predict key parameters

such as porosity, organic carbon content, and mineralogy and then

incorporated into a general basin model to determine burial and thermal

maturation history.

NATURAL TOXICANT IS NOT AN OXYMORON. EARTH

SCIENCE BASED PROBABILISTIC MODELLING OF

NATURALLY OCCURRING ARSENIC IN NEW BRUNSWICK

DRINKING WATER

Douma, S.L., stdouma@gmail.com, (Associate) Nova Tox Inc., 446

Hartleigh Ave., Ottawa, ON K2B 5J4 and Klassen, R.A. (retired)

NRCan, Geological Survey of Canada, Ottawa, ON

Despite its potential to inform, earth science knowledge and information is

slow to be integrated with environmental, ecological and human health

protection initiatives. In Canada, we have significantly large areas that

contain natural toxicants that have the potential to pose health risks to its

overlying population. Yet, we are seemingly unaware, uninformed and

unprotected.

Far from trivial, these naturally occurring toxicants have the potential

to cause morbidity (carcinogenic and non-carcinogenic disease) that

exceed those that would develop from ‘a pack a day’ smoking habit. We

present a modelling tool for the natural toxicant arsenic (a semi-metallic,

naturally occurring, nonessential trace element and one of the first

elements to be recognized for is cancer promoting agents) as an example

of how earth sciences can be used to predict, prevent and provide ongoing

health protection to Canadians.

PRECIOUS AND BASE METAL MINERALIZATIONS ASSOC-

IATED WITH THE REGIONAL MORE-TRONDELAG FAULT

ZONE, CENTRAL NORWAY

Drivenes, K., Larsen, R.B. and Sorensen, B.E., Norwegian

University of Science and Technology, Sem Saelands vei 1, 7491

Trondheim, Norway, kristian.drivenes@ntnu.no

The Paleozoic-Cenozoic Verran - and Hitra-Snaasa faults, comprise the

main sutures of the giant inter crustal More-Trondelag fault zone that can

be followed over 900 km from central Norway across the continental shelf

to Scotland. In Norway, it separates Proterozoic gneisses to the north from

Caledonian nappe complexes in the south. Many deposits are associated

with second order sub-parallel faults or smaller third order faults typically

oblique to the dominant NE-SW strike direction. The polymetallic deposits

at Flintheia and Skaudalen hold an average grade of 2.5 wt% Cu, 0.64 wt%

Zn, 0.59 wt% Pb, and 152 ppm Ag; and 4,0 wt% Cu, 0.83 ppm Au, 29.3

ppm Ag and 266 ppm Mo respectively.

In Flintheia the mineralizations occur as fracture controlled sulfide

mineralizations. Ag occurs in small inclusions in pyrite associated with Pb,

Cu and Bi minerals, and in larger galena grains. The larger galena grains

are selectively altered, sometimes pseudomorphosed, to covelite and other

copper sulfides, whereas coexisting chalcopyrite and pyrite remain

unaltered. Sphalerite is slightly altered to covelite along fractures. In the

larger galena grains, Pb is extracted and Ag remobilized and precipitated

in liesegang like textures in Cu-Ag-Pb-Bi-sulfides together with the Cu-

sulfides within the original grain during low temperatures and oxidizing

conditions. Average Ag content in unaltered galena relicts is 0.91 wt%.

The vein quartz is highly recrystallized with abundant chalcedony, often in

comb textures in micro brecciated pyrite. Fluid inclusions preserved in

coarse-grained quartz are CO

dominated. SEM-CL reveals extensive

zoning in the quartz with two main types: one blue luminescent with a

main peak around 420 nm and a minor peak at ca. 620 nm, and one type

with a main peak around 620 nm, giving it a yellow/orange luminescence.

The latter also has a markedly higher intensity.

The Skaudalen mineralizations occur as impregnations in

amphibolite facies biotite gneiss. The ore mineralogy comprises coarse-

grained chalcopyrite with inclusions of magnetite, molybdenite, pyrrhotite

and sphalerite. The quartz vein becomes progressively deformed towards

the dominating chalocopyrite grains. Small electrum grains accounts for

the gold anomaly. Ag is lattice bound in chalcopyrite, and is verified by

“corrosion roses” developed during polishing.

The polymetallic nature together with the complex textural patterns

imply that multiple sources and several ore-forming episodes formed these

deposits over extensive temperature, depth and time intervals. Significant

ore grades and unusual mineralization textures make these deposits

interesting in both an economical and academic sense.

GARNET AS A TRACERS FOR THE MINERALIZATION IN A

BANDED-IRON FORMATION-HOSTED OROGENIC GOLD

DEPOSIT; EVIDENCE FROM THE MUSSELWHITE DEPOSIT,

NORTH CARIBOU GREENSTONE BELT, WESTERN SUPERIOR

PROVINCE

Duff, J., Hattori, K., Schneider, D.A., Cossette, E., University of

Ottawa, Ottawa, ON K1N 6N5, [email protected], Jackson, S.,

Geological Survey of Canada, Ottawa, ON K1A 0E8, and Biczok, J.,

Goldcorp Inc., Musselwhite Mine, Thunder Bay, ON P7B 6S8

Musselwhite, an orogenic Au deposit, is located in the central portion of

the North Caribou Greenstone Belt (NCGB). Mineralization is hosted

within a meta(chemical) sedimentary banded-iron formation (BIF) which

is overlain and underlain by regionally continuous ca. 2.9 Ga amphibolite

grade volcanics rocks. The NCGB is bounded by ca. 2.72 – 2.87 Ga TTG-

granitiods and granites. Samarium-neodynium geochronology of garnet

from the ore zone has been reported to yield a 2.69 Ga age, which post-

dates plutonism and volcanism in the NCGB. Recent detrital zircon

analysis from the metasedimentary rocks overlying the Au-bearing unit

returned

207

Pb/

206

Pb peaks at ca. 2.87 and 2.60 Ga. Here, we present recent

LA-ICPMS trace element and EPMA major element compositions of

garnet from Musselwhite. Samples were collected from auriferous garnet -

grunerite schist, footwall and hanging wall schist in the mine, as well from

auriferous schist outcrops north of Musselwhite. A sample was also

collected from the non-mineralized meta-chemical sedimentary bed that is

continuous 24 km from the deposit. Major elements of garnet from

mineralized rocks show Mn and Mg rich rims and Ca rich rims.

Mineralized samples show positive Eu anomalies in the ore zone in the

mine, whereas auriferous rocks outside the mine show less prominent

anomalies. Low Eu anomalies occur in the non-mineralized sample

(Eu/Eu*= 0.706-2.19). The majority of garnet grains show high HREE

concentrations with a mean (Sm/Lu)

value of 1.6 and low LREE

(∑HREE/∑LREE = 41). Rims of garnet from mineralized samples show

large variations in Ni/MgO from ~ 0.14 to 15.5, and Y concentrations from

~ 0.89 to 198 ppm. The high Ni and low Mg are recorded in the core of

these grains from the ore, whereas their rims show low Ni. Trace element

zonation in garnet from the non-mineralized rocks is minor compared

these samples. The data suggests that garnet growth was contemporaneous

with precipitation of pyrrhotite and chalcopyrite; both sulfides are closely

associated with the introduction of Au. Gold-bearing fluid was derived

from rocks during metamorphism or extensive alteration of mafic rocks as

reflected by variably high Eu/Eu* values and Ca- rich rims in the garnet

crystals in the mineralized rocks. The origin of BIF-hosted Au deposits

remains enigmatic and the source fluids (magmatic or metamorphic) are

still in debate. Results here indicate that garnet effectively records the

history of hydrothermal activity associated with Au deposits and the data

indicates metamorphic fluid as the principle transporter of Au.

HYDROTHERMAL DESILICIFICATION AT DOME/KEEL

DETACHMENTS: A KEY ELEMENT IN FORMING HIGH-

GRADE MAGNETITE DEPOSITS IN THE MARY RIVER

DISTRICT, NORTH BAFFIN ISLAND

Duke, N., [email protected]; MacLeod, M., Nicpon, B., Fulcher, S.,

University of Western Ontario, London, ON N6A 5B7, and Iannelli,

T., Baffinlands Iron Mines Inc., Toronto, ON

The Mary River District in north-central Baffin Island is emerging as an

exciting new high-grade iron ore camp with numerous variably delineated

massive magnetite-(martite-hematite) deposits, the largest in excess of

500mt of 65-70% Fe. These deposits are hosted within a prominent

Algoma-type banded iron formation, a member of an upper BIF-komatiite-

quartzite assemblage capping the Neoarchean Mary River Group. The

Mary River Group is preserved in superstructural keels and the massive

iron oxide bodies develop where Mary River BIF is juxtaposed against

high grade polymetamorphic infrastructural gneiss, within a classic “dome

and keel” Paleoproterozoic tectonic framework. The massive magnetite

lenses have well developed footwall chloritite schist, and pervasive

chloritization extends well into bordering mylonitic gneiss. With loss of

silica, the Mary River BIF transits from typical magnetite-quartzite with

<45% Fe, to enriched BIF with >50% Fe, into massive magnetite.

Remnants of original BIF are occasionally preserved within the coarsely

granular magnetite.

Coarse idioblastic garnets overgrowing the multiple-foliated footwall

chloritite and randomly oriented cordierite-staurolite-andalusite

overgrowing chloritized footwall gneiss clearly demonstrate that

desilicification occurred prior to the late thermal peak of the Hudsonian

overprint. Randomly oriented grunerite overgrowing granoblastic

magnetite ore is attributed to late annealing under the terminal Hudsonian

amphibolite facies thermal conditions. The relative timing for

hydrothermal retrogression is therefore during regional Hudsonian dome

and keel development. Granular martite and platy hematite ores result from

post peak metamorphic oxidation of granoblastic magnetite along still

active deformation zones accommodating terminal isostatic adjustment.

Wholesale silica removal via hydrothermal fluidization of

Proterozoic dome/keel boundaries has not been widely reported in the

literature. However, pervasive chloritization of younger detachment faults

supplies a modern analogue. Here, meteoric fluids ponding at the

brittle/ductile interface of orogenic infrastructures play a formative role.

The hydrothermal disaggregation reflects a steep thermal gradient across

faults accommodating rapid unroofing. In the case of Mary River it is

perhaps more likely that dewatering of the low grade Mary River Group,

particularly of serpentinized komatiite members, was the primary fluid

source. Other possible analogues for hydrothermal silica removal from

background BIF to form residual massive magnetite ores at Proterozoic

dome/keel boundaries can be found in the IOCG literature.

NEW SHRIMP U-Pb ZIRCON AND APATITE FISSION TRACK

AGES CONSTRAIN THE DEFORMATIONAL HISTORY AND

TIMING OF CARBONATE REPLACEMENT MINERALIZATION

IN THE WESTERN FORTYMILE MINING DISTRICT, EAST-

CENTRAL ALASKA

Dusel-Bacon, C., USGS, 345 Middlefield Rd., MS 901, Menlo Park,

CA 94025, USA, [email protected], O'Sullivan, P.B., Apatite to

Zircon, Inc., Viola, ID 83872, USA, Aleinikoff, J.N., USGS, Denver

Federal Center, MS 963, Denver CO 80225, USA, Day, W.C.,

USGS, Denver Federal Center, MS 911, Denver, CO 80225, USA,

Slack, J.F., USGS, National Center, MS 954, Reston, VA 20192,

USA, and Siron, C.R., Full Metal Minerals, 409 Granville St., Suite

1500, Vancouver, BC V6C 1T2

Epigenetic base- and precious-metal prospects in the Mount Veta area of

the Fortymile district occur in the eastern Yukon-Tanana Upland (YTU),

which is bounded by the Tintina and Denali right-lateral fault systems. The

YTU is cut by steep NE-trending faults with both left-lateral and dip-slip

movement. New SHRIMP U-Pb zircon ages (n=29) in the Mount Veta

area document magmatic episodes at ca. 217–210, 188–184, 111–98, and

70 (±2) Ma. Intrusions of 210, 188, and 70 Ma occur within 3 km of the

Little Whiteman (LWM) Zn-Pb-Ag-(Cu) carbonate replacement prospect.

Sulfide bodies at LWM formed as NE-trending, steeply SE-dipping,

chimney-shaped replacements of Paleozoic marble in the hanging wall of

the NE-trending Kechumstuk fault and along contacts with steeply dipping

feldspar porphyry dikes. Within some dikes, the intensity of quartz-

sericite-pyrite alteration increases towards the sulfide lenses. Zircon from

one dike yielded a 187.7±4.8 Ma U-Pb age. Secondary sericite from

another altered porphyry dike yielded a

Ar/

Ar age of 187.5±2.0 Ma for

the most retentive 6 fractions (28% of

Ar released) with minor gas loss at

~65 Ma (P. Layer and J. Benowitz, written commun., 2011). These ages

are consistent with sulfide replacement during 187 Ma magmatism.

However, Pb isotopic compositions for sphalerite and galena from LWM

drill core are more radiogenic than those for K-feldspar from nearby

Jurassic intrusions and overlap with those from Cretaceous plutons. Pb

isotopic data allow an alternative interpretation in which the 187 Ma

Ar/

Ar sericite apparent age records initial alteration of the porphyry

dikes, whereas disturbance at ~65 Ma records mineralization by fluids at a

temperature below the closure temperature of the Ar system in sericite.

Apatite fission track (AFT) ages from igneous rocks (n=27) in the

Mount Veta area indicate multiple episodes of Paleogene (40 ± 10 Ma)

cooling through the ~110°C AFT closure temperature. However, geologic

relations around the 69-Ma Middle Fork caldera 20 km north of Mount

Veta suggest that these rocks were near the surface in the Late Cretaceous,

and therefore likely were reheated to >110°C sometime in the early

Tertiary. The nature of the suggested post-69-Ma reheating is unknown.

We interpret the Paleogene cooling implied by the AFT data to indicate

uplift, exhumation, and cooling related to far-field movement on the

Denali and Tintina faults. Two samples near faults have AFT ages of ca.

19 and 10 Ma, recording local re-heating by fluids in the Neogene.

TURNING WATER INTO WINE: A GEOLOGICAL INTRO-

DUCTION TO LITHIUM-RICH FORMATION WATER IN WEST-

CENTRAL ALBERTA

Eccles, D.R., APEX Geoscience Ltd., #200, 9797-45 Avenue,

Edmonton, AB T6E 5V8, reccles@apexgeoscience.com

The idea of a green mining operation—one that extracts minerals from

waste oil-field water for eco-friendly products—is appealing. Middle to

Late Devonian Beaverhill Lake, Woodbend and Winterburn group

formation waters associated with producing oil and gas wells in the Swan

Hills area of west-central Alberta contain up to 140 mg/L lithium (1 mg/L

= 1 ppm). This value is significant considering the average values of

lithium in Alberta formation waters are 10 mg/L (based on 1511 analyses),

and a Government led historical lithium resource study of the Swan Hills

area estimated some 515 000 tonnes of lithium over an area of 4,000 km

(non-NI 43-101 compliant). The high-lithium brines also contain elevated

potassium (up to 8000 mg/L), boron (up to 270 mg/L) and bromine (up to

410 mg/L), such that industry is considering the feasibility of a multi-

commodity extraction plant.

The occurrence of lithium in the world’s oil-field waters is poorly

understood and inadequately represented in the literature. The objectives

of this presentation, therefore, is to illustrate where lithium-rich formation

waters occur in Alberta and to explore the source environment,

mobilization and transport of lithium and related minerals to form these

unique brines. Industry data forms a valuable contribution to this work

and, where applicable, leading edge investigations will be incorporated.

Major ion and Sr, Pb and Li isotopic geochemistry show Alberta’s

lithium-rich brines form prior to halite precipitation, lack a freshwater

source and involve alteration of silicates (particularly Li- and K-bearing

minerals). In the Swan Hills area, viable lithium-source models should

invoke direct mobilization of silicate-bearing fluids from either the

crystalline basement or the immature siliciclastics deposited above the

basement (basal Cambrian sandstone, Granite Wash or the Gilwood

Member), to the Devonian Swan Hills, Leduc and Beaverhill Lake

formation waters. A number of thermal, potential-field and tectonic

features in west-central Alberta are reviewed in this introductory

investigation of lithium-rich oil-field waters that may one day become an

economically viable resource.

DIVERSITY, BIOGEOGRAPHY, AND BIOMINERALISATION OF

COLD-WATER CARBONATE PRODUCERS IN CANADIAN

WATERS: OVERVIEW AND NEW DIRECTIONS

Edinger, E.N., Geography, Biology, and Earth Sciences Departments,

Memorial University, St. John’s, NL A1B 3X9, Layne, G.D.,

Department of Earth Sciences Department, Memorial University, St.

John’s, NL A1B 3X5, and Neuweiler, F., Département de Géologie

et Génie Géologique, Université Laval, Québec, QC G1V 0AC

Cold-water carbonate producing organisms, sediments and rocks have

received limited study in Canada, compared to the cold-water scleractinian

bioherms of the northeast Atlantic, the main focus of COCARDE (Cold-

water Carbonates in Shallow and Deep time), the eastern US and Gulf of

Mexico, or the extensive cold-water carbonate systems of southern

Australia, the Gulf of California or the Mediterranean. Canada's climate,

oceanography, and glacial inheritance may limit the organisms and their

sedimentary products.

Dominant cold-water carbonate producing organisms in Canadian

waters include the coralline red algae, bryozoans, bivalve and gastropod

molluscs, sponges (indirectly), and corals - similar to the general bryomol

assemblage described from other broad cold-water carbonate shelves.

Coralline algae, producing magnesian calcite skeletons, are ubiquitous

members of Canadian shallow marine hard-substrate communities.

Branching corallines produce large amounts of carbonate sediment in some

fjords, while compact domal coralline algae may record high-latitude

climatic or ecological chaanges. Dominantly calcitic erect and encrusting

bryozoans are common epibenthos in shelf-depth waters, and are often

found associated with cold-water corals and sponges, but remain vastly

understudied. Carbonate-skeletoned cold-water corals include aragonitic

scleractinians, aragonitic or calcitic stylasterids, and calcitic gorgonians.

Solitary scleractinians have a relatively low diversity, while colonial

scleractinians occur mainly as isolated colonies, rather than in bioherms.

Stylasterid hydrocorals are common and relatively diverse in some British

Columbia waters, but rare in Atlantic Canada and the Arctic. The most

common carbonate-skeletoned gorgonian corals include Primnoids in

shallow, high-current settings, and Isidids in deeper, calmer settings. Cold-

water gorgonians construct "coral forests", whose habitat importance far

surpasses their sedimentary production. Sponges, especially demosponges

and hexactinellids, make an important contribution to habitat throughout

Canadian waters, and build glass sponge bioherms in shelf depth British

Columbia waters.

Modern cold-water carbonate sediment deposits appear relatively

rare in Canadian waters, perhaps due to dilution by the vast amounts of

siliciclastic sediments delivered to Canadian continental shelves by

Pleistocene glaciations. Preservation potential of cold-water scleractinians

and carbonate-skeletoned gorgonian corals may be relatively high, as

evidenced by sub-fossil skeletons several thousands of years old found

exposed on the seafloor, but the preservation potential of the environments

in which most of these organisms live is generally low. Many areas remain

unexplored, however, especially in the Arctic.

Emerging questions surrounding Canadian cold-water carbonates

include biomineralisation and skeletal microchemistry, rates of skeletal

growth and carbonate production, mineralogy, patterns of distribution and

abundance, and sedimentology and diagenesis of mound construction and

other habitat formation.

EVENT DEPOSITION AND BIOTURBATION GRADIENTS IN

ORGANIC-RICH MUDSTONES - THE LOWER MISSISSIPPIAN

BAKKEN FORMATION OF NORTH DAKOTA, WILLISTON

BASIN, USA

Egenhoff, S.O., Colorado State University, 322 Natural Resources

Building, Fort Collins, CO 80523-1482, USA, and Fishman, N.S., US

Geological Survey, Box 25046, MS 939, Denver, CO 80225, USA

Conventional depositional models for organic-rich mudstones typically

envision prolonged tranquil sedimentation in overall anoxic marine basins.

Although recently this paradigm has shifted towards a more differentiated

view based on recognition of bed-load transport structures and erosion

surfaces in mudstones, necessitating a thorough “rethinking” of our

understanding of the complexity of processes acting in such “anoxic”

settings. This study focuses on recognizing depositional events,

bioturbation structures and their stratigraphic and spatial distribution

within the upper shale member, Bakken Formation, an important source

rock and potential unconventional petroleum reservoir, Williston Basin,

U.S and Canada.

Facies analysis of the upper shale member reveals that this

depositional system is characterized by at least three distinct facies belts

with amorphous organic material occurring in all of them. On a transect

from proximal to distal these are: (1) a heavily bioturbated mudstone,

largely lacking sedimentary structures, (2) a laminated silt-rich mudstone

with horizontal and vertical bioturbation features, and (3) a radiolarian-rich

mudstone with varying content of silt and clay, and nearly exclusively

vertical bioturbations.

Evidence of event deposition exists in all facies belts, in the form of

sub-millimeter thick fine silt laminae interpreted as distal tempestites and

lag deposits from weak currents. The presence of vertical bioturbation in

laminated silt-rich mudstones, which forms the bulk of the sediment in the

unit, also argues against continuously anoxic conditions even some

millimeters below the sediment-water interface. Only some of the

radiolarian-rich facies, devoid of any trace fossils or tempestites, may

reflect temporary anoxia, whereas others are rippled indicating bottom

current reworking at least during portions of their depositional history.

The upper shale member represents an overall highstand unit,

sandwiched between the overlying Mississippian Lodgepole Limestone

and siltstones with carbonates of the middle Bakken member. Although the

basin center was at its greatest depth during such periods of elevated sea-

level, storms episodically influenced Bakken deposition, which points to

the Bakken depositional basin having been a relatively shallow trough with

maximum depth only slightly below storm wave base, perhaps <100 m.

Thus, important source rocks such as the upper shale member of the

Bakken can be deposited in relatively shallow water, above storm wave

base, with tempestites being a recognizable, common depositional feature.

THE BORING BILLION: IMPROVING OUR UNDERSTANDING

OF THE ITS GEODYNAMIC DEVELOPMENT AND ITS

MINERAL DEPOSITS

Eglington, B.M., University of Saskatchewan, 114 Science Place,

Saskatoon, SK S7N 5E2, bruce.eglington@usask.ca, Pehrsson, S.J.,

Geological Survey of Canada, 601 Booth St, Ottawa, ON K1A 0E8,

Evans, D.A.D., Yale University, New Haven, CT, USA, and Huston,

D., Geoscience Australia, Canberra, Australia

Understanding and visualizing the geology of multiple domains,

particularly those outside of one’s own areas of specialty, is usually

difficult. Database systems developed for the IGCP 509 project are

intended to facilitate this process by allowing users to extract information

for user-selected domains and to create time-space correlation charts which

illustrate lithostratigraphy, geochronology, geodynamic setting, rock class

and depositional setting. It is also possible to illustrate the age and general

character of metamorphism and deformation, as well as the timing and

style of mineralization and to highlight special features appropriate to

individual units.

This approach has been used to illustrate aspects of the geology of

the Grenville Province (sensu lato) of North America, the Sveco-

Norwegian Province of Scandinavia and the Namaqua-Natal Belt of

southern Africa. Geochronology for additional domains in Africa,

Australia, Antarctica and South America are also shown although the

compilation of lithostratigraphic information for these domains is only just

beginning. These various data sets will be used to help constrain plate

reconstruction models, hopefully building on to information already

available from the IGCP 440 project.

Studies of various mineralization styles during the past decade have

demonstrated that several associations may be uniquely associated with

geodynamic setting. For instance, volcanic-hosted massive sulphide

deposits have been classified in several ‘clans’ which appear to have

geodynamic significance, just as porphyry deposits and orogenic gold

deposits are formed in settings which are consistently linked to subduction

or collisional settings with distinctive vergence polarity at large scales.

Utilisation of the age and setting of ore deposits provides another

mechanism to help constrain or prioritise possible palaeogeographic

reconstruction models.

Investigation of the geodynamic setting of mineralization during the

‘boring billion’ (~1700-800 Ma) will draw on the information in the

DateView and StratDB databases (available online from http://sil.usask.

ca/databases.htm), from compiled time-space correlation charts and from

palaeogeographic reconstructions, so allowing comparison with time

intervals which are better endowed with economic mineralization.

Keynote LARGE SCALE CONTROLS ON THE SETTING OF

PALAEOPROTEROZOIC URANIUM MINERALISATION IN THE

NUNA SUPERCONTINENT (NORTH AMERICA AND

AUSTRALIA)

Eglington, B.M., University of Saskatchewan, Saskatoon, SK S7N

5E2, [email protected], Pehrsson, S.J., Jefferson, C.,

Geological Survey of Canada, 601 Booth St, Ottawa, ON K1A 0E8,

Evans, D.A.D., Yale University, New Haven, CT, USA, Huston, D.,

Geoscience Australia, Canberra, Australia, Quirt, D., AREVA

Resources Canada, Saskatoon, SK, and Lescuyer, J-L., AREVA,

Paris, France

Understanding the regional development of Palaeoproterozoic uranium

mineralisation has always been hampered by the disseminated nature of

information and by a lack of technology to draw together broad regional

data in formats suitable for systematic study. Databases developed for the

IGCP 509 project have facilitated collation of structured regional and

global data and new technologies facilitate reconstruction of past

palaeogeographies. Visualizing the development of the Nuna super-

continent relative to other cratons and fragments allows one to better

investigate broad regional patterns thought to influence fluid flow, fault

reactivation and mineralisation in the Athabasca, Thelon and Hornby Bay

basins of Nuna.

Reconstructions, performed in a GIS environment, utilise published

palaeomagnetic data augmented by regional structural vergence directions

which permit the ‘explosion’ of existing crustal domains at times dictated

by geology and geochronology. Known ore deposits, lithostratigraphy and

sample localities move with the continental fragments so that one can

‘watch’ the processes and events as they change in time and space and

study regional patterns which possibly controlled fluid flow leading to

mineralisation.

Nuna was formed by closure of the Manikewan Ocean and other

seaways in the interval 2.2 to 1.78 Ga. From 1.78 Ga to 1.65 Ga, the

geological history of Nuna is dominated by peripheral magmatism along

its western margin and coeval activity on the still open north-eastern

margin of Australia. The locus of orogenic activity changed through time,

shifting southwards, triggering reactivation of sympathetically oriented

pre-exisiting structures and basinal faults withinthe supercontinent interior.

From ca. 1.75 to 1.46 Ga, Nuna exhibits signs of attempted breakup that

overlapped with ongoing peripheral orogenesis. IOCG mineralisation at

Olympic Dam in Australia, unconformity uranium mineralisation in the

Athabasca Basin and Pb-Zn mineralisation in the Sullivan camp all relate

to this phase of Nuna development, with a locus of IOCG and SEDEX

mineralisation about a seaway between ancestral North America and

Australia. Regional geochronology illustrates zones where post-collisional

reactivation and/or uplift was focussed, possibly influencing fluid flow

within and around the sedimentary basins.

The style of supercontinent aggregation appears to have had a strong

influence on the nature of ore deposits formed and their preservation.

Major VMS, Ni-Cu-PGE and Orogenic Gold districts formed during the

interior orogenic phase whereas porphyry, sediment-hosted Pb-Zn, IOCG,

MVT and unconformity-uranium mineralisation are mostly associated with

the peripheral orogenic phase that overlapped with attempted breakup.

PERMANENT 4D ACQUISITION – PAST, PRESENT AND

FUTURE

Eisenhower, F., Stingray Geophysical Limited, Millbank House, 171-

185 Ewell Road, Surbiton, Surrey, KT6 6AP, UK, Frank.Eisenhower

@tgs.com

Permanently installed reservoir monitoring systems enable more frequent

4D monitoring leading to improved reservoir management and increased

total recovery. This paper reviews the history of permanent 4D system use

offshore from the initial installation in 1995 through to the present

permanent 4D system acquisition activity. The current state of the art in

permanent 4D technology is presented along with observations on where

the acquisition technology may be headed in the future. Two areas for

potential joint R&D projects are identified for industry consideration

which would be of particular interest to help operators maximise the value

of permanent 4D technology for applications in the conditions found

offshore Newfoundland.

The history of permanent 4D systems is longer than many in the

industry may recognise, starting with the first pilot acquisition project over

the Foinaven field in 1995. Over the past 17 years there have been 11

recognised projects undertaken. A brief review of the history and progress

from the early pilots through to the current full field installations will be

presented.

An overview of the current systems and technology available from

the main system/service providers will be presented, highlighting the

development and background of the existing technology options. An

objective view of the pros and cons of both electrical and fibre-optic based

technology for permanent 4D use will be discussed and presented.

The author will present his views on where the acquisition

technology may be headed based on the factors currently driving adoption

and implementation of permanent 4D systems and the Permanent

Reservoir Monitoring (PRM) 4D momentum currently building within the

industry. The near-term considerations for both providers and operators

will be discussed.

Two specific challenges for maximising the potential for permanent

4D acquisition offshore Newfoundland will be presented, one operational

and one technical. Both are proposed as potential subjects for joint R&D

collaboration between industry and academia.

On the operational side, a practical solution for the protection of

permanent seabed arrays against iceberg scour is required for the offshore

Newfoundland environment.

Longer-term, technology development of permanent seabed source

solutions to complement permanent receiver arrays will bring a step-

change reduction in repeat survey cost allowing a step-change increase in

repeat survey frequency, particularly in areas where the operational

weather window for conventional source acquisition is restricted.

BASIN EVOLUTION AT THE BEGINNING OF “SEQUENCE B”,

NORTHWESTERN CANADA

Elizabeth C. Turner, Turner, E.C., Department of Earth Sciences,

Laurentian University, Sudbury, ON P3E 2C6, [email protected]

The Mackenzie Mountains and Shaler supergroups (MMSG and SSG;

western NWT and northern NWT, respectively) of northwestern Canada

are assumed to be correlative successions in separate epicratonic open-

marine basins. This relationship is based on lithostratigraphy and

chemostratigraphy of the upper parts of the supergroups; the lower parts of

the supergroups remain largely unknown. The lower part of the Mackenzie

Mountains Supergroup (<1150?, >845 Ma), newly described from the

northwestern Mackenzie Mountains (NWT) and Wernecke Mountains

(YT), contains units that are not readily correlated lithostratigraphically

between the two areas. The basal unit (Dolores Creek Fm.; YT only; 260

m) lies with angular unconformity on the Pinguicula Gp. and consists of

organic-rich black mudstone and siltstone that was deposited under an

anoxic water column, interlayered with shallow-water microbial and

intraclastic dolostone. The overlying Black Canyon Creek Fm. (YT only;

~285 m) consists of shallow-water cherty dolostone that contrasts

compositionally with most of its putative equivalent in NWT, the Tabasco

Fm. (formerly “H1 unit”; lowest MMSG unit exposed in western NWT;

>485 m), which is dominated by a thick deeper-water stromatolitic

succession. Overlying terrigenous clastic units [Tarn Lake Fm. in YT

(~265 m); Tsezotene Fm in NWT(~1 km)] were deposited under different

conditions (tidal flat to shallow marine, and muddy outer ramp,

respectively), but could be lateral equivalents depending on basin

configuration. Stable isotope stratigraphy is unhelpful in deciphering

among the possible correlation schemes, because no distinctive excursions

are matchable. The MMSG basin began with a thin (~260 m), restricted,

anoxic, shallow-water phase that probably represents a rift environment,

whereas the SSG began with a thick (~1 km) shelf siltstone succession

(Escape Rapids Fm.) that probably records an open marine continental

shelf. Lithostratigraphic and chemostratigraphic comparison of the

lowermost carbonate formations in the MMSG with the SSG (Mikkelsen

Islands Fm.) may resolve the problematic relationships among these units.

Lithostratigraphic comparison of the lower parts of the supergroups (600-

1000 km apart) will illuminate the conditions under which different styles

of basin extension first developed in these two areas.

RECENT WORK ON ERNIETTOMORPHS FROM THE SOUTH

OF NAMIBIA

Elliott, D.A., Monash University, Clayton Campus, Wellington Rd.,

Melbourne, Victoria, Australia, 3800 david.[email protected].

In recent years, a diverse group of researchers has been working on the

Nama Group in Namibia. The Nama Group, representing the latest

Neoproterozoic and including overlying Cambrian sediments, outcrops

extensively in southern Namibia. It consists of a series of sandstone-

limestone cycles. Some of the earliest of these cycles outcrop at Aar Farm,

near the town of Aus. Work on Aar Farm has substantially extended

existing collections. In particular, it has produced remarkable specimens of

Pteridinium and Ernietta, two of the more unusual Ediacaran organisms.

Ernietta has been studied for over forty years. Among the Ediacaran

organisms, it has arguably been among the least-controversial, but we are

far from a complete understanding of its evolutionary or environmental

significance. The new specimens are representative of the 'Nama-style'

preservation, a three-dimensional form of soft-tissue preservation that has

interested researchers for some time. Newly discovered fossil features

associated with Ernietta may extend our understanding of this organisms

morphology during life, but also interesting are examples of multiple

Ernietta preserved together. Previous work has established that these

fossils cannot be easily related to modern taxa. The prevailing consensus is

that they represent a branch of the tree of life with no living descendants.

The similarity – and probable relationship – between Ernietta and

Pteridinium has been noted by many researchers. How this will ultimately

fit in with phylogenies of the Ediacaran fauna remains to be seen.

IS THERE ANY OIL PLAY IN THE CANADIAN LABRADOR SEA

BASINS?

Enachescu, M., [email protected], MGM Energy Corp, 4100, 350

Ave SW, Calgary, AB T2P 3N9, and Memorial University, St.

John's, NL A1B 3X5, Atkinson, I., Dillabough, G., Wahl, L. and

Wright, R., Nalcor Energy, Hydro Place, 500 Columbus Drive, PO

Box 12800, St. John's, NL A1B 0C9

Two very large basins, Hopedale and Saglek, cover the shelf, slope and

deep water of the Labrador continental margin. These are extensional

basins containing thick Mesozoic to Tertiary sedimentary fill including

quality sandstone reservoirs. The area was explored during the seventies

and early eighties when 6 gas and condensate discoveries were made. Only

one oil show was recorded attributable to an immature source rock.

Regional geology, reflection seismic, oil seep and conjectural evidence

point toward the existence of a lucrative oil play within sectors of the

Canadian Labrador Sea basins.

2012 EXPLORATION AND PRODUCTION UPDATE ON THE

CANADIAN ATLANTIC MARGIN

Enachescu, M.

1,2

, [email protected], Brown, D.E.

and Atkinson, I.

MGM Energy Corp, 4100, 350 7

Ave SW, Calgary, AB T2P 3N9;

Memorial University, St. John's, NL A1B 3X5;

Canada-Nova

Scotia Offshore Petroleum Board, TD Centre, 1791 Barrington

Street, Halifax, NS B3J 3K9;

Nalcor Energy, Hydro Place, 500

Columbus Drive, PO Box 12800, St. John's, NL A1B 0C9

The Canadian Atlantic Margin has six areas with significant hydrocarbon

discoveries:

1. Sable Subbasin producing gas since late 1999;

2. Jurassic Carbonate Bank containing the Deep Panuke gas field;

3. Jeanne d’Arc Basin, the only offshore East Coast North America oil

producing area;

4. Flemish Pass Basin containing the newest Atlantic oil discovery;

5. Hopedale Basin where several gas fields were found, and

6. Saglek Basin containing the Hekja gas field.

Production. During 2011, a total of 97.3 MMbbls of oil were

produced from the Jeanne d’Arc Basin, offshore Newfoundland. The

production from Hibernia, Terra Nova and White Rose fields and several

satellites averaged 266,494 bopd. Lately, the satellite field development

has helped maintain the production rate above 250,000 bopd. Over 1.3

billion barrels were produced to date from the area. In the Nova Scotia’s

offshore, the Sable Offshore Energy Project produced 100 Bcf during the

year, with an average production rate of 274 MMcf/d. A total of 1.8 Tcf

were produced since the start of the project.

Development. The Deep Panuke gas field, offshore Nova Scotia is

planned to start production during the summer of 2012, with anticipated

peak production of 300MMcf/d. The next major project offshore

Newfoundland is the Hebron field with development stating in 2012,

following project sanction. Hebron’s first expected oil is planned for 2017

and its peak production is estimated to be 150,000 to 170,000 bopd.

Exploration. Peak production from NL offshore oil fields came in

May 2007; Nova Scotia gas production peaked in December 2001. A low

level of exploration has characterized the past decade of exploration in

Atlantic Canada. No exploration wells have been drilled offshore Nova

Scotia since 2005, while a well or two per year was the usual drilling rate

offshore Newfoundland. Many basins and subbasins remain unexplored or

little explored. Three wells, Ballicatters M-96 and M-96Z and Glenwood

H-69 were recently abandoned or suspended in the northern Jeanne d’Arc

Basin without proving significant oil reserves. In spite of a successful

licensing round in the Hopedale Basin, no drilling in the Labrador Sea is

planned yet. Without new discoveries, the Canadian Atlantic Margin

petroleum industry is on a declining path with aging fields, shrinking

reserves and many remaining undrilled prospects.

Nevertheless, focused exploration efforts and good news comes from:

a) Mizzen oil discovery that brings a new intermediate to a deepwater

exploration area in the North Flemish Pass-Southeast Orphan Basin.

The Mizzen O-16 significant discovery has also triggered several

successful exploration licensing in the adjacent area;

b) Allochthonous Salt and Minibasin Province, southwestern Scotian

Slope where four deepwater parcels were won in January 2012 by

Shell with a record $970 million work commitment bid.

Research. On the Newfoundland and Labrador sector of the margin,

the Provincial Government and Nalcor Energy Oil and Gas initiatives

resulted in acquisition of modern high quality regional seismic data

coupled with satellite based sea slicks studies and geochemistry analysis of

shallow cores. The data and studies will be made available for licensing to

the industry. The Province of Nova Scotia’s recently released $15 million

Play Fairway Analysis (NSPFA) points toward the existence of Early

Jurassic oil prone source rocks in the deeper parts of the Scotian Slope.

The comprehensive study has been very favourably received by industry

and is available free for download.

Minimizing the geological risk is essential to increase exploration

activity and to lead to drilling success on the Canadian Atlantic Margin.

GREAT BEAR MAGMATIC ZONE ROCK PROPERTY

DATABASE: LINKING GEOLOGY AND GEOPHYSICS WITHIN

IOCG SYSTEMS

Enkin, R.J., Geological Survey of Canada, PO Box 6000, Sidney, BC

V8L 4B2, renkin@nrcanc.gc.ca, Hayward, N., Geological Survey of

Canada, Vancouver, BC, Lee, M.D., McMaster University,

Hamilton, ON, Corriveau, L., Geological Survey of Canada, Québec,

QC, Montreuil, J-F., Institut national de la Recherche scientifique,

Québec, QC, and Acosta, P., University of Alberta, Edmonton, AB

The two primary poles of mineral exploration are geological mapping and

geophysical surveying. In order to link these two great exploration

investments, labs such as the Geological Survey of Canada

Paleomagnetism and Petrology Laboratory and the McMaster Applied

Geophysics and Geological Imaging Centre have undertaken extensive

measurements of physical properties to strategically chosen rock

collections: density (bulk and skeletal), magnetic susceptibility and

remanence, and electrical impedance spectra for resistivity and

chargeability. The Great Bear magmatic zone (GBmz) Rock Property

Database provides a useful example of this approach. The current

exploration model for the GBmz is iron oxide copper gold (IOCG)

mineralization (and affiliated deposits) featuring a six-zone alteration

classification of mineral assemblages. From the high temperature-deeper-

earlier-core to the cooler-shallower-later-distal alteration indices, the zones

are identified as 1:Na(Ca); 2:Ca-Fe(Na); 3:High Temp K-Fe; 4:Skarn (if

carbonates are present); 5:Low Temp K-Fe; 6:Low Temp silicification.

Analysis of the distributions of physical properties as a function of the

lithologies and alteration zones of the range of rocks collected in the

GBmz reveals useful patterns to provide new exploration vectors. The

geometric mean magnetic susceptibilities [E-3 SI units ± standard error]

are: 1: 3.2±40%; 2: 17.7±16%; 3: 12.6±18%; 4: 1.5±83%; 5: 3.9±3.3%; 6:

2.1±15%. Note that the magnetite produced in the higher temperature

zones 2 and 3 lead to magnetic susceptibilities 6 to 8 times higher on

average than that of zone 6 samples. The iron oxide mineralization leads to

high magnetic remanence values which must be taken into account in

magnetic survey interpretation. One quarter of rocks identified to be in

zone 2 or 3 alteration have Koenigsberger ratios above 1, compared to 10

to 15% of the samples in the other zones. The correlation of high magnetic

and density values leads to hybrid density-magnetic potential field models.

Current work on resistivity-chargeability properties is motivated by strong

unexpected anomalies observed in electromagnetic surveys in the Port

Radium region. As of January 2012, rock properties from over 700

samples from the GBmz have been measured and compiled, and several

hundred are currently under examination. Through the petrophysical link

coupled with clear understanding of the relevant mineralization model,

new effective strategies are being developed to target and locate new

mineral deposits.

DIFFERENTIAL EXHUMATION AND CONCURRENT FLUID

FLOW AT THE NICO Au-Co-Bi-Cu DEPOSIT, GREAT BEAR

MAGMATIC ZONE, NWT - A PALEOMAGNETIC AND STRUC-

TURAL RECORD

Enkin, R.J., Geological Survey of Canada, PO Box 6000, Sidney, BC

V8L 4B2, renkin@nrcanc.gc.ca, Montreuil, J-F., Institut national de

la Recherche scientifique, Québec, QC, and Corriveau, L.,

Geological Survey of Canada, Québec, QC

The iron oxide copper-gold (IOCG) mineralization model is offering new

exploration possibilities, especially in the Proterozoic Great Bear

magmatic zone, NWT. The NICO Au-Co-Bi-Cu deposit, the numerous U-

Th-REE±Cu-Mo showings of the Southern Breccia and the nearby Cu-

Ag-(Au) Sue Dianne deposit provide well-exposed examples of IOCG-

type and IOCG-affiliated mineralization. A paleomagnetism study (39

sites, 318 oriented specimens) was undertaken in this region with the goal

of determining the interplay of hydrothermal fluids, deformation and iron-

oxide mineralization. Because of the high concentrations of large

magnetite grains in these altered rocks, hybrid alternating field and thermal

demagnetization was done to clean a large unstable magnetic component

from the useful paleomagnetic components. Strong stable magnetic

remanence was observed throughout the collection, almost fully carried by

magnetite even in dominantly hematite-bearing rocks. The rich range of

lithologies, alteration levels and contact relationships in this small area

provided the whole range of paleomagnetic stability tests. Negative

conglomerate and tilt tests reveal pervasive remagnetization. The

collection almost completely holds downward polarity (but not in the

present field direction), as do the reference directions observed in stable

Paleoproterozoic formations northwest of the Trans-Hudson Orogeny.

While 4 sites retain an untilted Paleoproterozoic direction, most sites hold

steeper remanence directions interpreted as variable tilting after remanence

was acquired, dominantly down to the south-east. Rare 3-component

magnetizations reveal magnetization acquisition during tilting. Five

contact tests offer the exotic result that dykes were magnetized at different

times than their contact zones, interpreted to be the result of subsequent

hydrothermal pathways exploiting the differential permeability pathways.

Combined with detailed analysis of polyphase structural evidence, the

paleomagnetic remanence may indicate a form of bookcase normal

faulting active during late deformation. Along with the complex results

revealed from many complementary methods used to examine IOCG

deposits, paleomagnetism provides quantitative proof of differential

exhumation and concurrent fluid flow in this mineralization setting.

A PROPOSED 725 Ma DOVYREN-KINGASH LIP OF SOUTHERN

SIBERIA, AND POSSIBLE RECONSTRUCTION LINK WITH THE

725-715 Ma FRANKLIN LIP OF NORTHERN LAURENTIA

Ernst, R.E., Carleton University, and Ernst Geosciences, 43

Margrave Avenue, Ottawa, ON K1T 3Y2, Richard.Ernst@

ErnstGeosciences.com, Hamilton, M.A., University of Toronto,

Toronto, ON M5S 3B1, and Söderlund, U., Lund University,

Sölvegatan 12, Lund, SE-22362, Sweden

Along the entire southern flanks of the Irkutsk promontory of the Siberian

craton, numerous mafic-ultramafic layered intrusions occur with Ni-Cu-

PGE ore deposits. Previous age studies by various methods have suggested

igneous emplacement broadly between 800 and 600 Ma. Here we present

the first U-Pb (ID-TIMS) baddeleyite ages for two of these intrusions

(samples from BHP Billiton). On the eastern margin of the promontory,

the large, well-exposed and lopolithic (Yoko-) Dovyren intrusion at the

northern end of Lake Baikal contains abundant, fresh baddeleyite and

gives an upper intercept age of 724.7 ± 2.5 Ma (5 fractions). Along the

southwest border of the promontory, an upper, differentiated gabbroic

portion of the Upper Kingash layered intrusion (East Sayan block, Kan

belt) yielded only sparse, minute baddeleyite grains (max. 20-30 microns),

but regression of the U-Pb data gives a similar age, at 726 ± 18 Ma (4

fractions). Lower intercepts in both cases suggest Paleozoic- and

Mesozoic-aged Pb-loss effects, likely due to docking of Phanerozoic

terranes of the Central Asian fold belt.

These two dated intrusions are located in widely separated terranes

bounding the southern Siberian craton and suggest that the many other

undated mafic-ultramafic intrusions (also commonly with Ni-Cu-PGE

potential) along the 1100 km distance of these bounding terranes may also

have a ca. 725 Ma age. Moreover, dykes and sills within the Irkutsk

promontory of the Siberian craton have yielded Ar-Ar ages similar to our

dated intrusions. This suggests that ca. 725 Ma mafic-ultramafic

magmatism is widespread in the Siberian craton and adjacent terranes, and

constitutes a 725 Ma large igneous province (LIP).

This 725 Ma Dovyren-Kingash LIP of southern Siberia is an age

match to the ca. 725-715 Ma Franklin LIP which covers an area of >1

Mkm

in northern Canada and western Greenland. It consists dominantly

of a radiating mafic dyke swarm with an arc of about 90°, converging to an

inferred mantle plume centre near Banks Island. Additional Franklin

components include the Coronation sills and the Natkusiak volcanic rocks

and associated sills of the Minto Inlier of Victoria Island. The temporal

equivalence between the Dovyren-Kingash and Franklin LIPs lends

support to a nearest neighbour relationship between southern Siberia and

northern Laurentia. That the 725 Ma Dovyren, Upper Kingash and related

intrusions of southern Siberia have significant Ni-Cu-PGE mineralization

enhances the intrinsic metallogenic potential of Franklin magmas

providing that northern Laurentia and southern Siberia can be

demonstrated to have been adjacent at this time.

INTRAPLATE MAGMATIC ‘BARCODE’ RECORD OF THE

CONGO CRATON (ANGOLA PORTION): NEWLY DATED

DOLERITE EVENTS AT 1502 AND 1110 Ma AND IMPLICATIONS

FOR NUNA AND RODINIA SUPERCONTINENTAL RECON-

STRUCTIONS

Ernst, R.E.

1,2

, [email protected], Hamilton,

M.A.

, Pereira, E.

, [email protected], Rodrigues, J.

Tassinari, C.

and Van-Dunem, V.

Carleton University, Ottawa,

ON;

Ernst Geosciences, 43 Margrave Avenue, Ottawa, ON K1T

3Y2;

University of Toronto, Toronto, ON M5S 3B1;

Laboratório

Nacional de Geologia, Apartado 1089, 4466 – 956 S. Mamede

Infesta, Portugal; FEUP, Universidade do Porto, Portugal;

Instituto

de Geociências, Universidade de São Paulo / CPGeo, Rua do Lago

562, São Paulo, SP, Brasil, CEP 05680-080;

Instituto Geológico de

Angola, CP 1260, Luanda, Angola

Positions of the large Congo craton in Precambrian supercontinent

reconstructions remain poorly constrained. New evidence from ongoing

geochronologic and paleomagnetic studies of widespread Proterozoic

mafic dykes and sills now permits some first-order magmatic ‘barcode’

comparisons with other continental blocks.

In Congo craton’s Angola portion, the only well-dated Proterozoic

intraplate event to this point is the 1370-1380 Ma Kunene Intrusive

Complex. We report new, precise U-Pb ID-TIMS dating of dolerites that

reveals two unanticipated additional Meosproterozoic intraplate events: at

1502 and 1110 Ma (details below). Identification of these three

Mesoproterozoic magmatic events (ca. 1380, 1500 and 1110 Ma) define an

initial magmatic ‘barcode’ for the western portion of Congo craton, which

can be compared with the record in other crustal blocks to identify former

nearest neighbours important to Precambrian supercontinents Nuna and

Rodinia.

A 1502±5 Ma U-Pb baddeleyite age has been obtained for the

prominent Humpata sill, potentially part of a broad dolerite sill province.

The combined presence of both 1500 Ma and 1380 Ma magmatism in the

Congo craton represents a critical match with similar ages published for

two suites of mafic dykes and sills in northern Siberia. This magmatic

‘barcode’ match suggests a nearest-neighbour relationship between

northern Siberia and the Congo (+ formerly attached São Francisco craton)

in the supercontinent Nuna. Intraplate magmatism at 1380 Ma is also

found on other blocks and is interpreted as heralding a final, widespread

breakup phase of Nuna.

A prominent NNW-NNE trending dolerite swarm (Huila dykes) in

southeastern Angola has yielded a precise U-Pb TIMS baddeleyite age of

1110±3 Ma. This age is currently unknown in Siberia, suggesting that

breakup of Congo-São Francisco craton from Siberia may have happened

in association with the 1380 Ma event. This 1109 Ma age is, however, an

important and precise match with existing U-Pb ages for the Umkondo

Large Igneous Province (LIP) of the Kalahari craton, and also with

intraplate magmatism on other blocks such as the Amazonian craton

(Hamilton et al., this meeting) and the Bundelkhand craton (India). Based

on this equivalence, we consider whether all these blocks (Kalahari,

Amazonia, and India) could have been nearest neighbours to the Congo-

São Francisco craton during the Mesoproterozoic, and shared a 1110 Ma

magmatic event in the Rodinia supercontinent. Although the latter also

represents an age match with the early phase of interior Laurentia’s

Keweenawan event, on paleomagnetic grounds, Mid-Continent Rift

magmatism is likely to have been distant and unrelated.

Keynote THE CAMBRIAN CONUNDRUM: THE CONSTRUCTION

OF ANIMAL BIODIVERSITY

Erwin, D.H., Laflamme, M. and Tweedt, S.M., Smithsonian Institution,

PO Box 37012, Washington, DC 20013-7012, erwind@ si.edu

A diversity of bilaterian clades first appear in the fossil record within a few

million years during the early Cambrian, and a variety of environmental,

developmental, and ecological causes have been proposed as explanations.

Molecular clock data indicate that Metazoa arose about 780 Ma, followed

by the origination of sponges and cnidarians. The basic metazoan

developmental toolkit arose by 700 Ma, demonstrating a macro-

evolutionary lag between the establishment of the tools necessary to

generate complex animals, and their later ecological success during the

Ediacaran, after 579 Ma and Cambrian (541 to 488 Ma) periods. We argue

that this diversification involved new forms of developmental regulation,

as well as innovations in networks of ecological interaction particularly

through ecosystem engineering of environments that facilitated increased

metazoan diversity.

A 3D EVALUATION OF RESERVOIRS ASSOCIATED WITH THE

BREAK-UP OF ALASKA AND ASSESSMENT OF THE IMPACT

OF MANTLE PLUMES

Evans, K.C.S., Davies, R.B., Davies, A., Lodola, D. and Martin R.,

Neftex Petroleum Consultants, 97 Milton Park, Abingdon OX14

4RY, UK

The North Slope of Alaska is an established petroliferous region with vast

amounts of data, much of which is now in the public domain, thereby

facilitating a comprehensive review of its geological history and its

petroleum systems. The tectonic history of North Slope is complex and has

had a profound influence on the deposition of both reservoir and source

rocks. Key unconformities that can be correlated to major tectonic events

are recognised in the stratigraphy. One such major feature is the Lower

Cretaceous Unconformity, or the Break-Up Unconformity, caused by

Northern Alaska rifting away from Arctic Canada.

The trigger for this break up is uncertain, although we propose it may

be related to the presence of a hot spot plume in the vicinity of Arctic

Alaska and the Canadian Arctic Islands during the Early Cretaceous. The

break-up caused very rapid uplift along the line of the Barrow Arch across

the North Slope and US Chukchi regions although the expression of the

resulting unconformity varies along this region. Following the uplift event,

subsurface data shows a very pronounced, but rapid subsidence phase in

the region leading to a return to deep marine conditions. This series of

events is consistent with the passage of a mantle plume and led to the

deposition of sandstones during the transgressive phase associated with the

rapid subsidence. The sandstones form important proven and potential

reservoir facies although they are relatively localised.

Here we show how we have used a comprehensive data set derived

from the public domain to address the distribution of petroleum elements

across the North Slope. The data set has been interpreted within a

proprietary global sequence stratigraphic model and used to build a set of

gross depositional environment maps that illustrate the changes in palaeo-

environments associated with the break-up event. By placing these maps

within a regional 3D model and applying proprietary palinspastic

reconstructions, we have gained much improved insights into the causes of

the major tectonic events as well as the potential extents of petroleum

elements relating to the Lower Cretaceous Unconformity. Results from

this approach to interpret data in the North Slope should also provide good

analogues for the neighbouring US Chukchi and Beaufort Sea regions.

A REVIEW AND UPDATE OF GEOLOGICAL MODELS AND

MINERALIZED ENVIRONMENTS FOR THE VOISEY’S BAY Ni-

Cu-Co DEPOSITS, NL

Evans-Lamswood, D., Brownfield Exploration, Vale Newfoundland

and Labrador Limited, Suite W200, Bally Rou Place, 280 Torbay

Road, St. John’s, NL A1A 3W8, and Lightfoot, P.C., Vale,

Brownfield Exploration, Copper Cliff, ON P0M 1N0

The Voisey’s Bay Ni-Cu-Co sulphide deposits occur within troctolites and

olivine gabbros of the 1.34 Ga. Voisey’s Bay Intrusion. The Voisey’s Bay

Intrusion is a member of the Nain Plutonic Suite and straddles the ca. 1.85

Ga. suture between Archean orthogneisses of the Nain Province to the east

and Paleoproterozoic paragneisses of the Churchill Province to the west.

The Voisey’s Bay intrusion consists of troctolite to olivine gabbro

rocks in two large magma chambers connected by an east-west trending

horizontal to sub-vertical conduit system. The Ovoid, Mini-Ovoid,

Discovery Hill and Reid Brook and the Eastern Deeps deposits are hosted

within or adjacent to the sub-horizontal portion of the conduit system. New

drilling and 3D reconstruction of the conduits highlights the continuity of

the conduit from both west to east and vertically between the two

chambers. The conduit forms a structural corridor which is one of the

principal exploration target domains for additional zones of mineralization.

A number of geological features provide additional information that

help to identify sites where mineralisation is trapped in the conduit-

chamber system within spaces created by structures that were reactivated

at the time of magmatism. A range of silicate and silicate-sulphide

textures, inclusion content and type coupled with host rock type underpin

an understanding of the pathways that controlled the emplacement of the

sulphide and its location in the conduit.

Exploration continues to follow targets along the trend of the

conduit. Examples where the model has evolved include the Reid Brook

Zone where reactivated structures in the wall rock have created space for

massive sulphides to migrate into the hangingwall and footwall; these

sulphides were likely emplaced at the time of formation of the conduit-

hosted ores as they have similar compositions. Within the Southeast

Extension, a detailed understanding of coinduit morphology and sulphide

metal tenor has helped identify discrete domains of sulphide that have been

emplaced from multiple conduit entry points into the Eastern Deeps

chamber. These ideas are critical to success as exploration of the deeper

extensions of mineral in the Reid Brook and Eastern Deeps is undertaken.

Lightfoot, P.C., Keays, R.R., Evans-Lamswood, D.E., and Wheeler, R.,

2011. Crustal contamination and multiple S-saturation events in Nain

Plutonic Suite magmas: evidence from Voisey’s Bay, Labrador,

Canada. Mineralium Deposita 47, 23-50.

Evans-Lamswood, D.M., Butt, D.P., Jackson, R.S., Lee, D.V., Muggridge,

M.G., Wheeler, R.I., and Wilton, D.H., 2000. Physical Controls

Associated with the Distribution of Sulfides in the Voisey’s Bay Ni-

Cu-Co Deposit, Labrador. Econ Geol 95, 749-769.

GEOLOGY OF THE VOISEY'S BAY DEPOSIT: STATE OF

UNDERSTANDING OF THE DIVERSITY IN ROCK AND ORE

TEXTURES AND SIGNIFICANCE TO PROCESS MODELS

Evans-Lamswood, D.

, Wheeler, R.

, Lightfoot, P.

, House, G.

Morrissey, K.

, Mulrooney, D.

and Pittman, S.

Vale, Brownfield

Exploration, Vale Newfoundland and Labrador Limited, Suite W200,

Bally Rou Place, 280 Torbay Road, St. John’s, NL A1A 3W8;

Vale,

Brownfield Exploration, Copper Cliff, ON P0M 1N0;

Vale

Newfoundland and Labrador Limited, Voisey's Bay Mine Site, PO

Box 7001, Station C, Happy Valley - Goose Bay, NL A0P 1C0

Extensive exploration and mining activity at Voisey's Bay has provided

unparalleled opportunity to assemble a geological understanding of the

mineral system that underpins the ongoing search for extensions to mineral

zones and new domains of mineralisation. We present a series of samples

that document the diversity in petrology, mineralogy, and textures found in

the Voisey's Bay Deposit. The Ovoid Deposit comprised a historic reserve

of 32.0 Mmt at 2.75% Ni, 1.59% Cu, and 0.137% Co that has now been

mined for 7 years at the rate of 2.2 Mmt pa. The ongoing mining activity

has provided unparalleled access to samples which document a spectrum

in sulphide types that record changes in composition from Po-Cpy-Pn-rich

loop-textured pegmatoidal massive sulphides with po grain sizes of 10cm-

2m which grade inwards towards small domains of Cubanite-rich ore. The

transition between these ore types is recorded in changing proportions of

magnetite and sulphide minerals that support the idea of inwards

differentiation of one of at least two discrete pulses of sulphide magma

with differing Ni tenors - one of these comprises a large part of the Mini-

Ovoid and the other represents the majority composition of the Ovoid. The

basal breccia sequence rocks are now understood to be complex coarse-

grained intergrowths of silicate and sulphide minerals as well as breccia

sequence rocks which are typically associated with mafic and ultramafic

fragments proximal to the entry point of a dyke into the Ovoid. We show

the variations in samples from different parts of the Mini-Ovoid and Ovoid

Deposit and show how these are linked to a facies model proposed by

Evans-Lamswood et al., 2000.

Exploration activity SE of the Ovoid has provided a new

understanding of the geometry of the conduit system, and now shows that

different sulphide types are present at the entry point of the Ovoid conduit

dyke relative to the Eastern Deeps conduit dyke. Representative samples

from each of these environments are shown in the context of the internal

stratigraphy of this complex environment. We show these features in

relation to samples from holes VB10910 and VB03582 from the

Southeastern extension. We also document some of the detailed internal

stratigraphy of the Eastern Deeps Deposit which is consistent with

emplacement of a weakly mineralised magma that formed the variable-

textured troctolite and a pulse of fragment-laden magma with abundant

immiscible sulphide which formed the economic heart of the Eastern deeps

deposit. We show these features using samples from drill core VB96-266.

We propose a model for the formation of the sulphide ores that

involves S-saturation and upgrading of the sulphides at depth and then

emplacement of multiple different batches of sulphide over a limited

period of time (Lightfoot et al., 2011).

Lightfoot, P.C., Keays, R.R., Evans-Lamswood, D.E. Wheeler, R., 2011.

Crustal contamination and multiple S-saturation events in Nain

Plutonic Suite magmas: evidence form Voisey’s Bay, Labrador,

Canada. Mineralium Deposita 47, 23-50.

Evans-Lamswood, D.M., Butt, D.P., Jackson, R.S., Lee, D.V., Muggridge,

M.G., Wheeler, R.I. and Wilton, D.H., 2000. Physical Controls

Associated with the Distribution of Sulfides in the Voisey’s Bay Ni-

Cu-Co Deposit, Labrador. Econ. Geol. 95, 749-769.

TRANSPRESSIONAL DYNAMICS AND THE ROLE OF CRUSTAL

HETEROGENEITIES IN THE LOCALIZATION OF THE

DESMARAISVILLE BASIN (ABITIBI): GEOPHYSICAL STUDY

AND ANALOGUE MODELLING

Fayol, N.

, noemiefayol@gmail.com, Harris, L.B.

and Jébrak, M.

Université du Québec à Montréal, CP 8888, succursale Centre-ville,

Montréal, QC H3C 3P8;

Institut National de la Recherche

Scientifique-Centre Eau-Terre-Environnement, 490 rue de la

Couronne, Québec, QC G1K 9A9

The Abitibi Subprovince contains many late Archean, 2685 and 2670 Ma

sedimentary basins in the southern Abitibi that host several major gold

deposits. Their association with terminations or flexures in regional E-W

faults, e.g. Destor-Porcupine and Larder Lake–Cadillac faults, as well as

their pronounced subsidence and molassic infill, abrupt facies changes and

asymmetry have collectively evoked comparisons with transtensional

basins.

The Desmaraisville basin, situated in the Abitibi Greenstone Belt

about 120 km WSW of Chapais, is characterized by a volcano-sedimentary

assemblage, mafic and felsic intrusions, and regional NE-SW faults. The

Auger and Lac Bachelor sedimentary sequences respectively occur SE of

the Coniagas mine and NW of the Bachelor mine (Métanor Resources

Inc.). The Lac Bachelor sedimentary rocks belong to the Haüy Formation

dated at 2692 ± 3 Ma in the Chapais region which represents the northern

Abitibi equivalent of the Timiskaming sequences. The Desmaraisville

basin can therefore be included as a Timiskaming-type basin.

It however differs to other such basins in its position within a NE-

SW deformation zone and enhanced TGI-3 Abitibi Project aeromagnetic

images do not reveal en relais faults that could have formed a trans-

tensional basin. The σ schistosity trajectory around a pluton suggests a

dextral movement along an E-W deformation zone and en echelon NW-SE

faults with dextral offsets are consistent with a transpressional Riedel

system during N-S shortening. Bouguer gravity data demonstrate the

presence of a denser block to the west of Desmaraisville and a less dense

domain east of the town. The “stair-step” shape of the block suggests the

presence of E-W dextral shear zones, one of which passes through

Desmaraisville.

Analogue tank models incorporating sand layers that simulate brittle

upper crust upon silicone-modelling clay that incorporates crustal

heterogeneities as identified from gravity data, floating upon a glucose

substrate were used to test our interpretations. Shortening of models

produces a basin located exactly in the Desmaraisville area. Some faults

formed during this experiment correspond to major structures in the field

such as de Wedding-Lamarck fault.

The formation of the Desmaraisville basin does not fit the currently

accepted model for “transtensional Timiskaming-type” basins, but it could

have developed at the interface between crustal heterogeneities during a

late N-S shortening phase in the Abitibi. Forthcoming studies will analyze

the relationships between transpressional dynamics and gold minerali-

zation in this basin.

ORGANIC AND INORGANIC PORES: THEIR NATURE AND

RELATIVE SIGNIFICANCE IN ORGANIC-RICH MUDSTONES

OF THE UPPER JURASSIC KIMMERIDGE CLAY FORMATION,

OFFSHORE UNITED KINGDOM

Fishman, N.S., U.S. Geological Survey, Box 25046 MS 939, Denver,

CO 80225, nfishm[email protected], Hackley, P.C., U.S. Geological

Survey, 12201 Sunrise Valley Dr., Reston, VA 20192, Lowers, H.A.,

U.S. Geological Survey, Box 25046 MS 973, Denver, CO 80225,

Hill, R.J., Noble Energy, 1625 Broadway, Denver, CO 80202, and

Egenhoff, S.O., Colorado State University, 1482 Campus Delivery,

Fort Collins, CO 80523

Organic-rich shales of the Upper Jurassic Kimmeridge Clay Formation

(KCF), offshore United Kingdom, are at varying levels of thermal maturity

in a suite of 9 cores, and samples from these core provide a unique

opportunity to evaluate the nature of the organic material and to document

changes in organic porosity as a function of thermal maturity. The KCF,

which is at depths ranging from ~6,100 ft to ~15,300 ft (subsea), is

thermally immature in the shallowest core samples, where TOC contents

are as high as 10 wt%, Ro values are ~0.35%, and hydrogen indices (HI )

are high (>400). In contrast, it is thermally mature in the deepest core (Ro

values ~1.2%), with high TOC contents (as much as 8 wt%) but low HI

values (<30).

Detailed petrographic study and SEM analyses reveals the presence

of at least four distinct types of organic macerals. Similar organic macerals

were observed in all cores across the study area, and include, include, in

decreasing abundance: 1) bituminite admixed with clays (deposited as

“marine snow”); 2) elongate (< 500 µm) lamellar masses (alginite or

bituminite) with small (<0.5 µm) quartz, feldspar, and clay entrained

within it (microbial mats); 3) discrete terrestrial grains (e.g. vitrinite,

fusinite); and 4) Tasmanites microfossils.

Organic pores, observed on ion-milled surfaces, vary as a function of

maceral type, but, importantly, do not increase systematically with

increasing thermal maturity (comparison of low vs high maturity samples).

Pores in lamellar masses are irregularly-shaped and typically small (<0.1

µm across), whereas regularly shaped pores (<1 µm across) occur in

terrestrial macerals. Irregularly-shaped pores (<0.3µm) exist in bituminite

admixed with clay. Other pores (inorganic pores), particularly interparticle

(i.e., between clay platelets (~1-2µm in length)), and intraparticle (i.e., in

partly dissolved K-feldspar and dolomite (<2µm across), as well as

framboidal pyrite (<0.1µm across) are present and noteworthy because

they compose much of the observable porosity in the Kimmeridge

mudstones in both immature and mature samples.

The absence of a systematic increase in organic porosity as a

function of either maceral type or thermal maturity and the relatively small

size of organic pores indicates that such porosity was unlikely to be related

to hydrocarbon generation. Instead, much of the porosity within KCF

mudstones must be largely interparticle or intraparticle so the petroleum

storage potential in these organic-rich shales largely resides in inorganic

pores.

ORIGIN OF THE REGOLITH AT THE IMPACT CRATER AT

MISTASTIN LAKE, LABRADOR – IMPACT EJECTA OR

GLACIAL TILL

Flynn, L.E., [email protected], and Sylvester, P.J., Memorial

University of Newfoundland, St. John's, NL A1C 5S7

The purpose of this study was to determine the origin of the regolith at

Mistastin Lake, northern Labrador, Canada (55º53’N, 63º18’W), a mid-

sized (~28km wide) complex crater formed by a meteorite impact event

36± 4 million years ago. The crater is located in granodiorite, mangerite

and anorthosite of the Mistastin Batholith.

The regolith may have formed as glacial till or impact ejecta or a

combination of the two; in particular, the lowermost unit may have been

derived as impact-derived ejecta from the shocked breccia of the crater. If

so, the spectroscopic properties of the mineralogy of the unit may serve as

a test target for remote sensing studies.

A sample of each of four regolith units was studied using scanning

electron microscopy (SEM) with mineral liberation analysis (MLA)

software to determine mineralogy; X-ray fluorescence spectroscopy (XRF)

and solution nebulization inductively coupled plasma mass spectro-metry

(ICPMS) to determine bulk chemical composition; and laser-ablation

ICPMS to determine dominant zircon age populations.

Results showed that the major minerals present in the samples are the

same as those present in the country rocks, which are quartz, plagioclase,

perthite, alkali-feldspar and biotite. Garnet, cordierite and aluminosilicate

are present in the samples, but not in the country rocks. XRF and ICPMS

showed that concentrations of SiO

(65.1-69.5 wt %), Al

(14.0-15.8 wt

%), TiO

(0.5-1.6 wt %) and Fe

(3.5-7.4 wt %) are similar to those in

previous measurements for the granodiorite and mangerite (SiO

: 66.0 and

61.4 wt %; Al

: 14.4 and 13.7 wt %; TiO

: 0.66 and 1.3 wt % and

: 4.8 and 8.1 wt %, respectively). The samples had a dominant zircon

population age of approximately 1.4 billion years, the age of the previously

dated country rocks.

The data indicate that the major component of the regolith was

glacial till derived from the Mistastin Batholith, particularly granodiorite,

with some mangerite. There is no evidence of impact ejecta in the regolith

or incorporation of the underlying shocked anorthosite breccia into the

lowermost unit. Another, less prominent, metamorphic source contributed

to the regolith, which may be from the western contact aureole of the

Batholith.

LOCATING BURIED REMAINS USING GROUND PENE-

TRATING RADAR IN CANADA

Forbes, S.L., University of Ontario Institute of Technology, 2000

Simcoe St N, Oshawa, ON L1H 7K4, [email protected]

Ground penetrating radar (GPR) is a non-invasive, geophysical tool used

for the detection of clandestine graves. GPR operates by detecting density

differences in soil by the transmission of high frequency electromagnetic

(EM) waves from an antenna. A 500 Megahertz (MHz) frequency antenna

is typically used for forensic investigations, as it provides a suitable

compromise between depth of penetration and sub-surface resolution. This

presentation will discuss a forensic research project conducted in

contrasting soil types in Ontario followed by police and forensic case

examples.

Domestic pig (Sus domesticus) carcasses were used as human

analogues for the decomposition research. Carcasses were clothed and

buried at consistent depths at three field sites of contrasting soil type (silty

clay loam, fine sand and fine sandy loam) in southern Ontario. GPR was

used to detect and monitor the graves for a period of fourteen months post

burial. Analysis of collected data revealed that GPR was able to detect

clandestine graves containing remains in silty clay loam and fine sandy

loam soils, but remarkably was not suitable for detection in fine sand soil.

The results of this research have applicability within forensic

investigations involving decomposing remains by aiding in the location of

clandestine graves. Several successful case examples will be presented.

Keynote PORTRAIT OF A MOUND BUILDING DEEP-WATER

CORAL

Freiwald, A., Senckenberg am Meer, Wilhelmshaven, Germany,

[email protected]

With increasing multibeam mapping of continental margins, driven by the

evaluation of mineral and biological resources within the exclusive

economic zones, some hundred-kilometre-long chains of up to 350-m-high

mound clusters became visible. Such examples were found around the rims

of the Rockall Bank and Porcupine Bank during the past 15 years. A 400-

km-long mound chain was discovered offshore Mauritania and similar

impressive structures are currently under research off southeast Brazil as

south as to Patagonia. Clusters of mounds also exist in the Florida Strait

and on Blake Plateau. All these structures exist in 500-1000 m water depth

but when viewed on a local focus, in much narrower bathymetric ranges.

Ground thruthing with ROV and manned subs and an IODP drilling

campaign revealed the nature of these mounds: coral carbonate mounds. In

the Atlantic and their associated marginal seas (Caribbean, Gulf of

Mexico, Mediterranean), the azooxanthellate scleractinian Lophelia

pertusa and its allies, Madrepora oculata, Enallopsammia rostrata and

Solenosmilia variabilis, are the main acters. Best ecological knowledge

exists for Lophelia pertusa. This azooxanthellate coral thrives under low

temperatures (4-14°C) and can withstand low oxygenated conditions and

therefore is even able to expand into oxygen minimum zones of upwelling

zones. The self-defense properties of the coral facilitate growth in high

particle-laden bottom-water currents and under severe current regimes.

Lophelia quickly responds to nutrient and food pulses which are advected

from fertile surface waters to the deep. Experiments have analysed the

“reef effect” by studying the carbon cycle of corals and the proportion of

utilized dissolved organic material. Within a single tidal cycle, up to 40 %

of dissolved organics are soaked by the reef community so that the

remaining water body is largely depleted. This observation goes in hand

with another peculiarity of cold-water reefs which are dominated by

suspension feeding organisms. Benthic systems in the bathyal zone

generally are driven by deposit feeding communities. The sedimentary

matrix of coral mounds shows a bimodality in the grain-size spectrum. The

coarse coral fragments (and other internally produced shelly material) is

embedded within silt and clay sized material of pelagic and locally of

terrigenous origin (eolian, riverine). In many of the Atlantic mounds,

remains of coccolithophores and planktonic foraminifers contribute to the

bulk of the sedimentary matrix - both became important sediment

producers during the advent of the Cretaceous. To conclude, corals without

particle-laden bottom waters would hardly be able to build a mound.

ROLE OF SELF-INCURRED RADIATION DAMAGE IN

DEVELOPMENT OF TUBULAR AND GRANULAR MICRO-

TEXTURES IN SUBMARINE VOLCANIC GLASS: IMPLI-

CATIONS FOR MARS EXPLORATION

French, J.E., Department of Earth and Atmospheric Sciences,

University of Alberta, 1-26 Earth Science Building, Edmonton, AB

T6E 2E3, [email protected]a, and Blake, D.F., Exobiology Branch,

NASA Ames Research Center, MS 239-4 Moffett Field, CA 94035-

1000, USA

The elucidation of microtextures developed during the natural corrosion

(dissolution and palagonitization) of basaltic glass by seawater has broad

implications for microbial ecology on Earth as well as for the future

Astrobiological exploration of Mars. On Earth, such microtextural features

have commonly been interpreted as vestiges of microbial activity. As a

result, the “biocorrosion” of basaltic glass has emerged as a putative

biosignature for the most geographically vast, deep, and long-lived

microbial ecosystem on Earth, having been observed in modern glasses of

the in situ oceanic crust worldwide as well as in ophiolites and greenstone

belts dating back to ~3.5 Ga. If such features were discovered in Martian

basaltic glass, either by remote robotic instruments or in terrestrial

laboratories after a sample is returned from Mars, such an interpretation

would have profound implications for the origin of life (multiple origins?

panspermia?). Evidence of bioalteration of basaltic glass along fractures is

typically divided into two distinct microtextural varieties: ‘tubular’ and

‘granular’. We propose that these tubular and granular microtextures can

form abiotically at the glass-palagonite interface simply as a result of

preferential dissolution of radiation-damaged basaltic glass by seawater.

Our abiotic (U-Th-Pb-radiogenic) paradigm is based on (1), optical

petrographic and Scanning Electron Microscopic (SEM) observations of

partially palagonitized basaltic glass pillow margins of the in situ oceanic

crust, (2), determination of U and Th concentrations in fresh basaltic glass

by Inductively Coupled Plasma – Mass Spectrometry (ICP-MS), and (3),

state-of-the-art theoretical modelling of alpha-recoil track and fission track

areal densities (i.e., accumulation of radiation damage) in basaltic glass.

Numerical modelling of radiation damage based on the known age (~108

Ma) and measured concentrations of U (42 ppb) and Th (132 ppb) in these

glasses suggests that they are absolutely riddled with radiation damage

(134 million alpha-recoil tracks per cm

; 1,183 fission tracks per cm

)

amenable to preferential corrosion/dissolution by seawater during

palagonitization along fractures. Calculated track areal densities suggest

that complex networks of ‘tubular’, elongate, branching, meandering

nanoscopic tunnels (typically ~100-200 nm wide) at the glass-palagonite

interface are the result of alpha-recoil track etching. These are

interconnected with rare, larger tunnels (~1-2 microns wide by ~8 microns

long) that are the result of fission track etching. Incipient palagonitization

of dense concentrations of alpha-recoil tracks is also common, resulting in

characteristic ‘granular’ microtexture.

LITHOLOGICAL DISCRIMINATION AND ALTERATION

RECOGNITION USING MULTIVARIATE STATISTICAL

ANALYSIS ON DRILL CORE MEASUREMENTS, MATAGAMI

VMS DISTRICT, ABITIBI GREENSTONE BELT, QUÉBEC

Fresia, B., bastien[email protected], Ross, P-S., Gloaguen, E. and

Bourke, A., INRS-ETE, 490 rue de la couronne, Québec, QC G1R 1P1

The Matagami mining camp in the northern Abitibi Greenstone Belt

(Superior Province) contains numerous volcanogenic massive sulphide

(VMS) deposits, many of which have been mined, and the camp has good

potential for additional discoveries. However, only limited information is

available on the 3D physical and mineralogical properties of the host rocks

for the Zn-Cu-Ag-Au mineralization; this hinders attempts at 3D

geophysical modeling, for example. In this context, the Ministère des

Ressources naturelles et de la Faune du Québec (MRNF) has

commissioned INRS to conduct high-resolution multi-parameter analyses

of drill cores from the area over the 2010-2012 period, using the multi-

sensor core logger contained in our new mobile laboratory. We have

collected more than 30,000 measurements for gamma density, volumetric

magnetic susceptibility, visible light and infrared spectrometry (alteration

mineralogy) and XRF geochemistry distributed over about 7,000 metres of

drill core, at a sample spacing of 20-30 cm.

The vast amount of data and the diversity of measured parameters

make it possible to use various approaches to analyze and interpret the

data:

• Lithogeochemistry: Measurements made with the portable XRF

analyzers, in conjunction with existing lithogeochemistry, can

facilitate protolith identification using mostly ratios of immobile

elements such as Ti, Al and Zr. Measurements of mobile elements

such as Fe and Si are useful to assess hydrothermal alteration.

• Mineralogy: Hydrothermal alteration minerals (abundance, mineral

chemistry) can be used as an exploration guide. However, complete

petrographic study encompassing several thousand samples is simply

not possible. Infrared and visible light spectroscopy thus makes it

easier to identify and characterize these minerals.

• Multivariate statistical analysis: Those techniques may be used to

group data and/or measurement points based on responses for each

parameter.

This third strategy is particularly useful for simultaneously

interpreting the entire database. We propose here an approach based on

statistical methods, mainly Principal Component Analysis (PCA) and

clusters analysis. PCA is initially used to determine the variables

dependant of the alteration and those dependent of protoliths. Cluster

analysis is then used to separate the data points based on their

mineralogical, physical and geochemical signature. Interpretations can be

verified on the line-scan images that are also acquired during logging.

By combining statistical and conventional approaches, we aim to use

the data acquired with the multi-sensor core logger to achieve a fairly

detailed resolution in the spatial discrimination of lithologies and alteration

related to the emplacement of ore deposits.

APPLIED REFLECTANCE SPECTROSCOPY AND MINERAL-

OGICAL STUDIES OF GOSSAN HILL, VICTORIA ISLAND,

NORTHWEST TERRITORIES, CANADA

Froome, J.

, Williamson, M-C.

, [email protected], Peterson,

R.C.

Department of Geological Sciences and Geological Engin-

eering, Queen’s University, Kingston, ON K7L 3N6;

Geological

Survey of Canada, 601 Booth Street, Ottawa, ON K1A 0E8

Iron-oxide and sulfate-rich alteration halos were discovered surrounding

exposed and sub-surface pyrite deposits in an area of positive relief known

as “Gossan Hill” on Victoria Island, Northwest Territories. This site

provides an excellent example of iron-sulfide and native sulfur deposit

alteration processes in an arctic environment where the permafrost exists at

shallow depth. Samples of surficial material were sieved into coarse (500u

ìm-1410 ìm, >1410 ìm) and fine (<500 ìm) fractions for spectral

reflectance and X-ray diffraction analysis at varying grain-sizes. Finer

grain sizes typically yielded greater absolute reflectance and enabled a

more direct comparison of samples with different initial grain size. Sieved

samples were analyzed with an ASD Inc. Terraspec Examiner VNIR/

SWIR spectrometer to characterize the spectral reflectance of each zone of

mineral alteration. X-ray Diffraction analysis was used to identify minerals

within the surficial alteration halo and the underlying source material.

Mineral assemblages were characterized by comparison with a library of

mineral spectral reflectance using The Spectral Geologist (TSG) software.

The spectral reflectance data was then smoothed and processed with TSG

and ENVI EX applications. Hull quotient, derivative and other spectral

profile correction techniques have been considered; however, care was

taken in order to avoid destruction of the faint SWIR spectral

characteristics produced by cations such as ferrous iron present in the

structure of pyrite and some ferrous iron oxides. Over-processing of

laboratory data was avoided to allow for direct comparison with remote

sensing imagery. Laboratory reflectance of each sample was averaged into

a weighted linear mix, with weighting placed on greater surficial volume,

finer grain sizes and greater absolute reflectance. The mixed spectral

profile was tuned to LANDSAT-7 and SPOT-5 multispectral images of the

study site by creating a limited profile of specific bands at 500-590nm,

610-680nm, 780 -890nm and 1580-1750nm. The results of the study

provide a test of remote predictive mapping techniques for gossans related

to ore bodies based on remote multispectral data.

IN SITU ELEMENTAL AND ISOTOPIC MICROANALYSIS OF

INDIVIDUAL MINERAL GRAINS: THE KEY TO UNRAVELING

COMPLEX GEOLOGICAL PROCESSES

Fryer, B.J., bfryer@uwindsor.ca, and Gagnon, J.E., University of

Windsor, Windsor, ON N9B 3P4

The petrographic microscope first provided geologists with the ability to

delineate mineral growth, alteration, and paragenetic sequences in rocks

exhibiting evidence of complex and often multi-stage histories. While the

ability to visibly recognize these temporal complexities has allowed

detailed relative chronologies of events to be determined, the lack of

complete chemical characterization at correspondingly small spatial scales

has often led to incomplete or erroneous interpretations with respect to

mineral or rock genesis.

Modern microbeam analytical systems, such as laser ablation

inductively coupled plasma mass spectrometry, can now provide multi-

element, high-sensitivity major, minor, trace, and ultra-trace chemical

analyses of minerals within petrographic thin sections and at the scale of

petrographic observations. Because the analyzers in these systems are

often mass spectrometer-based, these microbeam techniques can also be

used to obtain high-precision isotopic data. These data can be used to

further elucidate the origins and significance of the chemical complexities

we have been able to observe in geologic materials since the adaptation of

microbeam techniques to these applications. These techniques are

particularly well suited to the study of mineral deposits and their formative

processes, which can produce minerals with extreme compositional

variations over exceeding small spatial scales.

The fluorspar deposits associated with the St. Lawrence Granite of

southeastern Newfoundland provide an excellent example of the power of

these new in situ microbeam techniques. Mapping the trace element

chemistry continuously across growth zones within a single fluorite crystal

demonstrates the complexity of the compositional evolution of the

hydrothermal system, particularly the changing anomalous behaviour of Y

relative to the heavy rare earth elements (HREE). It is clear from the

changing magnitude and temporal relationship of the Y anomaly with

concentration variations of Y compared to REE, such as Ce and Lu in the

growing fluorite crystal, that Y geochemistry is ‘decoupled’ from that of

the REE and that the change of chemistry in the hydrothermal fluid from

which the fluorite crystallized is complex and varies rhythmically with

time. Adding in situ isotopic data for Pb and Sr will provide information

on the source of the chemical changes, e.g., magmatic fluid evolution

versus interactions with external fluids derived from the country rock the

granite has intruded.

THE CRUSTAL STRUCTURE OF THE EIRIK RIDGE AT THE

SOUTHERN GREENLAND CONTINENTAL MARGIN

Funck, T., Geological Survey of Denmark and Greenland, Øster

Voldgade 10, 1350 Copenhagen K, Denmark, [email protected], Andrup-

Henriksen, G., Niels Bohr Institute, University of Copenhagen,

Copenhagen, Denmark, Dehler, S.A., Geological Survey of Canada,

PO Box 1006, Dartmouth, NS B2Y 4A2, and Louden, K.E.,

Department of Oceanography, Dalhousie University, Halifax, NS

B3H 4J1

In 2009, the SIGNAL (Seismic Investigations off Greenland,

Newfoundland and Labrador) experiment was carried out to acquire

marine refraction seismic data in the area between southern Greenland and

Canada. Two lines were located on the Eirik Ridge off the southern tip of

Greenland where two different continental margin styles merge. The SW

Greenland continental margin is characterized by non-volcanic rifting

associated with the opening of the Labrador Sea. Here, wide continent-

ocean transition zones with serpentinized mantle are observed. In contrast,

the later opening of the NE Atlantic formed volcanic-style margins off SE

Greenland. The Eirik Ridge is a 300-km-long sediment drift and the

SIGNAL experiment was designed to study the underlying crustal

structure. SIGNAL line 3 is a 295-km-long refraction seismic line located

on the top of the Eirik Ridge and extends into the Labrador Sea. Line 2

(225 km) crosses the ridge and continues into the NE Atlantic. Dense

airgun shots were recorded by 24 and 20 ocean bottom seismometers

(OBS) on lines 3 and 2, respectively. Preliminary velocity models indicate

the presence of volcanic rocks, up to 4-km-thick on the ridge, which form

a basement high beneath the ~2-km-thick sediment drift. A high-velocity

lower crustal layer (7.1 to 7.5 km/s) with a thickness of up to 8 km

underlies the ridge. Moho shallows from 17 km just off the shelf break to

13 km at the feather edge of the ridge. Seaward of the ridge, 4 to 5-km-

thick oceanic crust is observed in the Labrador Sea, while initial oceanic

crust in the NE Atlantic has a thickness of 10 km. The models suggest that

the ridge formed on transitional and initial oceanic crust created during the

opening of the Labrador Sea. This crust was then modified by intrusions

and extrusions associated with the volcanic style margin formation in the

NE Atlantic around 56 Ma. Coincident reflection seismic data along the

two SIGNAL lines indicate the presence of inner and outer seaward-

dipping reflection sequences separated by an outer basement high. This

suggests a subaerial formation of the lavas on the ridge. Cooling and loss

of dynamic support by the Iceland plume resulted in the subsidence of the

ridge.

INSIGHTS INTO THE STABILITY OF CRYSTAL STRUCTURES

Gagne, O.C. and Hawthorne, F.C., University of Manitoba,

Department of Geological Sciences, 125 Dysart Rd., Winnipeg, MB

R3T 2N2, [email protected]

The general failure to make reliable crystal structure predictions from

chemical composition has been identified as the major problem in

Crystallography. A new approach that scrutinizes the atomic factors

affecting the stability of crystals, and how these factors can be turned into

predictive tools that gives insight into the atomic-scale reasons for

structure stability or instability is presented. A four-step methodology is

developed, addressing issues of (1) bond topology and ideal bond-

valences; (2) the assignment of atoms to vertices in the bond-topology

graph, and the resulting ideal bond-lengths; (3) 3-D distance-least-squares

refinement; and (4) energy evaluation. The result is a better understanding

of the connection between bond topology and site populations in crystals

from a priori considerations. In the first step, bond topologies are

represented as graphs and the mathematical approaches of Graph Theory

are used to represent structures in a simple and irreducible form. Following

the construction of a topology, a set of ideal bond-valences (the weights of

the graph) is calculated from the valence-sum and loop equations of the

topology and its associated vertex charges. The question then becomes

whether there is a specific combination of cations and anions that can

adopt this arrangement. The International Crystal Structure Database

(ICSD) enables comprehensive evaluation of the bond-valence ranges that

atoms may adopt by surveying the database for the dispersion of bond-

lengths for all combinations of atoms, oxidation states and coordination

numbers. This, combined with the sets of ideal bond-valences calculated at

step 1 allows assignment of atoms to the vertices of the graph of the

structure, where the ideal bond-valences must fall within the bond-valence

range of the atoms derived from the ICSD analysis. The bond-length bond-

strength correlation of Bond-Valence Theory is then used to convert the

topology into a set of ideal bond-lengths to be satisfied in three dimensions

for the structure to be physically feasible. A distance-least-squares

refinement in step 3 yields a structure in Cartesian space, while step 4

evaluates the structure in terms of energy. Different applications of the

methodology ensue from various approaches, such as the determination of

all possible chemical substitutions within a structure type, the

substantiation of the inexistence of certain charge arrangements within a

structure type, a stability study of “ad hoc” topologies and the probing for

the predicted level of symmetry and order/disorder in “ad hoc” topologies.

PETROGRAPHY AND FLUID INCLUSION ANALYSIS OF

AURIFEROUS AND BARREN VEINS FROM THE EAST BAY

TREND, RED LAKE, ONTARIO, CANADA

Gallagher, S.V., (240 Wallace Building) shaun.gallagher4@

gmail.com, Camacho, A. and Fayek, M., University of Manitoba 125

Dysart Rd., Winnipeg, MB, R3T 2N2

The East Bay Trend is a large structural corridor that parallels the East Bay

of Red Lake, Ontario and is interpreted to be a manifestation of the

regional D1 structure that crosscuts this complexly folded greenstone belt.

The southernmost 8 km of this corridor is host to a variety of small gold

deposits that demonstrate an assortment of mineralization styles. This

study aims to: (1) better define the styles of veining and characterize the

mineralizing fluids through the use of petrography, fluid inclusions,

geochronology and stable isotopes, (2) compare barren and auriferous vein

systems from deposits along the East Bay Trend, and (3) compare the fluid

history of the East Bay Trend to the nearby Campbell-Red Lake gold

deposit. There are four types of auriferous veins throughout East Bay,

including quartz, quartz-carbonate, quartz-tourmaline, and quartz-

actinolite veins. There is also abundant carbonate veining that generally

predates the auriferous system. These veins are typically hosted in the 2.9

Ga mafic volcanics that have significant silicification, carbonatization and

biotite/chlorite alteration adjacent to veining.

Carbonic, aqueous, and aqueo-carbonic (three-phase) are the three

main types of fluid inclusions, occurring in barren and auriferous veins

throughout the trend. The carbonic inclusions are the most abundant with

aqueous inclusions representing a smaller proportion and three-phase

inclusions as the least common. The homogenization temperatures of the

carbonic inclusions range from -13.2°C to 26.3°C. The homogenization

temperatures of aqueous inclusions range from 164°C to 345°C and have

salinities of 8 - 23 wt% NaCl equiv. The homogenization temperatures of

aqueo-carbonic inclusions range from 192°C to 398°C with salinities of 10

- 24 wt% NaCl equiv.

Fluid inclusions with variable liquid-vapor ratios dominate

throughout the auriferous veins in the East Bay trend. The most

prospective gold areas in this trend (McMarmac and Chevron) stand out

because three-phase (H

O+CO

+liquid) inclusions dominate over the other

types. These data suggest that immiscibility and effervescence play an

important role in gold precipitation. In addition, fluid mixing may also

play a part in precipitating gold as primary aqueous fluid inclusions from

Chevron and Abino yield wide ranges in salinities and homogenization

temperatures. Although three-phase inclusions and variable liquid-vapor

ratios occur in barren veins, they represent a small percentage of the

inclusions. These data will help refine genetic models for deposits located

in the East Bay Trend and will improve our understanding of the fluid

history associated with gold mineralization throughout the Red Lake area.

VOLCANOGENIC MASSIVE SULPHIDE DEPOSITS OF THE

PALEOPROTEROZOIC FLIN FLON DISTRICT: THEIR RECON-

STRUCTION AND POST DEPOSITIONAL MODIFICATION

Gibson, H.L., Lafrance, B., Mineral Exploration Research Centre,

Department of Earth Sciences, Laurentian University, Sudbury, ON

P3E 2C6, and Pehrsson, S., Geological Survey of Canada, 601 Booth

Street, Ottawa, ON K1A 0E8

The Paleoproterozoic Trans-Hudson Orogen (THO) is well known for its

contained volcanogenic massive sulphide (VMS) deposits that are

restricted to juvenile arc assemblages that were structurally juxtaposed

with VMS-barren back-arc, ocean-plateau (floor) and ocean island

assemblages during accretion resulting from initial closure of the

Manikewan Ocean (circa 1883 Ma). Assemblage boundaries are faults,

often former thrust faults, which are consistent with allochthonous

construction of the THO. The Flin Flon District (circa 1889 Ma) contains

the Flin Flon, Callinan and 777 deposits, which total more than

92.5 million tonnes at 2.21% Cu, 4.25 % Zn, 2.11 g/t Au and 27.22 g/t Ag,

and is the THO’s premier VMS district. The Flin Flon District occurs

within an oceanic arc assemblage that was amalgamated into the Flin Flon-

Glennie Complex during an interoceanic accretion event (1910–1870 Ma).

At Flin Flon, the VMS deposits are interpreted to have formed during

rifting of a basalt-dominated oceanic arc and the deposits are localized

within a volcanic –tectonic subsidence structure or cauldron defined by: 1)

a thick but aerially restricted package of predominately mafic megabreccia

deposits containing blocks up to 50m in size; 2) internal angular

unconformities; 3) basaltic and rhyolitic dike swarms and vents localized

within the presumed core of the cauldron; 4) numerous synvolcanic faults;

and 5) high-temperature epidote-quartz alteration. The VMS deposits are

associated with proximal coherent rhyolite and more distal rhyolitic

volcaniclastic facies that occur in distinct fault blocks within the larger

cauldron.

Structures that are most significant to the reconstruction of the Flin

Flon District and to ore modification include: 1) D1 and NNW-striking D

folds and faults that formed during accretion of the Flin-Flon Glennie

Complex, prior to deposition of the Missi Group (1847-1842 Ma), a

successor arc basin assemblage that unconformably overlies the volcanic

rocks; 2) Post-Missi, west verging D

and north verging D

thrust faults

that formed during final accretion of the Flin Flon-Glennie Complex and

collision of the amalgamated complex with the Sask craton; and 3) a

strong SE-plunging stretching lineation that formed during D4 thrusting

and deformed the ore lenses into their present flattened cigar shape.

COMPUTATIONAL MECHANICS AND THE DETECTION OF

INNOVATION IN EARTH SYSTEMS

Gipp, M.R., Marine Mining Corp., 856 Millwood Rd., Toronto, ON

M4G 1W6, drgipp@gmail.com

Many Earth systems consist of myriads of local interacting subsystems.

Intuitively one might expect the effects of these interactions to disappear

into chaos; we find instead that highly ordered structure often arises on a

global scale. We call such order “emergent properties”. The mechanisms

by which such emergent properties arise from local-scale interactions is

not understood and they may change despite a lack of observable changes

in local conditions. Such changes may appear as reorganizations of the

system on a global scale, which we refer to as “innovation”. Possible

examples of such innovation include the proposed change(s) in character

of plate tectonics during the Archaean; Neoproterozoic glaciations; and

magnetic pole reversals. Recognizing innovation in Earth systems on the

basis of geological time series is difficult due to our natural tendency to

interpret new observations in terms of our current understanding.

Computational statistics can be used to provide insight by characterizing

the complexity of Earth system behaviour from which we may recognize

changes in organization of Earth systems. The change in dynamics of

global glaciations during the Mid Pleistocene transition may be an

example of innovation.

MAJOR AND TRACE ELEMENT GEOCHEMISTRY OF

BIOTITES FROM THE VOISEY'S BAY AND MUSHUAU

TROCTOLITES, LABRADOR, CANADA

Glasgow, J.K., jennifer.glasgow@mun.ca, Wilton, D., Memorial

University of Newfoundland, St. John's, NL A1B 3X5, and Evans-

Lamswood, D., Vale, Torbay Road, St. John's, NL A1A 3W8

The Voisey’s Bay troctolite is the main host to nickel-copper-cobalt

sulphide mineralization at the Voisey’s Bay deposit in northern Labrador,

Canada. The troctolite is present in three main environments, viz.; a) as the

dominant phase in large layered magmatic chambers, b) as feeder dykes

beneath the chambers and c) as chilled margins adjacent to the chambers

and feeder troctolites. Biotite, a hydroxyl-bearing phase, accounts for up to

ten modal percent of troctolite from chambers, feeders and chills. Through

petrographic observations of biotite, primary and secondary biotite could

be distinguished in the troctolites. Scanning electron microscopy and

mineral liberation analysis (SEM-MLA) was used to define the modal

mineralogy of troctolite samples and more specifically to map

mineralogical associations of biotite with respect to other mineral phases.

Biotite is modally more abundant and coarser-grained in brecciated feeder

troctolites (vs. chamber troctolites), preferentially rimming blebby and

disseminated sulphides and oxides. Electron probe microanalyses (EMPA)

were completed to determine major and trace element geochemistry for

biotites from a variety of troctolites. There is a notable variation in the

fluorine content of biotites between the Eastern Deeps, Western Deeps,

Ashley-Floodplain, and Mushuau chamber zones. The highest fluorine and

chlorine values are observed in biotites from Ashley-Floodplain and the

lowest in biotites from the Mushuau troctolites. Furthermore, EMPA

geochemical data indicate that although biotite is present throughout the

Voisey’s Bay and Mushuau troctolites, the Western Deeps and Discovery

Hill troctolites contain phlogopite (the magnesian end member of the

biotite-phlogopite mineral group), not biotite. Major and trace element

geochemistry also indicates the existence of two chemically distinct biotite

phases throughout the Voisey’s Bay troctolites: those in chilled troctolites

and those in chamber and feeder troctolites.

Keynote A HIMALAYAN TOP-DOWN PERSPECTIVE INTO A

MID-CRUSTAL FLOWING OROGEN

Godin, L., Department of Geological Sciences & Geological

Engineering, Queen’s University, Kingston, ON K7L 3N6, godin@

geol.queensu.ca

The Nepal Himalaya offers an excellent top-down view of an active

thermo-mechanical continental collision orogen. This presentation offers a

synthesis of key observations and interpretations made over 15 years that

contribute to our understanding of continental collisional orogenic

systems, from a top-down perspective. Nonetheless, the understanding of

this prototypal system has significant limitations and need to be

complemented by observations made in deeper-exhumed orogens such as

the Grenville-Sveconorwegian system.

The Himalayan orogenic core in central Nepal exposes two

lithotectonic elements, separated by crustal-scale faults. The uppermost

orogenic superstructure package, the Tethyan sedimentary sequence (TSS),

is a Paleozoic-Mesozoic weakly-metamorphosed sedimentary sequence

originally deposited on the northern margin of the Indian craton. The

subjacent Greater Himalayan sequence (GHS), representing the

infrastructure, comprises amphibolite to granulite metamorphic facies

rocks and extensive granitic melts and migmatites. The TSS/GHS

interface, the South Tibetan detachment system, acted as a Miocene

normal-sense décollement zone during southward extrusion of the GHS,

coeval with slip along the Main Central thrust at the base of the GHS.

Our research documents significant thickening (>150%) of the TSS

early in the orogenic evolution, which is interpreted to have instigated

burial and metamorphism of the GHS in Eocene-Oligocene. This first

orogenic phase was then followed by extensive Miocene melt-weakening

and southward extrusion of the infrastructure, and decoupling of the

superstructure along the South Tibetan detachment system.

Based on microstructural, geochronological, and thermobarometry

studies, the GHS can be divided in two domains. The lower domain

contains peak metamorphic assemblages yielding a metamorphic field

pressure gradient that increases up structural section from 8 to 11 kbar,

whereas the upper portion of the GHS records a metamorphic pressure

gradient that decreases up structural section from 10 to 5 kbar. During the

extrusion phase, the GHS underwent almost equal coaxial and noncoaxial

strain at temperatures ranging between ~450°C to >700°C, similar to peak

metamorphic temperatures determined by thermometry. This flow style

was diachronous, occurring earlier in the upper part of the GHS, and

propagated structurally downward and toward the foreland. The extrusion

strain accommodated significant vertical thinning and horizontal stretching

in the hinterland part of the orogen, which was counterbalanced by vertical

thickening and horizontal shortening in the foreland. This hinterland-

foreland transition, coinciding with the boundary between the upper and

lower portions of the Greater Himalayan sequence, highlights the

complementarity of deformation processes between orogenic cores and

forelands.

EVIDENCE FOR COMPLEX SEDIMENT TRANSPORT PATH-

WAYS IN THE WESTERN CANADA SEDIMENTARY BASIN

DURING THE EARLY AND MIDDLE TRIASSIC

Golding, M.L., [email protected], Mortensen, J.K.,

Department of Earth and Ocean Science, University of British

Columbia, 6339 Stores Road, Vancouver, BC V6T 1Z4, Ferri, F.,

Resource Development and Geoscience Branch, Oil and Gas

Division, BC Ministry of Energy, Mines and Petroleum Resources,

PO Box 9323, Stn Prov Govt, Victoria, BC, Zonneveld, J-P.,

Department of Earth and Atmospheric Science, University of

Alberta, 1-26 Earth Sciences Building, Edmonton, AB T6G 2E3,

and Orchard, M.J., GSC Pacific, Natural Resources Canada, 625

Robson St., Vancouver, BC V6B 5J3

U-Pb dating of detrital zircons in clastic sedimentary rocks can provide

insight into the source of the sediment, and also the timing of tectonic

events that control sediment distribution. The Western Canada

Sedimentary Basin contains sediment of Early and Middle Triassic age

that was deposited in relatively deep water, on what is thought to have

been a passive margin. In northeastern British Columbia, these rocks

belong to the Toad and Liard formations at the surface, and to the Montney

and Doig formations in the subsurface. These subsurface formations are

important source and reservoir rocks for tight gas and shale gas plays in

B.C. As such they have received a large amount of attention, but the

tectonic environment they were deposited in is still unresolved. Although

previous models have involved a quiescent margin during the Triassic with

terrane accretion occurring only in the Jurassic, structural studies and

detrital zircon analyses from the Yukon have produced data that conflicts

with this scenario. Instead, collision between ancestral North America and

the Yukon-Tanana terrane may have occurred as early as the Late Permian.

If this is the case, then a large foreland basin would have been present

during the Early and Middle Triassic, and sediment would have been

derived from both the North American craton and from the terranes to the

west. Although evidence for this has been found in the Yukon, data from

B.C. is still sparse. Previous work in B.C. has not found any zircon grains

in Triassic sedimentary rocks that can unambiguously said to have been

derived from the west. However, detrital zircons with ages from the

Devonian and the Mississippian have been found in collections from

Williston Lake and the Alaska Highway. Igneous rocks of this age are not

common on the craton, but neither are they confined to the pericratonic

terranes. Possible source areas for these zircons include the Innuitian

orogenic wedge to the north and the Exshaw Formation to the east. The

samples have been dated using conodont biochronology and span a period

from the Smithian to the Ladinian. These results imply that during the

Early and Middle Triassic, the sediment transport pathways were more

complex in B.C. than has previously been thought, although no definitive

evidence for terrane accretion has yet been found. This may be due to the

presence of the Peace River Embayment at this time, which could have

prevented the alongshore movement of detrital zircons from terranes that

had accreted to the north.

A MINERALOGICAL STUDY OF HEXAGONAL PYRRHOTITE

ALONG THE COPPER CLIFF OFFSET, SUDBURY

Gordon, S., sx_gordon@laurentian.ca, and McDonald, A., Dept. of

Earth Sciences, Laurentian University, Sudbury, ON P3E 2C6

Pyrrhotite, present as both hexagonal (HPo) and monoclinic (MPo)

polytypes, is a common mineral present in Fe-Ni-S ores occurring in

quartz diorite of the Copper Cliff Offset (CCO), south range, Sudbury.

While MPo dominates in most Sudbury ores, those present in the CCO

show variable but high HPo:MPo ratios. This study addresses the

mineralogical, chemical and geological controls that could play roles in

stabilizing high HPo concentrations.

Modal mineralogy and quantitative HPo:MPo ratios were determined

through Rietveld analyses of powder XRD data. Combined image analysis

and application of magnetic colloid to polished thin sections (PTS)

confirmed the results obtained by Rietveld analyses, both in terms of the

bulk mineralogy and obtained HPo:MPo ratios. Optical microscopy of PTS

identified textural relationships present, including crystallographically

controlled lamellae of MPo and varying degrees of boxwork intergrowths.

Since MPo shows a strong ferromagnetic behaviour, unlike HPo, magnetic

susceptibility measurements were taken to empirically determine areas

with high concentrations of HPo; systematic trends were observed and are

currently being characterized.

The major and minor element chemistry of MPo and HPo were

determined by SEM-EDS. Results show that there are no significant

variations in Fe:S ratios or minor element (Ni, Co) concentrations. MPo

and HPo were found to have virtually identical average compositions of

Fe0.85-0.86S, with ranges in Fe:S for the two directly overlapping. These

observations appear to contradict results from previous studies of the Fe-S

system. The average minor element contents are also virtually identical,

with 1.02 wt.% Ni and 0.23 wt.% Co in MPo, and 1.09 wt.% Ni and 0.26

wt.% Co in HPo.

To evaluate the role that trace element concentrations could have in

the stabilization of HPo, LA-ICP-MS analyses were carried out on select

samples. The data indicates that the samples are devoid of Os, Ir and Pt

while Ru, Rh and Pd are present in low, but statistically similar

concentrations within both MPo and HPo. The average PGE con-

centrations in MPo are 0.42ppm Ru, 0.01ppm Rh and 0.1ppm Pd, while

HPo was found to have similar average values of 0.53ppm Ru, 0.04ppm

Rh and 0.05ppm Pd; the total PGE range for both MPo and HPo is 0-

1.26ppm.

Research into potential HPo stabilization factors is ongoing and

possible controls, such as textural relationships, modal mineralogy and

associated mineral chemistry, will be discussed.

SIMULTANEOUS IN SITU DETERMINATION OF BOTH U-PB-

TH AND Sm-Nd ISOTOPES IN MONAZITE BY LASER

ABLATION USING A MAGNETIC SECTOR ICP-MS AND A

MULTI-COLLECTOR ICP-MS

Goudie, D.J., d.goudie@mun.ca, Fisher, C.M., [email protected],

Hanchar, J.M., [email protected], Memorial University of

Newfoundland, Dept. of Earth Sciences, 300 Prince Phillip Dr., St.

John's, NL A1B 3X5, and David, W.J., Geologic Survey of Canada,

Ottawa, ON

Monazite is a common and resilient orthophosphate accessory mineral

found in a wide range of rock types, and is commonly used to constrain the

timing of geologic events (U-Pb-Th isotopes) and source materials (Sm-Nd

isotopes). We present a method which exploits these virtues of monazite

by simultaneously measuring its U-Pb-Th and Sm-Nd isotopic

compositions in situ, using a laser ablation system coupled to both

magnetic sector and multi-collector inductively coupled plasma mass

spectrometers (i.e., the ablated material is split using a baffled glass Y-

connector and simultaneously transported to the two mass spectrometers).

In addition, the MC-ICPMS is also configured to measure relative Ce, Nd,

Sm, Eu, and Gd contents. This approach offers the advantage of obtaining

both age, tracer isotope, and trace element data, in the same ablation

volume, thus reducing sampling problems associated with fine-scale

zoning and other internal structures. At the same time, this approach

maximizes the amount of data that can be obtained from a single analysis,

making it ideal for detrital monazite studies in which a large number of

grains need to be analyzed. Owing to the high concentration of target

elements in monazite (e.g., light rare earth elements, Th, U, Pb), the

sample can be precisely analyzed using a 20 µm laser spot size which

typically allows many analyses to be done on a single grain. The accuracy

and precision of the U-Pb data is demonstrated using six well characterized

Geological Survey of Canada monazite reference materials (three of which

are currently used as SHRIMP standards) and agree well with previously

determined ID-TIMS dates (Stern and Berman, 2000). Accuracy of the

Sm-Nd isotopic data are assessed relative to TIMS determination on a

well-characterized in house monazite standard.

JURASSIC TO CRETACEOUS (POST-RIFT) TECTONICS OF

THE EASTERN MARGIN OF THE CENTRAL ATLANTIC

(MOROCCO)

Gouiza, M.*, VU University, Amsterdam and Netherland Research

Center for Solid Earth Studies (ISES), and Bertotti, G., Delft

University of Technology and VU University, Amsterdam, g.bertotti

@tudelft.nl

The application of quantitative methods to constrain vertical movements

along the Morocco Central Atlantic margin (subsidence analysis for

sedimentary basins and low-temperature geochronology for exhuming

domains) has documented surprising displacements during Jurassic to

Cretaceous times, that is, following Central Atlantic oceanic spreading.

Basins located along the Moroccan coast (Doukkala, Essaouira-Agadir and

Tarfaya) subsided during Triassic to early Jurassic rifting but continued to

do so also after the appearance of oceanic crust. The observed magnitude

of subsidence cannot be explained by uniform thinning models compatible

with the regional geology. Largest discrepancies occur during the 170-

100Ma time frame when thermal subsidence models can justify <50% of

the documented subsidence. The area to the E of the subsiding domain

experienced km-scale exhumation during Jurassic-Cretaceous times. The

exhuming domain stretched from Rabat in the N to, at least, the Reguibate

shield for a distance of >1200km roughly parallel to the Atlantic margin.

The width (in E-W direction) of the area is poorly constrained. Kinematic

and fully dynamic models of rifted margin evolution are able to justify

only <30% of the observed upward movements. The subsiding and the

exhuming domains were not separated by any significant faults and the

transition between the two regions occurred by progressive W-ward tilting

of the substratum. Outcrop-scale observations suggest that this tilting and

the associated vertical movements were caused by crustal shortening,

roughly oriented E-W. The exhumation of large areas of Morocco allowed

for the onset of widespread erosion and the production of large amounts of

terrigenous sediments which were transported towards the Atlantic margin

by fluvial systems and were deposited in the subsiding basins. These

terrigenous deposits contrast with the otherwise monotonous and fine-

grained character of the Jurassic to Cretaceous offshore sediments of

Morocco.

The deformation style, the vertical movements and the sedimentary

succession of the margin bear significant similarities with the evolution of

the conjugate Central Atlantic margin, that is, North-East US and South-

East Canada suggesting non-orthodox connections between the two

margins during their post-rift stage.

AN UPDATE ON DIAMOND DRILLING AT THE MURRAY

BROOK VMS DEPOSIT

Graves, G., Votorantim Metals Canada Inc., Suite 1330-4 King St.

West, Toronto, ON M5H 1B6, [email protected]

The Murray Brook deposit is a polymetallic, volcanic hosted, massive-

sulphide deposit and is the fifth largest in the Bathurst Mining Camp.

Kennco produced an indicated resource of 21.5 million tonnes at 0.48%

Cu, 0.66% Pb, 1.95% Zn and 31.4 g/t Ag (Perusse, 1958). The deposit is

located on the northwest margin of the Cambrian to Middle Ordovician,

Bathurst Supergroup. The deposit is hosted by shale, siltstone and lithic

tuff assigned to the Mount Brittain Formation that is gradational into

feldspar crystal, lithic-lapilli tuff and flows.

Votorantim optioned the property from Murray Brook Minerals

following a review of the digital database and due diligence that included a

three hole drill program to twin historical drill holes. The Phase I

exploration program started in early 2011 and consists of diamond drilling

of the Murray Brook deposit to confirm previously reported massive

sulfide widths and grade. The Phase II drill program is designed to further

delineate the deposit in areas of low drill density, follow-up higher grade

intercepts, drill test the margins of the known massive sulfide body. A total

of 66 DDH have been completed by Votorantim for 11,000 meters and an

additional 18,000 meters of drilling is planned in 2012. An economic

evaluation of the resource will be based on the drill results.

HYDROTHERMAL REMOBILIZATION OF HFSE/REE: THE

ROLE OF F-RICH FLUIDS AT STRANGE LAKE, QUÉBEC,

CANADA

Gysi, A.P., alexander.gysi@mail.mcgill.ca, and Williams-Jones,

A.E., Dept. of Earth and Planetary Sciences, McGill University,

Montreal, QC H3A 2A7

The mid-Proterozoic Strange Lake pluton, which consists of peralkaline

granite intrusions and associated pegmatites, is host to a world-class rare

earth element (REE) and high field strength element (HFSE) deposit.

Previous studies have provided extensive evidence for the hydrothermal

remobilization and mineralization of the REE and HFSE. Similar

observations have been made for other alkaline and peralkaline igneous

bodies, notably, the Tamazeght (Morocco) and Khan Bogd (Mongolia)

complexes. These complexes have in common a high enrichment in

fluorine, which is known to enhance the solubility of the REE and HFSE

in fluids and melts. In this study, we focus on the F-rich alteration

observed in altered subsolvus granites and pegmatites located in the

northwestern part of the Strange Lake pluton. Field relations indicate that

the pluton experienced multiple F-rich fluid infiltration events, which lead

to the formation of veins and breccias, and pervasive alteration of the

granites. These infiltrations were largely confined to a narrow zone

dominated by pegmatites, which we suspect formed a porous corridor of

focused fluid flow. The mineral textures indicate strong interaction of the

granites and pegmatites with F-rich fluids. The co-precipitation of

secondary HFSE/REE minerals with hydrothermal fluorite suggests that

this interaction caused a change in physico-chemical conditions leading to

immobilization of the HFSE and REE. Preliminary observations indicate

that zirconosilicates and possibly pyrochlore were the most important

primary sources for the rare metals, and suggest that dissolution of these

minerals lead to the complexation of the rare metals with F

present in the

fluid. Other potentially important complexing ligands are Cl

and CO

-2

which, published fluid inclusion studies have shown, are present in high

concentrations in the fluid. We have investigated the capability of such

fluids to leach rare metals from the primary rock and their role in

remobilizing and concentrating the REE and HFSE. A key finding of this

investigation is that fluoride activity (a

) and in turn REE/HFSE mobility

is controlled by the availability of Ca in the environment. The

development of a robust model for the genesis of REE/HFSE deposits such

as that at Strange Lake will require a better understanding of the evolution

of these F-rich fluids from the magmatic-hydrothermal transition to the

final stages of fluid-rock interaction.

CRETACEOUS-PALEOGENE INVERTEBRATE FAUNAS FROM

BYLOT ISLAND, NUNAVUT PROVIDE DIRECT LINKAGE WITH

WEST GREENLAND STRATIGRAPHIC SEQUENCES

Haggart, J.W., Geological Survey of Canada, Vancouver, BC V6B

5J3, [email protected], Herrle, J.O., Institute of Geosciences,

Goethe University Frankfurt, D-60438 Frankfurt am Main, and

Biodiversity and Climate Research Centre (BIK-F), D-60325

Frankfurt, Germany; Schröder-Adams, C.J., Department of Earth

Sciences, Carleton University, Ottawa, ON K1S 5B6; and Burden,

E.T., Department of Earth Sciences, Memorial University of

Newfoundland, St. John’s, NL A1B 3X5

Cretaceous-Paleogene strata exposed on Bylot Island and the north coast

of Baffin Island, northeast Nunavut, Canada, serve as reference

stratigraphic successions for the Baffin Shelf, a region of significant

petroleum resource interest. Coeval successions with demonstrated

petroleum shows are known from offshore areas of West Greenland.

Accurate correlation between these regions is thus of vital interest for

petroleum exploration, as well as for interpreting the tectonic and

depositional history of circum-Baffin Bay basins.

Cretaceous-Paleogene strata of Bylot Island accumulated in a variety

of depositional environments, from fluvio-deltaic to deeper-water shelf

settings. Strata show locally abundant sulfur which may be responsible for

the poor preservation and low abundance of foraminiferal, calcareous

nannofossil, and radiolarian microfossils; where present, foraminifera are

of benthic agglutinated nature and indicate a deep water setting. Mollusks

and other macroinvertebrate groups are also relatively uncommon in the

strata and intrabasinal biostratigraphic correlation has thus relied primarily

on palynology, principally dinoflagellates and pollen and spores. Although

some palynological assemblages recognized in Bylot Island strata are also

recognized on the Newfoundland and Labrador Shelf and the western

Canadian Arctic, direct correlation with the succession of West Greenland

has not yet been fully established.

Paleogene strata of Bylot Island contain the gastropods Fusinus sp.,

Nekewis sp., and cf. Levifusus and cf. Vanikoropsis, as well as the

branching coral Faksephyllia sp., of Danian age; similar faunas are known

from the Agatdal Formation of West Greenland. Stratigraphically lower

strata of Bylot Island have produced sparse aporrhaid and nerinacean

gastropods, indicating a Maastrichtian age and suggested correlation with

the Kangilia Formation of West Greenland. Stratigraphically still lower

fossils from Bylot Island include turritellid and aporrhaid gastropods, as

well as possible sphenoceramid bivalves, indicative of a probable

Campanian age and suggesting correlation with the upper Atane and

possibly Itilli formations of West Greenland. Oldest macroinvertebrate

remains from Bylot Island include inoceramid bivalves assignable to a

likely Albian-Cenomanian age, and their containing strata are thus

correlative with the lower Atane Formation.

No stable isotope record spanning Late Cretaceous-Early Tertiary

time presently exists for the Canadian Arctic region. Ongoing bulk stable

organic carbon isotope studies of strata on Bylot Island will hopefully

refine local correlations, improve correlation with other basins in the

circum-Baffin Bay region, and provide a reference for paleoenvironmental

change across the northern Baffin Bay region during the Late Cretaceous

and Early Tertiary.

SYNTECTONIC DEEP-WATER CARBONATE MOUNDS: IMPLI-

CATIONS FOR THE EVOLUTION OF THE MESOPROTERO-

ZOIC BORDEN BASIN, NUNAVUT

Hahn, K., [email protected], and Turner, E.C., Laurentian

University, Sudbury, ON P3E 2C6

The Mesoproterozoic Borden Basin, host of the Nanisivik Pb-Zn deposit,

is one of the tectonostratigraphically complex Bylot Basins. Deposition of

syntectonic, deep-water black shale of the 1.1 Ga Arctic Bay Formation,

low in the stratigraphic succession, was accompanied by accumulation of

large, isolated carbonate mounds of the Ikpiarjuk Formation. The mounds

are centred along and elongate parallel to syndepositionally active

extensional faults, and are several kilometres in diameter, and several

hundred metres thick. This syndepositional fault activity at ~1.1 Ga may

have been related to tectonic stresses during assembly of Rodinia rather

than the much older Mackenzie igneous event (~1.27 Ga).

The Ikpiarjuk Formation mounds lack “normal” features of

Mesoproterozoic reefs and have an unusual origin. Some mounds contain a

faintly clotted to massive texture in outcrop. The clotted texture is defined

by variably connected, irregularly shaped voids. The voids are filled by

several generations of isopachous carbonate cement, by internal mud-grade

sediment, or both. Intraclast debrites on mound flanks indicate that at least

some mounds were gravitationally unstable and had relief from the

seafloor, or were eroded after deposition. In two locations, smaller

“moundlets”, <100 m wide and tens of metres high, are stratigraphically

below the larger mounds. In one location a moundlet is overturned within

flat-lying Arctic Bay shale, indicating that the fault which it was centred

on was active during deposition. Each mound has a different growth

history. Of the two mounds examined thus far, the “clotted” texture is

significantly different in each location. The size of voids in the “clotted”

texture, generations of isopachous cement, and abundance of internal

sediment is different among locations.

The mounds are interpreted to represent fossilised cold seeps of

unknown fluid composition, and to have accumulated where fluids entered

seawater through seafloor fissures associated with active intra-graben

faults. The clotted texture is similar to thrombolitic textures present in late

Neproterozoic reefs. This texture suggests that the formation of mounds

may have been influenced by microbial activity. The depositional

environment of the Ikpiarjuk Formation mounds was deep-water and

anoxic, which explains why the mounds are not analogous to “normal”

Mesoproterozoic reefs.

THE PORT HOPE SIMPSON RARE EARTH ELEMENT

DISTRICT – FELSIC VOLCANIC AND PEGMATITE HOSTED

MINERALIZATION IN SOUTHEASTERN LABRADOR, CANADA

Haley, J.T., j.haley@mun.ca, Sylvester, P.J., Memorial University of

Newfoundland, St. John's, NL A1B 3X5, [email protected], Miller,

R.R., Search Minerals Inc., Vancouver, BC V6C 3E8, and Gower,

C.F., Geological Survey of Newfoundland, St. John's, NL A1B 4J6

The Port Hope Simpson rare-earth element (REE) district is located on the

southeastern coast of Labrador, Canada. The recognized extent of the

district is 135 km along strike and 4 to 12 km wide. Nine prospects have

been announced by Search Minerals Inc., the current owner of the mineral

exploration rights for the entire district. The prospects were discovered in

2010 during a follow-up exploration program to a regional airborne

magnetic/radiometric survey. We have studied the geology and

geochemistry of the REE mineralization in order to understand its genesis

and distribution.

The regional geology of the Port Hope Simpson REE District is

extremely complex as it straddles three separate lithotectonic terranes

within the eastern Grenville Province, Labrador. The terranes include the

Lake Melville terrane, Mealy Mountain terrane and the Pinware terrane,

from north the south, respectively. Differing lithologies, structures,

metamorphic facies, along with multiple crystallization and metamorphic

events distinguish these terranes.

The Lake Melville terrane is characterized by the Alexis River

anorthosite, biotite-bearing granite, granodiorite, and quartz diorite-to-

diorite gneiss. The Mealy Mountain terrane is characterized mostly by

biotite granitic gneiss, K-feldspar megacrystic granite gneiss, quartz diorite

to dioritic gneisses, and pelitic to semipelitic sedimentary gneisses. The

Pinware terrane consists of felsic to intermediate intrusions and older

intercalated quartzofeldspathic supracrustal rocks. Intrusions consist

mainly of granite, K-feldspar megacrystic granite, quartz monzonite,

granodiorite, and felsic hypabyssal to volcanic rocks.

Most previous work has been dedicated to large-area regional

mapping during which stage the terranes were defined. The nature of the

protoliths of the host rocks for the REE mineralization, however, had not

been established. Based on detailed geological mapping in the Port Hope

Simpson area, together with approximately 25,000 lithogeochemical

samples, and the petrologic logs of 21,000 m of drill core, two main types

of REE mineralization are distinguished. One is highly evolved REE-Zr-

Y-Nb felsic volcanic rocks found within a highly sheared and

metamorphosed bimodal, previously unrecognized mafic-felsic volcanic

package. The second consists of heavy REE (HREE)-Zr-Y-Nb enriched

pegmatites that are both cross cutting and complexly deformed in places.

This second type has many subtypes, all of which are pegmatitic. In both

types of mineralization, the REE-enriched minerals are allanite, zircon and

fergusonite.

CENTURY-SCALE VARIABILITY OF CORALLINE ALGAL

CALCIFICATION RATES IN THE NORTH PACIFIC AND

NORTH ATLANTIC

Halfar, J., Chan, P., Geology Department, University of Toronto,

Toronto, ON L5L 1C6, Adey, W., Department of Botany,

Smithsonian Institution, Washington, 20560, USA, Hetzinger, S.,

IFM-GEOMAR, Leibniz Institut für Meereswissenschaften, Kiel,

24148, Germany, Williams, B., Keck Science Department,

Claremont Colleges, 925 N. Mills Ave, Claremont, California 91711,

USA, Steneck, B., Darling Marine Center, University of Maine,

Walpole, 04573, USA, and Lebednik, P., LFR Inc., Ecosystems

Services Group, Emeryville, California, USA

Ocean acidification may inhibit calcification pathways of marine plants

and animals. Recently, it has been suggested that aragonitic tropical corals

and other marine calcifiers already exhibit declining calcification rates.

Greater oceanic CO

uptake at mid-to-high latitudes may result in greater

inhibition of calcium carbonate secretion in subarctic organisms than in

those at lower latitudes. Such inhibition may be particularly evident in the

metabolically expensive high Mg-calcite skeletons of the shallow-water,

habitat-forming coralline algae. It has been shown that biogenic high Mg-

calcites exceed the solubility of aragonite at approximately 12 mol%

MgCO

. Here we present the first century-scale records of calcification

rates in the coralline alga Clathromorphum sp. from the North

Pacific/Bering Sea region and the subarctic NW Atlantic. Clathromorphum

forms annual growth increments in its massive skeleton and is known to

have a lifespan of up to several centuries. The seasonal MgCO

range in

Clathromorphum from our subarctic collection sites fluctuates between 10-

15 mol%. Century-long time series of calcification rates - the product of

skeletal density and linear extension - were generated at submonthly

resolution using Micro Computer Tomography. Results indicate that

coralline algal calcification rates display multidecadal cycles that covary

with regional climate indices such as the Pacific Decadal Oscillation.

Unlike studies of other marine calcifiers, this study has not detected a

significant decline in calcification rates during the past decades. This is

likely attributable to Clathromorphum calcification being metabolically

driven, with the organism maintaining significant physiological control

over both placement and dissolution of carbonate. Most carbonate in

Clathromorphum cells is deposited along an inner wall embedded in an

organic matrix of small, radially-placed high magnesium calcite crystals.

THE MANUELS RIVER HIBERNIA INTERPRETATION

CENTRE: A NEW GATEWAY TO THE GEOLOGICAL

TREASURES OF THE RIVER IN CONCEPTION BAY SOUTH, NL

Hall, J. and Deemer, S., Memorial University of Newfoundland, St.

John’s, NL A1B 3X5, [email protected]

A 7 km length of Manuels River provides access to Late Proterozoic

volcanics, Cambrian sediments, including a world-famous trilobite fauna,

and modern geological processes along the river and at its outlet into the

sea in Conception Bay. The Manuels River Natural Heritage Society

(MRNHS) has created a linear park along the river and has provided tours

of the river to the public, school classes and visiting community groups for

16 years or so. In collaboration with the Rotary Club of Avalon Northeast

(RANE), a new 1200 sq. m. interpretation centre is under construction to

facilitate access to the river. The new centre will have exhibits focussing

on the river’s geology, its flora and fauna, and its human history. Of

particular interest will be a recreation of the river’s bedrock geology, with

interpretation, and exhibits on the trilobite fauna, honouring the work of

Dr. Riccardo Levi-Setti, who has donated to MRNHS his collections from

many years spent on the river. The centre will also provide rentable audio-

guides to the river. Funding for the centre is coming from the Town of

Conception Bay South, the Hibernia Management and Development

Corporation, the Atlantic Canada Opportunities Agency, the Government

of Newfoundland and Labrador, RANE and MRNHS. In addition to

funding of the building, additional sponsorship is being sought for trail

enhancements and other features of the ‘Manuels River Experience’. The

centre should be open early in 2013.

A GAS HYDRATE RESOURCE INITIATIVE FOR NEWFOUND-

LAND AND LABRADOR

Halliday, E.J.

1,2

, [email protected], Zakeri, A.

, King, T.

and

Gillespie, R.

C-CORE, St. John’s, NL A1B 3X5;

Fisheries and

Marine Institute, Memorial University of Newfoundland, St. John’s,

NL A1C 5R3

WITHDRAWN

STRATIGRAPHIC FRAMEWORK OF THE LOWER

FIFTEENMILE GROUP IN YUKON AND IMPLICATIONS FOR

EARLY NEOPROTEROZOIC BASIN EVOLUTION AND CHEMO-

STRATIGRAPHIC SYNTHESIS IN NORTHWEST CANADA

Halverson, G.P.

, galen.halverson@mcgill.ca, Macdonald, F.A.

Strauss, J.V.

, Smith, E.

, Théou-Hubert, L.

, Cox, G.

, Sperling, E.

Popescu, A.

McGill University, 3450 University St., Montreal, QC

H3A 0E8;

Harvard University, 20 Oxford St., Cambridge, MA

02138 USA

Recent mapping, chemostratigraphy, geochronology, and sequence

stratigraphic analysis of Neoproterozoic strata in the Ogilvie Mountains

motivate redefinition and revised correlation of the early Neoproterozoic

(Tonian) Fifteenmile Group across Yukon. These results demonstrate that

subsidence in the Fifteenmile basin initiated prior to 811 Ma as a result of

north- to northwest-side down normal faulting that rotated and truncated

portions of the underlying Pinguicula and Gillespie Lake Groups. In the

Coal Creek inlier, where the lower Fifteenmile Group is most completely

preserved, these strata seal synsedimentary faults and mark the onset of

thermal subsidence. The basal Gibben formation fills localized half-

grabens and is widely capped by a distinct shoaling-upward carbonate

sequence bound above by a subaerial unconformity. The overlying

Chandindu formation records incipient stromatolite reef development over

bathymetric highs in the basin, which resulted in significant facies

variations along strike. Relict basin highs persisted through deposition of

the Basinal assemblage. Large stromatolite-cored reef systems developed

on these paleohighs and prograded to the north-northwest in a series of

highstand systems tracts, shedding reworked carbonate into and gradually

filling deepwater, shale sub-basins.

In the Hart River inlier, most of the Basinal assemblage and

overlying Craggy dolostone are missing beneath a major low-angle

unconformity at the base of the Callison Lake dolostone. In the Coal Creek

inlier, the Craggy dolostone records final filling of sub-basins and

progradation of a broad, shallow-water carbonate platform. The

spectacular exposure and mappability of contrasting depositional

environments through the lower Fifteenmile Group, from back-reef

supratidal flats and lagoons to fore-reef and deepwater settings with

abundant organic-rich shales, provide an exceptional opportunity to assess

spatial and temporal variability in chemostratigraphic proxies. For

example, carbonate δ

C profiles spanning the inferred onset of the Bitter

Springs negative carbon isotope anomaly show significant variability

between sections. When viewed within the sequence stratigraphic

framework, it is apparent that this variability is attributable to differences

between depositional environments, with higher δ

C values corresponding

to more restricted, back-reef settings and the lowest values belonging to

interspersed carbonates encased in relatively organic-rich shale in deeper

water settings. Despite the complication of the synoptic variability in the

carbon isotope values, temporal seawater trends can be extracted from

these rocks and applied to interregional and global correlation.

PRECISE, MATCHING U-Pb AGES FOR THE RINCON DEL

TIGRE MAFIC LAYERED INTRUSION AND HUANCHACA

GABBRO SILL, BOLIVIA: EVIDENCE FOR A LATE MESO-

PROTEROZOIC LIP IN SW AMAZONIA?

Hamilton, M.A.

, [email protected].ca, Sadowski,

G.R.

, Teixeira, W.

, Ernst, R.E.

and Ruiz, A.S.

University of

Toronto, Dept. of Geology, Toronto, ON M5S 3B1;

Universidade de

Sao Paulo, Geociencias, Sao Paulo, Brazil;

Carleton University, and

Ernst Geosciences, 43 Margrave Avenue, Ottawa, ON K1T 3Y2;

Universidade Federal de Mato Grosso, Cuiaba, Brazil

The SW margin of Amazonia in Bolivia and Brazil preserves a polycyclic

record of tectonic evolution, through successive accretion of arcs, ocean

basin closure, and an oblique microcontinent – continent collision

(Paraguá terrane to the rest of Amazonia) to form the Rondonian-San

Ignacio Province (1.56-1.30 Ga). Between this time and the eventual

Sunsás collisional orogen at ca. 1100-1000 Ma, which culminated in

Amazonia’s amalgamation into supercontinent Rodinia, this region

developed as a passive margin to foreland basin (Sunsás and Vibosi

sediments), locally with systems of aborted rifts developed in the foreland

(e.g. Huanchaca–Aguapeí basin). Here, we report two new identical,

precise U-Pb ID-TIMS ages for widely separated and important

ultramafic-mafic units that intrude these sedimentary sequences, and

speculate on regional intraplate magmatic equivalents that collectively

may define a previously unrecognized large igneous province (LIP).

The Rincón del Tigre (RdT) intrusion was emplaced as a very thick,

layered, differentiated, mafic-ultramafic sill between the Sunsás and

overlying Vibosi metasedimentary sequences, in the southeast tip of the

Sunsás belt. The intrusive RdT rocks, which carry important Ni-Cu-PGE

potential, vary from ultrabasic harzburgites and olivine bronzitites to

gabbros and granophyres. The intrusion has been deformed along with its

sedimentary envelope by upright fold structures related to Sunsás orogeny.

The most reliable published age for the complex is a Rb-Sr age of 992 ± 86

Ma determined on granophyre. We have recovered abundant, fresh

baddeleyite from a middle mafic (gabbro) unit of the RdT, which yields a

well-constrained primary age of igneous emplacement and crystallization

at 1110.4 ± 1.8 Ma. Approximately 500 km to the NW, platformal

Aguapeí sediments unconformably overlie Paraguá crystalline basement,

are flat-lying, undeformed and unmetamorphosed, and are intruded

conformably by a series of gabbroic sills. In the Huanchaca type area, two

principal sills occur up to 200 m thick, emplaced within Aguapeí Group

sandstones and pelites. Baddeleyite from a representative Huanchaca

gabbro sill documents an igneous crystallization age of 1111.5 ± 1.9 Ma.

This 1110-1112 Ma age matches LIPs on other cratons, including

Congo (Ernst et al., this meeting), Kalahari and Indian. We consider

whether all these cratons were nearest neighbour to Amazonia during the

Mesoproterozoic, and shared a ca. 1110 Ma LIP in the Rodinia

supercontinent. The new ages also coincide with the early phase of interior

Laurentia’s Keweenawan (Mid-Continent) event; however, on

paleomagnetic grounds, as shown previously, Mid-Continent Rift

magmatism is likely to have been distant and unrelated.

THE MESOZOIC ORPHEUS RIFT BASIN, OFFSHORE NOVA

SCOTIA AND NEWFOUNDLAND, CANADA: THE INFLUENCE

OF BASIN ARCHITECTURE ON SALT TECTONICS AND BASIN

INVERSION

Hanafi, B.R.

, [email protected], Withjack, M.O.

, Syamsir,

, Durcanin, M.A.

and Schlische, R.W.

Rutgers University,

Wright Lab, Bucsh Campus, 610 Taylor Rd, Piscataway, NJ 08854-

8066, USA;

ExxonMobil Oil Indonesia, Jakarta, Indonesia;

Nexen

Petroleum U.S.A. Inc., Plano, TX 75024, USA

The Orpheus rift basin is the part of the Mesozoic rift system of eastern

North America that formed prior to the opening of the North Atlantic

Ocean. The Cobequid-Chedabucto fault system (CCFS) bounds the

Orpheus and Fundy rift basins on the north; thus, it is likely that both

basins have a common tectonic evolution. Our study area, imaged by a

grid of 2D seismic-reflection profiles, covers the eastern part of the

Orpheus basin. Based on data from nearby wells, comparisons to the

Fundy basin, tectonostratigraphic packages bounded by unconformities,

the presence/absence of growth beds, and cross-cutting igneous intrusions,

we recognize four major tectonic episodes for the Orpheus rift basin:

Triassic to Early Jurassic rifting, Early Jurassic basin inversion during the

transition from rifting to drifting, Early Cretaceous uplift and erosion, and

Oligocene/Miocene uplift and erosion. In the study area, the Orpheus basin

has two distinct basin architectures based on the geometry of basement-

involved extensional faults. In the eastern part of the study area, most

basement-involved faults dip toward the south. In the western part of the

study area, however, the basement-involved faults dip toward the south

and the north, producing a horst-and-graben geometry. The synrift Argo

salt is thicker in the full grabens near the CCFS and in the fault blocks far

from the CCFS; thus, the fault geometries controlled the initial

thickness/distribution of the Argo salt. In areas with thinner salt, basin

inversion reactivated the basement-involved extensional faults below the

salt, and produced supra-salt compressional structures such as salt-cored

buckle folds and detached thrust faults. Thus, the salt layer decoupled the

shallow and deep deformation. In areas with thicker salt, salt structures

developed during rifting, producing salt walls/columns and wedged-shaped

mini basins. Basin inversion reactivated the basement-involved extensional

faults below the salt. In response, the salt columns narrowed,

accommodating most of the supra-salt shortening. Our work shows that the

style of post-rift basin inversion on the passive margin of eastern Canada

depends, at least in part, on the basin architecture and the distribution of

salt within the basin.

RECRYSTALLIZATION AND NEW GROWTH OF

EXTENSIVELY RADIATION-DAMAGED NATURAL ZIRCON

Hanchar, J.M., Department of Earth Sciences, Memorial University

of Newfoundland, St. John’s, NL A1B 3X5, [email protected],

Aylward, W., CREAIT Network, Memorial University of

Newfoundland, St. John’s, NL A1B 3X5, Power, M.J., Department

of Earth Sciences, University of Ottawa, Ottawa, ON K1N 6N5,

Wirth, R., Helmholtz Centre Potsdam, GFZ German Research Centre

for Geosciences, D-14473 Potsdam, Germany, Crowley, J.L. and

Schmitz, M.D., Department of Geosciences, Boise State University,

Boise, ID, 83725

This study was undertaken to investigate the physical and chemical

changes that occur in zircon when heated over a range of temperatures

(600°C to 1400°C), and times ranging from one hour to 36 hours, in order

to better understand how heat treatment leads to an improvement in the

precision and accuracy of isotope dilution thermal ionization mass

spectrometry (ID-TIMS) analyses of zircon. The zircon samples chosen for

these experiments are nearly completely metamict cm-sized crystals from

the Saranac Prospect in the Bancroft District of Ontario.

Approximately 10 grams of these zircon crystals were combined by

breaking into small pieces and ground under ethanol to a fine ~1

micrometer powder in an agate mortar and pestle in order to make enough

homogeneous material for several powder X-Ray and diffraction scans and

high-resolution transmission electron microscopy (HR-TEM)

measurements. While these large zircon crystals ground to a powder are

not the same physical state as what is typically analyzed in single zircon

ID-TIMS U-Pb analysis, the physical and chemical changes that occur

during the heat treatment used in chemical abrasion (CA)-TIMS should be

a similar process.

Aliquots of the ground powder were heated in situ using a Pt sample

holder-furnace in a Rigaku Ultima IV powder diffractometer in which time

simultaneous powder diffraction patterns were collected. Other aliquots of

the zircon powder were heated in a Pt crucible in a Deltech MoSi

vertical

tube furnace and then analyzed with X-ray powder diffraction using a

conventional sample stage. The powder X-ray diffraction results indicate

that below ~900°C the recrystallization of the zircon powder is incomplete,

even after 36 hours, with diffuse low intensity diffraction peaks. At 900°C

the zircon powder shows significant recrystallization, and the ingrowth of

tetragonal ZrO

, within one hour at that temperature. At 1200°C, the

recrystallization is essentially complete in one hour.

Samples of the unground zircon, the unheated powder, and the

powder heated at 900°C for 36 hours, were also investigated using HR-

TEM. The unground zircon and the unheated ground zircon powder

contain a mixture of amorphous and crystalline zircon material with

extensive porosity in the amorphous regions. The sample heated at 900°C

for 36 hours consists primarily of well crystallized zircon but also contains

small islands of tetragonal ZrO

(zirconia) often adjacent to amorphous

material. Also associated with the tetragonal ZrO

are areas of porosity that

may also be contain SiO

but that was not possible to verify.

PRISTINE MELT INCLUSIONS IN QUARTZ PHENOCRYSTS

FROM THE 2.7 Ga PAYMASTER PORPHYRY, TIMMINS

DISTRICT, ONTARIO

Hanley, J.J., Saint Mary's University, Halifax, NS B3H 3C3,

[email protected], and MacInnis, L., QuadraFNX Mining Ltd.,

Sudbury, ON P3E 5P4

We have characterized primary melt inclusions from a porphyry stock in

Timmins, Ontario, in order to evaluate the level of preservation of

inclusions that are hosted in intrusive rocks within Archean greenstone

belts. The Paymaster porphyry is one of a series of oligoclase-quartz,

tonalitic to quartz dioritic intrusions of volcanic arc affinity within the

Porcupine Group (2.69 Ga). Recrystallized melt inclusions in the porphyry

occur within growth zones in quartz phenocrysts and do not show

petrographic evidence of significant post-entrapment modification despite

recrystallization, and the considerable age and post-solidus history of the

host rock. Melt inclusions were homogenized in a piston cylinder

apparatus (900°C, 5 kbar) and analyzed by EMP and LA-ICPMS for

major/trace elements.

Trace elements show a systematic ~ 1 order of magnitude increase in

concentration from the earliest to latest growth zones, reflecting primary

fractionation. The only element that becomes depleted in the melt is Sr,

which shows a strong positive correlation with Ca, reflecting the

crystallization of large amounts of plagioclase during progressive melt

entrapment. Surprisingly, with the exception of Cu and some HFSE, the

most evolved melt inclusions are nearly identical in major/trace element

composition to the host porphyry bulk composition. Concentrations of Cu

in the melt inclusions are 2-3 times higher than in the bulk porphyry. This

may reflect the mobility of Cu during post-crystallization alteration and

deformation. However, given that other highly mobile trace elements are

not depleted (Ba, Rb, Cs, Pb), it is more likely that Cu was removed from

the original magma by a magmatic volatile phase, a suggestion that is

supported by the existence of associated Cu porphyry-style mineralization.

The bulk rock also shows an enrichment in Zr and Hf that is not observed

in the inclusions, reflecting the accumulation of zircon in non-equilibrium

crystallization proportions.

Aside from these minor inconsistencies in bulk rock vs. trapped melt

composition, the results of this study show that melt inclusions can offer

some insight into the evolution of very old intrusive systems, and cannot

be assumed to have been compositionally modified based solely on the age

and extent of deformation/alteration of their host rocks. On the other hand,

the chemistry of these ancient porphyry rocks has not experienced any

significant modification either, highlighting the importance of melt

inclusion studies in evaluating the level of chemical preservation and

representivity of bulk rocks that may or may not be suitable for

petrogenetic interpretation.

ANIMAL-SEDIMENT INTERACTIONS ON THE EARLY ORDO-

VICIAN MUDDY SEAFLOOR: THE IMPORTANCE OF NON-

STEADY SEDIMENT ACCUMULATION

Harazim, D., dharazi[email protected], and McIlroy, D., Memorial

University of Newfoundland, St. John's, NL A1B 3X5

Classic diagenetic facies models conceptualize near-shore marine

sediments as one-dimensionally accreting sediment piles in which the

reactivity of organic carbon steadily declines with depth. More than 60%

of all organic debris discharged to world’s continental shelves, is however

mineralized via non-steady diagenetic processes. The most important

conceptual foundation of non-steady depositional environments is that (1)

sediment accumulation is pulsed, (2) particle residence times in the

suboxic zone are very high, and (3) bottom sediments are frequently re-

worked and re-oxidized before being incorporated into the rock record.

Common routines for the characterization of organic-rich mudstone facies

rarely recognize this depositional environment from the rock record,

because characteristic grain size distributions, sedimentary structures, and

bioturbation styles are rarely defined at the appropriate scale. We present a

combined sedimentological-ichnological facies model for mud-dominated

shoreface and shelf facies members in the Cambro-Ordovician Bell Island

Group (Newfoundland). Normal-marine, mud-dominated shoreface and

shelf sediments capture sedimentary products of wave- and current-

dominated mud deposition and their characteristic macrofaunal

colonization styles. 27 m of mud-dominated sections were logged and

described in cm-resolution, comprising at least five sedimentological

facies. The studied section exposes well-bioturbated sand- and siltstones

that are interbedded with decimeter-thick packages of unbioturbated

mudstones. We record well-preserved mud-on-mud erosion surfaces,

decimetre-spaced combined flow structures and abundant mud ripples at

millimetre to decimetre-scale. Microstratigraphies and grain size trends

within mudstones and siltstones demonstrate a combination of current-

dominated and wave-advected sediment transport, generating turbidites,

wave-enhanced sediment gravity flows, and fabrics originating from post-

storm suspension fall out. In facies dominated by fluid mud deposition,

benthic macrofaunal communities exhibit significant reduction of trace

sizes, low bioturbation depth (<5cm) and rarely any cross-cutting

relationships. Abundant escape traces and sediment fabrics resembling

disruption due to fluid-sediment-swimming activity of macro-organisms

dominate intervals with high sedimentation rates. Preliminary geochemical

results reveal overmature organic matter with rather low total organic

carbon (TOC) values of approximately 0.7% throughout the succession.

TOC values above 2% were measured in intervals dominated by microbial

mats. Based on high-resolution sedimentological/ichnological analysis,

previous interpretations placing this facies into a sub-tidal and periodically

salinity-stressed depositional environment are refuted. Instead, we propose

that the water-column was fully oxic and of normal-marine salinity, and

that bioturbation intensity and colonization style were primarily controlled

by storm recurrence frequency, availability of organic matter as a food

source and time available for colonization.

WHAT DO GAMMA RAY LOGS TELL US ABOUT SEQUENCE

STRATIGRAPHY IN MUDSTONES?

Harris, N.B., Dept of Earth and Atmospheric Sciences, University of

Alberta, [email protected]

High gamma log signatures are typically interpreted in sandy clastics

sequences as indicators of marine transgressions, because high clay

content is commonly associated with distal marine facies. This model is

based on the potassium contribution to gamma ray logs, since potassium

contents are typically elevated in smectitic and illitic clays.

This association has also been used to develop sequence stratigraphic

models in mudstone successions, but here the underlying logic can be

problematic. In many mudstones, for example Upper Devonian shale

formations in North America, high gamma log is related to uranium

content and total organic carbon (TOC) content, not to potassium and clay

content. In these cases, for the gamma ray log to be useful for interpreting

stratigraphic sequences, TOC enrichment must occur during transgressions

or at maximum flooding surfaces. Is this necessarily the case?

The Woodford Shale, Permian Basin, west Texas, provides a good

test. Based on spectral gamma ray data, the total gamma log is dominated

by uranium and closely matches TOC; contributions from potassium and

thorium are minimal. The cyclic occurrence of carbonate turbidites

provides another model for interpreting stratigraphic sequences, based on

‘high stand shedding’. In parts of the section, peaks in TOC do coincide

with transgressive systems tracts; but in other parts, TOC peaks coincide

with high stands. This result suggests that in clay-poor mudstones, TOC

enrichment is complex and not related in simple ways to sea level cycles;

therefore simple sequence stratigraphic models based on gamma ray logs

must be regarded with caution.

APPALACHIANS TECTONIC MAPS

Hatcher, R.D., Jr., Department of Earth and Planetary Sciences and

Science Alliance Center of Excellence, University of Tennessee,

Knoxville, TN 37996–1410 USA

Tectonic maps have been employed to portray the relationships between

large and small tectonic units for many decades. A 1961 USGS–AAPG

tectonic map of the U.S. portrayed the Appalachians in a pre–plate

tectonics context. King’s 1969 North American tectonic map appeared at

the dawn of infusion of plate tectonics theory into geoscience, and at the

threshold of extensive detailed geologic mapping in the Appalachian

internides. Because of this, while most of King’s boundaries in western

North America survived into Muehlberger’s 1996 tectonic map, those in

the Appalachians internides mostly did not. King’s 1970 tectonic map of

the southern and central Appalachians improved his 1961 and 1969

tectonic maps, but it also suffered from a lack of new data on the

internides.

Williams’ monumental 1978 Appalachian tectonic map was the first

modern tectonic map covering the entire orogen and portrayed the

Appalachians at convenient scales (1:1M and 1:2M), showing state-of-the-

art details, and the clear differences between the northern and southern-

central Appalachians. Throughgoing elements also became more obvious.

It became the basis for the first application of the suspect terranes concept

to the orogen in the early 1980s, and is still useful. Keppie’s 1982 map of

the New England and Canadian Maritime Appalachians delineated most of

the tectonostratigraphic terranes and plutons that we still recognize, except

those added recently. The Hatcher et al., 1989, U.S. Appalachians tectonic

map attempted to integrate the terranes concept and accurately depict the

shapes of plutons and known tectonic units. The 2006 Hibbard et al.

tectonic map updates the 1978 map and attempted to interpret Appalachian

components in terms of tectonic kindred, to apply an updated Williams’

1970s Newfoundland model throughout the orogen, and to accurately

depict the shapes of plutons and other elements.

Prior to the 1989 Thomas et al. paleogeologic map of the subsurface

Appalachians and the 1991 Horton et al. terrane map of the southern and

central Appalachians, few attempts were made to portray the modern

geology beneath the Gulf and Atlantic Coastal Plains. Today it is possible

to produce tectonic maps of the entire Appalachians (e.g., 2010 Hatcher)

that interpretat subsurface geology from these data.

Doubtlessly, future tectonic maps will greatly improve these maps as

new techniques are invented, new data become available, and more of the

internides throughout the orogen are mapped in detail.

GAS HYDRATES IN SACKVILLE SPUR?

Hawken, J.E., McGregor GeoScience Limited, 177 Bluewater Rd.,

Bedford, NS B4B 1H1, jhawken@mcgregor-geoscience.com,

Mosher, D.C. and Campbell, D.C., Geological Survey of Canada -

Atlantic, PO Box 1006, Dartmouth, NS B2Y 4A2

Gas hydrates in shallow marine sediments represent a potential hazard to

deepwater hydrocarbon drilling and production. The presence of gas

hydrates along Canada's Atlantic margin has been inferred from the

observation of bottom simulating reflectors (BSRs) on seismic reflection

profiles. Given that BSRs can also be caused by the diagenesis of siliceous

sediments, additional geophysical data such as seismic velocity and well

log data are necessary to positively identify hydrate deposits. On industry

acquired 3D seismic data from offshore Newfoundland, a discontinuous

phase reversed BSR with a shingled appearance crosscuts Cenozoic drift

deposits of the Sackville Spur. This possible hydrate deposit occurs in an

area of active hydrocarbon exploration. The objective of this study is to

determine the origin of the Sackville Spur BSR, by comparing its mapped

occurrence with methane hydrate stability calculations in addition to

assessing well log responses through the shallow sediments. Preliminary

results show a strong correlation between the BSR and depth to the

theoretical base of the gas hydrate stability zone. A low velocity zone

below the BSR is suggestive of free gas trapped below hydrate bearing

sediments. However, a lack of significant increases on the resistivity log

through the sediments overlying the BSR, suggests that sediment-hosted

gas hydrate within the formation is not abundant.

Plenary Address FROM PRESERVATION OF FIRST CONTIN-

ENTAL CRUST TO ULTRA-HIGH-PRESSURE (UHP) META-

MORPHISM IN <1 BILLION YEARS - IMPLICATIONS FOR

EARLY ARCHEAN PLATE MARGIN PROCESSES, CRATON

FORMATION AND STABILIZATION

Helmstaedt, H.H., helmstaedt@geol.queensu.ca, Department of

Geological Sciences and Geological Engineering, Queen’s

University, Kingston, ON K7L 3N6

Nearly fifty years after it was first formulated for the modern Earth, the

question of how and when plate-tectonics began continues to stir

considerable debate. A survey of the literature reveals a full spectrum of

opinions amongst researchers placing its beginnings from as far back as

the Early Archean to as late as the Neoproterozoic, or even later.

Nonetheless, most agree that Earth's tectonic style must have evolved over

time from an early regime, dominated by numerous small plates or

platelets, to the more organized regime, characterized by larger plates, that

may be referred to as modern-style plate tectonics. An answer as to when

this transition occurred should ultimately come from the Precambrian

geologic record, and much emphasis has been placed therefore on

establishing "diagnostic" criteria that may be indicative for the presence or

absence of plate margin processes. Such criteria usually include ophiolites,

taken as evidence for sea-floor spreading, or high-pressure (HP) and ultra-

high-pressure (UHP) metamorphic belts, interpreted as paleo-subduction

scars. Regarding the earliest evidence for UHP metamorphism, defined by

the occurrence of diamond and/or coesite in demonstrably supracrustal

assemblages, a major disconnect exists between information from the

surface record and that obtained from the well-studied world-wide

kimberlitic upper mantle sample. As UHP metamorphic terranes are

restricted to <1 Ga rocks, it is generally assumed that UHP metamorphism

is a Neoproterozoic or younger process that was not possible in a much

hotter Archean Earth. Yet a convincing case can be made that coesite and

diamond eclogites from UHP melanges and coesite- and/or diamond-

bearing mantle eclogite xenoliths from kimberlites are complementary end

products of the same tectonic process. Both began their UHP metamorphic

history in subduction zones, but the former were exhumed together with

other, non-subductable crustal assemblages soon after continental or

microcontinental collision. The latter were part of the oceanic slab

subducted prior to collision. It may have continued its downward journey,

but parts of it were accreted to the roots of microcontinental nuclei and

could be exhumed only when picked up by younger igneous transport

media (e.g. kimberlites). As shown by ~2.9 Ga ages of the oldest known

eclogitic diamonds with subduction signatures, occurring in host rocks

with even older mantle extraction ages, deep subduction was alive and

well in the Mesoarchean, producing lithospheric roots sufficiently thick

and cool to reach into the diamond stability field. The required local

lowering of hotter Archean geothermal gradients was likely achieved by

large-scale tectonic imbrication as has now been imaged in reflection

seismic profiles on several Archean cratons. A range of Proterozoic ages

for eclogite xenoliths and eclogitic diamonds, also with subduction

signatures, has now been recognized in kimberlites and/or lamproites of

most diamond-bearing cratons, suggesting that underplating of UHP

metamorphic assemblages continued periodically throughout the

Proterozoic and may have contributed to craton stabilization.

RESULTS FROM SYSTEMATIC STUDY OF SOME BUZZARD

COULEE METEORITES

Herd, R.K.

1,2

, [email protected], Samson, C.

, Melanson, D.

, Fry,

, Ernst, R.E.

, McCausland, P.J.A.

, Umoh, J.

and Holdsworth,

D.W.

Department of Earth Sciences, Carleton University, Ottawa,

ON K1S 5B6;

Earth Sciences Sector, Natural Resources Canada,

Ottawa, ON K1A 0E8;

Department of Earth Sciences, University of

Western Ontario, London, ON N6A 5B7;

Robarts Imaging Institute,

University of Western Ontario, London, ON N6A 3K9

Samples of the Buzzard Coulee chondritic meteorite (fell November 20,

2008) were obtained by the National Meteorite Collection of Canada. The

masses ranged over an order of magnitude (from 109.14 to 8.8 grams),

were fully to almost-fully crusted, and were collected before the winter of

2008-2009. They afforded an opportunity for systematic study, to help

define a protocol and methodologies for examination of new meteorite

falls and finds, or for specimens from sample return missions to space.

Non-destructive laboratory work commenced. Digitized data were

preserved for archival and curatorial purposes, and in anticipation of

further research. Each fragment was examined, weighed, and

photographed on acquisition and as research proceeded. Average bulk

density by 3 independent methods was 3.44±0.03, 3.46±0.03, and

3.49±0.06 g/cm

, while average porosity was 6.14±1.5%, and grain density

was 3.69±0.03 g/cm

by helium pycnometry. All these values are similar to

those reported for H chondrites. The mass magnetic susceptibility (X) of

each sample was calculated using results from different laboratories and

different machines; the average log of X was 5.2±0.056 × 10

-9

/kg, also

typical of an H chondrite. Up to this point, the only recognized special

feature of any sample was apparent shock veins revealed in one mass with

missing crust.

The majority of the samples were subjected to X-ray Micro-

Computed Tomography (Micro-CT), providing one of the means for

calculating bulk volume and density, and information that is being used to

define metal concentrations and to calculate bulk metal contents. A fully

crusted sample revealed an essentially metal-free interior region invisible

from the exterior; this discovery method is probably unique in meteorite

studies.

The two variant samples (one with shock veins, one with a metal-

poor inclusion) were cut with a diamond-wire saw. The features defined by

the systematic non-destructive work were present in slices. Polished thin

sections were made to allow textural and analytical follow-up studies to be

reported here.

SEISMOGENIC DEFORMATION OF A CARBONATE

PLATFORM STRADDLING THE PRECAMBRIAN-CAMBRIAN

BOUNDARY, KARATAU RANGE, KAZAKHSTAN

Heubeck, C., christoph.heubeck@fu-berlin.de, and Evseev, S., Freie

Universität Berlin, Malteserstr. 74-100, 12249 Berlin, Germany

The “Lower Dolomite” of the Ediacaran-Cambrian Chulaktau Formation

straddles the Precambrian-Cambrian boundary in the Lesser Karatau

Mountains of southern Kazakhstan and immediately underlies some of the

world’s largest sedimentary phosphate deposits. It is not a stromatolitic

bioherm, as previously identified in the literature, but a carbonate platform

which was regionally and complexly deformed while in a

semiconsolidated state. Three subdivisions are recognized: The lower

section, approx. 3-5 m thick, is regionally shortened by flexural folds on a

meter-scale and also shows thrusting and imbrications of underlying

siliciclastic units; local extension is accommodated by soft-sediment

boudinage. The middle section, approx. 2-5 m thick, largely consists of a

megabreccia of angular and subrounded dolomite clasts up to m-size. The

upper unit, approx. 0-3 m thick, consists of microbially laminated

dolobindstone, dolorudstone and slab conglomerate cut by syndepositional

low-angle normal faults. Channelization and bank margin slumping at the

top of the Lower Dolomite was followed by karsting, prior to establishing

a high-energy, shallow-water, carbonate-phosphatic coastal environment.

A prominent unit of black chert at the top of the dolostone represents an

early diagenetic overprint, recognizable by silicified slump folds,

lithological boundaries trending oblique to bedding, the absence of

reworking, and the partial silicification of overlying basal phosphorites.

We interpret the Lower Dolomite as an example of an unevenly

lithified carbonate platform deformed by one or several large seismic

events. The lower unit deformed by local sliding, imbrications, and folding

while deformation in the overlying middle unit occurred by in-situ

disaggregation due to extensive shaking. Coseismic or early postseismic

uplift, possibly above sea level, led to rapid erosion, widespread

extensional gravitational normal faulting of soft sediment piles, drainage

incision and their fill by bank collapse and conglomeratic wedges. Our

documentation of a major regional seismic event at the pC-C boundary

calls for comparable investigations of this critical but typically

incompletely preserved contact in Earth history.

CRYSTAL CHEMISTRY OF THE MOUNTAIN RIVER BERYL

(EMERALD VARIETY), MACKENZIE MOUNTAINS, NORTHWEST

TERRITORIES

Hewton, M.

, [email protected], Marshall, D.

, Ootes, L.

, Loughrey,

and Creaser, R.

Simon Fraser University, Burnaby, BC V5A

1S6;

Northwest Territories Geoscience Office, PO Box 1500,

Yellowknife, NT X1A 2R3;

University of Alberta, Edmonton, AB

T6G 2R3

Emerald at the Mountain River occurrence in the Mackenzie Mountains,

Northwest Territories, is associated with extensional quartz-carbonate

veins hosted in organic-poor deepwater sandstones and siltstones of the

Neoproterozoic Windermere Supergroup. The section hosting the veins is

found within the hangingwall of a thrust fault that emplaced the

Neoproterozoic siliciclastics above Paleozoic carbonates. Emerald occurs

as euhedral milky green hexagonal crystals 1 to 5 mm in diameter and up

to 4 cm in length. Backscatter electron and cathode luminescence imaging

shows the crystals are rhythmically zoned with distinct cores. Substitution

of V

and Cr

for Al

in the beryl crystal structure (Be

)

imparts the green colour typical of emerald and the Mountain River

emerald contains high concentrations of both chromophores (2846 ppm V,

1430 ppm Cr). High concentrations of Sc (up to 0.31%) and Zn (exceeding

1%) in the emeralds are quite unusual, and do not occur in other emerald

deposits.

Hydrogen isotope compositions of water extracted from emerald

range between -65‰ and -49‰ (V-SMOW). The δ

V-SMOW

values for

emerald and quartz range between 16.2‰ and 17.2‰, and 17.9‰ and

18.9‰, respectively. One dolomite sample returned a δ

V-SMOW

value of

18.1‰. Temperature of mineralization was determined by mineral pair

V-SMOW

equilibration to be in the range 379 to 415°C. Fluid inclusion

analyses indicate saline (>22 wt% NaCl equivalent) CO

-bearing brines

and homogenization temperatures between 200 and 250°C. Combining

fluid inclusion isochores with isotope equilibration temperatures indicates

fluid pressures on the order of 2.0 to 4.5 kbar, corresponding to depths of 6

to 12 km. Euhedral pyrite intergrown with emerald yields a 5 point Re-Os

model 1 isochron age of 345 ± 20 Ma and an elevated initial

187

Os/

188

ratio of 3.2, indicating a crustal fluid source.

Emerald formation resulted from the circulation of hydrothermal

brines through organic-poor sedimentary rocks, which scavenged the

metals necessary for mineralization. The fluids involved and age of the

occurrence are synchronous with extensive base metal mineralization

(carbonate-hosted lead-zinc, sedimentary exhalative, and volcanogenic

massive sulphide) and the Manetoe Facies dolomitization event throughout

the northern Cordillera, supporting the argument for a large-scale

hydrothermal brine movement event during the Late Devonian to

Mississippian. The Mountain River emeralds are genetically most similar

to the Colombian-type mineralization model, with two exceptions: 1) the

host rocks are organic-poor, hence inorganic thermochemical sulphate

reduction was likely involved in mineralization; and 2) mineralization

occurred during a period of tectonic extension rather than compression.

THE BREVITY OF HYDROTHERMAL FLUID FLOW

REVEALED BY THERMAL HALOES AROUND GIANT Au-

DEPOSITS

Hickey, K.A., [email protected], Dipple, G.M., Barker, S.L.L.,

Dept Earth & Ocean Sciences, The University of British Columbia,

Vancouver, BC V6T 1Z4, Arehart, G.B., Geological Sciences &

Engineering, University of Nevada, Reno, NV, USA, and Donelick,

R.A., Apatite to Zircon Inc., Viola, ID, USA

Hydrothermal fluid flow is responsible for significant heat transfer in the

Earth’s upper crust, and is an important process in the formation of ore

deposits. The duration of hydrothermal fluid flow episodes is poorly

constrained. Active continental geothermal systems are thought to last for

at least 20 - 500 Kyr. For extinct hydrothermal ore systems, estimates for

the duration of hydrothermal fluid flow are largely constrained by the

precision of the U-Pb and

Ar/

Ar geochronometers and are thought to be

as short as ~100 - 500 Kyr. Here we demonstrate that thermochronology

data, coupled with thermal modeling, can be used to constrain the duration

of hydrothermal fluid flow. We present apatite fission-track (AFT) data

that define a conductive halo to the Eocene hydrothermal system

responsible for >1100 tonnes of gold in the Goldstrike property on the

northern Carlin trend, Nevada. Thermal modeling of conductive heat flow

and the ensuing AFT annealing provide first-order estimates for the

duration of hydrothermal fluid flow responsible for mineralization. Our

results indicate firstly that hydrothermal fluid flow was short-lived,

comprising one or more hydrothermal pulses < ~10 - 50 Kyr in duration,

and secondly, that large hydrothermal ore-deposits can form from

geologically brief episodes of fluid flow.

EVALUATING CRUSTAL SULFUR SOURCES IN MAGMATIC Ni-

SULFIDE DEPOSITS: APPLICATION OF A NEW MULTIPLE S

ISOTOPE METHOD TO THE VOISEY’S BAY NI DEPOSIT

Hiebert, R.S., Bekker, A., University of Manitoba, Winnipeg, MB

R3T 2N2, [email protected], and Wing, B.A., McGill

University, 845 Sherbrooke St. W., Montreal, PQ H3A 2T5

It is generally accepted that crustal contamination is required for the

formation of significant magmatic Ni-Cu-PGE sulfide deposits. Either the

addition of external S or SiO

promote early sulfide saturation. The most

direct indicator of the S source is S isotopes. However, the traditional use

of δ

S values is inadequate in deposits where sedimentary sulfides of

Archean age in the footwall might not have significantly different δ

values from those of mantle S. Even where sediments have variable δ

values, δ

S signatures can be reset to magmatic values by equilibrating

large amounts of silicate magma with initial sulfide melt. We used new

multiple S isotope methods to constrain the relationship between δ

S and

S values, which is helpful to differentiate between high-temperature

equilibrium fractionations found in magmatic S, and low-temperature

kinetic fractionations found in sedimentary S.

The Voisey’s Bay Ni-sulfide deposit, Labrador is hosted by a

troctolitic conduit system connecting two subchambers of the Voisey’s

Bay intrusion. The Voisey’s Bay intrusion is a part of the Nain plutonic

suite and intruded at approximately 1.3 Ga along the boundary between the

Proterozoic Tasiuyak Gneiss of the Churchill province and Archean

gneisses of the Nain province.

Several models for the formation of this deposit have been presented,

but there is still significant controversy over the cause of S saturation in

the magma to form the deposit. The general model suggests that

assimilation of an unknown silica-rich rock, likely in a mid-crustal magma

chamber, was followed by assimilation of a large amount of sulfidic

Tasiuyak gneiss, leading to sulfur saturation prior to emplacement.

However, the Tasiuyak gneiss does not have a high concentration of sulfur

(typically <<1 wt%), and traditional δ

S analysis cannot distinguish

between mantle and crustal sources in this deposit.

High-temperature equilibrium relationships are not preserved in our

measured δ

S and δ

S values. Instead they indicate that a kinetic process

is responsible for S isotope fractionations in the mineralization, troctolite,

and Tasiuyak gneiss. The observed slope of the data on a δ

S vs. δ

S plot

is consistent with bacterial sulfate reduction, suggesting a marine

sedimentary protolith to the Tasiuyak gneiss. This signature has apparently

been inherited by the troctolite and the mineralization during assimilation

of the Tasiuyak gneiss, despite the equilibration of the sulfide melt with a

very large amount of silicate magma, resetting the δ

S values in the

deposit to magmatic values.

PROVENANCE OF CLASTIC METASEDIMENTARY ROCKS OF

THE PALEOPROTEROZOIC AILLIK GROUP, MAKKOVIK

PROVINCE, LABRADOR: INSIGHT FROM NEW U-Pb GEO-

CHRONOLOGICAL DATA

Hinchey, A.M., Newfoundland and Labrador Geological Survey,

Government of Newfoundland and Labrador, St. John’s, NL A1B

4J6, [email protected], and Sylvester, P.J., Department of

Earth Sciences, Memorial University of Newfoundland, St. John’s,

NL A1B 3X5

The Makkovik Province of Labrador is part of a Paleoproterozoic

accretionary belt that developed on the southern margin of the North

Atlantic craton during the ca. 1.9-1.7 Ga Makkovikian-Ketilidian orogeny.

The Aillik domain represents one of three domains that characterize

province. The Aillik domain largely comprises: a) the Aillik Group

(previously termed the Upper Aillik Group), a supracrustal assemblage

consisting of metasedimentary and metavolcanic rocks; and, b) abundant,

syn- and post-deformation Paleoproterozoic intrusive suites which intrude

the Aillik Group.

The ca. 1883-1856 Ma Aillik Group comprises polydeformed, upper-

greenschist to lower-amphibolite facies, bi-modal volcanic rocks and

sedimentary lithologies and hosts abundant base-metal and uraniferous

showings. The Allik Group is composed of interbedded sandstone and

siltstone, conglomerate, tuffaceous sandstone, felsic tuff, rhyolite, volcanic

breccia, and lesser basalt that has been intruded by numerous suites of

variably deformed Paleoproterozoic granitic intrusions and swarms of

mafic and felsic dikes. The lithological units of the Aillik Group are

laterally discontinuous and strained, having complex local structures

resulting in repetition of the stratigraphy. Depositional basement of the

Aillik Group has not been identified, it cannot be coincident with present-

day basement, as folding and shearing during Makkovikian orogenesis

transported these Aillik Group rocks northwestward.

A sample of a polylithic conglomerate from an eastern exposure of

the group, contains a simple detrital zircon population of Paleoproterozoic

aged grains, with a dominant peak between 1870-1930 Ma, and no

Archean ages. A deformed granite clast at the base of the conglomerate

yielded a U-Pb ID-TIMS age of ca. 1880 Ma. The conglomerate is

contained with a section of the ca. 1850 Ma Aillik Group, and the detrital

zircon population indicates a restricted local source of older (ca. 1880 Ma)

Aillik Group sediments being recycled was the main source for the

younger (ca. 1850 Ma) Aillik Group sediments.

A sample from metasandstone which is stratigraphically lower then

the conglomerate sample and located some 20 km to the west, was also

analyzed for detrital zircons. The metasandstone yielded a more complex

detrital zircon distribution with abundant Paleoproterozic and Archean

zircon, characterized by equally prominent age peaks at 1930 to 2100 Ma

and 2500 to 2600 Ma. The abundance of Paleoproterozoic and Archean

ages indicates a more complex source for the lower stratigraphic units with

the Aillik Group. The abundance of the Archean ages indicates a

significant source of Archean age detritus, possible basement, that is yet

unrecognized in the region.

Keynote CANADA'S PARTICIPATION IN PLANETARY

MISSIONS

Hipkin, V.J., Canadian Space Agency, St Hubert, QC J3Y 8Y9,

[email protected]

This talk will present an overview of the first decade of Canadian Space

Agency planetary mission contributions, and discuss future opportunities

and directions.

Around August 6th 2012, NASA's Mars Science Laboratory is

anticipated to land in Gale Crater in Mars equatorial region. At the end of

its robot arm is the Alpha-Particle X-Ray Spectrometer experiment

contributed by the Canadian Space Agency. Principal Investigator Ralf

Gellert from the University of Guelph leads a team of Canadian and US

scientists who will use APXS data to assess the elemental composition of

soils and rocks. This will be the second Canadian experiment in 5 years to

land on the surface of Mars, following the Phoenix MET lidar in 2008. The

CSA is also collaborating with NASA on the MATMOS instrument on the

2016 ExoMars Trace Gas Orbiter Mission, and contributing the OLA

instrument on the OSIRIS-REx mission to asteroid 1999 RQ36, Canada's

first involvement in a sample return mission. CSA's Exploration Core

program with additional investment in Canada's space industry through

Canada's 2009 Economic Action Plan is developing robotics and science

instrument prototypes for potential future contributions.

PALEOLATITUDE OF WEST AVALONIA FROM PALEO-

MAGNETISM OF CA. 600 Ma VOLCANIC ROCKS OF THE

HARBOUR MAIN GROUP NEAR COLLIERS, AVALON

PENINSULA OF NEWFOUNDLAND

Hodych, J.P., Department of Earth Sciences, Memorial University of

Newfoundland, St. John’s, NL A1B 3X5, [email protected], and

Buchan, K.L., Geological Survey of Canada, 601 Booth Street,

Ottawa, ON K1A 0E8

The Harbour Main Group near Colliers on the central Avalon Peninsula

includes the Blue Hills Basalt conformably overlying the Peak Tuff which

has yielded a U-Pb zircon age of 606 ± 3 Ma. We sampled seven sites

from oxidized flow-tops in the Blue Hills Basalt and one site from welded

ash-flow tuffs in the Peak Tuff. On thermal demagnetization, the Peak Tuff

site and five of the Blue Hills Basalt sites yielded stable hematite-borne

remanences that predate folding (most of which occurred before the Early

Cambrian). We also sampled basalt boulders in a conglomerate that

unconformably overlies the Blue Hills Basalt. Basalt boulders with stable

hematite remanence were magnetized in directions that were scattered

from boulder to boulder as expected from primary remanence. Similar

results were obtained from rhyolitic boulders in an intraformational

conglomerate in the Peak Tuff. Hence, the tilt-corrected stable hematite

remanence at six of our volcanic sites is likely primary and provides a 39 ±

10° paleolatitude estimate for the Avalon Zone of Newfoundland at ca.

600 Ma. This paleolatitude can be compared with those based on published

primary paleopoles from other well-dated Ediacaran units in the Avalon

Zone of Newfoundland – namely, 34 ± 8° for the ca. 580 Ma Marystown

Group of the Burin Peninsula, and 19 ± 11° for the ca. 570 Ma Bull Arm

Formation of the Bonavista Peninsula. Taken together, these data indicate

that West Avalonia drifted at mid to low paleolatitudes through the 600-

570 Ma period. This may also help constrain the location of the Amazonia-

West Africa landmass (which lacks primary paleopoles) because

geological evidence suggests that West Avalonia lay nearby during this

period.

THE 1.1 Ga MIDCONTINENT RIFT SYSTEM IN NORTH

AMERICA: PASSIVE OR ACTIVE RIFTING?

Hollings, P.

, peter.hollings@lakeheadu.ca, Cundari, R.

and Smyk,

Department of Geology, Lakehead University, 955 Oliver

Road, Thunder Bay, ON P7B 5E1;

Ontario Geological Survey,

Ministry of Northern Development and Mines, Suite B002, 435

James St., South Thunder Bay, ON P7E 6S7

The Midcontinent Rift (MCR) of North America comprises ~1,500,000

of basaltic sheets, flows and intrusive rocks emplaced in the Lake

Superior region during the Mesoproterozoic. Traditional models for the

MCR invoke formation as the result of impingement of a mantle plume

under the Superior Province, similar to those invoked for active rift

systems. However, recent geochronological studies have shown that

magmatism associated with the MCR may have extended for at least 60

m.y., considerably longer than is typical for Large Igneous Provinces (LIP)

(e.g., <1 m.y. for the bulk of Deccan magmatism). Many ancient, plume-

related LIP have been identified by the presence of extensive radiating

dike swarms. However, to date, no radiating swarm has been identified in

the MCR. Rather, the majority of dikes preserved around the rift are

broadly rift arm-parallel and restricted to within a few tens of kilometres of

Lake Superior. Furthermore, dykes within the Logan basin, which spans

the area from Thunder Bay to the Minnesota border, are grouped into three

lithological units based primarily on their orientation: the east-northeast- to

northeast-trending Pigeon River dykes; the east-northeast-trending Mt.

Mollie dyke; and the north-northwest- to northwest-trending Cloud River

dykes. This implies a variation in the stress field/extension directions over

time and suggests a more complex rifting history. Geochemical and

isotopic data for the MCR, including variable ε

NdT

values over time, have

been interpreted as evidence for a complex petrogenetic model in which

the influence of plume-related mantle waxed and waned throughout the

history of the MCR. This could suggest that the plume signature of the

magmas is a result of the remelting of underplated material left by earlier

mantle plumes.

These lines of evidence, taken in conjunction with the presence of an

angular unconformity beneath the basal member of the Osler Volcanic

Group (the oldest volcanic sequence recognised on the north shore of the

rift) are permissive of a passive rifting model for the MCR, rather than the

traditionally accepted active model. Alternatively, the MCR may represent

a hybrid model where the plume itself impacted at some point beneath the

Superior Craton and the magma channelled to the paleocratonic margin

where it initiated rifting.

PERI-LAURENTIAN VOLCANOGENIC MINERALIZATION

WITHIN NORTHERN IRELAND: AN EXTENSION OF THE

BUCHANS ARC SYSTEM

Hollis, S., Roberts, S., School of Ocean and Earth Science, National

Oceanography Centre, Southampton, UK, sph1e08@soton.ac.uk.,

Earls, G., Dalradian Gold, Belfast, Northern Ireland, UK, Herrington,

R., Department of Mineralogy, Natural History Museum, London,

UK, Cooper, M., Geological Survey of Northern Ireland, Belfast,

Northern Ireland, UK, and Piercey, S., Department of Earth Sciences,

Memorial University of Newfoundland, St. John's, NL

The Caledonian–Appalachian orogen is one of the best preserved and most

intensely studied examples of a long-lived collision zone within the

geologic record. Early Paleozoic closure of the Iapetus Ocean resulted in

the accretion of a diverse set of arc terranes, ribbon-shaped

microcontinents and oceanic tracts to the Laurentian margin during

Grampian–Taconic orogenesis. Within central Newfoundland, Canada, a

complex tectonic collage of peri-Laurentian, Cambro-Ordovician tracts is

preserved, many of which host significant VMS mineralization. For

example, the Annieopsquotch Accretionary Tract is host to the world-class

Buchans deposits (e.g. 16Mt mined at 14.5% Zn, 7.6% Pb, 1.3% Cu,

126g/t Ag and 1.4g/t Au), as well as smaller VMS deposits such as Pilley's

Island, Gullbridge (3 Mt at 1.1% Cu), Lake Bond and Shamrock. New

resources include: Lundberg (20.7 Mt inferred at 2.78 % Cu+Pb+Zn),

Clementine West and Little Sandy.

The Tyrone Igneous Complex (TIC) of Northern Ireland is broadly

equivalent to the Annieopsquotch Accretionary Tract of Newfoundland,

and represents a tectonically dissected arc-ophiolite complex accreted onto

an outboard segment of the Laurentian margin during the early Ordovician.

The potential for VMS mineralization within the TIC has been recognized

for some time, although individual prospects were not forthcoming. Gold

and base metal mineralization is most prevalent within the upper part of

the volcanic sequence. Through a combination of detailed field mapping,

U-Pb geochronology, extensive geochemistry and high-resolution airborne

geophysics, several key stratigraphic horizons were identified which were

ideal for the formation and preservation of VMS deposits. Specific

petrochemical assemblages indicative of rifting and high temperature

magmatism were targeted for detailed prospecting and follow up drilling in

2011, particularly around areas with intense hydrothermal alteration.

Prospecting identified new occurrences of outcropping hydrothermally

altered volcanics which host Zn-Pb(Cu)-Au mineralization coincident with

geophysical and geochemical anomalies. VMS-style mineralization is

primarily restricted to rhyolite flow/dome complexes and felsic

volcaniclastics often associated with auriferous silica-flooded (crackle-

brecciated) rhyolites. Targets have been defined for a new regional drilling

campaign in 7 key areas. Drilling has commenced.

GEOLOGICAL/HERITAGE WONDERS OF THE BONAVISTA

PENINSULA: THE DISCOVERY GEOPARK PROJECT

Holloway, S.C., Discovery Regional Development Board, 263

Memorial Drive, Suite 203, Clarenville, NL A5A 1R5,

[email protected], Norman, J., Discovery Geo-

Heritage Management Committee, johnnorman21@gmail.com,

McCallum, A., Geological Survey of Newfoundland and Labrador,

Department of Natural Resources, PO Box 8700, St. John’s, NL A1B

4J6, amandam[email protected]

The Bonavista Peninsula is located on the eastern coast of Newfoundland.

The rocky peninsula, which juts out into the North Atlantic, caught the

attention of the early European explorers who made landfall there,

discovering our New founde land. For generations, the environment has

shaped a resilient people who have made their living off the cold, harsh but

vibrant fishing grounds. Until recently, no one knew that for more than

half a billion years, the bedrock of the peninsula has held important

secrets. These landscapes and seascapes provide a unique glimpse of a

crucial stage in the ancient history of the Earth, including nature’s earliest

experiments with evolution of animals.

The geological significance of the Bonavista Peninsula was not

revealed until 2003, when the region was first mapped in detail by the

provincial geological survey. These rocks, part of an ancient ocean long

since vanished, preserve some of the earliest multi-cellular life after

“Snowball Earth.” In addition to recording a crucial period in Earth

history, the region provides a glorious, readily accessible outdoor

laboratory. In 2011, the provincial government formally recognized the

significance of several paleontological (fossil) sites within a number of

communities, including the Ediacaran fauna in Trinity Bay North and

Elliston.

A regional steering committee is working to explore and educate the

public about the coastal geological heritage of the peninsula’s assets. The

committee receives support and advice from various levels of the

provincial and federal government. They have worked with geoscientists

and a consulting firm to create a development plan and interpretative

framework. Participation in two Best Practice Missions provided

operational and management models of established Geoparks. In 2009, a

visit to the Copper Coast and Marble Arch Caves Geoparks in Ireland, and

the 2011 mission to Stonehammer, North America’s first Geopark,

reinforced the importance of community ownership, building partnerships

and the high level of preparation for the application process to the Global

Geoparks Network. A five-year development and work plan has since been

created.

The bedrock and landscape is a remarkable natural phenomenon, and

there is enormous potential for the development of a Geopark on the

Bonavista Peninsula. There are numerous sites of geological value that

intertwine with the rich history and distinctive culture of the Discovery

Trail. Many of these areas are economically depressed and would benefit

from coordinated, regional geotourism efforts to promote, preserve and

protect the geo-heritage sites and the unique cultural traditions.

PHOTOSYNTHETIC (?) MICROBIAL MATS OF THE MIDDLE

ARCHEAN MOODIES GROUP, BARBERTON GREENSTONE

BELT (SOUTH AFRICA)

Homann, M., martin.h[email protected]e, Heubeck, C., Engelhardt,

J. and Drabon, N., Institute of Geological Sciences, Freie Universität

Berlin, Germany

The composition of the Archean atmo- and biosphere, the circumstances

favoring the evolution of microbial life, and the origin of (oxygenic)

photosynthesis are vigorously disputed.

Probably one of the best places to address some of these issues is the

Moodies Group (3.2 Ga) of the Barberton Greenstone Belt (South Africa),

which exposes one of Earth's oldest siliciclastic sequences with common

macroscopic microbial mats. In order to constrain their setting, facies, and

habitat we measured ten detailed stratigraphic sections spread ~11 km

apart along strike in the interior of the greenstone belt where Moodies

strata are relatively unmetamorphosed, preserving the remains of microbial

mats and associated sedimentary structures in outstanding quality. Our

results indicate a tidally influenced coastal depositional system in which

microbial mats occur within an interval of ~1000 m thickness. They form

green anastomosing or flat laminations < 1mm thick, interbedded with

medium- to coarse-grained and gravelly sandstones. Microbial mats

colonized coastal (and fluvial?) habitats of varying energy and

occasionally experienced subaerial exposure.

Based on the microbially induced sedimentary structures, we

distinguished four facies along a land-to-sea transect: 1) wavy laminae

interbedded with nodular Fe-oxide concretions indicative of a restricted

shallow-water setting; 2) nearly flat laminae associated with high shear

stress suggestive of an intertidal setting; 3) wavy laminae associated with

herringbone cross-bedding, underlain by bedding-parallel chert bands ~0.2

cm thick, indicating a subtidal setting and 4) crinkly laminae associated

with petees (~0.7 cm height) and gas or fluid escape structures of up to 6 m

height, of a yet unknown setting.

We tentatively conclude, based on exclusion arguments, the

phototactic micromorphology and consistent shallow-water facies that the

Moodies microbial mats, were at least in part photosynthetic communities.

DECIPHERING THE MONIAN SUPERGROUP: EVIDENCE OF

?CAMBRIAN AVALONIAN NEOPROTEROZOIC ARC EXHUM-

ATION FROM THE NEW HARBOUR GROUP, NORTH WALES,

U.K.

Horák, J., jana.horak@museumwales.ac.uk, Department of Geology,

National Museum of Wales, Cardiff CF10 3NP, Wales, UK,

Linnemann, U., Museum of Mineralogy & Geology, Königsbrücker

Landstraße 159, D-01109 Dresden, Germany, and Evans, J., NERC

Isotope Geosciences Laboratory, Kingsley Dunham Centre,

Nottingham NG12 5GG, UK

The Monian Supergroup (MSG) is a low grade, variably deformed,

metasedimentary sequence exposed in northernmost Wales. It has been

interpreted as a Peri-Gondwanan, fore-arc accretionary complex although

the age of depositional remains contentious - proposals range from

Neoproterozic to Early Ordovician. U-Pb detrital zircon data from the

basal unit (South Stack Group) indicate a Cambrian (Series 3, Guzhangian)

maximum depositional age. However in resolving one problem, this age

questions the relationship between the South Stack Group and the over-

lying New Harbour and Gwna groups. Although the New Harbour Group

shows a coherent structural history with the South Stack Group, some

workers suggest that the Gwna Group metabasites are correlatives of 550-

560 Ma blueschist metabasites. If such an interpretation is correct this

implies that the MSG is not a contiguous stratigraphy.

New U-Pb detrital zircon data from the upper part of the New

Harbour Group (Skerries Formation) in northern Anglesey have been

obtained to provide an additional age constraint on MSG deposition. The

Skerries type locality succession includes boulder beds of granite and

granophyre. These igneous clasts have a calc-alkaline arc affinity and an

igneous U-Pb zircon age of 649.1 ± 5.0 Ma, with an inherited component

of c. 1500 Ma. Detrital zircons from the sandstones interbedded with the

boulder beds show the main population at 560 – 760 Ma with other

significant populations at 1500 Ma and 1100 Ma. The zircon inheritance

age suggests an almost exclusively arc-dominated source of East

Avalonian affinity for these sediments, although the granites cannot be

matched directly to any exposed complexes in Southern Britain. This is

consistent with Sm-Nd data for the New Harbour Group which suggest an

immature source. A northerly or north-easterly-derived source has been

established for the New Harbour Group (on the basis of sedimentary

structures) suggesting an outboard provenance for the boulders and

cobbles. This contrasts with the southerly derived underlying South Stack

Group which has a more mature Sm-Nd signature and Palaeoproterozoic

and Archean inherited zircon components, not seen in the New Harbour

Group. This therefore suggests a significant change in depositional

architecture and exhumation of an arc block in the latest Cambrian or early

Ordovician which has implications for the existing tectonic interpretation.

The only alternative to this model is a major structural discontinuity

between the South Stack Group and New Harbour Group that has not as

yet been identified.

RECENT DEVELOPMENTS UNDERSTANDING THE VOL-

CANIC, MAGMATIC, TECTONIC, AND METALLOGENIC

EVOLUTION OF THE ELY GREENSTONE FORMATION,

VERMILION DISTRICT, NE MINNESOTA

Hudak, G.J.

, Heine, J.

, Lodge, R.W.D.

and Jansen, A.C.

Precambrian Research Center/

Economic Geology Group, NRRI,

University of Minnesota Duluth, Duluth, MN 55811 USA;

Laurentian University, Sudbury, ON P3E 2C6;

Washington State

University, Pullman, WA 99164 USA

The Ely Greenstone Formation comprises a well-preserved stratigraphic

sequence of Neoarchean supracrustal and associated intrusive rocks in the

southwestern part of the Wawa-Abitibi Terrane in the Vermilion District

of northeastern Minnesota. The Lower Member of the Ely Greenstone

(LMEG) comprises calc-alkalic and tholeiitic basalt and basalt- andesite

lava flows and tuffs with subordinate felsic lava flows, tuffs, epiclastic

rocks and iron formations. The Soudan Iron Formation Member (SMEG)

comprises Algoma-type interlayered cherty iron formation, basalt lava

flows, epiclastic rocks and felsic tuffs. The Upper Member of the Ely

Greenstone Formation (UMEG) is composed of a monotonous sequence of

poorly-vesiculated tholeiitic basalt lava flows and localized Algoma-type

iron formation lenses. The UMEG is commonly interstratified with the

Lake Vermilion Formation (LVF), which is composed of greywacke, slate,

conglomerate, and dacite tuff, as well as subaerial to submarine dacite to

trachyandesite lava flows, tuffs, and associated intrusions (the informally

named Gafvert Lake Sequence (GLS). Locally, it is believed that the LVF

unconformably overlies the LMEG and SMEG strata. Previous studies

(Schulz, 1980) interpreted volcanological and sedimentary textures to

indicate a change from a subaerial / shallow subaqueous setting to a deeper

subaqueous environment during the temporal genesis of the Ely

Greenstone Formation. This interpretation is supported by our more recent

and detailed field studies. Previous lithogeochemical studies by Southwick

et al. (1998) indicate that a sharp transition from arc-like volcanism

(LMEG) to MORB-like volcanism (UMEG) occurs abruptly at the top of

the SMEG. However, new major- and trace element data indicate the

lithogeochemistry of volcanic rocks in the LMEG is more complicated

than previously recognized. Arc-like basalts and basaltic andesites and FI-

and FII-type rhyodacites and rhyolites characterize the FLS. In the CBS,

arc-like basalts and basaltic andesites transition up-section into E-MORB,

OIB and back-arc basin-like basalts. These basalts are temporaly

associated with FIII-type felsic volcanic rocks. The UMEG is

characterized by MORB-like basalt compositions that may also be the

product of back-arc spreading (Southwick et al., 1998). A model

encompassing initial arc development followed by back-arc development

and rifting during the final stages of the LMEG immediately prior to

SMEG deposition appears to be most consistent with the observed

volcanological and lithogeochemical characteristics in this part of the

Vermilion District. Iron formations within the SMEG occur immediately

up-section from the proposed arc – back-arc transition, a stratigraphic

position shown in many studies to have high prospectivity for hosting

volcanogenic massive sulfide orebodies.

INTERACTIONS OF SINISTRAL FAULTS AND CAMP DIABASE

DIKES DURING THE FINAL STAGES OF PANGEA BREAKUP IN

THE SOUTHERN APPALACHIANS

Huebner, M.T., mhuebne1@utk.edu, and Hatcher, R.D., Jr.,

[email protected], University of Tennessee, 1412 Circle Drive,

Knoxville, TN, 37996-1410

Evidence recording the breakup of Pangea spans the mid-Triassic through

the earliest Jurassic in the southern and central Appalachians.

Emplacement of numerous CAMP diabase dikes post-dates Triassic

rifting, deposition, and subsequent inversion of Mesozoic rift basins.

Diabase dike orientations mostly trend NW (290-345) in the southern

Appalachians, and rotate to a more N and NE trend in the central

Appalachians and New England. A narrow N-S-trending fanned swarm

also occurs in the Carolinas, although the age of these dikes is

indistinguishable from the more abundant NW-trending set. Collective

dike emplacement likely occurred over a few m.y. or even less, although

dike characteristics suggest individual emplacement was nearly

instantaneous. The lack of country rock contamination, uniform texture,

and extreme surface area to width (mostly <25 m) require very rapid

propagation to prevent heat transfer and crystallization prior to dikes

reaching the upper crust. Assuming moderate estimates of Young’s

modulus and crustal density, we estimate individual dikes penetrated the

thickness of the crust (35 km) in 3 minutes.

Emplacement of CAMP diabase dikes was coeval with movement

along numerous small-displacement faults filled with silicified cataclasite

throughout the southern Appalachian orogen, indicated by faults

crosscutting dikes, and vice versa. Siliceous cataclasite faults generally

trend NE, NNE, and E-W, although geographic control of orientation

similar to CAMP dikes is not apparent. A single strain ellipse does not

resolve all orientations of diabase dikes (YZ plane, mode I fractures) and

siliceous cataclasite faults (shear planes).

Many siliceous cataclasite faults reactivate older (mostly

Alleghanian) faults that formed at a much deeper crustal level. The

Towaliga fault (AL-GA) is a major Alleghanian garnet-grade dextral

strike-slip fault that trends ~070° in its SW segment, changes to ~035° at

the NE end of the Pine Mountain window (central GA), and continues NE

through the Inner Piedmont. Isolated, km-scale rhomboidal to elongate

pods of intensely deformed silicified cataclasite occur along both segments

of the fault. These likely represent mineralized fault-fracture meshes that

formed in dilational step-overs along discrete sinistral strike-slip faults,

and crosscutting relationships confirm deformation temporally overlaps

CAMP dike emplacement. Other nearby faults with isolated cataclasite

pods exhibit similar trends, kinematics, and temporal characteristics, but

do not reactivate preexisting faults. Siliceous cataclasite faults also share

some spatial relationship with low-temperature (400°C) ribbon quartz

mylonite that likely formed during the late Alleghanian or early stages of

Mesozoic rifting, although timing of this mylonite is poorly delimited.

THE QAVVIK-TATIGGAQ TREND: AN EVOLVING UNCON-

FORMITY-RELATED URANIUM CORRIDOR OF THE

NORTHEAST THELON BASIN, NUNAVUT

Hunter, R.

, [email protected], Lafrance, B.

Lesperance, J.

and Zaluski, G.

Cameco Corporation, 2121 11

Street West, Saskatoon, SK S7M 1J3;

Department of Earth

Sciences, Laurentian University, Sudbury, ON P3E 2C6

The Qavvik-Tatiggaq Trend (QTT) is a 25 km E-W-trending corridor

within the northeast part of the Thelon Basin. It hosts two newly-

discovered, basement-hosted, uranium deposits named the Qavvik and

Tatiggaq deposits, as well as a zone with anomalous uranium values in the

overlying sandstone sequence. The mineralization is structurally-controlled

and situated within the Neoarchean Woodburn Lake Group and

Paleoproterozoic Hudson Suite rocks. These rocks underwent multiple

ductile and brittle deformation events during the Taltson-Thelon and

Trans-Hudson orogenies. The mineralization is located proximal to ENE-

trending dextral fault zones, as well as NE-, E-, and NW-trending faults;

all of which are interpreted to have been initiated and reactivated during

these two orogenic events, as well as after the deposition of the Thelon

Formation. Uranium mineralization is associated with distinct alteration

assemblages consisting of hematite, clay, bleaching, and sulphide. The

protracted deformation history is important as it has led to the creation of

crustal-scale fault zones, formation of long-lived sedimentary basins,

subsequent structural reworking and fault reactivation, and eventually

generation and migration of hydrothermal fluids and deposition of

uranium.

PLIO-PLEISTOCENE MASS WASTING AND CONTOURITIC

ARCHITECTURE ON THE CONTINENTAL SLOPE IN SALAR

BASIN, SOUTHEAST GRAND BANKS OF NEWFOUNDLAND

Huppertz, T.J., MARUM-University of Bremen, Leobener Strasse,

28359 Bremen, Germany, huppertz@uni-bremen.de, King, E.L.,

Geological Survey of Canada, PO Box 1006, [email protected], and

the Spanish NEREIDA team

Multibeam bathymetric renderings coupled with a seismostratigraphic

framework have demonstrated the diversity and ubiquity of Cenozoic mass

wasting along the southeastern Canadian continental slope. Increased

environmental and energy interest on the slope dictates a temporal and

process understanding of slope sediment instability. The Salar Basin, on

the SE Grand Banks slope, presents a mixed setting of canyons,

translational slides and along-slope sediment supply that enables a contrast

of these processes through the onset and domination of glacial sediment

supply. A rudimentary seismostratigraphic framework supported by

exploration well stratigraphy (base Pliocene) focuses on the Plio-

Pleistocene interval which comprises nearly half the sediment succession

above the break-up (Avalon) unconformity. Mid-slope contouritic

deposition dominated over mass wasting deposition through and into the

Pliocene, creating a terrace. This is followed by a change to shelf and

slope-based sedimentation style, presumed to reflect the onset of shelf-

crossing glaciations. The Salar Basin upper to mid slope area presents

three dominating architectural regimes driving seabed morphology: a

failure dominated steep upper Zone 1 (shelf break to 1200 m water depth),

a terrace hosting a greater proportion of un-failed strata, Zone 2 (1200-

1500 m), and a lower, hummocky and intensely mass wasted Zone 3. The

zones are bounded by canyon systems to the north and south. Slope angles

on the upper zone are 3 to 5°, where sharp failure scarps of translational

slides have dominated, maintaining long-term bypass, locally exposing

Pliocene strata and even bedrock. Upslope failure limits are generally

determined by the outer shelf till boundary, however, some till failure

occurred. The terrace (< 3° slope) developed as a Pliocene/early

Pleistocene contouritic drift. Coincident with the change in shelf

sedimentation style linked to mid Pleistocene glaciations, there was an

increased mass wasting frequency, derived from zone 1 failures. These

terminated on the terrace and interbedded with a dominant hemipelagic

sedimentation creating a thick sediment package onlapping zone 1 which

inherited and further enhanced terrace building. Zone 3 slope angles are

comparable to the steep upper slope. Pervasive retrogressive slides have

removed more than half of the glacially-dominated section leaving almost

none of the seabed undisturbed. High resolution seismic coupled with

sparse cores may allow a rough chronology of the latest slide events. The

slope sedimentation architecture demonstrates that the persistent late

Tertiary contouritic style in the stratified sediments was maintained despite

the change in sedimentation style with glacial onset, yet increased mass

wasting also marked this change.

THE SECOND ANNUAL TEACHERS’ MINING TOUR - AN

INSTRUCTIONAL DEVELOPMENT PROGRAM FOR

EDUCATORS

Hymers, L.A., Ontario Mining Association, 5775 Yonge Street,

Toronto, ON M2M, 4J1 [email protected], Steer, B., Canadian

Ecology Centre, 6905 Hwy 17, PO Box 430, Mattawa, ON P0H 1V0,

and Williams, J., Prospectors and Developers Association of Canada

Mining Matters, 904-1200 Eglinton Avenue East, Toronto, ON M3C

1H9

Members of the Canadian Earth Science Education and Outreach

Community share a collective concern about the limited number of

students choosing to pursue a post-secondary education in Earth Science.

This is a problem for post-secondary institutions and Earth Science

departments and ultimately leads to a paucity of youth entering Earth

Science careers, including mining. The Canadian Earth Science Education

and Outreach Community has been working individually and collectively

toward addressing this concern. One approach that is used is to provide

instructional development opportunities to educators that teach Earth

Science courses. The Ontario Teacher’s Mining Tour, an educator

professional development program, is an example.

The goal of the Tour is to provide teachers with the information and

resources they need to be proficient Earth science teachers and to

encourage their students to pursue post-secondary education and careers in

Earth sciences. The objectives of the tour are to expose educators to all

phases of the mining cycle through engagement with industry, Earth

science and mineral education professionals, and through participation in

Earth science and mineral industry themed presentations, educational

resource workshops and field trips. Additional objectives are to create and

cultivate a network of teachers using mining as a theme in their

classrooms, and to facilitate informed decisions among participants with

regard to the economic, social and environmental aspects of the mining

industry. The Tour curriculum includes modern mining techniques and

technologies, environmental responsibility and workplace safety, mining

careers, and activities, applications, and resources for teachers and students

in the classroom.

2011 marked the second annual Teachers’ Mining Tour, held at the

Canadian Ecology Centre (CEC) located in the Samuel De Champlain

Provincial Park, near Mattawa Ontario. Twenty seven Ontario teachers

participated in the program that included presentations by experts, industry

professionals, and consultants, and site visits to mines and mining

manufacturing operations in Sudbury and North Bay. Feedback from the

teachers who participated in the inaugural 2010 program informed the

2011 Tour program, including content and presenters.

The 2011 program received favourable reviews from participating

teachers, industry participants and sponsoring organizations. During the

current academic year additional feedback was gathered both from the

teachers who participated in the inaugural Tour and those who participated

in year two. Formal surveys were circulated onto them to gauge how their

tour experiences informed their teaching. The results of these surveys will

be discussed.

1.2 Ga CRUSTAL EXTENSION IN THE CENTRAL GRENVILLE

PROVINCE

Indares, A.D.

, aindares @mun.ca, Moukhsil, A.

, Lasalle, S.

and

Dunning, G.

Memorial University, St John's, NL;

Ministère des

Ressources Naturelles et de la Faune du Quebec, Val d'Or, QC

In addition to unravelling mountain building processes, understanding

orogenic belts also involves recognition of the origin and pre-orogenic

history of their constituent lithotectonic elements. In deeply exhumed

orogens original rock units are largely transformed into gneisses by means

of high-grade metamorphism, anatexis and deformation, making

investigations of the protoliths particularly challenging. However even in

such cases, detailed field studies, together with geochemical and age data,

have the potential to provide insight on complex pre-orogenic tectonic

settings. An example is the recent recognition of a 1.2-1.3 Ga

intracontinental rift system in the hinterland of the central Grenville

province, south of the Manicouagan reservoir. Rock units of that age range

previously known in this area include: ~1.3 Ga granitoid plutons intrusive

into the SE margin of Labradorian-age crust and ~1.2 Ga bimodal (felsic-

mafic) to intermediate composition supracrustal sequences (Banded

Complex) adjacent to ~1.4 Ga units farther to the SE. Based on its

lithological makeup and geochemical signature the formation of this

complex was attributed to crustal extension. However the original setting

and relations with adjoining units were poorly constrained.

Recent detailed fieldwork revealed that SE of the Banded Complex,

along strike, a ~1.4 Ga layered mafic complex (LMC) is variably

impregnated by felsic material, grading into a mafic migmatite which in

turn gives place to a layered quartzofeldspathic sequence (LQFS). LQFS

generally consists of massive quartzofeldspathic layers with varied

proportions of quartz and feldspars, but also contains heterogeneous mafic

layers, ‘bleached’ felsic layers, garnetites, felsic gneisses with garnet and

sillimanite-rich nodules, and calcsilicate rocks. This association is inferred

to represent a hydrothermally altered volcanic belt. The LQFS is

interpreted as a dominantly volcaniclastic sequence deposited in a crustal

extension setting after cutting through the LMC, the injected parts of

which represent the walls of an intracontinental rift. These field relations

are locally well preserved despite Grenvillian age deformation and

granulite facies metamorphism. A crustal extension origin is also

consistent with geochemistry of mafic layers of the LQFS which indicates

an asthenospheric mantle origin with little or no lithospheric

contamination. A 1238 ± 13 Ma emplacement age is constrained by U/Pb

igneous zircon data from a nodular felsic gneiss of the LQFS. This age,

together with the regional distribution of units suggest that LQFS and the

Banded Complex were formed during broadly the same extensional event

affecting the Laurentian margin several 10s of My prior to the Grenvillian

orogeny.

EFFECT OF DEPLETED CONTINENTAL LITHOSPHERE

COUNTERFLOW AND INHERITED CRUSTAL WEAKNESS ON

THE FORMATION OF THE NEWFOUNDLAND-IBERIA AND

NOVA SCOTIA-MOROCCO CONTINENTAL MARGINS

Ings, S.J.

1,2

, [email protected], and Beaumont, C.

Department of

Oceanography, Dalhousie University, Halifax, NS, B3H 4J1;

ExxonMobil Canada, 100 New Gower St., Suite 1000, St. John's,

NL A1C 6K3

In the past two decades, significant advances have been made in

understanding the present-day structure of rifted continental margins using

reflection and refraction seismic techniques. Despite these advances, we

have only a rudimentary understanding of the processes involved in the

development of non-volcanic rifted margins, particularly the role of depth-

dependant crustal extension, inherited crustal weaknesses, flow of lower

continental mantle lithosphere, and syn-rift sedimentation.

In this study we use 2D thermo-mechanical finite element modeling

to investigate the evolution of upper-mantle scale systems (1200 km wide,

600 km deep). The results are compared with the Newfoundland – Iberia

and Nova Scotia – Morocco conjugate margin pairs. The models include

thick (200 km) chemically depleted mantle lithosphere, inherited crustal

weaknesses, and syn-rift sedimentation. When the lithosphere is thick and

chemically depleted, the hotter buoyant lower mantle lithosphere flows

toward to rift axis during rifting allowing the formation of exhumed

continental mantle lithosphere. The result is the formation of wide tracts of

exhumed mantle lithosphere, subsequently serpentinized owing to

hydration, which forms transitional crust between extended continental

crust and oceanic crust, consistent with observations of serpentinized

continent-derived mantle rocks in the transitional crust region of the

Newfoundland – Iberia conjugates, and similar interpretations from the

northern Nova Scotia margin.

Inherited crustal weak zones that are offset from the main central rift

axis can be reactivated as offset rift basins. Extension in these basins

depends on their proximity to the central rift and the ease with which crust

decouples from mantle: narrow (<50 km) basins when crust does not

decouple, and longer-lived wider basins for moderate decoupling. For

weak crust that readily decouples during depth-dependent extension, the

offset rift basins can remain active throughout rifting, giving rise to highly

allochthonous crustal terranes that are translated toward and over the

central rift axis. Syn-rift sedimentation can enhance extension in offset rift

basins; significant and widespread syn-rift sedimentation can result in the

development of wider continental margins in general, especially when the

crust is weak. Model results illustrate how offset weak zones and thick

depleted mantle lithosphere flow can result in complex multi-stage rifting

that has implications for the timing and structural evolution of syn-rift

sediment depocenters.

OVERPRINTING MAGMATIC AND TECTONIC EVENTS IN

ACCRETIONARY OROGENS AND THEIR INFLUENCE ON

MINERALIZING SYSTEMS: EXAMPLE FROM THE NORTHERN

CORDILLERA

Israel, S., [email protected]k.ca, Murphy, D.C., Yukon Geological

Survey, Whitehorse, YK, Crowley, J., Boise State University, Boise,

ID, and Mortensen, J.K., University of British Columbia, Vancouver,

The northern Cordillera of British Columbia, Yukon and Alaska comprises

several tectonic terranes that were accreted to the Laurentian margin over

approximately 150 My. The Yukon-Tanana and Stikine terranes are

characterized by a Paleozoic to late Mesozoic volcanic arc and associated

siliciclastic rocks that were amalgamated to form the Intermontane terranes

prior to accretion to the margin. Outboard of the Intermontane terranes, the

Insular terranes, mainly comprised of the Alexander terrane and

Wrangellia, are characterized by Proterozoic through late Mesozoic rift

and arc-related volcanic rocks and thick platformal sequences. Wrangellia

was likely built on the flanks of the Alexander terrane, itself a composite

terrane, and the whole mass was then accreted to the western margin of the

Intermontane terranes by the Middle Jurassic.

The Coast belt is a complex of Middle Jurassic to Tertiary arc

magmatic rocks that developed along the western margin of the

Intermontane terranes as a result of subduction of Farallon and Pacific

ocean crust and the convergence of the Insular terranes. Accretion of the

Insular terranes was a prolonged, episodic event that included

transpressive, transtensive and orthogonal subduction, as well as periods of

transcurrent faulting. The prolonged nature of subduction led to multiple

overprinting magmatic, tectonic and metallogenic events affecting the

suture zone between these two superterranes. These generated several

mineralizing systems, including porphyry copper-gold, epithermal gold

and orogenic gold deposits. Mid-Cretaceous epithermal gold deposits are

found at the flanks of a large batholithic core of the same age. Slightly

younger and cross-cutting intrusion-related and orogenic gold systems

occur in the core of the batholith, where they were exposed and re-

mobilized during renewed magmatism and inflation of the main magmatic

axis in the Late Cretaceous. Late Cretaceous porphyry copper-gold

deposits and associated epithermal gold mineralization cross-cut and

remobilize earlier mineralization. Continued magmatism into the latest

Cretaceous and Paleocene occurred at the outboard margin (SW) of the

mid-Cretaceous magmatic axis and is associated with porphyry copper-

gold-molybdenum and epithermal gold deposits. In the forearc of the latest

Cretaceous to Paleocene subduction zone, compressional faults were

conduits for fluid flow and the formation of orogenic gold systems.

New mapping and geochronological analyses of igneous rocks from

southwest Yukon illustrates the close relationships between subduction

and mineralizing events and the resulting concentration of magmatic and

metallogenic belts in the northern Cordillera.

FOSSILIZATION OF MICROBIAL ETCHINGS FROM THE

STONYFORD VOLCANIC COMPLEX: A LINK BETWEEN

MODERN SEAFLOOR BIOALTERATION AND PUTATIVE

ICHNOFOSSILS IN OPHIOLITES AND GREENSTONE BELTS

Izawa, M.R.M., [email protected], Banerjee, N.R.,

Flemming, R.L., Dept. Earth Sciences, University of Western

Ontario, 1151 Richmond St., London, ON N6A 5B7, Hetherington,

C.J., Dept. Geosciences, Texas Tech University, Box 41053,

Lubbock, TX 79409-1053 USA, Shervais, J.C., Dept. Geology, Utah

State University, 4505 Old Main Hill, Logan, UT 84322-4505 USA,

and Schultz, C., Dept. Geology, San Jose State University, San Jose,

CA 95192-0102 USA (presently: CH2M HILL, 1737 North First

Street, Suite 300, San Jose, CA 95112-4524 USA)

Microscopic hollow tubular and granular structures in relatively young,

sub-aqueous basaltic glass have been reported from numerous submarine

localities worldwide. Several independent lines of evidence, including

morphology, presence of biologically-important elements (e.g., C, N, S, P),

associations with organic matter, carbon isotope compositions, and

geological context point to a microbial origin. Titanite-rich tubular features

of similar morphology in metabasalts from ancient ophiolites and

greenstone belts have similarly been interpreted as ichnofossils in rocks of

up to ~3.5 Ga age. Nevertheless, a convincing mechanism for preservation

of originally hollow microbial alteration textures in basaltic glass has

remained illusive. In the present study, we document tubules in basaltic

glasses from the Jurassic Stonyford Volcanic Complex (SVC) that are

intermediate between hollow tubules commonly found in modern oceanic

crust and ancient titanite-mineralized tubules. Tubules hosted in glassy

material are mostly hollow, with sparse occurrences of infilling materials,

likely including Fe-oxyhydroxides, phyllosilicates, and traces of titanite.

Tubules are rooted on fracture surfaces and glass shard boundaries that

would have been exposed to circulating fluids on the seafloor. Hollow

tubules are indistinguishable from similar features hosted in basaltic

glasses from in situ ocean crust. Throughout the sample, there are domains

where basaltic glass has been replaced by an assemblage of zeolites with

minor quartz and calcite along cracks and fractures. At glass-alteration

interfaces, all hollow tubules observed abruptly change to mineralized

tubular features containing fine-grained titanite and other minerals. The

tubular features are continuous across the sharp transition from glassy to

zeolitized domains. The mineralized zones of SVC tubules are remarkably

similar to titanite-mineralized tubules documented in ancient metabasaltic

rocks. In particular, they share a common occurrence along shard

boundaries and fractures in basaltic glass, are filled with fine-grained

titanite, commonly trending approximately perpendicular to shard edges or

fractures, do not cross one another, and are of similar but somewhat larger

diameter to hollow tubules. The observations reported here demonstrate a

convincing mechanism for the formation of titanite-mineralized tubules

along pre-existing microbially-etched tubules, and reinforces the

interpretation of titanite tubules in ancient metabasalts as microbial

ichnofossils.

Keynote THE ORIGIN OF THE ALPHA RIDGE AND ITS LINKS

TO THE HIGH ARCTIC LARGE IGNEOUS PROVINCE

Jackson, H.R.

, rujackso@nrcan.gc.ca, Dossing, A.

, Funck, T.

and

Shimeld, J.

Geological Survey of Canada Atlantic, 1 Challenger Dr.,

Box 1006, Dartmouth, NS B2Y 4A2;

National Space Institute, DTU

Space, Denmark, Juliane Maries Vej 30, DK-2100 Copenhagen,

Denmark;

Geological Survey of Denmark and Greenland (GEUS),

ØsterVoldgade 10, DK-1350 Copenhagen, Denmark

The formation of the Alpha Ridge and the significance of the widely

distributed High Arctic Large Igneous Province (HALIP) have been an

enigma due to lack of direct evidence to constrain the geodynamic

evolution of the region. A new 350 km long seismic refraction line was

collected from the coast of northern Canada to the southern Alpha Ridge

with a recorder spacing of 1.5 km and a shot spacing of 22 km to define

the sedimentary to Moho structure. Near the coast the crustal velocities are

5.6 - 6.5 km/s and the depth to Moho is 30 km, compatible with the

adjacent continental crust. On the Alpha Ridge there is a near-seabed

velocity of 4.7-5.4 km/s interpreted as extrusive volcanics on the basis of

seismic reflection and magnetic character. This layer is underlain by

velocities of 6.1-6.6 km/s and 6.8-7.3 km/s, with Moho at depths of 26-32

km. The velocity structure of the Alpha Ridge is similar to that observed

on other large plateaus in the oceans. In addition, a 550,000 sq km

aeromagnetic survey was flown over the section of the Alpha and

Lomonosov ridges adjacent to North America and Greenland. The survey

comprises of a set of 800 km long flight lines, spaced 12–15 km apart,

subparallel to the Lomonosov Ridge. We present the results of

aeromagnetic data compiled from the new LOMGRAV survey and

reprocessed NRL-98/-99 data. The combined magnetic and seismic

refraction data provide hitherto undetected tectonic links between the

HALIP and the Alpha Ridge that serve as important constraints on the

plate tectonic setting and history.

IMPLICATIONS OF NEW U-Pb ZIRCON AGES FROM THE

CORONATION MARGIN REGION OF THE SOUTH-CENTRAL

PALEOPROTEROZOIC WOPMAY OROGEN, NORTHWEST

TERRITORIES, CANADA

Jackson, V.A.

, [email protected], Ootes, L.

, van Breemen,

, Bennett, V.

, Davis, W.J.

, Bleeker, W.

, Ketchum, J.

and Smar,

NWT Geoscience Office, Yellowknife, NT X1A 2R3;

Geological Survey of Canada, Ottawa, ON K1A 0E8;

Geomantia

Consulting, Whitehorse, YT Y1A 3H4;

University of British

Columbia, Vancouver, BC V6T 1Z4

In the northwestern Canadian Shield, the superbly exposed

Paleoproterozoic Wopmay orogenic belt is a widely quoted example of

Precambrian plate tectonics and terrane accretion. Results from an 8-year,

100 km by 100 km bedrock mapping transect with associated

geochronological studies in south-central Wopmay orogen are presented.

In south-central Wopmay orogen, the Coronation margin is a

complex region encompassing sialic basement, sedimentary and volcanic

rocks of low- to high-metamorphic grade, and granitic to gabbroic

intrusions. The widespread and variably deformed tonalitic, granodioritic,

and granitic basement rocks yield Archean U-Pb zircon ages ranging from

>3000 Ma to ca. 2575 Ma. Exposures of thickly bedded and upright-

folded, low-grade sandstone and stromatolitic carbonate of the passive

margin sequence are minimal and restricted to near the craton edge. An

extensive polydeformed and metamorphosed pelitic sequence with minor

carbonate, sandstone, and mafic volcanic rocks, rests unconformably on

the Archean basement. As such this sequence is part of an autochthonous

(not exotic) succession within the Coronation margin. Paleoproterozoic

intrusions were emplaced at ca. 1877, 1867, and 1858 to 1850 Ma. At ca.

1877 Ma and 1850 Ma there was coincident resetting of Archean U-Pb

systematics and regional metamorphism. The ca. 1877 Ma syn-

deformational intrusions are possible correlatives with the Hepburn

intrusive suite, but historical models indicate this suite was emplaced about

10 m.y. earlier during the ca. 1885 Ma Calderian orogeny. Plutonic phases

of ca. 1885 Ma are not identified within south-central Wopmay orogen.

The pattern of metamorphic isograds that developed around the ca. 1850

Ma Rodrigues granite, suggests the thermal aureole is related to

emplacement of this large pluton, potentially within a metamorphic core-

complex type environment. These younger intrusions are coeval with the

latest magmatism in the Great Bear magmatic zone to the west, and

intruded in a post-orogenic, potentially transtensional setting. Finally, a

Morel sill in the study area has yielded an 1868 Ma U-Pb zircon

crystallization age, 15 m.y. younger than its previously speculated age.

The new mapping and U-Pb zircon results, in conjunction with lithospheric

geophysical experiments, allow us to test previously proposed and new

hypotheses on the evolution of Wopmay orogen.

CONGLOMERATES AND CONGLOMERATES IN THE URANI-

FEROUS NORTHEAST THELON BASIN REGION, NUNAVUT:

GUIDES FOR UNRAVELLING >800 Ma OF SEQUENCE

STRATIGRAPHY AND METALLOGENY

Jefferson, C.W., Anand, A., Rainbird, R., Pehrsson, S., Davis, W.,

Peterson, T., Geological Survey of Canada, 601 Booth Street,

Ottawa, ON K1A 0E8; McEwan, B., Bethune, K., University of

Regina, 3737 Wascana Pkwy., Regina, SK S4S 0A2; Calhoun, L.,

White, J.C., Department of Earth Sciences, University of New

Brunswick, Fredericton, NB E3B 5A3; and Patterson, J., Fellow,

Science College, Concordia University, Montreal, QC H3G 1M8

Some twenty conglomeratic markers in the northeastern Thelon Basin

region are distinguished by context, composition, texture and fabric. Many

overlie local to profound unconformities. They record pre- syn- and post-

depositional deformation, sequence boundaries, and mineralization.

Stratigraphy helps the GSC’s Geomapping for Energy and Minerals

(GEM) Program provide a framework for exploration. Of seven

Neoarchean assemblages, the first six constitute the Woodburn Lake group

and the seventh is a Rae craton scale 2.6Ga mafic to felsic

intrusive/extrusive suite. The Neoarchean is structurally intercalated (D

)

with early Paleoproterozoic platformal Ps1-3 (lower Amer and Ketyet

River groups). Ps4 is molasse, overlies D

nappes with profound

unconformity, and contains 1.9Ga detrital zircons and D

-style deformed

clasts. The 1.83 to <1.54Ga Dubawnt Supergroup comprises three rift-fill

groups: Baker Lake (5 subaerial volcanic and siliciclastic sequences),

Wharton (conglomerate, aeolian quartzarenite, bimodal volcanics and

coarse feldspathic alluvial sequences), and Barrensland (alluvial

conglomerate to sandstone sequences, topped by mafic potassic lavas and

marine dolostone). Some conglomerate highlights follow.

Polymict, quartz dominated conglomerate previously interpreted as

Neoarchean is intercalated in outcrop and drill core with the 2.7Ga

Woodburn Lake group around Meadowbank gold mine. We suggest it is

structurally intercalated basal Ps1, based on similarities with better

constrained <2.6Ga Ps1 to the northwest. This raises the questions of

whether pre-deformed cobbles of sulphidized BIF constrain the primary

age of gold mineralization and whether other conglomerates in the

Woodburn Lake group are truly Archean.

Conglomerate units help define the Ps1-Ps2 facing direction. Ps1

comprises basal schist ± basal conglomerate, quartzarenite, ± upper

conglomerate. Ps2 is characterized by graphitic schist, intercalated with

three discontinuous components that, where present, are always in order:

impure sandstone - dolostone - basalt. Highly attenuated isoclinal D

folds

defined by such facing directions and the flat synforms of cuspate-lobate

explain the 400-1000m widths of Ps1 map units, whose pre-D

thicknesses were only 100-200m.

Conglomerate characteristics and angular unconformities around the

margins of northeastern Thelon Basin have allowed us to recognize aeolian

sandstone as Wharton, not Barrensland group. Wharton conglomerate is

highly feldspathic with dominantly quartz pebble framework, whereas

overlying Wharton is aeolian quartzarenite. Conversely, basal Barrensland

conglomerate is highly polymict (including Wharton clasts) in a quartzose

matrix whereas overlying Barrensland is clay-altered fluvial arkose.

Unconformity-associated uranium deposits may be discovered below the

Barrensland, and within or below the Wharton groups.

CAN TARGETING CRITERIA FROM ATHABASCA BASIN BE

ADAPTED TO URANIUM EXPLORATION IN THELON AND

OTHER NORTHERN PALEOPROTEROZOIC BASINS? A

PROGRESS REPORT

Jefferson, C.W., cjeffers@nrcan.gc.ca, Chorlton, L., Pehrsson, S.,

Peterson, T., Davis, W., Potter, E., Gandhi, S., Bleeker, W., Keating,

P., Fortin, R., Buckle, J., Miles, W., Rainbird, R., LeCheminant, A.,

Paulen, R., McClenaghan, B., Hillary, B., Geological Survey of

Canada, 601 Booth St., Ottawa, ON K1A 0E8; Quirt, D.,

Wollenberg, P., AREVA; Wheatley, K. Forum; Riegler, T., U of

Poitiers; Ramaekers, P., MF Resources., Tschirhart, V., Tschirhart,

P., Morris, W., McMaster U; Scott, J.M.J., Cousens, B., Carleton U;

McEwan, B., Bethune, K., Riemer, W., U of Regina; Calhoun, L.,

White, J.C., MacIsaac, D., Leblon, B., Lentz, D., LaRocque, A.,

Shelat, Y., UNB; Patterson, J., Concordia U; Bridge, N., Banerjee,

UWO; Sharpe, R., Fayek, M., U of M; Robinson, S., Layton-

Matthews, D., Queen's U; Enright, A. and Stieber, C., U of Ottawa

This question has driven investigations of northern Canadian basins since

Rabbit Lake was discovered in 1968, and is the guiding hypothesis for

GEM’s Northern Uranium for Canada Project. Discovery of Kiggavik in

1977 and Cameco’s recent exploration success just west of there

demonstrate that the answer is YES for the Thelon Basin region, yet this

and the other northern basins remain under-explored. We contribute

improved geoscience knowledge of areas around Thelon, Angikuni and

Hornby Bay basins to further evaluate this hypothesis. Speculative

interpretations below do not necessarily represent the views of co-authors

or corporations who contributed knowledge.

Known uranium resources near Thelon Basin are basement-hosted

and occur beyond present sandstone cover. Our studies focus on

integrating regional compilations with detailed mapping, and geological,

geophysical and drift prospecting models, while refining Thelon Basin

stratigraphy. Basement to Thelon basin differs from the Paleoproterozoic

fold-thrust belts beneath Athabasca Basin: six Neoarchean sequences of

ultramafic to felsic volcanic and sedimentary rocks are structurally

intercalated with thin sequences of Paleoproterozoic platformal

siliciclastics, minor dolostone and continental tholeiitic basalt. Graphitic

metapelite is fertile beneath Athabasca Basin but barren in the few drill

intersections below Thelon Basin. Disseminated cigar-shaped sandstone

uranium deposits in Thelon’s basement differ contextually from uranium

and copper occurrences in the rift component of Athabasca’s basement. In

Thelon’s Kiggavik area, Neoarchean metagreywacke is the preferred

uranium host, especially where intruded by high-level 1.75 Ga granite.

Intersecting reactivated faults localizing illite, chlorite and hematite

alteration around uranium deposits are key in both basins, although details

of mineralogy and zoning differ. Both basins developed intracontinentally

by reactivated faulting and were filled by big rivers, but have different

sequence stratigraphy, sandstone composition, diagenetic and

hydrothermal alteration events. Exploration success depends on

understanding each basin’s parameters and adapting to the similarities and

differences.

We assess other “types” of uranium deposits with the unconformity

paradigm and reinterpret Lac Cinquante and Port Radium veins in circum-

Angikuni (southern Baker Lake Basin) and Hornby Bay Basin areas

respectively as exhumed unconformity deposits with greater vistas for

exploration. We consolidate discovery of Dessert Lake Basin as correlative

with Athabasca and Thelon basins, and establish its dimensions under

which favourable basement domains project. We establish that stratigraphy

and structural evolution of Hornby Bay Basin are more similar to

Athabasca than Thelon basins, yet with greater fault throws. Hornby

Basin’s thermal and uranium pulses at ~1270 Ma may be measureable in

Athabasca Basin.

INVESTIGATION OF SAMPLE RESOLUTION REQUIRED FOR

X-RAY FLUORESCENCE ANALYSIS TO IDENTIFY HETERO-

GENEITY IN FINE-GRAINED SUCCESSIONS

Johnston, M.J., Macquaker, J.H.S., Department of Earth Sciences,

Memorial University of Newfoundland, St. John’s, NL A1B 3X5,

mjohnston@mun.ca, and Turner, J.N., School of Geography,

Planning and Environmental Policy, University College Dublin,

Belfield, Dublin, Ireland

This study aims to determine the sampling resolution necessary to

accurately identify elemental trends through fine-grained successions. To

do this two types of X-ray fluorescence (XRF) analysis were conducted on

outcrop samples collected from the fine-grained Carboniferous aged

(Brigantian) Benbulben Shale exposed at Streedagh Point in Sligo County,

Ireland. A total of 19 samples were collected along with a detailed log,

over a 5.4 m interval. The samples were analyzed with both conventional

XRF techniques and an ITRAX XRF core scanner. The mineralogy

(determined with X-Ray Diffraction) and microlithofacies variability

(determined by optical and SEM techniques) were also investigated to

provide context and identify the character of the fine-grained succession.

The ITRAX scanner uses an XRF to record elemental responses at 2 mm

intervals across each sample. After the scan, samples were crushed,

converted into pressed pellets and analyzed using conventional XRF

techniques. The scan is particularly useful, as the sedimentological

controls on mineralogical distributions (e.g. quartz, calcite) can be

determined. Combined with textural analyses this technique enables spatial

elemental distributions to be recorded and interpreted in terms of different

depositional processes responsible for rock formation. The ITRAX scan

identified significant variations in elemental composition across mudstone

samples due to a variety of factors including, mineralogy, bedding, amount

and type of cement, bioturbation and shifts in facies. To compare between

techniques the average response for each element was calculated from the

scan using all data points across individual samples. Comparison between

conventional XRF techniques (pressed pellet) and the ITRAX scanning

technique yielded remarkably consistent results. While the conventional

XRF technique provides very accurate results, the sampling resolution is

often much to coarse to identify significant elemental excursions and

trends within the measured unit. In very fine-grained rocks (i.e.

mudstones/shale), where processes and events are preserved in the rock

record at a very small scale, conducting such a bulk analysis can result in

not identifying key information. Scanning techniques providing high-

resolution data are very useful in these fine-grained rocks as they can

elucidate a higher degree of heterogeneity, helping to identify important

rock properties.

SULFUR ISOTOPE INVESTIGATION OF IRON-DISULFIDE

MINERALS IN THE FINE-GRAINED EXSHAW FORMATION

Johnston, M.J., Macquaker, J.H.S., Layne, G.D., Department of Earth

Sciences, Memorial University of Newfoundland, St. John’s, NL A1B

3X5, [email protected], and Piercey, G, CEAIT Network –

MicroAnalysis Facility, Memorial University, St. John’s, NL A1C 5S7

A 5 m section of the Exshaw Formation was measured and logged in Jura

Creek, Alberta, Canada to investigate (using SIMS, XRD & XRF) the

depositional and early diagenetic processes controlling the precipitation of

varying iron-disulfide mineral assemblages (including pyrite, marcasite,

sphalerite, and millerite) present in a basal arkosic arenite and in the

associated overlying mudstones. This formation, along with its lateral

equivalent the Bakken Shale is significant because it is a regional tight gas

reservoir target. Proportions of marcasite to pyrite are particularly

significant because they can provide insight into the geochemical

conditions (oxygen concentrations, pH and redox) at the time of

deposition. Recent research has suggested that the most likely cause for the

formation of early marcasite in marine shales is the oxidation of pyrite and

reprecipitation of marcasite under the acidic conditions that ensue.

Microlithofacies variability (determined by optical and SEM techniques)

was also investigated to provide context and identify the character of the

fine-grained succession, which hosts the sulfide minerals. Apart from a

basal arkose arenite the lithofacies include both laminated and thin-bedded

mudstones, which are variably bioturbated and contain agglutinated

benthic foraminifera. Mineralogically the mudstones are predominantly

composed of quartz (62 to 79 %), feldspar (10 to 20 %), clay minerals (10

to 18 %) and variable proportions of pyrite. The arkosic arenite is a

phosphate-bearing lag deposit containing sand-sized (100 to 250 µm)

detrital quartz, and a significant early diagenetic component, including the

iron-disulfide minerals. Sulfur isotope analysis of pyrite and marcasite

identified three populations of δ

S with pyrite displaying ranges from -8.1

‰ to -14.9 ‰ and -30.7 ‰ to -38.6 ‰; and marcasite displaying a range

from 6.3 ‰ to 14.5 ‰. These results suggest multiple sources of sulfur

entering the system during the deposition of the unit. The pyrite oxidation

and re-precipitation theory fails to explain either i) the significant

difference in δ

S between marcasite and earlier deposited (based on

textural analysis) pyrite or ii) the co-occurrence of other metal sulfides

(e.g. sphalerite and millerite). One potentially more plausible formation

pathway of marcasite in this case appears to be a process similar to basinal

brine deposited Pb-Zn type ore deposits, which often contain associated

sulfides such as sphalerite and millerite.

PALINSPASTIC RESTORATION OF APPALACHIAN – VARIS-

CAN CONTINUITY

Johnston, S.T., Shaw, J., University of Victoria, PO Box 3065 STN

CSC, Victoria, BC V8W 3V6, st[email protected], Guttierez-Alonso, G.,

Universidad de Salamanca, Salamanca, 37003, Spain, and Weil, A.,

Bryn Mawr College, 101 N. Merion Ave., Bryn Mawr PA 19010,

USA

The Appalachians of North America and the Variscan of Europe are

commonly interpreted as components a single orogen that developed in

response to the continental collisions that heralded the formation of

Pangea. Post-Pangean deformation in the Appalachian - Variscan realm is

restricted to Triassic to Cretaceous rift-phase extension and subsequent

drift-phase solid body translations related to Atlantic and related basin

opening. Locally significant Alpine overprints are restricted to the

Mediterranean and Pyrenean domains. Palinspastic closure of the Atlantic

ocean should, therefore, restore continuity of the Appalachian and

Variscan orogens. It does not, which begs the question why? Palinspastic

closure of the Atlantic restores the Variscan orogen of Iberia against the

Grand Banks - Flemish Cap continental margin offshore of Newfoundland,

hence part of the problem is the inaccessibility of the offshore continuation

of the Appalachians. However, a larger problem is that the Variscan

orogen of westernmost Europe has been depicted as a convex to the west

arcuate feature referred to as the Ibero-Armorican Arc. The Ibero-

Armorican arc geometry, which requires closure of the orogen to the west

leaving no easy way to establish continuity with the Appalachians, is based

on assumed continuity of geological belts of southern Great Britain and

northern France, including the Rheic suture, around the Cantabrian

orocline, a 180 degree bend that characterizes Variscan orogen of northern

Iberia, into western and southern Ibera. It is now recognized that two

coupled oroclines characterize the Variscan orogen in Iberia, the convex to

the west Cantabrian and a more southerly, convex to the east Central

Iberian Orocline. Together these coupled oroclines (1) define a continental

scale S-shaped fold of the Variscan orogen; (2) call into question the

assumed continuity and westward closure of geological belts implied in the

Ibero-Armorican arc interpretation; and (3) re-open the question of how

the Variscan and Appalachians relate to one another. We show that the

Ibero-Armorican arc interpretation can be modified to accommodate the

second Iberian orocline, but suggest that the predictions of such a model

are difficult to reconcile with our current understanding of Variscan

geology. Alternatively, the southern limb of the Central Iberian orocline,

which is truncated against the Atlantic Iberian margin, may have originally

been continuous into the Appalachians. However, this geometry has its

own difficulties: it results in two separate Rheic sutures, a northern suture

represented by the Lizard complex of Cornwall, and a southern represented

by the Beja-Acebuches of Iberia.

LITHOGEOCHEMISTRY OF THE 130-80 Ma HIGH ARCTIC LIP

(HALIP) EVENT AND IMPLICATIONS FOR Ni-Cu-PGE

PROSPECTIVITY

Jowitt, S.M., School of Geosciences, Monash University, Melbourne,

Australia, VIC 3800, sim[email protected], Ernst, R.E., Dept of

Earth Sciences, Carleton University and Ernst Geosciences, 43

Margrave Ave., Ottawa, ON K1T 3Y2, richard.ernst@

ernstgeosciences.com, and Williamson, M-C., Geological Survey of

Canada, 601 Booth Street, Ottawa, ON K1A 0E8, mwilliam@

nrcan.gc.ca

The lithogeochemistry of a suite of samples from Axel Heiberg and

Ellesmere Islands has been examined to determine the Ni-Cu-Platinum

Group Element (PGE) sulphide prospectivity of the High Arctic Large

Igneous Province (HALIP) event; this research represents the first

systematic analysis and interpretation of the magmatic sulphide potential

of this event. The HALIP consists of volcanic rocks, dyke swarms and sills

of Cretaceous age that are scattered widely across the high Arctic. They

occur prominently in the Sverdrup Basin Magmatic Province of the

northern Arctic islands of Canada, and also in northern Greenland,

Svalbard and Franz Josef Land. In the Arctic islands of Canada, the event

spans some 70 Ma, with an early, tholeiitic phase of igneous activity from

130-90 Ma followed by alkaline magmatism between 85-60 Ma. The two

types of magma present in the HALIP differ in their Ni-Cu-PGE magmatic

sulphide prospectivity; the geochemistry of the alkaline magmas is

suggestive of unfertile or poorly fertile magmas which were S-saturated

when they left the mantle. As such, these magmas did not sequester

significant amounts of chalcophile elements during partial melting and are

probably unfertile and unprospective. In comparison, the presence of

chalcophile element-undepleted samples within the tholeiitic HALIP suite

indicates that the magmas that formed these rocks were S-undersaturated

when they left the mantle and sequestered significant amounts of Cu and

PGEs from the mantle during partial melting. In addition to chalcophile-

undepleted samples, the presence of crustally contaminated chalcophile

element-depleted samples within the tholeiitic suite suggests that at least

some of these fertile magmas assimilated crustal material and became

sulphur saturated prior to emplacement. This S-saturation event segregated

immiscible magmatic sulphides from the silicate magma which may have

been deposited within ultramafic or mafic intrusives associated with the

older tholeiitic segments of the HALIP. This suggests that the tholeiitic

portion of the HALIP should be considered prospective for Ni-Cu-PGE

sulphide mineralisation, and any mafic-ultramafic sequences associated

with this portion of the HALIP should be considered targets for Ni-CU-

PGE mineral exploration. In addition, if further sampling indicates that the

alkaline magmatic suite was fertile in part, then the evidence of crustal

contamination within this suite suggests that it may also be prospective;

however, the older, higher degree partial melt-related tholeiitic suite most

likely represents a better target for Ni-Cu-PGE exploration.

NEW INSIGHTS INTO THE FORMATION PROCESSES OF

SUPERIOR-TYPE BANDED IRON FORMATIONS: CARBON-

ATES, AN ADDITIONAL SOURCE FOR KENO-MAGNETITE

FROM THE LUCE IRON ORE DEPOSIT, LABRADOR CITY,

NEWFOUNDLAND AND LABRADOR

Kaul, A., Sylvester, P.J., Department of Earth Sciences, Memorial

University, St. John’s, NL A1C 5S7, alexander.kaul@mun.ca, and

Blake, M., Mining Operations Technical Services, Iron Ore

Company of Canada, Labrador City, NL A2V 2L8

Banded Iron Formations (BIFs) are the main sources of iron ore today with

the Paleoproterozoic Labrador Trough being host to one of the largest

reserves in the world. With a significant reserve and resource base, the

Iron Ore Company of Canada (IOC located in Labrador City, Labrador) is

the largest iron producer in Canada. The Luce Iron Ore Deposit is one of

IOC’s main assets. This deposit is subdivided into three open pits: Luce

South, Main and Basin.

The main stratigraphic unit mined by IOC within the Luce Deposit is

the Wabush Iron Formation. It is subdivided into three members: The

Lower, Middle and Upper Iron Formation, with the middle unit being the

main source of iron ore. This formation has been extensively folded and

metamorphosed to upper amphibolite facies during the Trans-Hudsonian

and Grenvillian orogenies. The main minerals in the Wabush Iron

Formation are specular hematite/martite, kenomagnetite (iron-deficient

magnetite), carbonate (dolomite, ankerite and siderite) and quartz.

Carbonate increases with magnetite/hematite and is most abundant in the

Lower and Upper Iron Formation. Carbonate beds are present in the

Middle Iron Formation on the scale of several meters in thickness.

Based on optical microscopy and Scanning Electron Microscopy-

Mineral Liberation Analysis, kenomagnetite, specular hematite/martite,

goethite, limonite and Fe-dolomite are identified as the main iron-bearing

minerals. Textural relationships reflect both martitization (specular

hematite/martite replacing kenomagnetite, reflecting oxidation) and

mushketovitization (kenomagnetite replacing specular hematite/martite,

reflecting reduction). Thus the ores consist of several different generations

of kenomagnetite and specular hematite/martite that likely formed during

regional metamorphism, contact metamorphism (associated with intrusion

of the Mesoproterozoic Shabogamo Gabbro) and perhaps recent,

groundwater alteration. Furthermore, BSE imaging revealed iron zoning in

Fe-dolomite partially replaced by kenomagnetite. Coarse kenomagnetite is

found in association with carbonate beds, which indicates that a portion of

Fe-oxide minerals in the Wabush Iron Formation is derived from

replacement of carbonates rather than entirely from recrystallization of

original sedimentary Fe-oxides. Trace elements do not distinguish

kenomagnetite formed from carbonate replacement vs. recrystallization of

primary sedimentary Fe-oxide.

Total rare earth element concentrations of the BIFs are typically less

than 10 ppm, but increase in some samples to approximately 50 ppm.

Chondrite-normalized REE patterns are light REE enriched ([La/Sm]

typically 2 to 5), with small positive europium anamolies (Eu/Eu*

commonly 1.1 to 1.4) and small negative cerium anomalies (Ce/Ce*

commonly 0.7 to 0.9), indicating that Wabush iron formation was

deposited in a near shore environment with both terrestrial and deep ocean

REE signatures.

AQUEOUS GEOCHEMISTRY AND SUBSTRATE UTILIZATION

BY MICROORGANISMS AT AN ACTIVE SITE OF SERPENT-

INIZATION, TABLELANDS OPHIOLITE, NEWFOUNDLAND

Kavanagh, H., Rietze, A., Szponar, N., Morrill, P.L., Department of

Earth Sciences, Memorial University of Newfoundland, St. John’s, NL

A1C 5S7, and Brazelton, W.J., NASA Astrobiology Institute, Dept. of

Biology, East Carolina University, Greenville, NC 27858, USA

The Tablelands in Gros Morne National Park Newfoundland, is an

ophiolite thought to have been obducted during the closing of the Iapetus

Ocean, several hundred million years ago. The Tablelands host ultra-basic,

reducing springs containing dissolved H

and CH

, which suggest that

there is active serpentinization occurring in the subsurface.

Serpentinization provides an environment that can support abiogenic

and/or biogenic production of methane. Serpentinization is suspected to

have occurred on Mars and may be occurring in the subsurface today.

The geochemistry of the water has been analysed at various sites

within the Tablelands. Nutrient concentrations such as sulfate (0.12-1.01

ppm), phosphate (0-1.05 ppm) and nitrate (0.01-0.86 ppm) have been

determined, to see what nutrients are available for microorganisms and to

examine how life is surviving in this extreme environment. Concentrations

of dissolved organic carbon and dissolved inorganic carbon have also been

determined. These carbon pools will help determine possible substrate

sources for microbes at these sites.

C-labeled carbon substrate experiments were performed to

determine if methanogens are present and what carbon source(s) they may

be using.

C-labeled organic acids (acetate, propionate and formate) and

bicarbonate were added to water and sediment collected from the most

basic and reducing spring. The

C-labeled acetate experiment was the only

experiment to show a

C enrichment in CH

. This suggests that

methanogens may be active in the spring and may use an acetotrophic

metabolic pathway.

Examining possible life in Tablelands ultra-basic reducing springs

will help better understand carbon cycling in serpentinization environ-

ments at the surface, and possibly in the subsurface.

THREE-DIMENSIONAL GEOLOGICAL MAPPING IN

MANITOBA, AN OVERVIEW

Keller, G., greg.kelle[email protected], Matile, G., Manitoba Geological

Survey, 360-1395 Ellice Avenue, Winnipeg, MB R3G 3P2

Increasing demand for groundwater and hydrocarbons have been the two

main drivers for three-dimensional (3D) mapping in Manitoba. To assist in

meeting these demands and to broaden knowledge of the subsurface, the

Manitoba Geological Survey (MGS) is developing a 3D geological model

of the Phanerozoic succession in southern Manitoba, south of latitude

55°N. The MGS spent a great deal of time designing a workable

infrastructure for data collection, integration and output as it relates to 3D

modelling. A cross-section methodology was used to create the National

Geoscience Mapping Program (NATMAP) southeast Manitoba model, as

well as the Lake Winnipeg model. The Targeted Geoscience Initiative

(TGI) Williston Basin model on the other hand, was modelled directly

from high-quality drillhole data. A modified version of the cross-section

methodology was used to model all of Manitoba’s Phanerozoic terrane

south of 55°N.

Several datasets directly and indirectly related to the geological

interpretation are used during the modelling process. Geological maps and

reports from various geologists including published and unpublished

subsurface and surficial information are considered. Data representing

various aspects of paleogeography for the area are also included. This

allows a greater understanding of both glacial retreat and glacial Lake

Agassiz which factor strongly in the interpretation. Overall, the goal is to

integrate every piece of available information from every available source

into the cross-sections.

In order to interpret the southern portion of Manitoba, south of 55°N,

data from all previous geological models in the province were combined.

This methodology was selected in order to resolve two issues: 1) subtle

nomenclature differences from area to area, and 2) modelling issues

resulting from rock formation edges along escarpments plotting in 3D at

elevations other than the projected trend. To accomplish this, geological

transects representing a 5 km wide east-west swath containing all available

geological data, along with hand-drawn rock and Quaternary (sediment)

units from previously completed regions, have been combined into 134

province-wide georeferenced vertical maps. Hand-drawn transects from

Phase 1 (southeast Manitoba NATMAP), Phase 2 (Lake Winnipeg), and

Phase 3 (southwest Manitoba) were scanned, georeferenced and combined

in ArcGIS with computer-generated transects containing predicted

stratigraphy points from the TGI Williston Basin project. All 134

province-wide transects, depicting up to 41 rock formations and 35

Quaternary units, have been digitized and imported into the 3D modelling

software.

CATHODOLUMINESCENT IMAGES AND CHEMICAL COM-

POSITION OF QUARTZ FROM AURIFEROUS VEINS IN THE

MUSSELWHITE MINE, NORTHERN ONTARIO

Kelly, C.J., [email protected], Hattori, K.H., Department of

Earth Sciences, University of Ottawa, 140 Louis Pasteur, Ottawa,

ON K1N 6N5, and Biczok, J.B., Musselwhite Mine, Goldcorp,

Thunder Bay, ON P7B 6S8

Cathodoluminescent SEM (CL-SEM) images of quartz have been used to

show the evolution of mineralized hydrothermal systems. The technique

was particularly effective in displaying the timing of metal introduction in

porphyry copper deposits, but it has not been applied to orogenic gold

deposit. This study is the first documentation of CL-SEM images of quartz

from the banded iron formation-hosted gold deposit at Musselwhite mine

in the North Caribou terrane of the western Superior province of Canada.

Gold in the deposit is accompanied by sulphides (pyrrhotite and

chalcopyrite), grunerite and garnet.

Two samples are used for this study. One represents a high-grade

quartz vein associated with abundant sulphides, which is hosted by

alternating bands of garnet-bearing green amphibole and grunerite. The

second sample is a lean ore in alternating bands of garnet-bearing green

amphibole and grunerite. Sulphide content is low in the second sample.

Quartz in the high grade sample are less than 0.4 mm in size, have well

defined crystal faces and show minor undulose extinction and no evidence

of grain-boundary migration. Quartz in the lean ore sample is generally

small ranging from 0.15 to 0.5mm in size, showing evidence of grain

boundary migration and weakly developed undulose extinction.

The observed samples are essentially free of inclusions of other

minerals and fluid inclusions. Transmitted and reflected-light microscopy

show transparent, well-crystalline quartz in both samples. Back-scattered

electron images show homogeneous compositions of quartz, yet Cl-SEM

images show several fragments within individual grains. Variation in the

CL response of quartz is most likely caused by defects within quartz

structure and minor elements of Ti, Al and Na. The fragmentation is

apparent in the high-grade samples. This evidence suggests that the

auriferous hydrothermal activity at the Musselwhite mine is accompanied

by complex deformation causing fragmentation and recrystallization of

quartz.

STRATA AND STRUCTURE OF DISMEMBERED HUMBER ARM

ALLOCHTHON BETWEEN BONNE BAY AND BAY OF ISLANDS:

IMPLICATIONS FOR REGIONAL PETROLEUM EXPLORATION

Kelly, M.L. and Burden, E.T., Department of Earth Sciences,

Memorial University of Newfoundland, St. John's, NL A1B 3X5,

mikelly.18@gmail.com

Regional mapping of the allochthonous sedimentary and igneous rocks of

the Humber Arm Allochthon show these strata as key fragments in the

assembly Taconic Orogen in western Newfoundland. So too, these beds

also hold some of the critical elements for a petroleum system, and namely

source and seal. However, by their very nature, regional maps are unable

to clearly identify features that may be important for resource exploration.

To help address this matter a detailed 1:50000 map of sedimentary strata

and structure from Bay of Islands to Bonne Bay is being completed.

Much of the area is traditionally divided into three tectonic slices of

sedimentary and igneous rocks separated by broad zones of mélange. In

our work, rocks of the Blow Me Down Brook formation form the most

expansive sedimentary unit in the map area and contain many of the same

strata identified south of the Bay of Islands. Surprisingly large areas are

nearly flat-lying; elsewhere, the formation contains large antiforms that

may be analogues for subsurface hydrocarbon reservoirs or seals.

Many of the muddier and calcareous sedimentary rocks, historically

interpreted as mélange are becoming reclassified as tightly folded beds and

broken formation belonging to Irishtown, Cooks Brook and Middle Arm

point formations. Oil stains on fractures in some of these muddy beds

indicate some live oil remains underground.

In our assessment, mélange south of Trout River Pond is determined

to be a much narrower zone lying on or about a major thrust. At North

Arm, a relatively narrow belt of mélange is reassigned to the Middle Arm

Point and Eagle Island Formations. The sedimentary characteristics of

much of the mélange in the map area suggest that it was formed from the

fragmentation and mixing of predominantly the Middle Arm Point and

Eagle Island formations with other igneous rock lithologies from higher

slices in the allochthon.

By carefully assessing rock loosely identified as mélange larger

structures are being identified. These should become useful analogues for

ongoing seismic assessments being conducted offshore in the Gulf of St

Lawrence.

THE ROLE OF CRUSTAL CONTAMINATION IN THE ORIGIN

OF RARE OCCURRENCES OF PRECIOUS METAL MINERAL-

IZATION IN THE VOISEY’S BAY Ni-Cu-Co DEPOSIT,

LABRADOR

Kelvin, M.A. and Sylvester, P.J., Memorial University of

Newfoundland, St. John's, NL A1C 5S7

Rare occurrences of precious metal (PM), including platinum-group

element (PGE), minerals offer a unique perspective on the development of

the Voisey’s Bay Ni-Cu-Co magmatic sulfide body. This deposit has low

abundances of precious metals compared to other magmatic sulfide

deposits. However, rare occurrences of elevated concentrations (>0.5 ppm,

Pt+Pd+Au) have been identified and show some variability amongst their

distribution within areas of the deposit and in their relationship to Ni and

Cu concentrations (Naldrett et al. 2000; Lightfoot et al. 2011). This cannot

be explained by a traditional model for the partitioning of PGE and PM

into the fractionating sulfide magma alone. Partially digested xenocrysts

and isotopic compositions of the troctolitic and gabbroic host rocks

suggested that early contamination of the Voisey’s Bay parental magma by

crustal country rocks (Tasiuyak paragneiss and Nain gneisses) triggered

sulfide saturation to form the massive ore bodies (Li and Naldrett, 2000,

Amelin et al. 2000, Lambert et al. 1999). This contamination may also be

an important contributor to the PGE and PM mineralization process.

This project presents new PGE/PM mineralogy and geochemistry

from six samples from the Discovery Hill, Ovoid and Southeast Extension

zones of the Voisey’s Bay deposit and compares this data to previously

reported data of the Ovoid and a hornblende-gabbro dyke intersecting the

Southeast Extension zones with the objective of determining a genetic

model for precious metal mineralization. The PGE and PM mineral phases

show differences and similarities in each zone with respect to abundance,

grain-size and their relationships to associated minerals. These minerals

include sperrylite (PtAs

), froodite (PdBi

), michenerite (PdBiTe),

volynskite (AgBiTe), stutzite (Ag

5-x

), electrum (Au-Ag alloy), a Re-Cu-

S(?) phase, an Ir-As phase and native-Ag. Other important trace mineral

phases identified are altaite (PbTe), native-Bi, breithauptite (NiSb),

tsumoite (BiTe) and Pb-Te melt inclusions. Most often, the PGE and PM

minerals are associated with pentlandite, galena and chalcopyrite. Our

results are consistent with crystallization of precious metal minerals from a

highly differentiated Cu-rich sulfide magma coexisting with an immiscible

melt containing As, Bi, Te, Sb, Sn and Pb, which were inherited from a

crustal source. Enrichments of As, Bi, Te, Sb, Sn and Pb in localized areas

of the magmatic system provided complexing agents to form the PGE/PM

minerals, which may be responsible for the differences observed in the

precious metal mineralogy between the Discovery Hill, Ovoid and

Southeast Extension zones.

TUFFS AND TURBIDITES: A DEEPER INSIGHT INTO THE

DEPOSITIONAL ENVIRONMENT OF CHARNWOOD FOREST,

Kenchington, C.G., Department of Earth Sciences, University of

Cambridge, Downing Street, Cambridge, CB2 3EQ, UK, cgk27@

cam.ac.uk, Wilby, P.R., British Geological Survey, Kingsley

Dunham Centre, Keyworth, Nottingham, NG12 5GG, UK, and

Rhodes, S., Aggregate Industries, Bardon Hill Quarry, Coalville,

Leicestershire, LE67 1TL, UK

The Avalon Assemblage represents the oldest known occurrence of

Ediacaran macrofossils. Associated with sedimentary rocks indicative of

deep-marine environments, these fossils have long proved enigmatic.

Although fossils of the assemblage were first found in Charnwood Forest

(UK), this region has long been considered the poor cousin of the

extensive and better-known exposures in Newfoundland. Recent cleaning,

silicone rubber moulding and casting of a total of c.150m

of the currently-

known fossiliferous surfaces in Charnwood Forest have, however, revealed

this region to be surprisingly rich, in terms of both abundance and

diversity. Several new bedding planes at two localities have thus far been

discovered. With the re-examination of beds already known, over a

thousand new specimens have been recognised. We have identified at least

nineteen taxa, including seven that have never been reported and a further

nine that have not been reported from Charnwood Forest. The outcrop

exposures are supplemented by >530m of drillcore, including 10m of core

intersecting the principal fossiliferous horizons at a key locality.

Approximately 300m of this core is from a series of seven closely-spaced

short holes drilled over c.0.5km

The Avalon region at this time formed part of a peri-Gondwanan

volcanic arc, yielding a thick volcaniclastic, largely turbiditic succession.

The Charnwood succession is dominated by turbiditic facies but includes a

number of tuffs, some of which are welded; however, the crystal-rich tuffs

below which the Newfoundland fossils are preserved have not been

observed in Charnwood Forest. Bedding plane features such as low-relief

pustules and irregular wrinkles have been taken to suggest the presence of

microbial mats, which are frequently implicated in the preservation of

Ediacaran macrofossils; however, preliminary examination of the drillcore

has yet to provide confirmatory evidence. As such, they may not be as

prevalent in Charnwood Forest as previously believed. Detailed

sedimentological analysis of all available material currently underway will

doubtless reveal further important sedimentary structures not observable in

the field. These will provide additional insight into aspects of the

depositional environment (substrate consistency, frequency of inundation,

etc.) which would have influenced both the ecology and preservation of

the organisms. Greater understanding of the subtle differences in the

taphonomy of the Newfoundland and Charnwood Forest biotas, together

with the detailed view we are gaining of the depositional environment will

provide a clearer picture of where and how these organisms lived, as well

as the conditions required for their preservation and the biases that these

induce.

PLATE TECTONIC IMPLICATIONS OF THE GEOMETRY AND

KINEMATICS OF THE BAY OF FUNDY TRIPLE JUNCTION

Keppie, F., Dept. of Natural Resources, NS B3J 2T9, keppiedf@

gov.ns.ca

Rifting across the Bay of Fundy and emplacement of the Central Atlantic

Magmatic Province (CAMP) at ca. 200 Ma represents an early stage in the

Mesozoic breakup of Pangea. Determining the pre-rift geometry of Pangea

and the volume of space occupied by rift magmatism requires

reconstructing the geometry and kinematics of terrane breakup. Critically,

between Nova Scotia and New Brunswick, the Bay of Fundy opened as a

rift-rift-rift triple junction involving the main arm of the Bay of Fundy to

the west, and the Chignecto Bay and Minas Basin arms to the east. Given

that the Chignecto Bay and Minas Basin arms appear to taper and

terminate at their eastern ends, application of the principles of plate

tectonics suggests that the Meguma Terrane rotated in a counter-clockwise

fashion relative to North America as it rifted away. This constraint appears

to contradict the common hypothesis that the Meguma Terrane rotated in a

clockwise fashion relative to North America along the Minas Fault System

and Collector Anomaly and this needs to be addressed in plate tectonic

models.

STRUCTURAL INTERPRETATION OF TECTONIC CON-

STRAINTS IN THE KENNETCOOK BASIN: INSIGHTS FROM

NEW MAPPING

Keppie, F., Dept. of Natural Resources, NS B3J 2T9, keppiedf@

gov.ns.ca

Tectonic constraints, inferred from new bedrock mapping in the eastern

part of the Kennetcook Basin, Meguma Terrane, Nova Scotia, have

implications for the formation and evolution of hydrocarbon and mineral

systems in the Devono-Carboniferous strata of Nova Scotia. Broadly,

doubly-plunging upright fold systems, about hinge traces trending ENE

across the Kennetcook Basin, appears to explain much of the geometry and

distribution of both the basement (Goldenville, Halifax, and Rockville

Notch Groups) and basin (Horton, Windsor, Mabou, and Cumberland

Groups) strata. Basement fold systems appear to be out-of-phase with

basin folding, however; synclinoriums in basement strata are draped by

anticlinoriums in the basin strata, and vice versa, to a first approximation.

This geometry is consistent with the following tectonic history: (1)

Neoacadian shortening of the Meguma Terrane, prior to formation of the

Kennetcook Basin in the late Devonian (ca. 406-388 Ma); (2) formation of

a regional erosion surface and the Kennetcook Basin's initial topography,

in the late Devonian/early Carboniferous (ca. 370-350? Ma); (3) deposition

of Kennetcook Basin strata, between ca. 360-280 Ma; and, (4) Alleghenian

upright folding of both basement and basin strata in the late

Carboniferous/early Permian (ca. 325-275 Ma). Where applicable,

evolutionary models for basin formation and growth can be improved by

recognizing the early stage role of topographic inversion.

AN INVESTIGATION OF PREDICTIVE METHODS FOR ESTI-

MATING RARE-EARTH ELEMENT (REE) RESOURCES IN THE

STRANGE LAKE MAIN ZONE DEPOSIT, LABRADOR-QUÉBEC

Kerr, A. and Rafuse, H., Geological Survey of Newfoundland and

Labrador, Department of Natural Resources, PO Box 8700, St.

John's, NL A1B 4J6, [email protected].ca

The current interest in exploration for Rare-Earth Elements (REE) has led

to the reassessment of many deposits that were previously explored for Y,

Nb, Zr and Be. The Main Zone deposit at Strange Lake was defined for

these commodities in the 1980s, but was not assessed in detail for REE. It

is currently an exempt mineral land, for which mineral rights rest with the

province of Newfoundland and Labrador. Subsequent exploration in

nearby Québec has outlined a discrete deposit (the B-Zone) that contains a

potentially important REE resource. Reassessment of the original Main

Zone deposit by the Department of Natural Resources focused initially on

the reanalysis of archived reject samples from 1980s drilling programs,

with a view to evaluating methods for prediction of REE contents and

resources from existing data, notably for Y and Be.

Historical Y data and new Y analyses correlate well (although the

latter are generally some 20% lower), but the two datasets for Be compare

better. The REE show strong correlations with Y, and moderate cor-

relations with Be, but are poorly correlated with Zr and Nb. In the case of

the heavy REE (Gd to Lu), the correlations with Y are very strong and

nearly linear, but the light REE (La to Eu) show much weaker correlations

with Y. There are strong correlations amongst individual REE within both

the heavy and light REE groups, but correlations between the light and

heavy REE are less marked. Simple linear regression methods were used

to derive equations for prediction of REE abundances from historical Y

data, and two such methods were tested, using results from a second batch

of reanalyzed samples. The method seems to work in practice, and could

be of value in resource estimation, even if it cannot always reproduce

observed REE profiles at a sample level. The new REE analyses are also

of geological interest, and suggest that there are subtle differences between

the REE profiles of low-grade mineralized granites, and those of high-

grade pegmatite and aplite zones. A preliminary comparison between data

from the Main Zone and the B-Zone suggests that the B-Zone contains a

higher proportion of light REE, and a lower proportion of heavy REE.

BEYOND STRANGE: AN OVERVIEW OF GEOLOGICALLY

DIVERSE RARE-EARTH ELEMENT (REE) DEPOSITS IN THE

PRECAMBRIAN OF LABRADOR

Kerr, A., Geological Survey of Newfoundland and Labrador,

Department of Natural Resources, PO Box 8700, St. John's, NL A1B

4J6, [email protected]

The Labrador Peninsula is best known for Strange Lake, where possible

world-class deposits of REE, Zr and Nb are located on a remote segment

of the Labrador-Québec border, but it also contains other diverse styles of

REE mineralization.

North of the Grenville Front, the ~ 1290 Ma Flowers River Igneous

Suite hosts disseminated magmatic-hydrothermal REE mineralization in

permeable ash-flow tuff units within a central caldera sequence. Enriched

zones contain moderate heavy REE proportions (LREE:Y:HREE =

67:21:12), and range from stratiform to dyke-like, but their character and

mineralogy remain poorly known. New discoveries of disseminated to

podiform oxide-rich REE mineralization have awakened interest in the

large and poorly-mapped Mistastin Batholith. These locally have very high

grades, and are strongly enriched in the light REE (LREE:Y:HREE =

96:2:2). The host rocks are thought to be small late-stage evolved plutons,

and the oxide-rich mineralization is likely orthomagmatic, related to

cumulate processes and/or development of Fe-oxide-rich residual magmas.

The Grenville Province contains the most diverse mineralization.

Undersaturated alkaline metaplutonic rocks of the ~ 1330 Ma Red Wine

Intrusive Suite host REE-Zr mineralization as concordant bands and layers

enriched in eudialyte, and also in pyroxenites containing eudialyte and

mosandrite. The original relationships are obscured by strong ductile

deformation, but mineralization is suspected to have originally been

orthomagmatic. Eudialyte-rich zones are enriched in the heavy REE

(LREE:Y:HREE = 53:28:19) and also lack radioactivity. A completely

different style of REE mineralization occurs in Grenvillian-age mylonitic

zones in central Labrador, and also in southeastern Labrador. The former is

strongly enriched in light REE (LREE:Y:HREE = 95:3:2), whereas the

latter contains significant heavy REE (LREE:Y:HREE = 74:16:10), but

there are many similarities between them. Outside the strongly mylonitic

zones in both areas, there exist discordant vein-like or pegmatite networks

that have variable REE enrichment and LREE:Y:HREE balance, and these

may represent precursor mineralization. It is suggested that these REE-rich

rock types were physically concentrated through intense deformation and

transposition in shear zones, and perhaps geochemically homogenized by

related fluid flow. However, other models can certainly be entertained! A

third style of light-REE-enriched mineralization in the Grenville Province

consists of concordant oxide-rich zones in granitoid orthogneisses. This

mineralization is tentatively suggested to be the deformed and

metamorphosed equivalent of orthomagmatic zones now recognized in the

Mistastin Batholith. In summary, much of the REE mineralization in the

Grenville province is likely pretectonic and related to older

(Mesoproterozoic?) magmatic events.

DIFFERENT APPROACH FOR CLASSIFICATION OF AWIFS

SATELLITE DATA AND THEIR COMPARISION WITH UN-

SUPERVISED CLASSIFICATION

Khosla, D., Rayat Institute of Engineering and Information

Technology, S.B.S. Nagar, Punjab, India, [email protected],

Khosla, A., Punjab Technical University, Kapurthala, Punjab, India,

[email protected], and Mishra, V.D., Snow and Avalanche Study

Establishment, Defence Research and Development Organization,

Chandigarh, India

The variations in the local climate, environment and altitude as well as fast

snow cover building up and rapid changes in snow characteristics on

Himalayan region. This change can be monitor one bases of Image

classification. We have proposed a novel technique for classification of

AWiFS satellite image using signature file which is made on basis of

threshold value. This threshold value is calculated by different algorithm

(NSDI, S3, NDCI) for categorizing images into different classes. We have

made 5 classes dry snow, moist snow, wet snow, rocks and vegetation. But

some problem is with shadow (topographic effects). So we have applied

topographic technique for removing shadows from images. The

experiment results show classification accuracy of 7th Jan 2010 is 95% as

compare to unsupervised classification is 89%.

PROVENANCE AND PALEOGEOGRAPHY OF THE CARBONI-

FEROUS SUCCESSION, NORTHEASTERN SIBERIA

Khudoley, A.K., akhudoley@gmail.com, Ershova, V.B., Saint-

Petersburg State University, University emb. 7/9, Saint-Petersburg,

199034, Russia, and Prokopiev, A.V., Diamond and Precious Metal

Geology Institute, Siberian Branch, Russian Academy of Sciences,

Lenin Avenue 39, Yakutsk, 677980, Russia

The study area is located in the Arctic portion of the Siberian Craton on its

northeastern margin, where the Early Carboniferous was marked by an

extensive marine transgression. Carbonate sedimentation was widely

distributed in Tournaisian but, starting from Visean, clastic sedimentation

predominated.

In clastic Carboniferous succession we studied 4 samples for U-Pb

detrital zircon ages distribution, 8 samples for Sm-Nd isotopic system, and

22 samples for chemical composition. Detrital zircons from all samples

have similar age populations, although there are some variations. Zircons

of Paleoproterozic-Archean, Neoproterozoic and Devonian-Early

Carboniferous ages are most widespread, whilst Cambrian and Ordovician

ages constitute an insignificant portion. The analyzed samples are

dominated by Proterozoic-Archean zircons. These zircon populations

could have been derived from weathering of nearby basement rocks of the

Siberian Craton and/or reworking of Meso-Neoproterozoic clastics, widely

distributed in the northern Siberian Craton. The abundance of

Neoproterozoic zircons in the studied samples suggests additional

provenance areas, as the basement of the Siberian Craton does not contain

correlative magmatic rocks. For similar reason the Siberian Craton

provenance must be rejected as a possible source area for Paleozoic

zircons. The only known potential provenance areas with magmatic rocks

comparable in age with the Palaeozoic zircon populations are the Altay-

Sayan and/or Taimyr orogenic belts. Chemical studies of the clastic rocks

point to erosion of both felsic and mafic rocks, whereas variation of ε

Nd(t)

value from -9.2 to -0.2 show variable amount of juvenile rocks that

basically is in agreement with the Taimyr and/or Altay-Sayan orogenic

belts provenance and transportation of clastic material by continental-scale

river systems from southwestern (Altay-Sayan) and northern (Taimyr)

Siberian provenance.

NEW, PRECISE, PALEOPROTEROZOIC AGES AND PALEO-

MAGNETISM FROM THE WYOMING CRATON

Kilian, T.M.

, [email protected], Bleeker, W.

, Chamberlain,

K.R.

, Evans, D.A.D.

Yale University, 210 Whitney Ave., New

Haven, CT 06854 USA;

Geological Survey of Canada, 601 Booth

Street, Ottawa, ON K1A 0E8;

University of Wyoming, 1000 E.

University Ave, Dept. 3006, Laramie, WY 82071 USA

We present six new precise U-Pb baddeleyite ages for two different

Paleoproterozoic dyke swarms in the Wyoming craton. Four NNE- to NE-

trending dykes from the Bighorn Mountains are dated at ca. 2155-2160 Ma

(U-Pb), and even though they are represented by quite different trends

(010-015° vs. 048°) they are all likely part of a single LIP, which we name

the Powder River swarm, with an emplacement age range distinct from

two events in the Superior craton: Biscotasing at 2170 Ma and Riviere du

Gué at 2149 Ma (see Ernst and Bleeker, 2010, CJES). We also dated the

large, differentiated, Wind River dyke located more than 200 km to the

southwest, as 2157 ± 5 Ma (U-Pb); this intrusion was previously dated by

Harlan et al. (2003, Tectonophysics) as 2170 ± 8 Ma with high degree of

discordance. The Wind River dyke shares a distinctive chemical zonation

with that of the Powder River pass dyke in the southern Bighorns; and,

after about 30° clockwise restoration of the former region, the two dyke

segments can be projected along strike between the two uplifts, suggesting

they could be the same intrusion. Our paleomagnetic data from the Powder

River dyke swarm in the Bighorns, integrated with clockwise-corrected

data of Harlan et al. (2003), support a viable reconstruction at ca. 2160 Ma

of southeastern Wyoming directly adjacent to southern Superior. Our

paleomagnetic reconstruction closely resembles that proposed by Roscoe

and Card (1993, CJES), which aligned the Snowy Pass Supergroup of

Wyoming against the Huronian Supergroup of southern Superior.

Additionally, we dated a NW-trending mafic dyke in the same region

of the southern Bighorn Mountains to 1899 ± 5 Ma, which along with

parallel dykes in the same region define what we name the Sourdough

swarm. Paleomagnetic data from these dykes define a pole that is distinct

from that of the nearly coeval (ca. 1880 Ma) Molson dykes from Superior

craton, both in present North American coordinates and in the

Wyoming+Superior fit described above. These discrepancies suggest that

the Sourdough swarm was emplaced after Wyoming rifted away from

supercraton Superia, but before it arrived in its present location within the

Laurentian assembly of cratons. Ongoing studies of the Kennedy dyke

swarm and other magmatic events from 2200-1900 Ma will most likely

narrow down the time of rifting within the Superia and also spur novel

comparisons with other cratons that may have been part of that landmass.

#2 MINE TOUR HAS HELPED PRESERVE NEWFOUNDLAND’S

MINING HISTORY, AND HAS PUT BELL ISLAND ON THE MAP

AS A TOURIST DESTINATION

King, C., [email protected], Durdle, R. and McCarthy, T.,

Bell Island Heritage Society, PO Box 219, Bell Island, NL A0A 4H0

After 71 years of iron-ore mining, Bell Island was left with much more

than a hole in the ground when mining ceased in 1966. It was left a history

of toil, tragedy and people struggling to survive in difficult times. This

history must be preserved and told to the families of the miners and the

people of the world.

In 1994, 28 years after the mines closed, a committee was formed to

preserve and share this history before all the artefacts and stories were lost.

Artefacts were collected and hastily arranged in a made-over building so

that a museum could open in the summer of 1995 to coincide with the

100

anniversary of the start of mining at Bell Island. Within 2 years the

committee was incorporated as the Bell Island Heritage Society, a new

building was completed and the abandoned #2 iron-ore mine was opened

to tourists.

Before a backdrop of an actual underground mine, where tunnels

fade off into the darkness in all directions, enthusiastic guides easily

capture the attention and imagination of visitors, young and old. Visitors

are awed as they learn how ore was mined in the early 1900’s when men,

boys and horses worked together, with little help from machinery, to

extract the ore from under the ocean.

Since opening, the mine tour has welcomed well over 125,000

visitors from around the world. Because the mine is so accessible, we

proudly tell our story to elementary and high school students who are

learning about mining in Newfoundland and Labrador; to geology and

mining engineering students from universities; to people who are aware of

our contribution towards the war efforts in both world wars and to visitors

who are just seeking something different and exciting to experience.

The Museum and Mine Tour now hire a total of 9 workers during the

tourist season. The increase in the number of visitors has also increased the

volume of sales in local gift shops, local restaurants and Bed and Breakfast

establishments. It is clear that we have not yet reached our limit. With the

proposed improvements to our facility and exhibits, we can greatly

increase our numbers and extend our season.

SHELF-BASED EARLY AND MID PLEISTOCENE GLACIAL

RECORDS ON THE GRAND BANKS OF NEWFOUNDLAND

King, E.L., Geological Survey of Canada, 1 Challenger Dr.,

Dartmouth, NS, B2Y 4A2, [email protected], and Pitts, M.,

formerly Acadia University, Wolfville, NS

Till sheets or their remnants and sub-glacial fluvial channels provide direct

evidence that Pleistocene glaciers covered the Grand Banks, but limited

accommodation space resulted in removal by subsequent sea-level low-

stands and glacial erosion such that timing, extent and ice regimes have yet

to be clarified. However, several shelf basins have afforded preserved

remnants of glacial deposits predating the last glacial maximum (LGM). A

late Tertiary age canyon at the mouth of Laurentian Channel allowed a

glacial depocenter nearly 800 m thick and directed ice sheets to a proto

Laurentian Channel. Over 14 stacked tills are preserved, together with

thick glacimarine stratified muds beveled between glacial sheet erosion

surfaces, making it the most complete shelf record along the Atlantic

Provinces margin. Stratigraphic position of the lowermost till with respect

to tentatively dated mid Pleistocene till tongues on the adjacent St Pierre

Bank slope suggests that it has an early Pleistocene age. The Channel

evolved to a straighter, narrower, more flat-bottomed form, supporting

multiple mid-Pleistocene ice streams. This Laurentian Channel sequence

must represent full glaciation cycles, stadials and possibly auto-cyclic ice

stream regime behavior.

Elsewhere on Grand Banks, overdeepened basins down-ice of

basement rocks have preserved mid Pleistocene till remnants off Bonavista

Bay and Halibut Channel. The overdeepening apparently results from

enhanced erosion on steeper slopes and harder basal ice tools. Stacked till

remnants and glacimarine muds are represented, cut by the latest (LGM)

glacial erosion. The mid-shelf bank-top glacial record is limited to LGM

and deglaciation tills and muds except for buried tunnel valleys which can

survive multiple glaciations. A multi-generational tunnel valley fill

includes possible till, colluvium and waterlain facies. Nowhere do the up

to 400 m deep tunnel valleys communicate with slope situated canyons or

their paleo-equivalents. They rarely extended beyond mid shelf, suggesting

that only the largest of glaciations reached the shelf-break on the outer

bank. However, this may have more to do with glacial meltwater regime

and ice cap profile than ice terminus position. Generally the easternmost

outer bank shelf-break has only one till preserved, probably from the

penultimate glaciation. A variation on this is a landward prograding body

with stacked channels at the shelf break adjacent Lilly Canyon, interpreted

as ice marginal. In Trinity Trough, Northeast Newfoundland shelf, a buried

tunnel valley complex attests to an early meltwater-dominated regime and

contrasts with the ice stream generated till blankets and slope-based

glacigenic debris flows of later glaciations.

Keynote HEAVY MINERAL CHEMISTRY AS A KEY TO UNDER-

STAND SANDSTONE PROVENANCE IN THE DAVIS STRAIT

AND THE LABRADOR SEA REGION

Knudsen, C., [email protected], Keulen, N.T., Thrane, K., Geological

Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, DK-

1350 Copenhagen K., and Burden, E., Memorial University, St.

John´s, NL

Heavy mineral chemistry in 105 samples was determined using CCSEM

analysis (Computer Controlled Scanning Electron Microscopy), which is a

fully automated particle analysis technique developed at GEUS for the

determination of chemical and physical properties of a large number of

mineral grains. CCSEM enables determination of the modal abundances of

individual mineral fractions (e.g. ilmenite, rutile, zircon, or garnet) as well

as their compositional variation together with grain-size and –shapes

parameters of c. 1200 grains per sample. 21 of the samples represent

sandstone from the Disko Nuussuaq Basin, 14 samples of sandstone from

wells in the Labrador Sea and 70 representing stream sediments in West

Greenland representing part of the potential sediment source area.

The composition and relative abundance of heavy minerals is a result

of the sand provenance as well as of different types of events such as

weathering, transportation and diagenesis. The garnet composition is a

result of both the composition of the rock in which the garnet was formed

originally and the metamorphic history. There is a systematic com-

positional variation in garnet composition in Western Greenland as a

function of these factors. Ilmenite is sensitive to chemical alteration and as

the content of iron decreases during alteration, the composition yield

information about the maturity of the sediment. Mafic silicates are not very

robust in the sedimentary cycle and where present the sediment is rather

immature and locally minerals like olivine is preserved indicating that the

route from source to sandstone was extremely short.

Plenary Address MICROBES AND THEIR IMPACT ON THE

EVOLUTION OF THE EARTH SURFACE SYSTEM

Konhauser, K., kurtk@ualberta.ca, University of Alberta, Edmonton,

AB T6G 2E3

From their origins, perhaps some 4 billion years ago, microorganisms have

had a profound influence on shaping our planet. From localised niches,

that occur on the order of micrometers, to ecosystems as immense as the

oceans, microbial populations are intimately involved in transforming

inorganic and organic compounds to meet their nutritional and metabolic

needs. Given sufficient time, the collective metabolic activities of

countless microniches can even modify the dynamics of the entire Earth,

controlling the composition of the oceans and atmosphere. One method for

tracking biological innovation through time is through the chemical

analyses of ancient marine chemical sediment, such as banded iron

formations (BIF). Because these rocks precipitated directly from seawater,

their trace element compositions can be used as proxies for paleo-marine

chemistry, and by extension, the nutrient availability for the ancient marine

biosphere. Two examples are provided here. First, it has been shown that

the nickel content in BIF has changed dramatically over time, and that a

drop in Ni availability in the oceans around 2.7 billion years ago would

have had profound consequences for microorganisms that depended on it,

that being methane-producing bacteria called methanogens. These bacteria

have a unique Ni requirement for their methane-producing enzymes, and

crucially, these bacteria have been implicated in controlling oxygen levels

on the ancient Earth as the methane they produced was reactive with

oxygen and kept atmospheric oxygen levels low. It is possible that a Ni

famine eventually led to a cascade of events that began with reduced

methane production, the expansion of cyanobacteria into shallow-water

settings previously occupied by methanogens, and ultimately increased

oxygenic photosynthesis that tipped the atmospheric balance in favour of

oxygen, the so-called Great Oxidation Event (GOE) at 2.5 Gyr. Second, a

recent compilation of Cr enrichment in IF shows a profound enrichment

coincident with the GOE. Given the insolubility of Cr minerals, its

mobilization and incorporation into IF indicates enhanced chemical

weathering at that time, most likely associated with the evolution of

aerobic continental pyrite oxidation.

PRINCIPAL TERRANE BOUNDARY IN THE KAOKO BELT OF

NW NAMIBIA REVEALED BY DETRITAL ZIRCON DATING

Konopásek, J. and Košler, J., University of Bergen, Allegaten 41,

5007 Bergen, Norway, jiri.[email protected]

The Kaoko Belt (NW Namibia) is built of two terranes with contrasting

pre-collisional tectonic setting and different tectono-thermal evolution

during the Neoproterozoic Damara orogeny. Central and eastern part of the

belt is built by Archaean–Mesoproterozoic basement with its Neopro-

terozoic (meta-)volcanosedimentary cover. The western part of the belt –

the Coastal Terrane – has no pre-Neoproterozoic basement exposed. It

consists of volcanosedimentary rocks intruded by plutons related to the

activity of a Neoproterozoic magmatic arc to the west of the Kaoko Belt.

We have dated detrital zircons in several metaquartzite samples located in

the hangingwall and footwall of the c. 580-550 Ma igneous complex that

has been previously interpreted as intruding the terrane boundary during

the peak of Damara orogeny. The main goal of this study was to determine

potential differences in detrital zircon records that would allow to

recognize contrasting sedimentary sources, maximum sedimentation ages,

and to clarify the position of the boundary between the two terranes.

Samples collected east of the presumed terrane boundary show solely

Archaean–Mesoproterozoic ages and the observed age populations mostly

match the protolith ages of c. 2.6, 2.0, 1.76, 1.67 and 1.5 Ga recognized in

the basement of the Kaoko Belt. Age populations of c. 1.2 and 1.0 were

also detected east of the presumed terrane boundary. Metaquartzites

collected west of the terrane boundary show similar age groups of c. 2.5,

2.0, 1.7 and 1.5 Ga. In addition, all samples of this group contain

significant amounts of c. 1.0 Ga old zircons and some zircons with ages of

c. 1.3, 1.2 and 1.1 Ga. All samples collected west of the presumed terrane

boundary contain Neoproterozoic detrital zircons showing ages of c. 800,

750, 700 or 650 Ma so far only reported from igneous rocks of the Coastal

Terrane. Presence of similar zircon age populations in the studied rocks

suggests possible recycling of the same pre-Neoproterozoic basement.

However, samples collected west of the presumed boundary contain

zircons coming probably from the evolving Neoproterozoic magmatic arc.

Our study confirms that the boundary between the two principal tectonic

blocks of the Kaoko Belt is sealed by the Neoproterozoic igneous

complex. A large-scale shear zone that was previously proposed as an

eastern limit of the Coastal Terrane is regarded as a late structure that has

developed inside this unit during the late stages of the Kaoko Belt

evolution.

The authors acknowledge support of the Czech Science Foundation

(project P210/11/1904).

WHAT ABOUT THE FLUIDS? RE-EXAMINATION OF THE

PETROLOGY OF PROTEROZOIC A-TYPE GRANITES FROM

THE NORTH KHETRI COPPER BELT, RAJASTHAN, INDIA

Kontak, D.J., Department of Earth Sciences, Laurentian University,

Sudbury, ON P3E 2C6, dkontak@laurentian.ca, and Kaur, G.,

Department of Geology, Panjab University, Chandigarh-160014,

India

This work addresses the nature and origin of a group of Proterozoic (1660-

1690 Ma) granites intruding intercalated metasedimentary (siliciclastics

and carbonates) and metavolcanic rocks of the Proterozoic Delhi

Supergroup in the northeast end of the Aravalli Mountains of Rajasthan

Province, India. These granites have attracted attention because of their

spatial association with the Khetri Cu deposits of suggested IOCG affinity.

The granites (Gorwala, Gothara, Biharipur, Dabla) are 2-5 km

size, fine-

to medium-grained with <3-5% mafics (amphibole, biotite), and

characterized by zones of miarolitic cavities and pegmatites. An A-type

affinity and correlation with plagiogranties has previously been proposed

based on elevated Na

O (to 11 wt. %) and depleted K

O, Rb, Sr and Ba

contents. In addition, evidence for commingling of mafic and felsic

magma has been suggested (e.g., Biharipur granite). Recent field work and

supporting mineralogical studies indicate that some of the earlier

conclusions are suspect, as follows: (1) exo- and endoskarns are well

developed in the wall rock and marginal phases of the granites, the latter

equating to the field evidence for commingling, which is therefore

discounted. However, lamprophyre dykes do cut several granite bodies

which may be interpreted to suggest contemporaneous mafic and felsic

magmatism; (2) albitite rocks peripheral to the main Biharipur intrusion

are reinterpreted as massive, fine-grained marble with minor (<0.5%)

diopside and garnet; and (3) the granites record pervasive alteration and

development of albitite from initial amphibole (Fe/(Fe+Mg) = 0.5) and

biotite (Fe/(Fe+Mg) = 0.75) - bearing leucogranites (<3-5% mafics) due to

interaction with orthomagmatic fluids. Furthermore, detailed petrography

and supporting SEM-EDS analysis of two of the granites (Gorwala,

Gothara) indicate metasomatic transformation was accompanied by the

development of pit-textured albite (An

) and alkali feldspar (Or

formation of secondary amphibole, biotite and titanite, and development of

dissolution cavities lined with allanite, epidote, apatite, fluorite, calcite,

hematite, zircon, bastnaesite, thorite and uraninite. The presence of both

high-density, highly saline (L-V-Halite-Multi-solids) and low-density fluid

inclusions in most of these neomorphic phases indicates metasomatism

was mediated by a saline fluid, likely generated from a magmatic fluid

which unmixed in the high level setting. The above observations indicate

that much of the mineralogy and, hence, chemistry of these granites is not

primary, which must be considered when classifying such rocks, especially

as albitites and drawing analogies with plagiogranites.

MEGUMA GOLD DEPOSITS, NOVA SCOTIA: OVERVIEW OF

PAST AND CURRENT RESEARCH WITH IMPLICATIONS FOR

CURRENT MODELS

Kontak, D.J., Department of Earth Sciences, Laurentian University,

Sudbury, ON P3E 2C6, dkontak@laurentian.ca, Horne, R.J., Acadian

Mining Corp, Halifax, NS, Cao, Y., State Key Laboratory of

Geological Processes and Mineral Resources, China University of

Geosciences, Beijing 100083, China, and Ulrich, T., Department of

Earth Sciences, Aarhus University, Hoegh-Guldbergs Gade 28000

Aarhus, Denmark

Meguma gold deposits conform to slate belt hosted quartz vein deposits

formed during orogene contraction with vein formation and mineralization

related to fluid focusing into regional antiforms. Veins are quartz dominant

with sulphide (Aspy-Po-Py) – carbonate and accessory Zn-Pb-Cu-Sb

sulphides, and gold occurs in all vein types and fine-grained wall rock

lithologies. Decades of study have established the following: (1) vein

formation occurred in the later stages of flexural-slip folding during

tightening of fold limbs; (2) relative timing of veins post-dates regional

cleavage formation and in some cases is related to syn- to post intrusion of

380 Ma granites, which is consistent with absolute dating of vein-hosted

silicates and sulphide phases at 408 and 380 Ma (Re-Os, Ar-Ar); (3) vein

fluids are dominated by a H

O-CO

± CH

type fluid (X

CO2

= 0.15) with 5

to 10 wt. % equiv. NaCl; and (4) stable isotopic data (O, S, C, D) indicate,

in general, a metamorphic signature, but other isotopic (Pb, Sr, Os) and

geochemical (REE) data suggest multiple fluid sources involving crustal

and sub-crustal reservoirs. More recent research complements the above,

further supporting a model of multiple fluid reservoirs, based on the

following: (1) a regional variation of δ

H2O

(calculated for 400°C) from

11.5 to 9.5‰, the latter coinciding with proximity to granites; (2) fluid

inclusion evaporite mound analysis (N=850, 15 deposits) indicates distinct

fluid types (Na, Ca-Ca, K-Na) with variable enrichment in F, Cu, Sn, Hg,

Mo, and U; (3) LA ICP-MS analysis of fluid inclusions indicates inter-

deposit variation (values in ppm) for Li (<250), B, (<3000), As, (<1000),

W (150), Sb (250) and Sn (200); (4) carbon "leads" in ribbon-textured

quartz veins reveal high levels (wt. %) of As, S, Cu, Pb and Zn; and (5)

XRF analysis (7,000 samples, > 20 elements) of pulps from exploration

drilling confirms widespread enrichment of As, Ca, and S, but very little

for Cu, Zn, Pb, Sb, Bi, and none for K, Rb or Ba, which is consistent with

very low concentrations of these elements in fluid inclusions. These data

support two stages for quartz veins and associated gold formation at 408

and 380 Ma that involved generation of H

O-CO

fluids that interacted

with variable host rock lithologies at different scales and also other fluids,

one of which had a magmatic parentage. Current models for similar

metallogenic settings (e.g., Australia) which suggest derivation of metals

from a proto-ore source in the host rocks would not be inconsistent with

our findings.

Keynote CANADA GOT THE MOUNTAINS, SCOTLAND GOT

THE DEBRIS: EARLY NEOPROTEROZOIC TORRIDONIAN AND

MOINE SUCCESSIONS RECORD PROXIMAL GRENVILLE

FORELAND BASIN SEDIMENTATION IN NORTHERN

SCOTLAND

Krabbendam, M., British Geological Survey, West Mains Road,

Edinburgh EH9 3LA, Scotland, UK, [email protected]

The Grenville Orogen was pivotal in the construction of the Rodinia

Supercontinent and represents one of the largest orogenic systems on

Earth. Detrital zircon geochronology has shown that the erosional debris

from the orogen was widely dispersed into 1200 – 950 Ma sedimentary

successions located across Laurentia and Baltica, some close to the

Grenville Orogen, others 1000’s of miles distant.

A well-exposed, 8-15 km thick, proximal succession is represented

by the siliclastic Torridonian and (metamorphosed) Moine sequences of

Northern Scotland. These successions are here interpreted to record three

pulses of foreland-basin (sensu-stricto) deposition, linked with orogenic

phases identified within the Genville Orogen. Foreland-basin deposition

was preceded by rifting recorded in the c. 1180 Ma Stoer group.

The earliest foreland-basin deposition (Pulse 1) may be represented

by the shallow marine-fluvial Sleat group (c. 3.5 km thick), containing rare

Elzevirian (c. 1250-1200 Ma) zircons, but no Ottawan phase (1080-1020

Ma) zircons. The Sleat group may record uplift at the start of the Ottawan

phase.

The main pulse of foreland-basin deposition (Pulse 2) is represented

by the Torridon and metamorphosed Morar (lower Moine) groups. The

Torridon Group comprises a c. 7 km thick, fining-upward sequence of

high-energy fluvial to ?lacustrine deposits (Pulse 2a). In the Morar Group

this is a more distal transgressive cycle of moderate to low-energy fluvial-

marine siliclastics capped via a flooding surface by below-wave-base

marine deposition, followed by a further regressive-transgressive marine-

deltaic cycle (c. 3 km thick, Pulse 2b). The succession contains numerous

Ottawan zircons (1080-1020 Ma), but no zircons from late-Grenville

granites (990-950 Ma). Deposition between c. 1020-980 Ma is likely,

coincident with the Rigolet phase, exhumation of Grenvillian eclogite in

Scotland (c. 995 Ma) and general cooling and unroofing of much of the

Grenville Orogen. Sedimentation patterns and similarities in detrital zircon

ages during Pulse 2 suggest basin overfilling and large-scale sediment by-

passing into more distant basins, now located in East Greenland, Svalbard

and Scandinavia.

The later Glenfinnan/Loch Eil (upper Moine) ?shallow marine

succession (?3-5 km thick, Pulse 3) contains 980-950 Ma zircons,

presumably from late-to post-Grenville granites and probably record

relatively slow post-orogenic denudation.

Deposition in northern Scotland appears to be primarily controlled by

varying sediment flux from the Grenville Orogen and subsidence caused

by orogenic loading. Similar pulses of deposition may also be recorded by

the proximal Oronto and Bayfield groups in the upper Keweenawan

Supergroup of the Lake Superior region of North America.

EVIDENCE FOR A LATEST ARCHEAN CONTINENTAL FRAG-

MENT IN THE MIDDLE OF THE MANIKEWAN OCEAN

Kremer, P.D.

, [email protected], Rayner, N.

and Corkery,

M.T.

Manitoba Geolgical Survey, 360-1395 Ellice Ave.,

Winnipeg, MB R3G 3P2;

Geological Survey of Canada, 601 Booth

St., Ottawa, ON K1A 0E8

The Southern Indian Domain of northern Manitoba lies in the internides of

the Trans- Hudson Orogen, and consists largely of metasedimentary

gneisses and migmatites with lesser amounts of volcanic rocks, all of

which were metamorphosed to mid to upper amphibolite facies. It is

flanked to the north by the ca. 1.865-1.850 Ga Chipewyan Batholith, a

voluminous continental magmatic arc, which separates it from the

southeastern Hearne craton margin and overlying Wollaston Supergroup,

and is bounded to the south by the Lynn Lake – Leaf Rapids Domain.

At Southern Indian Lake, two areas dominated by volcanic rocks are

preserved around a newly recognized fragment of latest Archean to earliest

Proterozoic crust. U-Pb and Sm-Nd isotopic data from the Archean rocks

at Southern Indian Lake show similarities to the Sask craton. However,

broad terranes of juvenile rocks that record little to no evidence of

interaction with an underlying crustal component occur between Southern

Indian Lake and the known extent of the Sask craton, suggesting a cratonic

fragment separated from other crustal components in the Trans-Hudson

Orogen. The volcanic rocks can be broadly subdivided into a > 1.90 Ga

juvenile series, which includes ocean floor and tholeiitic arc members, and

ca. 1.90-1.88 Ga isotopically evolved, bimodal arc volcanic and

volcaniclastic rocks. All sedimentary rocks in the area share a common

dominant to subdominant detrital zircon mode between 2.3 and 2.5 Ga

derived from shedding of the Sask-like continental rocks, but differ in their

younger zircon populations. Where sediments associated with arc volcanic

rocks show a prominent (arc-derived) peak between 1.88 and 1.90 Ga, this

zircon population is absent in clastic sediments interlayered with juvenile

volcanic rocks.

This talk will present the results of mapping, trace element

geochemical, Sm-Nd isotopic and U-Pb geochronological analyses from

the various tectonostratigraphic assemblages in the Southern Indian Lake

area. Collectively, the data provide evidence for volcanism and

sedimentation at ca. 1.9 Ga in an active continental margin setting around

a cryptic Archean microcratonic block. The scenario is similar to other

proposed microcontinental fragments between the Hearne and Superior

cratons, such as the Meta Incognita and Sugluk microcratons, which

played an important role in the prolonged evolution of the Trans-Hudson

Orogen prior to terminal collision.

A SYNGENETIC MODE FOR LODE GOLD VEIN FORMATION

AND IMPLICATIONS

Kretschmar, U.H., Golden Scarab Corporation, 408 Bay St, Orillia,

ON L3V 3X4, [email protected]

The simple premise that quartz-gold lode veins (LV) form at the same time

as the enclosing rocks underlies a “new” empirical model of their genesis,

with major implications for existing models (Kretschmar, WorldGold

2011, in press). Detailed maps and drill core provide direct evidence of

sea-floor hot spring origin in the 1) Cambro-Ordovician Meguma gold

deposits of NS, 2) Archean Chester Twp, Ontario TTG (trondhjemite-

tonalite-granodiorite)- hosted Côté L deposit, 3) Sage Gold- Prodigy Gold

“Hercules” veins in the Elmhirst intrusion, Beardmore, ON, and 4) high

grade LVs in the Maskwa batholith, MN. A proposed “Gold Cycle” (GC)

systematizes LV description. Footwall pyroclastics, epiclastics or

sedimentary lithologies fine upwards into chloritic tuff or pelagic/pelitic

chlorite-carbonate sediments and LVs occur within or on top. The GC is

terminated by the next influx of detritus. Using Bouma turbidite

terminology, LVs occur within or at the top of the E (upper, silt-slate-

pelagic-pelitic) division in predominantly A-E turbidites. E units may also

be graded tuffs or volcanic flows and reflect alternation of oxidizing and

reducing conditions. In the literature, E units are “shear zones” or

“lamprophyre or mafic dikes”. They are small scale correlative

conformities described by Thurston et al. (2008, Ec Geol 103

p. 1097). GC

“A” division lithologies encompass gabbro, diorite, granite, syenite, TTG

suite and volcano-sediments. Textures (laminar, massive quartz or silica

gel) support sea-floor deposition. Fluid PTX parameters for LVs are well

studied. Independently, Strelly Pool cherts (De Gregorio et al., 2006) show

carbonaceous material and graphite - common in gold-bearing LVs - was

abiotically generated at 2-300ºC and 550 bars pressure. A GC origin

explains asymmetric alteration and stable isotope disequilibrium between

LV and host rocks. Applications show: 1) the Bourlamaque batholith in

Val d’Or, Quebec is an isoclinally folded sheet of quartz-feldspar-

hornblende crystal tuff, and eight mines can be correlated across a syncline

with an overturned south limb, 2) the Côté Lake deposit hosted by a fault-

bounded block of felsic crystal tuffs on the limb of an overturned anticline,

3) the Hercules veins are in mafic crystal tuffs which correlate over 10 km.

GCs represent a new facing direction indicator which survives high grade

metamorphism. Vent geometry (fracture, point source or diffuse seep),

bottom topography and fracture spacing, obtained from mine grade-

thickness plots ranges from 250 to 600 m. LVs are commonly 1-3 km long

and 1-3 m thick. A syngenetic origin simplifies and unifies genetic models.

Implications include the need to re-examine TTG genesis since often

“mafic enclaves, inclusions or rafts” are GC “E” lithologies.

IROQUOIS & EURO-CANADIAN IMPACT ON CRAWFORD

LAKE: PALYNOLOGICAL EVIDENCE

Krueger, A.M., andreakru@yahoo.com, and McCarthy, F.M.G.,

Brock University, 500 Glenridge Ave., St. Catharines, ON L2S 3A1

Crawford Lake is a unique body of water located near the edge of the

Niagara Escarpment in a park run by Conservation Halton that includes an

Iroquoian village learning center. The lake occupies a small (2.4 ha, ~250

× 150 m) but deep (z

max

24 m) dolostone bedrock basin that is thought to

have been excavated by hydraulic mining during the last deglaciation

(McAndrews and Boyko-Diakonow, 1989). Due to its dimensions, the lake

is meromictic (does not fully turnover), resulting in anoxic bottom waters

in the deepest part of the basin. This, in turn, allowed undisturbed annual

laminae (varves) that have an exceptional fossil record to accumulate over

much of the last millennium. Not only are cysts of dinoflagellates

abundant in the sediments, but even the cellulosic theca produced by these

phytoplankton are preserved in some intervals- one of a handful of reports

of dinocyst thecae in the fossil record (Krueger, in prep.). The thecae are

found in varves containing abundant non-arboreal (herb) pollen recording

human activity (land clearing and agriculture) in the Crawford Lake

catchment. Both Iroquois farming (~A.D. 1286-1500) and Euro-Canadian

forestry and agriculture (since ~A.D. 1867) introduced large amounts of

nutrients into the lake, increasing primary productivity and further

depleting the bottom waters of oxygen. As suggested by the diatom

(Ekdahl et al., 2004) and rotifer (Turton and McAndrews, 2006) records,

Crawford Lake did not return to pre-disturbance status following Iroquois

farming. Surprisingly, the peak dinoflagellate cyst abundance is in

sediments deposited from 64 cm from 59 cm (~A.D. 1290-1330), so more

intense eutrophication appears to have been associated with Iroquois

farming than with Euro-Canadian disturbance over the last 150 years.

Ekdahl, E.J. et al., 2007. Diatom assemblage response to Iroquoian

and Euro-Canadian eutrophication of Crawford Lake, Ontario, Canada. J.

Paleolimnol. 37: 233-246.

Krueger, A.M. in prep. Freshwater dinoflagellates in studies of

cultural eutrophication: a case study from Crawford Lake Ontario. MSc

Thesis, Brock Univ.

McAndrews, J.H. & Boyko-Diakonow, M., 1989. Pollen analysis of

varved sediments at Crawford Lake, Ontario: evidence of Indian and

European farming. In: Fulton RJ (ed) Quaternary Geology of Canada and

Greenland. Geological Society of America, Boulder, Colorado, USA. 528-

530.

Turton, C.L. & McAndrews J.H., 2006. Rotifer loricas in second

millenium sediment of Crawford Lake, Ontario, Canada. Rev. Palaeobot.

Palynol., 141: 1-6.

Zn ISOTOPE EVIDENCE FOR IMMEDIATE RESUMPTION OF

PRIMARY PRODUCTIVITY AFTER SNOWBALL EARTH

Kunzmann, M., marcus.kunzmann@mail.mcgill.ca, Halverson, G.P.,

Earth & Planetary Sciences/GEOTOP, McGill University, Montreal,

QC, Sossi, P.A., Research School of Earth Sciences, Australian

National University, Australia, Raub, T.D., Department of Earth

Sciences, University of St. Andrews, UK, Payne, J.L., School of

Earth & Environmental Sciences, University of Adelaide, Australia,

and Kirby, J., CSIRO Land and Water, Glen Osmond, Australia

Zinc is assimilated in the surface ocean by primary producers and exported

to the deep ocean where it is released by re-mineralization. Previous

studies of Zn isotopes in the marine environment indicate a consistent

biological control. Organisms preferentially assimilate the light isotopes,

leaving behind an enriched surface ocean and generating a surface-to-deep

isotope gradient akin to that of δ

C of dissolved inorganic carbon. Since

Zn is incorporated in carbonate in trace amounts and without significant

isotopic fractionation, Zn isotope ratios in carbonate rocks deposited in the

surface ocean should track fluctuations in primary productivity.

We analyzed Zn, C, and O isotope ratios in a 14 m-thick section of

the Nuccaleena Formation, a ~635 Ma old cap dolostone that drapes

Marinoan age glacial deposits in the Adelaide Rift Complex in South

Australia. Carbon and oxygen isotope composition and sedimentological

features mirror other Marinoan cap dolostones worldwide. The δ

(

Zn/

Zn, versus JMC-Lyon) composition begins with a decline from

0.47 ‰ at the base to a nadir of 0.07 ‰ at 5.6 m. Above this level, δ

increases to a maximum of 0.07 ‰ at the top of the section. In contrast, the

insoluble residue fraction (silt and clay) yields values comparable to

previously reported values for siliciclastic rocks, which cluster around

mean continental crust (0.2-0.3 ‰).

The effect of diagenesis on the Zn isotope composition in carbonates

is as yet unknown. However, is seems likely that post-depositional Zn

exchange would drive the δ

Zn composition towards the composition of

the detrital component. Hence, it cannot account for the observed trend of

decreasing, than increasing values. We assume the values are primary

seawater signatures and propose a two-stage model to explain them.

During the first stage, the δ

Zn composition evolves toward the bulk of

the continental crust as the intense weathering input during the post-glacial

super-greenhouse climate dominates the ocean Zn budget. The trend of

increasing δ

Zn values can be interpreted by an invigorated biological

pump, driven by a high-nutrient flux coupled to continental weathering,

which depletes

Zn in the surface ocean and exports it to the deep ocean.

Preservation of the biological signal in the δ

Zn profile is a consequence

of the hydrological conditions that prevailed after snowball Earth. Partly

melt-derived, brackish surface waters subject to intense heating would

have capped cold, more saline deep water, suppressing upwelling and

homogenization of the marine Zn isotope reservoir.

COUPLED ISOTOPIC U/Pb DATING AND LA-ICP-MS

ANALYSES FOR DETERMINING GENETIC CONDITIONS OF

THE END GRID URANIUM DEPOSIT (THELON BASIN,

CANADA)

Lach, P., Cuney, M., Mercadier, J., Boiron, M-C., Dubessy, J., G2R,

Lorraine University, CNRS, CREGU, Boulvard des Aiguillettes, BP

239, F-54506, Vandoeuvre-lès-Nancy, France, and Brouand, M.,

AREVA, BU Mines, Tour Areva, 1, Place Jean Miller – 92084 Paris

La Défence Cedex

The giant unconformity-related uranium deposits from the Paleo-

proterozoic Athabasca Basin in Canada and Kombolgie Basin in Australia

are so far the main high-grade uranium resource in the world.

Consequently, they are currently heavily researched by exploration

companies in the Athabasca and Kombolgie sedimentary basins but also to

underexplored ones, like the Paleoproterozoic Thelon Basin in the

Northwest Territories in Canada. In this basin, significant uranium

mineralizations have been recently intercepted in the Kiggavik district.

The aim of the present study is to test if the End Grid deposit from

this district has similar age and geochemical characteristics to the known

giant unconformity-related U deposits from the Athabasca Basin, 1000 km

to the south. REE pattern of uranium oxides by LA-ICP-MS and isotopic

U/Pb dating by ion microprobe on the same minerals from the End Grid

deposit are compared with data obtained by the same techniques on

unconformity-related uranium deposits from the Athabasca, and especially

to those from the Shea Creek area.

A bell-shape REE pattern, centered on gadolinium, is found for all

the uranium oxides of the End Grid deposit. This pattern is strictly

identical to the one of the uranium oxides of Shea Creek deposit. This bell-

shape patterns are identical to the REE patterns obtained in other deposit

from the Athabasca Basin, and more generally similar to all patterns

obtained on uranium oxides from unconformity related deposits

(Mercadier et al. 2011).

The currently measured U-Pb isotopic ages on uranium oxides from

End Grid deposit are 1293±7 Ma and 1187±19 Ma. The oldest ages,

obtained in the present study on the best preserved uranium oxides from

the Shea Creek deposits, are around 1200 Ma. Although these ages are 150

Ma younger than those obtained by Kister (2003) on the Shea Creek area,

these new age determinations confirm major U deposition events between

1350 and 1200 Ma for Athabasca and Thelon deposits, as already

determined in most Athabasca Basin deposits (Cumming and Kristic,

1992).

In conclusion, both REE patterns and age determinations on uranium

oxides demonstrate that the End Grid deposit shares similar characteristics

to the unconformity related deposits. This opens new considerations for U

exploration in the Thelon basin, near the unconformity, and its basement.

References:

Cumming and Kristic, (1992). Canadian journal of Earth sciences, 29:

1623-1639

Kister P, (2003). Unpub. PhD thesis INPL: 333

Mercadier et al, (2011). TERRA NOVA, 23: 264–269

GEOLOGICAL SETTING OF IRON ORE MINERALIZATION IN

THE SNELGROVE LAKE AREA, LABRADOR TROUGH,

LABRADOR

Lachance, N.S., nicola[email protected], Piercey, S.J., Memorial

University, 300 Prince Phillip Dr., St. John’s, NL A1B 3X5,

Seymour, C., Altius Resources, Suite 202, Kenmount Business

Center, 66 Kenmount Road, St. John's, NL A1B 3V7

The Snelgrove Lake property located in western Labrador is underlain by

the Proterozoic Sokoman Formation, the same formation that hosts world-

class iron ore deposits in the Wabush-Labrador City and Schefferville

areas. Rocks in the area have been structurally modified, forming a series

of tight folds that are tilted to an almost vertical angle. The folding has

created interesting targets for exploration, as it seems to have thickened

some of the iron oxide-rich beds in fold noses. Detailed mapping and

sampling for petrography and lithogeochemistry was carried out in order to

characterize lithological facies and assess the nature of the iron formations

in this area so as to compare them with other regional iron ore deposits.

Stratigraphic units rich in iron comprise two major divisions: a lower

unit consisting of thin beds of black ferruginous shale that contains iron

mostly in the form of fine grained magnetite. It is overlain by the Sokoman

Formation, which is generally divisible into: a) a lower unit of greenish

laminated silicate chert; b) a middle unit of silicate chert rich in hard bluish

grey hematite and dark grey magnetite that contains jasper and iron oxide

sands, ooliths and intraclasts; and c) and an upper unit, only exposed in

some parts, that is similar to the middle unit but contains leached lenses of

greyish white porous chert. Iron formations are interbedded with pillow

basalts and mafic volcaniclastic sequences, as well as sills consisting of

fine- to medium-grained gabbro or diabase. The Sokoman Formation is

overlain and underlain by fine grained sedimentary rocks that probably

reflect a relatively deeper water environment in comparison with the

shallow water features of the middle Sokoman Formation. The later likely

represents a period of shallowing or regression within a general

transgressive cycle.

In the Schefferville area, leaching of silica through meteoric

processes in the Cretaceous period is interpreted to have created the iron

enrichment that produced soft reddish iron oxide ores. In contrast, locally

enriched iron formations of the Snelgrove Lake area are composed of hard,

metallic bluish-grey iron oxides, which are distinctly different from the

direct shipping ores of the Schefferville area. These locally enriched iron

formations at Snelgrove Lake are likely to have been leached of their silica

content, but by processes different than those that occurred in Schefferville

(e.g., syndiagenetic?).

EXTINCTION OF THE EDIACARA BIOTA

Laflamme, M.

, [email protected], Darroch, S.A.F.

, Tweedt,

S.M.

, Peterson, K.J.

and Erwin, D.H.

Smithsonian National

Museum of Natural History, Washington, DC 20013-7012 USA;

Yale University, PO Box 208109, New Haven, CT 06520-8109

USA;

Dartmouth College, Hanover, NH 03755 USA

The Ediacaran-Cambrian boundary signals a drastic change in diversity

and in the structure of ecosystems, which, coupled with a strong negative

C isotope anomaly, has been interpreted as evidence for a mass extinction.

The Ediacara biota, consisting of stem group animals in addition to extinct

higher-order clades, shifts to the familiar (and not so familiar) Cambrian

and Paleozoic faunas. Although metazoans are demonstrably present in the

Ediacaran, their ecological contribution is dwarfed by Ediacaran-type

clades such as the Rangeomorpha and Erniettomorpha, while Ediacaran-

type constructions such as fronds, flat-lying-recliners, mat-stickers, and

mat-scratchers are virtually non-existent in younger assemblages. To

evaluate the likelihood of a terminal Proterozoic mass-extinction, we

explored temporal and biogeographic distributions of Ediacaran taxa

combined with evaluations of morphospace ranges throughout the

Ediacaran. The paucity of temporally-resolved localities with diverse

Ediacaran assemblages, combined with difficulties associated with

differences in taphonomic regimes before and after the transition hinders

the evaluation of a proposed Ediacaran mass-extinction. However, the

demonstration of geographic and morphometric range changes offers a

novel means of assessing the downfall of Ediacara-type taxa at the hands

of emerging metazoans. Ultimately, the combination of studies on

morphospace occupation, ecosystem construction, biostratigraphy, and

biogeography showcases the severity of the end Ediacaran extinction on

the early evolution of macroscopic life.

A DETAILED PETROGRAPHIC, GEOCHEMICAL AND

GEOCHRONOLOGICAL STUDY OF THE HARE BAY GNEISS IN

THE NORTHEAST GANDER ZONE, NEWFOUNDLAND

Langille, A.E., [email protected], Dunning, G.R. and Jenner, G.A.,

Memorial University of Newfoundland, St. John's, NL

Rocks classified as the Hare Bay Gneiss of the northeast Gander Zone

have not been studied in detail, as previous work focuses on the granitic

intrusions and structural history in the area. In an effort to better

understand the Hare Bay Gneiss and its importance to the Gander Zone as

a whole, this study combines field observations with petrological,

geochemical and geochronological data from well-exposed sections from

Wind Mill Bight Provincial Park in the north to Hare Bay.

The mapped coastal exposure at Windmill Bight shows a strongly

sheared rock assemblage including megacrystic granite, proto-mylonite,

garnetiferous two-mica leucogranite, granodiorite as well as later cross-

cutting garnetiferous pegmatite, intermediate dykes, mafic intrusions, and

tourmaline-bearing quartz veins. Trace element geochemistry is being

completed on these igneous volcanic rocks and U/Pb zircon CATIMS ages

will be reported. The predominant rock types in this area appear to

constitute a sheeted intrusive complex rather than a gneiss.

Three road cut cross sections to the south were also mapped. The

Greenspond section includes several varieties of granitic orthogneiss in

contact with an undeformed siliceous unit and cut by two-mica

leucogranite and late pegmatite veins. Geochemical analyses will be

compared to those from the Windmill Bight section. Both the leucogranite

and the orthogneiss were collected for U/Pb zircon age determinations.

The Trinity and I Love You sections also featured orthogneisses and late

two-mica leucogranitic intrusions that are often garnet bearing. In the “I

Love You” outcrop an orthogneiss is cut by a unique tonalitic intrusion

containing titanite grains with plagioclase coronas. The Trinity section has

mafic blocks within an orthogneiss.

Geochemical samples were taken from each locality and the I Love

You tonalite and orthogneiss were sampled for geochronology. Additional

geochemical samples as well as four samples for U/Pb zircon dating were

collected north of Cape Freels and along roads in Valleyfield and Hare

Bay.

Through mapping and extensive petrological, geochemical and

geochronological sampling the complexity of the Hare Bay Gneiss is

apparent, and lithologic and event correlations between outcrop areas is

not obvious. This study will provide new documentation of the nature of

key representative units of the Hare Bay Gneiss in the northeast Gander

Zone.

ASSESSING ACCRETIONARY PROCESSES IN ANCIENT MUD-

RICH CARBONATE MOUNDS

Larmagnat, S., Laval University, 1065 avenue de la Médecine,

Quebec, QC G1V 0A6, stephanie.larm[email protected]

Phanerozoic mud-rich carbonate mounds display three mechanisms of

accretion: biomineralization, marine cement precipitation, and

organomineralization. Biomineralization refers to skeletogenesis, cement

precipitation refers to fluid flow-through, and organomineralization refers

to mineral precipitation that involves a non-living organic substrate.

Assessing the relative importance of these three accretionary modes in

ancient mud-rich carbonate mounds establishes a continuum from

essentially organomineralic (deeper water, suboxic) to cement-rich

(marine-phreatic zone, sea-floor relief, low net-accretion). The

contribution of skeletons (brachiopods, bryozoans, polychaetes,

foraminifera, red algae, corals) varies greatly from insignificant to

important in function of water depth and level of adaptation. This paper

presents details of four examples of mud-rich carbonate mounds from the

Palaeozoic of Canada and the Mesozoic of Morocco. At the Chute

Montmorency locality (Middle Ordovician, Quebec), bioherms are

lenticular bodies where in situ bryozoans could represent up to 70% of the

bioclastic fraction. The reefal framework built by trepostome bryozoans

provides large growth cavities where polymud fabric developed.

Accretionary mechanisms rely mainly on biomineralization whereas

organomineralization takes place within intra-reefal cryptic spaces but

remains of minor importance. Cementation is absent. At the Anticosti

Island locality (Lower Silurian, Quebec), mud-rich buildups display two

distinct facies both characterized by the abundance of marine cement. The

crinoid-fenestrate bryozoan mudstone-wackestone facies is distinguished

by its volumetrically important polymud fabric and both shelter cavities

and stromatactis. In this facies, biomineralization is of minor importance

whereas organomineralization and, to a lesser extent, marine cementation

within stromatactis are responsible for the net accretion. Regarding the

fenestrate bryozoan cementstone facies, the contribution of

biomineralization remains minor and organomineralization is absent. In

this case, net accretion is the result of extensive marine cementation. At

the Foum Zidet locality (Upper Sinemurian, Morocco), mounds contain

mainly macroscopically preserved, calcified siliceous sponges locally used

as substrate by encrusting bryozoans and polychaetes. Thus, mounds

accretion combines organomineralization and, to a lesser degree,

biomineralization whereas marine cement precipitation is lacking. At the

Jebel Assameur locality (Bajocian, Morocco), mud-rich buildups display

important amounts of scleractinian corals and coral debris. Accretionary

processes consist on biomineralization that develop classical patch reefs.

Organomineralization is restricted to cryptic spaces where it combines

with biomineralization and cement precipitation is minor. Our comparative

study illustrates how mud-rich carbonate mounds sharing similar

geometry, macro and micro fabrics can evolved from the varying input of

accretionary processes. Mud-rich carbonate mounds, commonly named

mudmound, are indeed a morphological convergence.

DISTINGUISHING METAPELITES FROM HYDROTHERMALLY

ALTERED METAVOLCANIC ROCKS IN GRANULITE FACIES

BELTS: A ZIRCON STUDY FROM THE GRENVILLE PROVINCE

Lasalle, S., [email protected], Fisher, C.M., Dunning, G. and Indares,

A.D., Department of Earth Sciences, Memorial University of

Newfoundland, St. John’s, NL A1B 3X5

A detailed U-Pb zircon and P-T study of two types of aluminous gneisses

(metapelite and hydrothermally altered felsic volcanic rock) from the

Canyon domain of the central Grenville Province provides important

constraints to the geologic evolution in this area. Both types of rocks were

metamorphosed under granulite facies conditions during the Grenvillian

orogeny and consist of Quartz + Plagioclase + K-feldspar + Garnet +

Sillimanite ± Biotite. The metapelite is foliated and contains large garnet

porphyroblasts wrapped in sillimanite and biotite bearing quartzo-

feldspathic matrix, while the metavolcanic rock has a nodular texture with

generally elongated domains of garnet±sillimanite and large quartz

domains floating in a K-feldspar rich matrix. Phase equilibria modelling

constrained the metamorphic peak at about 8-11kbar and above 835°C for

both rocks. Zircon in the metapelite is clear, inclusion-free, mainly sub-

rounded to round, and is interpreted to be of detrital origin with relict

cores, often igneous, overgrown by metamorphic rims. In rare cases, the

whole zircon is inferred to be of metamorphic origin. In contrast, zircon

from the altered metavolcanic rock is yellowish-brown, fractured, displays

obvious cores, and contains a distinctive inclusion suite. The dominant

type of internal texture in the metavolcanic zircon consists of a large bright

core with fine oscillatory zoning overgrown by a darker, structure-free

layer. This morphology and internal texture is consistent with igneous

crystallization followed by minor metamorphic overgrowth. LA-ICPMS

U-Pb spot analyses (30µm) were obtained from cores and/or rims of about

50 zircon grains in each sample. In the metavolcanic rock, the majority of

the concordant data form a cluster between about 1200Ma and about

1300Ma and ages of cores and rims overlap. The weighted average

207

Pb/

206

Pb age for 16 of the highest quality concordant analyses of igneous

zircon grains is 1238±13Ma (MSWD=1.4). In the metapelite, cores are

significantly older and yield a spread of ages (1500 to 1950Ma) confirming

a sedimentary origin for this rock. In contrast rim ages are ca. 1050Ma,

which represent the age of Grenvillian metamorphism in this area. The

results of this study highlight the capability of separating gneisses from

gneisses with a combination of careful petrography and accessory mineral

analyses.

UPPER ORDOVICIAN SHALE GAS AND OIL IN QUEBEC

Lavoie, D., Geological Survey of Canada - Quebec Division, 490 de

la Couronne, Quebec City, QC G1K 9A9, [email protected]

In eastern USA, industry interest has recently focused on Upper

Ordovician black shales in Ohio, which is the oil-rich Utica Shale. As in

Ohio and New York, the Upper Ordovician black shales in Quebec (Utica

and Macasty) form a thick marine clastic succession that overlies the

predominantly shallow marine carbonate facies of the Cambrian-

Ordovician St. Lawrence Platform. Over the years, the hydrocarbon

exploration targets in southern Quebec consisted primarily of the

dolomitized facies of the carbonate platform (e.g., Beekmantown, Trenton-

Black River), a small field (St. Flavien) was exploited and some sub-

economic discoveries made.

Previous work on the source rock potential of the Utica Shale in

southern Quebec has led to a regional understanding of the distribution of

thermal domains at the surface of the St. Lawrence platform. A regional

SW-oriented increase in thermal conditions from the condensate zone near

Quebec City to the dry gas zone in the Montréal area is known, whereas a

significant increase of maturation is observed at the Platform-

Appalachians boundary. In the subsurface, data allows to identify general

NW-SE oriented increase in thermal conditions of the Utica whereas

domains with contrasting TOC and/or HI are now mapped in the Utica.

Because of limited sub-surface information for the Macasty Shale on

Anticosti Island, the thermal and geochemical character of the Macasty is

less complete. Current available data indicate that roughly the northeastern

half of the island is in the oil window, the remaining southwestern part

being in the dry gas zone. The average and maximum TOC and HI values

in the Macasty are usually higher compared to those of the Utica, the data

for the Macasty indicate an oil-prone Type I and II organic matter.

For the Utica Shale (50 to 300 m thick), extensive testing of their

potential to release natural gas through high pressure hydraulic fracturing

started a few years ago. It has been recently documented that the

calcareous shales of the Utica have the capacity to release significant

volume of natural gas, whereas a liquid-rich window has been identified

near Quebec City; a situation in line with our current understanding of

regional thermal maturation in southern Quebec. On Anticosti Island,

preliminary data from the industry indicates that the Macasty shales (20 to

80 m thick) are, at least locally, oil-rich. However, the potential of these

shales to release economic volume of oil is still unknown.

MASS SPECTROMETRIC MICROANALYSIS AND IMAGING:

WHAT CAN THEY TELL US ABOUT MARINE BIOMINERAL-

IZATION?

Layne, G.D., Dept. of Earth Sciences, IC 1047, Memorial University,

St. John's, NL A1B 3X5

Mass spectrometer based microanalysis – using LA-ICP-MS and SIMS

techniques – is widely used to study marine biomineralization. Both

techniques are now routinely applied to studies of reef forming tropical

corals and fish otoliths. Further, these techniques can reveal useful

elemental and isotopic records, on a micron scale, in a wide variety of

other fauna – e.g., cold water corals, foraminifera, and algal rhodoliths.

Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-

ICP-MS) provides rapid trace element analyses, with a pronounced

strength for quickly mapping detailed compositional profiles of marine

organisms such as tropical corals. Many geoscientists and oceanographers

are also familiar with the utility of Secondary Ion Mass Spectrometry

(SIMS) for microanalysis of trace elements (Na, Mg, Fe, Mn, Sr, Ba) and

stable isotopes (especially δ

O) in carbonate skeletons. Although often

more time consuming than LA-ICP-MS, SIMS provides a spatial

resolution fine enough to measure sub-daily variations in faster growing

organisms (e.g., reef building tropical corals like Porites lutea). SIMS is

also capable of 2D (and 3D) mapping of samples through scanning ion

imaging (SII).

Mass spectrometric microanalyses can access a paleoceanographic

archive that extends well beyond their now traditional application to the

study of elemental and isotopic proxies for sea surface temperature (SST)

in more equatorial regimes. For example, periodicity in the micron scale

chemistry of many organisms yields information valuable in assessing

growth rates, and in interpreting the meaning of growth banding features

visible with light microscopy, SEM or other imaging. Intriguingly, an

increasing number of deep coldwater organisms are being recognized as

showing monthly growth banding – generally interpreted as a coupling to

the flux of nutrients from surface waters.

High resolution mass spectrometry, with advanced large format

SIMS instruments, can determine Sr isotope variations in carbonate

biomineralization with sufficient accuracy to examine habitat contrasts –

particularly in fish species that change residence between fresh and marine

environments on a seasonal or longer term basis. Another incipient

application of SIMS is the determination of δ

B in carbonate skeletons as

a proxy for the pH of ancient seawater.

An exciting recent development is the availability of “NanoSIMS”

instruments - optimized to deliver sub-micron resolution scanning ion

images. These have the potential to allow more rapid development of

information on organisms that do not grow symmetrically, and to allow the

location and assessment of very short term variations or disruptions

consequent to disease, major storms or anthropogenic insults such as

industrial pollutants.

3D MORPHOLOGY AND PERMEAMETRY OF OPHIOMORPHA

IRREGULAIRE; IMPLICATIONS FOR RESERVOIR QUALITY

Leaman, M. and McIlroy, D., Memorial University of

Newfoundland, St. John's, NL A1B 3X5, mary.l[email protected]

Ophiomorpha comprises a predominant ichnofabric in many bioturbated

siliciclastic petroleum reservoirs worldwide. Nevertheless its full effect on

reservoir permeability, especially in three dimensions, is not yet

understood. The aims of this research are (1) to amalgamate traditional two

dimensional permeametry data, with contemporary three dimensional

models of Ophiomorpha irregulaire and (2) to increase the current

understanding of production properties of reservoirs containing O.

irregulaire.

This study incorporates both core and field samples. Core samples

were collected from the L-55 Ben Nevis well, Ben Nevis Formation,

Jeanne d’Arc Basin, offshore Newfoundland. Three core specimens were

used to obtain spot permeametry (in one cm

increments) conducted by a

steady-state probe permeameter. Field specimens were collected from the

deep marine Juncal Formation, California to create high resolution three-

dimensional morphological models by utilising a serial grinding method.

The volume of the trace fossil was calculated from the 3D model.

The three dimensional model revealed a meander maze, a

distinguishing morphological feature of O. irregulaire. The volume of the

meander maze is 3.5 cm

, occupying 17.7% of the total volume. Each core

segment displayed a different sedimentary facies; (1) a very fine-grained

cemented sandstone; (2) a highly bioturbated fine-grained sandstone; and

(3) a fine-grained sandstone with primary sedimentary features visible. Of

the three fabrics the Ophiomorpha irregulaire burrows exhibit an average

decrease in permeability of 66%, compared to the sedimentary fabric

surrounding the burrow. Coupled with the volume of the burrow, one can

extrapolate the decrease in permeability on a reservoir-wide scale, by

taking into account the percent of bioturbation, lateral variability, and

connectivity of burrows. These findings will enable a more realistic

evaluation of reservoir quality and allow correct delineation of production

properties before exploration is undertaken.

UNDERSTANDING MODERN COLD-WATER CORALS

HABITATS IN CANADA USING MULTI-SCALE BATHYMETRIC

DATA ANALYSIS

Lecours, V., Edinger, E.N. and Devillers, R., Memorial University of

Newfoundland, St. John's, NL A1B 3X9, [email protected]

Knowledge of modern cold-water corals in Canada has significantly

improved during the last decade through studies using data from scientific

trawl surveys and commercial fisheries bycatch. While such data improve

our understanding of coral biogeography at a global scale, they provide

almost no information on the characteristics of coral habitats at a local

scale. By contrast, direct observations using Remotely Operated Vehicles

(ROV) allow descriptions of coral habitat at a local scale, but can miss

larger-scale habitat features. This project studies modern cold-water coral

habitats using bathymetric datasets of different resolution to understand the

role of scale on our understanding of corals’ habitat.

High-resolution multibeam sonar, video and oceanographic data were

collected in July 2010 and November 2011 using the Canadian ROV

ROPOS. ROPOS operated between 1000 and 3000 m depth in the Flemish

Cap and the Orphan Knoll regions, off Newfoundland and Labrador, and

between 100 and 500 m depth in three sites of the Strait of Georgia

(Sabine Channel, McCall Bank and Coral Knoll) in British Columbia.

Multibeam data were collected from two different altitudes above the

seafloor, providing centimetre- and decimetre-scale bathymetric data. In

addition, ship-based multibeam data and the General Bathymetric Chart of

the Oceans (GEBCO) world bathymetric dataset, covering the same

regions, provided two other scales of analysis. Different terrain parameters

(e.g. slope, rugosity, complexity) were derived from those bathymetric

datasets using a Geographic Information System (GIS), and statistically

analyzed in relationship to corals distribution and abundance, in order to

quantitatively characterize seabed morphology in coral habitats.

Corals in the deep Flemish Cap sites studied mostly occupied

bedrock and ice-rafted debris. Corals on the Orphan Knoll mounds studied

grew on bedrock, bedrock-derived talus, and ice-rafted debris. The

dominant coral fauna observed in those areas included gorgonians,

antipatharians, soft corals and localized solitary scleractinians. In the Strait

of Georgia coral sites studied, the seabed is composed of glacially scoured

bedrock, and the coral fauna was dominated by the gorgonians Paragorgia

and Primnoa. A glass sponge reef surveyed was mostly developed on soft

substrates.

The next step in this project is to quantify the relationship between

the distribution and abundance of corals and the morphology of the

seafloor measured at different scales. We aim to determine which scale is

best to understand those relationships, which seafloor morphology terrain

parameters best explain coral distribution and abundance, and the

differences in habitat characteristics among different corals species or

groups.

Keynote MONITORING SUBSURFACE OIL RELEASED FROM

DEEPWATER HORIZON MC 252 IN THE GULF OF MEXICO

AND OIL SPILL CLEAN UP ON GRAND ISLE, LOUISIANA

Lee, K., Department of Fisheries and Oceans Canada, Dartmouth, NS

B2Y 4A2, ken.lee@dfo-mpo.gc.ca

The Deepwater Horizon MC252 released methane gas and oil under

pressure which facilitated the formation of a plume of physically dispersed

oil within the water column. Furthermore, to reduce the impact of the

surface oil reaching sensitive coastal environments, the dispersant Corexit

9500 was also directly injected into the wellhead at a depth of 1500m.

Very small oil droplets (<100 microns in diameter) resulting from physical

dispersion and dispersant additions would rise to the surface very slowly,

and ocean turbulence could keep them entrained in the water column for

months.

Sea-going data was collected from the R/V Brooks McCall to monitor

the presence of the small oil droplets and their subsurface dispersion. The

vessel was also equipped with standard oceanographic equipment to

measure conductivity, temperature and depth (CTD), Colored Dissolved

Organic Matter (CDOM) and in situ dissolved oxygen (DO

). During the

study period, over 190 discrete locations were sampled from the wellhead

to a distance of approximately 50 km. Based on real-time data recovered

during the CTD down-cast, sample depths were selected for the recovery

of water samples for analyses of oil droplet size (LISST laser particle size

analysis) and hydrocarbon fluorescence.

The LISST particle size analysis correlated with CDOM results

which showed an anomaly attributable to oil at 1000–1300m depth with

the strongest signal near the wellhead during oil release and reduced levels

with distance in the direction of ocean currents along the isobath. The DO

data from CTD casts showed a depression attributed to biochemical

oxygen demand from the microbial degradation of subsurface oil. The data

provided insights on the transport, fate and effects of oil released from the

Deepwater Horizon MC252 well. Discussion is also given to the

significance of the interaction of oil with fine mineral particles in the

process of oil spill clean up.

ANALOGUE MODELS OF MIXING AND UNMIXING OF

MAGMATIC SULPHIDE ORES IN THE VOISEY’S BAY

DEPOSIT, LABRADOR

Leitch, A.M., Woodford, C., Memorial University, Department of

Earth Sciences, St John's, NL A1B 3X5, aleitch@mun.ca, and Evans-

Lamswood, D., Vale Limited, St John's, NL

Sulphide liquids can form a dense, fluid immiscible phase in magmatic

systems. Distribution coefficients for valuable metals between sulphide

and silicate are very high (a few hundred to tens of thousands) but to form

an economic magmatic sulphide ore deposit it is advantageous if there is

intimate contact between the phases so that the sulphides can efficiently

scavenge the metals. Evidently this happened in the Voisey’s Bay

magmatic sulphide deposit. Analogue laboratory experiments, where

magmas are represented by common liquids at room temperature and

pressure, are convenient ways of investigating and illustrating the physical

processes involved.

The Voisey’s Bay intrusion is a 1.34 Ga intrusion of mainly

troctolites and olivine gabbros within older gneisses, and is one the oldest

members of the predominantly anorthositic Nain Plutonic Suite in

Labrador, Canada. The intrusion consists of a sub-vertical magmatic

conduit several kilometres long and ~30m wide, between two kilometre-

scale magma chambers. Mineralization with sulphide ores occurs

principally at the base of one magma chamber and in bends and kinks in

the conduit. Sulphide mineralization occurs as lenses of massive ore,

disseminated blobs within the troctolite host or ‘net-textured’ ore, where

sulphide makes up a background matrix containing a network of silicate

crystals. Field evidence suggests that emplacement of the bulk of the liquid

sulphide ore occurred rapidly. Questions of interest include: where and in

what form the sulphide phase first arose; and how the sulphide was

transported to shallow emplacement depths.

We have carried out simple analogue experiments to model the

situation where a sulphide phase forms in drops or pockets in a crystal-rich

lower crustal magma chamber, and is mobilized upward by tectonic forces

(e.g. caldera collapse). Water droplets (representing dense, fluid,

immiscible sulphide) were introduced into a mush of plastic shavings and

vegetable oil (silicate crystals and liquid) and then compressed the mush.

We found that in certain circumstances, the analogue sulphide was

preferentially squeezed from the crystal mush, emerging as an emulsion of

sulphide droplets in silicate liquid. Such an emulsion would be easier to

transport upward against gravity than larger slugs of heavy sulphide liquid.

UNSTRUCTURED GRID MODELLING TO CREATE 3D EARTH

MODELS THAT UNIFY GEOLOGICAL AND GEOPHYSICAL

INFORMATION

Lelièvre, P., Carter-McAuslan, A., Tycholiz, C., Farquharson, C. and

Hurich, C., Department of Earth Sciences, Memorial University, St.

John's, NL A1B 3X5, [email protected]

Earth models used for mineral exploration or other subsurface

investigations should be consistent with all available geological and

geophysical information. Geophysical inversion provides the means to

integrate geological information, geophysical survey data, and physical

property measurements taken on rock samples. Inversion is a

computational process that recovers models of the subsurface that could

have given rise to measured geophysical data while maintaining

consistency with the geological knowledge available.

Throughout the development of a mineral exploration site, geological

ore deposit models are commonly developed based on available data and

subsequent interpretations. Geological contacts are often known at points

from delineation drilling or outcrop observations. The contacts can be

interpolated or extrapolated throughout the subsurface volume of interest.

The accuracy of these models is crucial when used to determine if a

deposit is economic.

Such 3D geological models are typically created on unstructured

wireframes, which are sufficiently flexible to allow the representation of

arbitrarily complicated subsurface structures. However, geophysical

modelling algorithms typically work with regular rectilinear meshes of

brick-like cells when parameterizing the subsurface because this simplifies

the development of numerical methods. Rectilinear meshes create

pixelated models that will always be incompatible with wireframe

geological models, regardless of how fine a discretization is used. To

address this incompatibility, we are using unstructured tetrahedral meshes

in our geophysical modelling methods.

We will present our modelling methods and apply them to examples

from the Voisey's Bay massive sulphide deposit in Labrador. The processing

stages involved when working on unstructured grids will be demonstrated,

from building 3D reference models from point-located downhole data and

vertical cross-sections, to using those models to constrain joint inversions of

potential field and seismic data. We will compare that process to the

equivalent steps required for rectilinear meshes.

By working directly with unstructured discretizations of the

subsurface in our modelling methods, we are able to represent arbitrarily

complicated features and seamlessly combine geological and geophysical

data. It is thereby possible to have geological and geophysical models that

are, in essence, the same Earth model.

STRUCTURAL CHARACTERIZATION AND

Ar/

Ar DATING

OF OROGENIC GOLD DEPOSITS OF THE BOURLAMAQUE

PLUTON, VAL D’OR, CANADA – TECTONIC IMPLICATIONS

FOR THE ARCHEAN ABITIBI GREENSTONE BELT

Lemarchand, J., Tremblay, A., Université du Québec à Montréal, CP

8888, Succursale Centre-Ville, Montréal, QC H3C 3P8, tremblay.a@

uqam.ca, Ruffet, G., CNRS (CNRS/INSU) UMR 6118, Géosciences

Rennes, 35042 Rennes Cedex, France, and Gobeil, C., COrporation

Alexis Minerals, 1876, 3E Avenue, Val-d'or, QC J9P 7A9

Two types of orogenic gold occurrences have been described in the Val

d’Or mining camp of the Abitibi greenstone Belt: (1) «early» (>2696 Ma)

quartz-carbonate-chlorite veins, and (2) «late» (<2680 Ma) quartz-

tourmaline veins. These «late» veins are abundant in the 2700 ± 1 Ma

(U/Pb zircon age), synvolcanic Bourlamaque pluton in the Val d’Or area,

and are exposed in the Sullivan, Dumont, Lac Herbin, Ferderber, Beacon,

Wrightbar and Beaufor deposits. They are typically hosted by ductile, EW-

trending and south-dipping shear zones that are currently considered to be

the product of faulting and hydrothermalism genetically related to the

Cadillac Tectonic Zone, a 1

-order regional structure that may represents

the channelway for Au-rich fluids towards 2

- and 3

-order structures

hosting the quartz veins. The Lac Herbin deposit exposes the development

of Riedel-type structures related to steeply-dipping shear zones that host

the auriferous quartz veins. The Beaufor mine shows a similar network of

Riedel shears but gold mineralisation is hosted there by moderately-

dipping secondary structures, suggesting a more efficient hydrothermal

activity as compared to Lac-Herbin. North-dipping barren structures with

dextral slip component, such the Beaufor and Perron faults in the Beaufor

deposit, and the «K» Zone, the Beacon and Lac Herbin-South faults of the

Sullivan, Beacon and Lac Herbin deposits, respectively, currently

interpreted as 2

-order shears, more likely represent post-mineralization

faults.

Fifty-seven samples have been dated by

Ar/

Ar single-grain step-

heating method. Dating on amphiboles from the undeformed Bourlamaque

pluton yield ages as old as ~2690 Ma, consistent with the crystallisation

ages of the intrusion. Muscovite

Ar/

Ar dating from mylonites and

related Au-rich quartz veins of the Lac Herbin, Beaufor and Beacon

deposits yielded ages between 2610 and 2420 Ma, a time range that is

clearly younger than the inferred timing of regional metamorphism (ca.

2660-2680 Ma).

Ar/

Ar spectra from the Lac Herbin and Beaufor

deposits show systematic and reproducible patterns: muscovites from the

sheared quartz veins range from ~2610 to ~2530 Ma whereas muscovites

from the hosting mylonites yield high-temperature apparent ages that are

consistent with the veins but show perturbations as young as 2515-2520

Ma in the low temperature steps. This is attributed to late stages

deformation following the main event of auriferous hydrothermalism. Our

structural and geochronological results have major implications regarding

both the typology of mineralized quartz-tourmaline vein structures of the

Val d’Or mining camp and the source of mineralizing fluids which are

currently considered to be of metamorphic origin.

HIGH DENSITY

O ISOTOPIC MAPPING OF HYDRO-

THERMAL FLUID FLOW PATHWAYS WITHIN CARBONATE

ROCK-HOSTED GOLD DEPOSITS: NE NEVADA

Lepore, W.A., [email protected], Hickey, K.A., Barker, S.L.L.,

Dept Earth & Ocean Sciences, The University of British Columbia,

Vancouver, BC V6T 1Z4, and Smith, M.T., Pilot Gold Inc., 1031

Railroad Street, Suite 110 Elko, Nevada 89801 USA

The Long Canyon deposit is a sediment-hosted gold deposit located in

northeastern Nevada, over 150 km east of the Carlin Trend. The deposit

geology, geochemistry and mineralogy suggest that it is a Carlin-type

deposit, although the host rocks are slightly older, Cambro-Ordovician

age, and were deposited in a platform carbonate rather than a continental

slope setting. This project tests the extents of auriferous hydrothermal fluid

infiltration through carbonate rocks at Long Canyon using patterns of

O depletion to define the limits of fluid-rock interaction. In

particular, patterns of isotope depletion are used to assess the structural

and lithologic controls on fluid flow, and the lateral extent of fluid rock

interaction beyond the limits of trace element halos genetically associated

with gold mineralization (antimony, thallium, mercury and arsenic).

Carbon and oxygen isotope ratios were measured using the Mineral

Deposit Research Unit’s Mineral Isotope Analyzer (MIA) at the University

of British Columbia. This laser-based desktop analyser provides rapid

analysis of oxygen and carbon isotope in carbonate rocks and enables the

mapping of isotopic depletion at a sample density not previously

attempted.

In this study several scales of sampling were tested, with increasing

resolution of petrophysical and physicochemical controls on depletion

patterns; from contiguous drill assay pulps over drilling cross sections, to

surface sampling along traverses, to closely spaced hand sample coverage

down drill holes, to micro-drilled samples. Presented here are the results of

over 2,800 unique O

carbonate sample compositions from across the

deposit. Results indicate stable isotope depletion mapping around

carbonate-hosted ore bodies with sufficient sample density can provide far

field vectors to fluid flow paths beyond what traditional lithogeochemistry

alone may show. Additionally, it is evident from the pattern of oxygen

isotope depletion that hydrothermal fluid flow responsible for

mineralization was largely constrained to brittle damage zones within

boudin necks, or incipient boudin necks, within massive dolomite units.

There was minimal lateral flow within or vertically across stratigraphic

units without pre-existing structural damage.

EMERGENT MONIAN (POST-PENOBSCOTTIAN) ACCRETION-

ARY THRUSTS ON THE OUTBOARD MARGIN OF EAST

AVALONIA, ANGLESEY, NW WALES

Leslie, A.G.

, [email protected], Schofield, D.I.

, Gillespie M.R.

Burt, C.E.

, Morgan, D.

and Milodowski, A.E.

British Geological

Survey, Murchison House, Edinburgh, EH9 3LA, UK;

British

Geological Survey, Columbus House, Tongwynlais, Cardiff, CF15

7NE, UK;

British Geological Survey, Keyworth Nottingham, NG12

5GG, UK

Anglesey (Ynys Môn) records a complex and protracted history of tectonic

accretion along the outboard margin of East Avalonia. Late

Neoproterozoic subduction and accretion included emplacement, at around

560 Ma, of the Penmynydd Zone blueschist facies assemblage. However,

much of the present tectonic architecture of the island is a product of SE-

vergent, and later south-vergent, accretionary tectonics that commenced in

the Early Ordovician. Coaxial, to intensely non-coaxial SE-vergent,

Monian/Penobscottian deformation assembled Late Neoproterozoic rocks

along with the Middle Cambrian to Early Ordovician Monian Supergroup.

Post-Penobscottian deposits include early to mid-Arenig tuffs and

olistostromal molasse deposits of Gwna Group affinity, the latter

reworking an uplifted Late Neoproterozoic shelf. Renewed late-Arenig

subsidence accommodated a strongly asymmetric, overstepping and SE-

migrating, marine, Middle Ordovician to early Silurian foreland basin

succession. These overstepping post-Penobscottian successions are now

arranged in a south- (or SSE) vergent, accretionary thrust duplex. The

Mynydd-Mechel Thrust Sheet occupies the highest structural level of this

(Salinic?) duplex, and the basal Mynydd-Mechel Thrust clearly oversteps

and truncates earlier accretionary stacking and consequent fabrics,

including the Carmel Head Thrust.

Translation on the Mynydd-Mechel and Carmel Head thrusts

succeeded significant uplift and erosion of the accretionary margin of this

Anglesey sector of East Avalonia. That theme, of active over-riding of

tectonic molasse, is continued in Anglesey until the Early Devonian at

least. The axially sourced fluvial Old Red Sandstone of central eastern

Anglesey was over-ridden by the Mynydd-Mechel Thrust Sheet, survives

as outlying erosional klippe.

New field observations have identified several locations where

emergent thrusts must have cropped out at surface, at the foot of an active

fault scarp shedding detritus in front of the advancing thrust sheet hanging

wall. Basal thrusts override undeformed but silicified breccio-

conglomerate molasse resting unconformably on crystalline footwall

rocks. The footwall rocks host a locally very dense, and largely disor-

ganised, network of quartz veins. Most of these veins, and rare occurrences

of injected tuffisite, are inferred to be a product of thrusting-induced fluid

overpressuring. The breccio-conglomerate molasse includes fragments of

vein quartz and quartz-veined rock, and is itself cut by quartz veins.

Different generations of quartz veining may correspond to discrete

thrusting events.

The poster illustrates these new observations, which are unique in the

UK.

A MONIAN (PENOBSCOTTIAN-SALINIC) ACCRETION

HISTORY ON THE OUTBOARD MARGIN OF EAST AVALONIA,

ANGLESEY, NW WALES

Leslie, A.G.

, Schofield, D.I.

, Burt, C.E.

, Morgan, D.

, Wilby,

P.R.

, Leslie, A.B.

British Geological Survey, Murchison House,

Edinburgh, EH9 3LA, UK;

British Geological Survey, Columbus

House, Tongwynlais, Cardiff, CF15 7NE, UK;

British Geological

Survey, Keyworth Nottingham, NG12 5GG, UK, [email protected]

Anglesey (Ynys Môn) records a complex and protracted history of tectonic

accretion along the outboard margin of East Avalonia. The evidence for

Late Neoproterozoic subduction and accretion is provided by ca. 650 Ma

metamorphism in the Coedana Complex, ca. 615 Ma intrusion of the

supra-subduction zone Coedana Granite, and emplacement, at around 560

Ma, of the Penmynydd Zone blueschist facies assemblage. However, much

of the present tectonic architecture of the island is a product of SE-vergent,

and later south-vergent, accretionary tectonics that commenced in the

Early Ordovician, consistent with Penobscottian accretion in the northern

Appalachians. Coaxial to intensely non-coaxial SE-vergent

Monian/Penobscottian deformation assembled the Late Neoproterozoic

rocks along with the Middle Cambrian to Early Ordovician Monian

Supergroup.

That accretionary assembly is overstepped on successive

unconformities by early to mid-Arenig, tuffs, and then by olistrostomal

molasse deposits of Gwna Group affinities that rework an uplifted Late

Neoproterozoic shelf. Renewed late-Arenig subsidence accommodated

deposition of a strongly asymmetric, overstepping and SE-migrating,

marine, Middle Ordovician to early Silurian foreland basin succession.

Deposition possibly occurred in a strongly (sinistral) transtensional régime

but these post-Penobscottian successions are now arranged in a south- (or

SSE) vergent, accretionary thrust duplex. Mylonitic rocks of the Mynydd-

Mechel Thrust Sheet occur at the highest structural level in this (Salinic?)

duplex, the basal Mynydd-Mechel Thrust clearly oversteps and truncates

the earlier accretionary stacking and consequent fabrics, including the

Carmel Head Thrust.

Translation on the Mynydd-Mechel and Carmel Head thrusts must

have succeeded significant uplift and erosion of the accretionary margin.

At several locations, these thrusts override molasse deposits derived from

the advancing thrust sheet and the basal thrust must have been emergent at

the foot of an active fault scarp shedding detritus. This theme of active

over-riding of tectonic mollase is continued in Anglesey until the Early

Devonian at least. The axially sourced fluvial Old Red Sandstone of

central eastern Anglesey is over-ridden (in the Acadian?) by what is now,

an outlying klippe of the Mynydd-Mechel Thrust Sheet.

PROCESSES AND SEABED IMPACT OF MAJOR STORMS ON

GRAND BANKS

Li, M.Z., Geological Survey of Canada - Atlantic, Bedford Institute

of Oceanography, Dartmouth, NS B2Y 4A2, [email protected],

Prescott, R.H., Prescott and Zou Consulting, Halifax, NS, Wu, Y.,

Tang, C.L., Fisheries and Oceans Canada, Bedford Institute of

Oceanography, Dartmouth, NS, and Han, G., Fisheries and Oceans

Canada, Northwest Atlantic Fisheries Centre, St. John’s, NL

Storms can generate significant surface waves and strong wind-driven

currents on the Grand Banks, Newfoundland. The strong waves and wind-

driven currents induced by the major storms can cause seabed scouring and

bedform mobility, and hence impact the engineering design and safety of

offshore seabed installations. The wind-driven current pattern and

sediment transport processes during storms are also important to predicting

the dispersion of material from oil spill incidents. Wind, wave hindcast

data, and ocean and wind-driven currents predicted from a 3D ocean

model for 22 selected major storms for the past 50 years were used to

investigate the pattern, processes, and impact on the seabed by major

storms on the Grand Banks. These wave and ocean current data, together

with model-predicted tidal current and observed grain size data, were

coupled in a sediment transport model to predict seabed shear stresses,

magnitude and frequency of sediment mobility, and sediment transport

flux for the selected major storms.

Wind and waves are to the NE during most of the major storms on

Grand Banks, and the associated storm-induced currents are predominantly

to the SE. Although stronger wind tends to generate stronger currents,

significant variance exists and suggests that other factors, e.g. storm track

and storm center translation speed, also affect the storm impact. Storms

significantly alter current patterns on Grand Banks. At the peaks of major

storms, surface wind-driven currents are dominantly to the SE and can

reach as high as 140 cm/s, more than 4 times stronger than that under non-

storm conditions. In the near-bottom layer, strongest currents up to 50-70

cm/s occur on the western Grand Banks and are dominantly to the

southeast and east. Near-bottom currents reach about 30 cm/s and are to

the north and northwest on the NE Grand Bank. Under non-storm

conditions, seabed shear velocity is < 2 cm/s and low sediment transport

occurs only in isolated spots. During major storms, bottom shear velocity

is increased to >10 cm/s due to strong waves and wind-driven currents and

significant sediment transport is widely predicted on the Grand Banks.

Maximum sediment transport rate reaches about 2-3 kg/m/s and occurs on

the SE Grand Bank. Maximum seabed forcing during major storms can

transport up to small pebbles, and intermittent transport of sediment should

occur on most bedforms during these storms.

Keynote MAGMA CHAMBER GEOMETRY AND THE

LOCALIZATION OF Ni-Cu±(PGE) SULPHIDE MINERAL-

IZATION: GLOBAL EXAMPLES AND THEIR RELEVANCE TO

VOISEY’S BAY

Lightfoot, P.C., Vale, Brownfield Exploration, Copper Cliff, ON

P0M 1N0, and Evans-Lamswood, D., Vale Newfoundland and

Labrador Limited, 280 Torbay Road, St. John’s, NL A1A 3W8

The distribution of magmatic Ni-Cu-platinum group element (PGE)

deposits and mineralization in mafic intrusions is controlled by the

geometry of the magma chamber which is often recorded in the form and

shape of the intrusions (Lightfoot, 2007). The recognition that the Ovoid

Deposit and the Eastern Deeps Deposit at Voisey’s Bay are localized

where a dyke enters a larger intrusive body has been a key observation

that has underpinned much of the exploration activity. These

relationships are not unique. Some of the best examples of

mineralisation within intrusions adjacent to feeder conduits are found in

China; the Hong Qi Ling Number 1 Intrusion in Jilin Province shows the

juxtaposition of a small mineralised mafic intrusion adjacent to a mafic

dyke. These relationships are repeated at Huangshandong and

Jingbulake in Xinjiang Province, where disseminated sulphides are

localized at the base of differentiated intrusions above comagmatic

dykes, and at Jinchuan in Gansu Province, where the configuration of

the intrusion is controlled by regional structures that create space for the

emplacement of a small intrusion. Many other small differentiated

intrusions have dyke-like keels, including the weakly mineralized

Qingquanshan Intrusion in Sichuan Province. A few examples of

mineralization occur in chonoliths like the Kalatungke Intrusion in

Xinjiang province, which broadly resembles the morphology of the

Babel-Nebo Intrusion in Western Australia. This presentation

emphasizes the significance of these empirical relationships and shows

how the geology of deposits like Eagle in Michigan and Double Eagle in

Ontario are explained by this model. The ongoing exploration focus at

Voisey’s Bay respects these relationships, and continues to provide a

new level of understanding of the controls of magma chamber

development and intrusion geometry on the localization of

mineralization (Lightfoot et al., 2011).

NEOARCHEAN IS A PERIOD OF TRANSITION FROM VERT-

ICAL TO HORIZONTAL TECTONISM: STRUCTURAL AND

GEOCHRONOLOGICAL EVIDENCE FROM THE SUPERIOR

PROVINCE, CANADA

Lin, S., Parks, J., Department of Earth and Environmental Sciences,

University of Waterloo, Waterloo, ON N2L 3G1, shoufa@

uwaterloo.ca, Heaman, L.M., Department of Earth and Atmospheric

Sciences, University of Alberta, Edmonton, AB T6G 2E3, and

Simonetti, A., Department of Civil Engineering and Geological

Sciences, University of Notre Dame, Notre Dame, IN 46556, USA

“Vertical tectonism” and “horizontal tectonism” are two contrasting

processes that have been proposed for Archean tectonics. Vertical

tectonism is due to density inversion and is characterized by buoyant rising

of granitoids (diapirism) and sinking of greenstones (sagduction).

Horizontal tectonism is similar (but probably not identical) to the present-

day plate tectonics and is characterized by regional scale horizontal motion

(drift) of “plates” or “microplates” and the resulting interactions (e.g.

collision) among them. The two processes need not be mutually exclusive,

and it is not necessary to downplay the significance of one to validate the

other. Recent results show that both processes played an important role in

Archean tectonic evolution. Furthermore, in the Superior Province, there is

convincing evidence that the two processes occurred synchronously (and

poten-tially interactively) at the late stages of Archean cratonization, and

horizontal shearing (a result of horizontal tectonism) is concentrated in

synclinal keels (a result of vertical tectonism).

“Timiskaming-type” groups are the stratigraphically youngest

supracrustal rocks in many Archean greenstone belts. Traditionally these

groups are interpreted to have been deposited in strike-slip basins opened

by horizontal plate tectonic processes. More recent studies have suggested

that they were deposited in inter-diapiric basins formed by vertical tectonic

processes during synchronous vertical and horizontal tectonism.

The Island Lake Group is such a group in the northwestern Superior

province. Ages of detrital zircons in the group match the known ages of

volcanism and plutonism in the surrounding area. They change from the

bottom to the top of the group and indicate a scenario that involves erosion

down through a supracrustal pile in the early stage of basin formation and

sedimentation, and unroofing of plutons in the latter stages. This supports

the interpretation that the sediments were deposited in synclinal keels

between granitoid domes during diapirism and sagduction as a result of

vertical tectonism.

It is suggested that synchronous vertical and horizontal tectonism

was a common process in the Neoarchean and represents a transition from

dominant vertical tectonism in the Mesoarchean (and Paleoarchean?) to

dominant horizontal tectonism in the Proterozoic and Phanerozoic.

REMARKABLE INSIGHTS INTO THE PALEOECOLOGY OF

THE AVALONIAN EDIACARAN BIOTA

Liu, A.G., Department of Earth Sciences, University of Cambridge,

Downing Street, Cambridge, CB2 3EQ, UK, [email protected],

McIlroy, D., Department of Earth Sciences, Memorial University of

Newfoundland, St. John’s, NL A1B 3X5, Matthews, J.J. and Brasier,

M.D., Department of Earth Sciences, University of Oxford, South

Parks Road, Oxford, OX1 3AN, UK

Ediacaran macrofossils from the Avalon region (Newfoundland and the

U.K.) document the emergence of some of the earliest large and complex

organisms on the planet. While the Ediacaran taxa preserved in these areas

have variously been interpreted as extinct phyla, fungi, bacterial colonies

and metazoans, in recent years a raft of new data and discoveries has

revealed remarkable insights into Ediacaran biology, ecology, and

taphonomy.

In the absence of abundant morphological characters, one way to

explore the biological affinities of the Ediacaran biota is to study their

paleoecological attributes, in order to gain evidence about behaviour and

community interactions. Recent finds include simple horizontal surface

locomotion traces, ~565 Ma, at Mistaken Point, Newfoundland. These

specimens can be taken to suggest that at least some Avalonian organisms

were capable of active movement. This finding sits at odds with previously

accepted views, and reasons for their rarity will be discussed.

The discovery of a diverse assemblage of juvenile Charnia masoni,

Trepassia wardae, and other rangeomorph forms (all <30 mm in length), as

well as wavy filamentous fossils from the Drook Formation of Pigeon

Cove, Newfoundland, provides new insights into the early ontogenetic

growth stages of those organisms. These fossils allow for discussion of

reproductive strategies within the rangeomorphs. The juveniles also reveal

the potential for preservation of minute forms in the Avalonian

successions, opening a previously unrecognised taphonomic window into

their biology.

Finally, comprehensive reassessments of the taphonomy of some

Ediacaran macro-organisms, and recognition of time averaging within the

preserved fossil communities, require a re-evaluation of previous

measurements of ecosystem attributes. Such an undertaking suggests that

the use of modern ecosystem parameters to interpret the paleoecology of

extinct communities must be carefully applied, and conclusions drawn

from them need to be considered in the context of significant

methodological limitations.

These studies combine to improve our knowledge of the features,

behaviours and interactions that can be extracted from Ediacaran deep-

marine paleocommunities. When taken together with new discoveries of

diverse and spectacularly preserved Ediacaran fossil assemblages from

across the Avalon zone, it becomes apparent that there is currently much

potential for further breakthroughs in Late Ediacaran paleoecology,

making this a fascinating time to be working in this field.

SETTING AND STYLES OF HYDROTHERMAL MUDSTONES

NEAR THE LEMARCHANT VOLCANOGENIC MASSIVE

SULFIDE (VMS) DEPOSIT, CENTRAL MOBILE BELT,

NEWFOUNDLAND

Lode, S., Piercey, S.J., Department of Earth Science, Memorial

University, 300 Prince Philip Drive, St. John’s, NL A1B 3X5,

[email protected], Copeland, D.A., Devine, C. and Sparrow, B.,

Paragon Minerals Corporation, 140 Water Street, Suite 605, St.

John's, NL A1C 6H6

In some volcanogenic massive sulfide (VMS) s there is a close association

of black shales and hydrothermal mudstones and massive sulfide

mineralization, yet our understanding of the relationship of these muds to

VMS genesis and exploration is incomplete. The Lemarchant VMS deposit

is an excellent location to study the relationship of black

shales/hydrothermal muds to VMS mineralization because there is an

intimate relationship between precious-metal bearing Zn-Pb-Cu sulfides

and hydrothermal sedimentary rocks. The Lemarchant VMS deposit is

hosted by the late Cambrian Tally Pond volcanic belt, Central Mobile Belt,

Newfoundland and represents a bimodal felsic VMS deposit with a typical

stratigraphic sequence consisting of rhyolite domes and/or breccias with a

stockwork stringer zone, overlain by the massive sulfides, one or more

barite bed(s), and are capped by hydrothermal sediments/mudstones. Mafic

volcanic flows, predominantly pillowed basalts, are deposited on top of

this sequence and represent a new cycle of volcanic activity. Metalliferous

mudstones represent a hiatus in this volcanic activity, where the deposition

of hydrothermal matter dominates over the abiogenic pelagic background

sedimentation. In the drilled cores these mudstones/shales occur either

stratigraphically on top of the massive sulfide deposits or as interflow

muds in basaltic units. The sulfide-rich hydrothermal sediments comprise

brown to black graphite-rich mudstones and finely laminated shales, which

can be intercalated by siliciclastic and/or kidney-shaped chert layers as

well as by fine layers of organic matter. The sulfides occur parallel to the

bedding in the organic-rich layers indicating biological activity, but also in

later-stage veins, which are cross-cutting the original bedding. The main

sulfide phases are pyrite and pyrrhotite plus minor amounts of

chalcopyrite, sphalerite, arsenopyrite and galena. Pyrite mostly occurs as

euhedral grains or as framboids (diagenetic?), whereas pyrrhotite forms

fine granules or irregular shaped grains to massive grains filling veins.

Ongoing research includes detailed mineralogical-petrographical studies of

the sulfides, whole-rock lithogeochemical analyses, and sulfur isotope

geochemistry. The research is aimed at understanding both the role that

basin redox conditions has on the genesis of the Lemarchant deposit,

discriminating the relative contributions of hydrothermal, detrital or

hydrogenous (seawater-derived) materials in the genesis of the shales,

distinguishing between hydrothermal, diagenetic and biological sulfur

sources in the sediments, and utilizing the latter to create potential

exploration vectors at Lemarchant and for other shale-associated VMS

systems.

TRACE ELEMENT GEOCHEMISTRY AND PHYSICAL VOL-

CANOLOGY OF THE SHEBANDOWAN GREENSTONE BELT,

SUPERIOR CRATON, CANADA; IMPLICATIONS FOR VMS

MINERALIZATION AND TECTONIC PROCESSES IN THE

NEOARCHEAN

Lodge, R.W.D., [email protected], Gibson, H.L., Mineral

Exploration Research Centre, Department of Earth Sciences,

Laurentian University, Sudbury, ON P3E 2C6, and Stott, G.M.,

Ontario Geological Survey (Ret.), Stott Geoconsulting Ltd, 92 Crater

Crescent, Sudbury, ON P3E 5Y6

To better understand the volcanotectonic setting and volcanogenic massive

sulphide (VMS) metallogeny of the Shebandowan Greenstone Belt (SGB),

northwestern Ontario, the spatial distribution of trace element data,

epsilon-Nd values, and the volcanic lithofacies and architecture were

examined across eleven regional-scale transects. The SGB has been

subject to a century of near continuous base metal exploration, but these

efforts have yet to yield an economic VMS deposit. The SGB were

previously interpreted to be deposited in a submarine arc- to rifted arc-like

setting, which is an ideal setting to form VMS mineralization. This

disparity in VMS-potential versus favourable VMS-setting is magnified

when compared to other time-equivalent and VMS-endowed 2720 Ma

greenstone belts in the Wawa Subprovince.

Element mobility resulting from complex and often superimposed

alteration requires the use of immobile trace elements to discriminate

between different geodynamic settings in ancient volcanic successions.

Primitive mantle-normalized trace element concentrations of basalts have

distinctive geochemical signatures depending on the geodynamic setting.

For example, arc basalts have negative Nb, Ta, and Ti anomalies and

LREE enrichment, whereas MORB have depleted to flat LREE patterns.

Felsic to intermediate rocks that are most commonly associated with VMS

mineralization have flat REE patterns or have slight LREE enrichment (FII

to FIV rhyolites). When the spatial distribution of signature geochemical

trace element patterns is analyzed across the SGB, discrete and

homogeneous geochemical domains are apparent. Although isoclinaly

folded, volcanic successions with arc-like and MORB-BABB

geochemistry are separate, which suggests that these distinct, geochemical

successions are not stratigraphic. The fold-thrust belt geometry of the

SGB, and the presence of “geochemically” separate geodynamic domains

suggests that their contacts are faults, and that they were justaposed

through horizontal tectonic - accretionary - processes.

The lithofacies of arc-like and rift-type basalts are very similar but do

vary across the SGB. They range from massive and pillowed flows

associated with ultramafic flows and sills, to highly amygdaloidal mafic

flows and breccias. Felsic to intermediate lithofacies vary in abundance

across the SGB and range from massive flows, breccias, to volcaniclastic

deposits with accretionary lapilli. The spatial distribution of rift

environments, FII-type felsic and intermediate volcanics, and VMS-

alteration has highlighted two successions in the SGB that have the highest

VMS-potential. These areas are associated with highly amygdaloidal mafic

flows, and basalt breccias with mature arc-like felsic volcaniclastics. A

shallower-water, mature arc setting may account for the lack of economic

VMS deposits.

PERCHED BOULDER BERMS AS AN INDICATOR OF FLASHY

DISCHARGE IN EPHEMERAL RIVER DEPOSITS IN THE

PRECAMBRIAN AND PLEISTOCENE

Long, D.G.F., Laurentian University, Sudbury, ON P3E 2C6,

[email protected]

Clusters of boulders and cobbles on the upper part of lateral accretion

surfaces in mixed sandy-gravelly fluvial deposits are a potential indicator

of highly variable to catastrophic discharge characteristics in ephemeral

and highly seasonal fluvial systems. An example of cobble berms,

developed on the part of lateral accretion surfaces in the Neoproterozoic

Whyte Inlet Formation, Bylot Supergroup, north of Fury and Hecla

Straights, Canada, is suggestive of irregular peak discharge, with velocities

in the order of 2.4 m/sec. Boulder and cobble grade examples in Middle

Pleistocene cliff exposures near Monteceto California show similar

evidence of similar upper-flow regime conditions, with maximum flow,

based on boulder size, in the order of 3.5 m/sec. The major difference in

the two examples is that the Pleistocene examples have higher mud

content, presumably due to a combination of provenance and enhanced

weathering by organic acids.

CARBON, GOLD AND URANIUM ON INTERFLUVIAL

DEGRADATION SURFACES IN THE PALEOPROTEROZOIC

HURONIAN SUPERGROUP, CANADA

Long, D.G.F., McDonald, A.M., Laurentian University, Sudbury, ON

P3E 2C6 dlong@laurentian.ca, Minter, W.E.L., University of

Capetown, SA, and Shaw, M., Geo-Consult Internationa, SA

Laterally extensive auriferous pyritic conglomerates framework-supported,

cobble and boulder conglomerates of shallow braided river origin in the

basal 30 m of the Huronian Supergroup in the southern part of the Cobalt

Plain have been interpreted as pre-oxygenic modified placer deposits.

Recent drilling by Ginguro Exploration (Sudbury) has confirmed

significant gold values in the conglomerates over an area of at least 3 × 10

km. Gold values are not restricted to the basal pyritic conglomerates, but

also occurred well up in the upper part of the predominantly sandy

Mississagi Formation within thin beds of small to medium pebble

conglomerate, with only trace amounts of pyrite. In all cases high gold

values are associated with enhanced uranium concentrations. SEM scans

revealed scattered black-material of fine sand grade that is analogous to

fly-spec carbon the Witwatersrand. Comparison of the carbon and oxygen

maps support this interpretation, as does Raman Spectral analysis, which

indicates that it a kerogen. Pores in the carbon grains are filled with

uraninite, with enhanced values of gold and yttrium. The presence of

carbon in these small pebble conglomerates suggests that they may

represent erosional channels developed on the alluvial braidplain (fan).

They are not continuous across the basin, as inter-fluvial areas would have

developed as flat-topped barriers to lateral channel migration. Clay

deposition, combined with concentration of organic material may have

occurred in low flow stages within channel thalweg ponds, with the

organic material being remobilized during metamorphism. Given the link

between fly spec carbon and the high uranium content in Witwaterand

placers it is suggested that comparable high U

/Au ratios in the

Huronian deposits might be used as a vector to predict the location for

settings with optimal gold potential.

THE POTSDAM GROUP IN NEW YORK STATE, ONTARIO AND

QUEBEC: STRATIGRAPHIC RELATIONSHIPS AND CHARACTER

OF CONTINENTAL AND SHALLOW MARINE SEDIMENTATION

IN A TECTONICALLY ACTIVE CONTINENTAL BASIN

Lowe, D., Arnott, R.W.C., Earth Sciences Department, University of

Ottawa, Ottawa, ON K1N 6N5, [email protected]

The Cambrian to Early Ordovician Potsdam Group in the St. Lawrence

Lowlands (Ontario, Quebec and New York State) preserves a record of

early Paleozoic sedimentation in a continental basin that was coeval with

sedimentation on the passive-margin Laurentian Platform. Previous work

suggests that the Potsdam Group consists of an assemblage of eolian to

shallow marine sedimentary rocks with a distinctive geographical and

stratal zonation. These past observations also suggest that the Potsdam

Group records a protracted transgression that eventually covered

continental facies with shallow marine deposits. This simple depositional

history, however, is complicated by outliers in the lowest part of the

succession consisting of siliciclastic and carbonate rocks, the latter of

marine affinity, as well as by a number of significant internal stratal

discontinuities.

In the western part of the St. Lawrence Lowlands a number of

discrete stratal units have been recognized and stratigraphically upward

include: (a) undifferentiated basal outliers, (b) eolian strata, (c) mostly

fluvial strata, and (d) shallow marine strata. Discontinuities separate these

units, and nowhere is the succession fully preserved. Unit (a) overlies

Grenville basement rocks and in many places is tectonically deformed, and

in some places marine in origin. Above Unit (a) structural deformation is

less common and less intense, and all units, except for Unit (d), are non-

marine. Field evidence suggests that unconformities occur above units (a)

and (b). Following deposition of each unit, sediment was lithified, locally

structurally deformed and eroded. In addition, a major change in climate,

specifically from dry to wet, is indicated across the top of Unit (b). The

contact between units (c) and (d) is also a sharp, locally erosional

discontinuity marked by a change from mainly terrestrial to fully marine

conditions. Below the contact, poorly-sorted to boulder conglomerate,

overlain by a silcrete horizon, indicates a period of uplift, rapid erosion

and deposition followed by non-depositon and paleosol development. This

was followed by marine inundation, Unit (d), which then grades

conformably upward into carbonate rocks of the overlying Beekmantown

Group.

In summary, the Potsdam Group in the western St. Lawrence

Lowlands records a long history of mostly continental clastic deposition

interrupted by periods of tectonic uplift and erosion, with transgression

near its top. Tectonism along the western basin margin was the dominant

factor that controlled accommodation, erosion, and sedimentation, and

ultimately distribution of stratal units throughout the area.

THE TIMING AND DURATION OF GRANITE-RELATED

MAGMATIC-HYDROTHERMAL EVENTS IN SOUTHEASTERN

NEWFOUNDLAND: RESULTS OF Re-Os MOLYBDENITE

GEOCHRONOLOGY

Lynch, E.P., Earth and Ocean Sciences, School of Natural Sciences,

NUI Galway, Ireland, e.ly[email protected], Selby, D.,

Department of Earth Sciences, Durham University, Durham, DH1

3LE, UK, and Wilton, D.H.C., Department of Earth Sciences,

Memorial University, St. John’s, NL A1B 3X5

The geology of southeastern Newfoundland includes an arcuate belt of

late-orogenic leucogranites associated with variable intrusion- and vein-

hosted mineralization (e.g. Mo, Cu, W, Sn, F). Granite magmatism and

related hydrothermal activity developed during the latter stages of the

Acadian Orogeny and was spatially focused along the Gander-Avalon

suture zone. We present the results of Re-Os molybdenite geochronology

from mineralized localities in southeastern Newfoundland that constrains

the timing and duration of this regional-scale, magmatic-hydrothermal

event.

From east to west the results are: (1) At Granite Lake in south-central

Newfoundland (Gander Zone), quartz vein-hosted Mo-Cu-W

mineralization in the Wolf Mountain Granite has a mean age of 386.8 ±

1.6 Ma (n = 3). This date is inferred to constrain the age of the granite

which also hosts disseminated molybdenite. (2) On the south coast,

molybdenite from the Moly Brook Mo-Cu deposit and adjacent Grey River

W deposit define mean ages of 380.8 ± 1.6 Ma (n = 4) and 381.3 ± 1.8 Ma

(n = 2), respectively. Here, mineralization is spatially associated with

minor granite intrusions. (3) Further east (Avalon Zone), disseminated and

vein-hosted molybdenite in the Harbour Breton Granite is dated at 381.2 ±

1.9 Ma and 382.5 ± 1.7 Ma, respectively. These model ages are identical

within uncertainty and constrain the age of the pluton and mineralization.

(4) In the southern Ackley Granite, disseminated molybdenite from four

localities has the following ages: Ackley City, 379.4 ± 1.7 Ma (n = 5);

Motu, 378.1 ± 1.7 Ma (n = 1); Wylie Hill, 380.2 ± 1.6 Ma (n = 2); Anesty

Hill South, 379.2 ± 4.6 Ma (n = 1). (5) At Belle Island, located between

the Harbour Breton and Ackley granites, vein-hosted molybdenite

associated with a granite stock is dated at 382.3 ± 1.5 Ma. (6) On the Burin

Peninsula, molybdenite from a quartz-fluorite veinlet within the St

Lawrence Granite yielded a model age of 365.8 ± 2.8 Ma. This date is

younger than the accepted age of the granite (374 ± 2 Ma) and likely

reflects prolonged hydrothermal activity during granite cooling and/or

unroofing.

These data indicate that a spatially focused episode of granophile

mineralization evolved in this region between ~ 387 – 366 Ma, with a

principal magmatic-hydrothermal event occurring at ca. 380 Ma. The Re-

Os ages correlate late-orogenic granite magmatism across the Gander-

Avalon zones and establish a geochronological framework for granophile

mineralization in this sector of the Newfoundland Appalachians.

THE KAMISTIATUSSET (KAMI) IRON DEPOSIT, WABUSH,

LABRADOR – A DEPOSIT ON THE EDGE

Lyons, E., P.Geo, edly[email protected], Alderon Iron Ore Corp., PO

Box 8520, Victoria, BC V8W 3S1

The Kamistiatusset (“Kami”) iron oxide deposits lie on the southeastern

flank of the metamorphosed Labrador Trough iron formation and

associated stratigraphy between Wabush, Labrador and Fermont, Quebec.

The Rose and the Mills Lake deposits have an indicated resource of 490

million tonnes at 30.0% iron with an additional inferred resource of 598

million tonnes at 30.3% iron. Between 2008 and 2012, 226 drillholes

totalling 68,130 m have been drilled to delineate the deposits. The project

is operated by Alderon Iron Ore Corp. of Montreal, QC.

The Kami deposits are atypical of the past and currently producing

iron mines in the Labrador-Quebec metataconite belt in that the iron oxides

are 65% magnetite: 35% hematite. These will be the first high-magnetite

iron oxide deposits brought into production in the region. Each deposit

formed in separate iron formation basins, juxtaposed together by two main

phases of deformation and thrust faults; each has distinctive

characteristics. The Rose deposit was deposited on the margins of the

informally named Wabush Basin while the Mills Lake deposit may be

related to more distal parts of the Mont-Wright basin.

The deposits show the cumulative effects of geological events from

Paleoproterozoic deposition through the Grenville orogeny and later

deformations culminating in deep weathering attributed to the Cretaceous

weathering. Certain structural features are poorly documented in the

literature yet significantly impact the deposit geometry. The prevalence of

deep weathering in the district also has received little regional study. The

economic impacts of each of these elements will be discussed.

Geometallurgical methods were used from initial stages of

exploration to help guide metallurgy and future mining development.

These include tracking trace element and mineralogical deportment

spatially throughout the deposits in fine detail in order to assess the

relationship between observed stratigraphy and potential economic

consequences. These studies assist in the rapid understanding of deposit

details that reduces economic risk in fast-paced development projects. The

complex magnetite-hematite deposits respond well to integrated

approaches that assess the mineralogical and structural components.

GEOCHEMISTRY AND REFINED CORRELATIONS OF

EDIACARAN STRATA IN NORTHWESTERN CANADA:

IMPLICATIONS FOR THE AGE OF EDIACARAN FAUNA AND

THEIR RELATIONSHIP TO THE PUTATIVE SECOND RISE OF

OXYGEN

Macdonald, F.A., [email protected], Strauss, J.V., Sperling,

E., Johnston, D.T., Harvard University, Cambridge, MA 02138 USA,

Halverson, G.P., McGill University, Montreal, QC H3A 2T5, and

Narbonne, G., Queen's University, Kingston, ON K7L 3N6

Ediacaran strata are present in the Ogilvie, Wernecke, and Mackenzie

Mountains of NW Canada. These successions contain Ediacaran fauna,

abundant trace fossils, large carbon isotope anomalies, and significant

shifts in Fe speciation data that have been previously attributed to a rise in

oxygen coincident with the first appearance of Ediacara fauna. Here we

report new geological mapping, stratigraphic sections, detrital zircon

geochronology, Fe speciation, trace element, and C

carb

, C

org

and S isotope

data from Ediacaran exposures across northwestern Canada. These data

demonstrate that the Ediacaran fauna from the relatively distal Sekwi

Brook sections occur above an unconformity and are not correlative with

the Sheepbed Formation at more proximal sections near Shale Lake. The

Ediacara-bearing unit at Sekwi Brook that has previously been correlated

with the Sheepbed Formation due to its stratigraphic position beneath the

Gametrail and Blueflower Formations; however, the fossiliferous strata are

not associated with the Hayhook cap carbonate, are bound by a basal

unconformity recorded by a significant incised channel that contains

abundant resedimented carbonate, ooid, and coarse quartz grains, all of

which are absent in the Sheepbed Formation near Shale Lake and

elsewhere in NW Canada. The lower Ediacaran bearing unit at Sekwi

Brook is also isotopically distinct from both the Sheepbed Formation and

the type Gametrail Formation. A new stratigraphic name is probably

appropriate for these sub-Gametrail strata at Sekwi Brook. These data

imply that the reported link between Fe speciation data and the first

appearance of Ediacaran fauna in the Mackenzie Mountains reflects a

miscorrelation. These data imply there is no relationship between the

reported Fe speciation data and the first appearance of Ediacaran fauna.

Instead, a large negative carbon isotope anomaly, potentially correlative

with the Shuram anomaly, occurs in the overlying Blueflower Formation

directly above the first well developed trace fossil assemblages.

THE FIFTEENMILE GROUP: A SEDIMENTARY RESPONSE TO

EARLY NEOPROTEROZOIC RIFTING ON THE NORTH-

WESTERN MARGIN OF LAURENTIA

Macdonald, F.A.

, [email protected], Halverson, G.P.

, Cox,

G.M.

, Payne, J.

, Sperling, E.

, Eyster, A.

, Smith, E.F.

and Strauss,

J.V.

Harvard University, Cambridge, MA 02138;

McGill

University, Montreal, QC H3A 2T5;

University of Adelaide, North

Terrace, Adelaide, SA, 5005

Geological mapping of the early Neoproterozoic Fifteenmile Group in the

western Ogilvie Mountains of Yukon, Canada, has revealed large lateral

facies changes in both carbonate and siliciclastic sedimentary rocks. These

lithological differences are the product of topographic relief that was

created by syn-sedimentary north by northwest (NNW) side down normal

faulting during deposition of the lower formations of the Fifteenmile

Group. A NNW-facing reef complex developed above sealed normal faults

with distinct reef-core, fore-reef and slope facies. Up-section, carbonate

facies prograde northwest in multiple highstand tracts with the Bitter

Springs isotopic stage and an 811 Ma ash in the penultimate transgressive

sequence. Hf isotope data suggest that the 811 Ma ash was sourced from a

LIP in South China. With these data, we propose a new tectonic model for

the Neoproterozoic evolution of NW Canada, beginning at ca. 1.1 Ga with

the accretion of the Yangtze and Cathaysia Blocks, and the formation of

the Pinguicula Group in a foredeep basin that outlined the Mackenzie Arc.

The ca. 1.1 Ga Sibao orogeny in China provided a local source of

Grenville-age zircons to the Fifteenmile Group as well as zircons that fill

the 1.4-1.6 Ga ‘North American magmatic gap’, which otherwise lack an

obvious source. This collision marked the final amalgamation of Rodinia

in a modified SWEAT-Missing Link reconstruction. The Pinguicula Group

is unconformably overlain by the Fifteenmile Group, which formed in an

extensional basin adjacent to the coeval Tsezotene, Katherine, and Little

Dal groups. Correlations between specific formations within these groups

are tested with carbon isotope chemostratigraphy. Importantly, new age

constraints on successions in the western US indicate that there are no

known basins that formed between 1.0 and 0.8 Ga between the Laird line

and Mexico, such that the basin forming event which accommodated the

Fifteenmile Group and equivalents in the Shaler and Mackenzie Mountains

supergroups is strictly a phenomenon of the NW margin of Laurentia and

not the whole of the western margin. The uniqueness of early

Neoproterozoic rifting in NW Laurentia is likely related to its proximity to

the plume that Australia-South China-Laurentia passed over, which

manifested itself sequentially in the Gaidner, Gubei, Gunbarrel, and

Franklin LIPs. Paleomagnetic and geochronological studies will provide

further tests for the proposed tectonic model.

AMS MAGNETOFABRICS AND EMPLACEMENT OF FRANKLIN

DIKES, VICTORIA ISLAND, ARCTIC CANADA

MacDonald, W.D.

, wdmacdon@binghamton.edu, Bedard, J.

Hayes, B.

, Naslund, H.R.

, Carpenter, J.

and Steigerwaldt, K.

State University of New York, Binghamton, NY 13902, USA;

Geological Survey of Canada, 490 de la Couronne, Quebec, QC

G1K 9A9

Cardiff University, Cardiff, Wales, CF310 3YE, UK

The extensive Franklin platform of Neo-Proterozoic mafic sills and flows

covers a large area of NW-central Victoria Island in the Canadian Arctic

Islands. Magnetofabric studies have been carried out on sills and dikes of

this Large Igneous Province. In this report, magnetofabric results are

presented from two dikes which fed sill complexes in the vicinity of Minto

Inlet. These dikes were sampled at 21 sites: 4 sites in a smaller feeder dike

north of Minto Inlet, and 17 sites in a much larger feeder dike system south

of Minto Inlet. Approximately 104 oriented cores were drilled from

oriented blocks from those Minto feeder dikes. Generally speaking,

magmatic flow axes can be inferred from crystal alignments in igneous

rocks, although factors other than flow gradients may influence crystal

lineations. Also, the orientation of the axis of maximum susceptibility,

max

, is generally reliable as a proxy for crystal lineations in igneous rocks.

The orientation of the K

max

axes in these two dikes is predominantly steep

to the south. Subordinate near-horizontal orientations of K

max

were also

found. The observed Kmax patterns suggest a southern magmatic source

region for the dikes that were sampled. Suggested explanations for the

shallow-plunging K

max

axes, consistent with near-horizontal flow or other

interpretations, are also discussed.

LATE DEVONIAN-EARLY CARBONIFEROUS RIFT-RELATED

BI-MODAL MAGMATISM WITHIN THE EASTERN COBEQUID

HIGHLANDS AND ASSOCIATED REE AND EPITHERMAL-AU

STYLE MINERALIZATION, NOVA SCOTIA, CANADA

MacHattie, T.G., Nova Scotia Department of Natural Resources,

Halifax, NS B3J 2T9, [email protected]

Bimodal Late Devonian to Early Carboniferous mafic and felsic plutonic

and volcanic rocks dominate the geology of the central and northeastern

Cobequid Highlands of mainland Nova Scotia. From southwest to

northeast the main lithotectonic units include: the Folly Lake Pluton (mafic

intrusives), Hart Lake-Byers Lake Pluton (felsic intrusives), Byers Brook

Formation (felsic volcanics), and Diamond Brook Formation (mafic

volcanics).

Significant rare earth element (REE) and associated Y, Zr, Nb

mineralization has recently been discovered along the contact zone

between granitic rocks of the Hart Lake-Byers Lake Pluton and overlying

cogenetic felsic volcanic and volcaniclastic rocks of the Byers Brook

Formation. REE mineralization is represented by fine- to coarse-grained

magmatic/hydrothermal granitic dykes that range in thickness from < 1 to

> 50 cm. Chemically, the mineralized dykes are characterized by elevated

SiO

(up to 75 wt.%), Fe

T (~7-13 wt.%), F (0.06-1.4 wt.%),

exceptional heavy rare earth (HREE) and high-field-strength (HFSE)

element enrichments (e.g. Y > 6000 ppm, Yb > 1000 ppm, Zr > 10000, Nb

> 1000 ppm), and anomalous Sn (200-800 ppm), W (20-200 ppm), Sb (2-8

ppm) and Zn (200-800 ppm). The origin of the dykes is interpreted, in part,

to be related to differentiation of a high-level, unusually HFSE-rich, (Na-

Fe)-amphibole-bearing alkali-feldspar granite phase of the Hart Lake

pluton. A prominent role for REE-partitioning into Na-Fe-F-rich

hydrothermal fluids of magmatic origin is suspected.

New detailed mapping within the Byers Brook and Diamond Brook

Formations has provided several new and important discoveries: (1)

epithermal-style Au mineralization has been confirmed via visible Au

found within silicified/sulfidized basalt; (2) associated with the new Au

discovery are anomalous concentrations of As, Cd, Sb, and Pb; (3)

numerous locations within the Byers Brook and Diamond Brook

Formations are host to silicified and sufidized volcanic rocks containing

anomalous concentrations of one or more of the following elements (As,

Ag, Cd, Sb, Pb, Zn, Se, Cd), and thus may also contain Au; (4) The main

centre for rhyolite magma and subsequently basaltic magma production

and eruption was within the most easterly portions of the Byers and

Diamond Brook Formations; (5) the subdivision of the Diamond Brook

Formation needs revision to reflect the east to west transition from

exclusively compound vesicular basalt flows to stratigraphically equivalent

intercalations of basalt, felsic volcanic/volcaniclasic rocks and notably

significant occurrences of epiclasitic and silicicalstic rocks.

TECTONOMAGMATIC HISTORY OF THE EASTERN

COBEQUID HIGHLANDS OF NOVA SCOTIA: IMPLICATIONS

FOR AVALONIAN LITHOSPHERIC EVOLUTION AND COR-

RELATIONS WITHIN THE APPALACHIAN OROGEN

MacHattie, T.G.

, [email protected], Murphy, J.B.

, White, C.E.

and McFarlane, C.

Nova Scotia Department of Natural Resources,

Halifax, NS B3J 2T9;

St. Francis Xavier University, Antigonish,

NS;

University of New Brunswick, Fredericton, NB E3B 5A3

New mapping, geochronology, and geochemical studies in the eastern

Cobequid Highlands of Nova Scotia have revealed previously unrecog-

nized Neoproterozoic, Early Ordovician, and Late Devonian to Early

Carboniferous tectonomagmatic events that have important implications

for lithospheric evolution and lithotectonic correlations within Avalonia.

North of the Rockland Brook fault in the southeasternmost part of the

Cobequid Highlands a newly recognized ca. 740-750 Ma calc-alkaline

gabbro/diorite, granodiorite, and granite magmatic suite intrududes

polydeformed ortho- and paragneissic units of the Mount Thom complex.

Together these units represent some of the oldest and volumetrically most

significant portions of Avalonian crust yet recognized in the Appalachian

orogen. Geochemistry and Nd isotopic compositions for the suite suggest

formation in a continental margin volcanic arc setting, and evolved

isotopic compositions of gabbroic rocks in particular implicate the

involvement of previously enriched lithospheic mantle during this stage of

Avalonian crustal formation. Currently U-Pb age investigations are

underway to ascertain the age of orthogneissic units of the Mount Thom

Complex to test the possibility that they are portions of the postulated

Meso- to Paleoproterozoic Avalonian basement based on Nd model ages.

Immediately south of the Mount Thom complex a newly recognized ca.

485 Ma bi-modal gabbro/diorite, syenite/granite intrusive suite has been

documented. This suite is similar in age and composition to the recently

discovered Ordovician West Barneys River plutonic suite in the southern

Antigonish Highlands of Nova Scotia. Geochemical and Nd isotopic

signatures suggest an extensional, within-plate continental setting, and the

isotopic composition of mafic end-members of this suite require input

from depleted asthenospheric mantle sources. South of the Rockland

Brook Fault, and the newly recognized ca. 750-740 and 485 Ma magmatic

suites, new U-Pb zircon geochronology has documented a ca. 580 Ma calc-

alkaline diorite, granodiorite, and granite magmatic suite. Geochemical

and Nd isotopic compositions suggest a continental margin volcanic arc

setting for this suite. East of the ca. 580 Ma suite, and in faulted contact

with Late Carboniferous sedimentary rocks is an undated bimodal plutonic

suite comprised of granite and diorite, and less abundant hybrid rocks

derived via mixing and mingling of these end-members is found. Based on

mineralogical, textural, and compositional similarities with ca. 360-355

Ma intrusive rocks found north of the Rockland Brook Fault this suite is

interpreted to be of similar age. Geochemical and Nd isotopic

compositions of this suite suggest that Neoproterozoic Avalonian crust was

reworked during this magmatic event.

THE RAGLAN HILLS GABBRO: A POTENTIAL Ni-Cu DEPOSIT

Magnus, S.

, seamusmagnus@hotmail.com, Easton, R.M.

, and

Cousens, B.

Department of Earth Sciences, Carleton University,

Ottawa, ON K1S 5B6;

Precambrian Geoscience Section, Ontario

Geological Survey, Sudbury, ON P3E 6B5

The Central Metasedimentary Belt of the Grenville Province in Ontario is

host to several mafic intrusive suites, such as the Lavant and Killer Creek

gabbroic suites, within which Ni-Cu-PGE mineral exploration has so far

proven to be unfruitful. Recently, First Nickel Inc. has reported the

presence of Ni-Cu and PGE mineralization in different parts of the Raglan

Hills gabbro, one of several mafic intrusions in the Bancroft Domain.

Subsequently, this study was initiated to better understand the geology,

geochemistry and metallogeny of the Raglan Hills gabbro, and to compare

it to other Grenvillian gabbros in order to gain insight into the nature of

Ni-Cu-PGE mineralization within the Central Metasedimentary Belt. One

month of fieldwork was completed in 2011, from which the data and

preliminary interpretations presented herein are based.

The Raglan Hills gabbro has been subjected to at least 2 regional

metamorphic events at circa 1160 and 1050 Ma, respectively. Despite this

history, deformation of the Raglan Hills gabbro is concentrated along the

margins of the body, and local preservation of primary textures occurs in

the core of the body. The Raglan Hills gabbro has been previously

assigned to the Killer Creek gabbroic suite, based on limited data.

Three main rock types are present in the Raglan Hills gabbro, each

with distinct major- and trace-element geochemical signatures in both

major and trace elements; these are referred to as primary gabbro,

deformed gabbro, and hornblendite.

The primary (pyroxene-bearing) and deformed gabbro (amphibolites)

phases have been observed in diamond-drill core to grade into and out of

one-another, suggesting that the deformed gabbro is the product of

metamorphosing the primary gabbro, likely through the introduction of a

hydrous phase. Both rock types display relatively flat REE patterns at

roughly 10 to 20 times chondritic values, and negative anomalies in the

high-field-strength (HFSE) elements (Th, Zr, Hf, Ti), as well as P, Nb and

Ta. These anomalies suggest that the magma was crustally-contaminated

during emplacement.

The hornblendites (meta-pyroxenites) have been observed to cross-

cut igneous layering preserved in the gabbroic units, both in outcrop and in

diamond-drill core. These rocks are enriched in REEs and phosphorous,

but have less pronounced negative HFSE anomalies. These hornblendites

may represent a slightly more evolved magma, albeit more mafic; and

perhaps the mechanism by which magma was fed from the magma

chamber (the Raglan Hills gabbro) into mafic dykes, sills, and

metavolcanic rock units surrounding the intrusion.

MINERAL CHEMISTRY AND THERMOMETRY OF MAFIC

AMPHIBOLITE-FACIES ROCKS IN NUVVUAGITTUUQ

GREENSTONE BELT, CANADA

Majnoon, M., mohadeseh.majnoon@mail.mcgill.ca, Minarik, W.G.,

Hynes, A., Trzcienski, Jr., W.E., McGill University, 3450 University

St., Montreal, QC H3A 2A7, and O'Neil, J., Laboratoire Magmas et

Volcans, Université Blaise Pascal, Clermont-Ferrand, France

The dominant lithologies of the Nuvvuagittuq Greenstone belt (Northeastern

Superior Province, Canada) are composed of mafic amphibolite-facies rocks

(referred as the Ujaraaluk unit). With a minimum age of 3.8 Ga and possibly

as old as 4.3 Ga, these rocks are among the oldest in the world. The

Nuvvuagittuq Greenstone belt occurs in the western Minto Block which was

last pervasively metamorphosed at ca. 2.7 Ga.

Rocks from the Ujaraaluk unit are generally Ca-poor and subdivided

into a high-Ti and a low-Ti group based on their bulk chemical

composition. The low-Ti rocks are interpreted to stratigraphically overlie

the high-Ti rocks. Here we present a detailed mineral chemistry and

thermometry study of the Nuvvuagittuq mafic rocks to investigate if their

paragenesis is controlled by a metamorphic gradient through the belt or

whether it is controlled by geochemical variations.

Petrography and mineral chemistry reveal two different rock types:

garnet + biotite + plagioclase + quartz schists without amphibole, occuring

primarily in the central part of the area, and amphibole schists composed

of biotite + amphibole + plagioclase + quartz ± garnet. Amphibole may be

either cummingtonite or anthophyllite or Mg- and Fe-hornblende occuring

alone or in combination. Although the mineral assemblages are different,

no systematic geographical distribution is found in the field.

Garnets, primarily in the central part of the Nuvvuagittuq Greenstone

Belt, are mostly unzoned with respect to major cations; most have thin

rims reflecting cation exhange on cooling. Garnet-bearing samples have

higher whole-rock FeO* and Al

than garnet-poor samples. Biotite-

garnet geothermometry was applied to both rock types from 18 localities,

and gives temperatures clustering around 660°C. Whole-rock chemistry,

garnet mineral chemistry and thermometry across the region suggest that

the presence of garnets is a result of the whole-rock chemistry rather than

metamorphic grade.

We suggest that the event responsible for metamorphism of the

Minto Block at 2.7 Ga was also the main metamorphic event that affected

the Nuvvuagittuq Greenstone Belt. This conclusion is also supported by

Neoarchean Sm-Nd ages obtained in the Nuvvuagittuq garnets. Any earlier

metamorphism, likely given the protracted history of these rocks, has

apparently been obliterated.

MORPHOLOGY OF DETRITAL MAGNETITE IN GLACIAL

TILL: CASE STUDY FOR APPLICATION TO MINERAL

EXPLORATION FOR VMS DEPOSITS AT IZOK LAKE,

NUNAVUT

Makvandi, S., sheida.makvandi.1@ulaval.ca, Beaudoin, G.,

[email protected], Université Laval, Département de

géologie et de génie géologique, 1065, avenue de la Médecine,

Quebec, QC, G1V 0A6, and McClenaghan, B., Geological Survey of

Canada, 601 Booth street, Ottawa, ON K1A 0E8, bmcclena

@nrcan.gc.ca

Surface textures and shape of detrital mineral grains document their

history from hypogene formation to erosion and transport to a sedimentary

deposit. We report results from a study of the surface textures and shapes

of detrital magnetite from glacial till that contains debris eroded from the

amphibolite-grade Izok Lake Zn-Cu-Pb-Ag VMS deposit. The surface

textures and grain shapes are integrated with distance from the deposit and

ice-flow paths to outline criteria useful for application in VMS exploration.

A total of 279 grains from the 0.25-2.0mm ferromagnetic fraction of host

rocks, mineralized rocks, till samples up- and down-ice from the deposit

were examined. Mineral grains were liberated from rocks using electric

pulse disaggregation so as not to destroy or break grains. Surface texture

and shape have been investigated using a Scanning Electron Microscope.

Magnetite in gabbroic rocks displays an angular shape and the

predominant textures including triangular pits, and overgrowth. In iron

formations, magnetite is porous and forms aggregates with silicates.

Magnetite in gahnite-rich rocks has irregular to triangular dissolution pits,

overgrowth, cracks, and sub-conchoidal and step-like fractures.

Disseminated magnetite is abundant at the contact of gahnite-rich zones

and massive sulfides. It is locally porous and fractured. In mineralized

rocks, magnetite is euhedral with cracks and sub-conchoidal, step-like, and

irregular fractures. Porous magnetite in all these rocks locally forms rims

surrounding primary hematite. The porous nature of the magnetite is the

result of hematite reduction to magnetite in presence of Al, Ca, Mg oxides

or silicates. Presence of these elements in magnetite composition was

verified using an Electron Probe Micro-Analysis. It shows that magnetite

surface features correlate with its chemistry. Triangular pits are likely

growth defects similar to those reported on diamonds.

In detrital magnetite, grain roundness and the number of cracks

gradually increase as distance increases from the mineralization along ice-

flow paths. Appearance of spherical fractures, widespread dissolution

features, presence of pits resulted from dissolution of inclusions, and

precipitation textures characterize detrital magnetite and contrast it from

magnetite in host rocks. These textures are compatible with glacial

transport and have been developed as the grains have experienced more

erosion and transport. The final shape of detrital magnetite is a function of

its primary crystallization shape and its glacial transport, and can be used

to estimate relative distance of glacial transport. Accordingly, magnetite

shape and surface texture information combined with mineral chemistry

can be useful for VMS exploration in glaciated terrain.

NEW FISSION-TRACK DATA IN THE NORTHEASTERN GASPÉ

BELT: IMPLICATIONS FOR BURIAL HISTORY OF ORDO-

VICIAN AND DEVONIAN SOURCE ROCKS IN THE GASPÉ

PENINSULA

Malo, M.

, [email protected], Roden-Tice, M.K.

, Pinet, N.

Grundman, G.

and Parent, A.

Institut national de la recherche

scientifique, Québec, QC G1K 9A9;

Center for Earth and

Environmental Science, SUNY Plattsburgh, Plattsburgh, NY 12901;

Geological Survey of Canada, Québec, QC G1K 9A9

The Gaspé Belt is the largest middle Paleozoic belt in the Canadian

Appalachians. In the Gaspé Peninsula, it consists of Upper Ordovician to

Middle Devonian sedimentary rocks, with minor volcanics, resting

unconformably on Cambrian-Ordovician rocks of the Humber and

Dunnage zones.

Lower Devonian siliciclastic rocks of the Indian Point, York River

and Battery Point formations were collected on both sides of the Bras

Nord-Ouest fault for apatite fission track (AFT) dating. These Devonian

rocks, mainly deformed during the Middle Devonian Acadian orogeny, are

unconformably overlain by flat-lying Carboniferous strata. Post-Devonian

reactivation of a few faults is documented by the offset of a Carboniferous

dyke.

Seven surface samples yielded a sufficient amount of apatite to allow

AFT dating. AFT ages range between 284 ± 35 and 247 ± 27 Ma (Permian

to lowermost Triassic) with mean track length from 11.7 to 12.3 ± 1.7

microns. AFT ages are younger than the sandstone ages, which indicate

that the AFT clock has been reset and thus the hosting rocks experienced

temperature higher than ~100°C, in agreement with organic matter

maturation data. The difference in AFT ages for samples from both sides

of the Bras-Nord-Ouest Fault is probably not significant, indicating that

post-Carboniferous vertical motions along the fault were not enough to

alter the AFT age distribution.

In the study area, previous thermal modeling studies considered that

the maximum burial occurred during the sedimentation of the Middle

Devonian Malbaie Formation, which was followed by Acadian

deformation and erosion before deposition of a relatively thin (~ 500 m)

Carboniferous cover, and low denudation rates up to the Permian. In an

alternative scenario, significant burial was reached due to the

sedimentation of a pluri-kilometric Carboniferous sedimentary pile as it is

recognized in the Gulf of St. Lawrence. In this case, sampled rocks left the

apatite partial annealing zone (~60-120°C; ~oil window) later, after the

Upper Paleozoic Maritimes Basin sedimentation, in agreement with AFT

ages. New thermal models indicate that a realistic solution in which

calculated organic maturation values closely match observed values in

wells can be generated for both scenarios with geologically acceptable

parameters. However, these two scenarios may differ significantly on the

timing of hydrocarbons generation and migration.

EFFECTS OF LICHEN COVER ON REMOTE SENSING BASED

NORTHERN MINERAL EXPLORATION

Maloley, M., mmalo[email protected], Harris, J., Peter, J., White,

H.P. and Gauthier, R., Natural Resources Canada, Ottawa, ON K1A

0E4

Optical remote sensing systems offer mineral mapping solutions for

Canada’s North through the measurement of a contiguous, high resolution

spectral measurements of non-vegetated surfaces. Past research has shown

that minerals, with distinct visible and infrared reflectance properties, can

be detected with satellite based observations. Although a large portion of

the Canadian North is above the tree- line and considered exposed and

therefore optimal for mapping of surficial geology, lichen cover can

signifcantly obscure underlying mineral signatures. This paper attempts to

address lichen cover issues by comparing in situ and remotely sensed

spectral measurements of surficial mineralogy from the massive sulphide

deposit at Izok Lake, Nunavut. The in situ spectral measurements consist

of both lichen covered sites and co-located sites with the lichen removed

by pressure-washing. The remotely sensed imagery consists of

hyperspectral imagery acquired ProSpecTIR-VS sensor imagery on August

17, 2010 at 1.0m resolution with 360 bands between the 390-2500 nm

spectral range. The spectral properties of lichen and non-lichen minerals

were compared and hyperspectral "unmixing" techniques were employed

to map both percent lichen cover and mineral composition for exposed

rock. Simulations of scale effects were also considered to test the

suitability of current and proposed operational sensor resolutions, such as

Landsat at 30m, for mineral mapping in regions of significant lichen cover.

SM-ND PROVENANCE STUDY OF THE PERMIAN TO

PALEOGENE STRATA, THE NORTHEAST PART OF SIBERIAN

CRATON

Malyshev, S.V., ser[email protected], Khudoley A.K., St.

Petersburg State University, St.Petersburg, Russia, Prokopiev A.V.,

Diamond and Precious Metal Geology Institute, Yakutsk, Russia, and

Ershova V.B., St. Petersburg State University, St.Petersburg, Russia

The Northeast part of the Siberian Craton contains a thick Permian –

Paleogene clastic succession in which Permian – Jurassic rocks were

deposited on the craton’s margin, Cretaceous rocks were deposited in the

Priverkhoyansk foreland basin and Lena-Anabar sedimentary basin,

whereas Paleogene rocks fill in rift basins. We have carried out a Sm-Nd

study to identify possible provenance of clastic rocks. Forty two sandstone

and shale samples of different stratigraphic levels were analyzed. For

provenance analysis we used variations in ε

Nd(t)

values where ε

value is

referred to the time of sedimentation. Data on Th/Sc ratio values are

incorporated as well.

Permian sediments have ε

Nd(t)

values varying from -2 to -11 that

reflects mixed cratonic and juvenile sources. Significant deviations to less

negative (more juvenile) values between -6 and +1 represent mixing

derivation of mafic rocks and recycled Permian sediments. The Th/Sc ratio

values from Triassic sediments are typical for mafic rocks, that points to

their wide distribution in the provenance. Jurassic sediments show

heterogeneity with ε

Nd(t)

values from -2 to -12 and can be explained by

existence of two source areas with predominance of cratonic and juvenile

rocks. Cretaceous and Paleogene sediments show significant decreasing in

Nd(t)

values up to -20, suggested as increasing input of the cratonic source.

Data on Th/Sc ratio values correspond with this conclusion.

According to the Nd isotopic and Th/Sc data we propose that studied

clastic succession were derived from several types of sources such as

cratonic and juvenile ones. The cratonic sources were the Precambrian

basement highs including, probably, the Anabar and Aldan shields.

Juvenile components are likely derived from Taimyr orogen in Permian

and from Norilsk traps and their correlatives in Triassic and Jurrassic time.

TECTONIC AND DEPOSITIONAL CONTROLS AFFECTING OIL

AND GAS PRODUCTION FROM THE UTICA SHALE, EASTERN

NORTH AMERICA

Martin, J.P., jpm1959@buffalo.edu, and Jacobi, R.D., rdjacobi@

buffalo.edu, Shale Resources and Society Institute, University at

Buffalo

Experience developing shale gas plays in the past 30 years has

demonstrated that every shale play is unique. Each individual play has

been defined, tested and expanded based on understanding the geology,

resource distribution, natural fracture patterns, and limitations of the

reservoir, and each play has required solutions to problems and issues

required for commercial production. The Ordovician Utica Shale and its

equivalents are no different.

These shales were deposited very broadly across the foreland basin

created during the Taconic orogeny and cover thousands of square miles

across eastern North America. The complex relationship between the

development of the orogeny and the basin are critical to understanding the

development of productive black shale reservoirs.

Deposition of the Utica black shale beds occurred during an active

tectonic period, cyclically depositing shale and carbonate units.

Syndepositional faulting resulted in variable depositional rates and depths,

causing TOC variations across the faults separating the fault blocks.

During and after deposition, Taconic tectonism promoted the development

of fractures, folds and faults. In eastern NYS these early fractures are now

filled with vein material. These early fractures may have been migration

pathways for early hydrocarbon generation, since the fracture fills (veins)

commonly contain anthraxolite. Later fractures were generated during later

orogenic cycles, including the Alleghanian and more recent stress fields.

These fracture remain vein-free, but they probably also acted as

hydrocarbon migration pathways.

Ultimately, deposition and bed heterogeneity can be traced to this

complex structural history. Analysis indicates that rapid declines in

thermal maturity occur over very short distances away from the overthrust

zone. These factors affect the presence of organic material, catagenesis,

and the development of organic porosity. Understanding how these factors

affect hydrocarbon quantity and quality may help answer whether we can

identify the sweet spots in the Utica Shale.

RHEOMORPHIC FENITE AND CRUSTAL CARBONATITES:

NEW COMPLICATIONS IN THE GRENVILLE CRUST, OLD

CHELSEA AREA, QUEBEC

Martin, R.F. and Sinai, F., Earth and Planetary Sciences, McGill

University, Montreal, QC H3A 2A7

The recent (2009) opening of an extension of Autoroute 5 north of Old

Chelsea, Quebec, has produced striking roadcuts over a length of 2 km,

with a wide variety of rock types and a very complex and bewildering

juxtaposition of igneous, metamorphic, and metasomatic assemblages of

minerals. We focus here on an unexpected discovery of evidence of

fenitization of the regionally developed quartzofeldspathic gray gneiss.

This transformation occurs near dikes of orange calcite, which typically

have a selvage of tiny euhedral diopside crystals and apatite granules.

Above the dikes are diffuse zones of fracture-controlled reddening of the

gray gneiss, in which the original mineralogy is replaced by a more felsic,

alkali-feldspar-dominant “syenitic” material. The orange calcite in those

dikes [δ

C ¡Ö –1‰, δ

O ¡Ö 16‰] is isotopically intermediate between

the regionally developed white marble [δ

C ¡Ö 3‰, δ

O ¡Ö 24‰] and a

typical mantle-derived carbonatite [δ

C ¡Ö –5‰, δ

O ¡Ö 6‰]. We

contend that the regional marble was locally metasomatized by an alkaline

fluid of mixed crust and mantle derivation, then melted. Upon

crystallization, this carbonate melt gave off a strongly alkaline H

O-

dominant fluid that converted the gneissic host-rock into a quartz-bearing

syenitic composition. Nearby, we see evidence of zoned dikes of unusual

syenite that cut the orange dikes or are cut by them. The margin of the

syenite dikes contain a peristeritic sodic plagioclase, whereas the core is

pink and K-feldspar- dominant. There are also signs of coarse graphic

granite in some dikes. The whole package is consistent with an influx of

fluids and heat at the Late Ottawan stage of the Grenville event in the area,

at roughly 1040 Ma. We attribute this activity to renewed delamination,

rapid rise of an asthenospheric mantle in the process of degassing,

aggressive metasomatism of deep crustal units, and localized production of

coeval anatectic syenitic, granitic and carbonatitic magmas. Whether such

fenitization reactions active on a broader scale are responsible for large

plutons of syenite in the area (e.g., the Wakefield syenite) merits an in

depth investigation. Models for the evolution of the Grenville crust must

necessarily involve input from the mantle.

NYAINQÊNTANGLHA GLACIATION: COUPLING BETWEEN

TECTONICS, LANDSCAPE MORPHOLOGY AND GLACIAL

EROSION

Martins, M.C., mikael.mar[email protected], and Schoenbohm, L.M.,

University of Toronto, 359 Mississauga Road N, Mississauga, ON

L5L 1C6

The Nyainqêntanglha Mountain range is located 300 km northwest of

Lhasa and immediately south of Namtso Lake in central Tibet. It strikes

southwest-northeast and spans a distance of over 600 km. The range is

bounded to the southeast by a normal fault. 30 peaks within the range

surpass 6,000 m elevation, and 4 peaks are over 7,000 m high, with the

highest peak reaching 7,162 m. In this study we analyzed 590 glaciers

located throughout the range to see how they interact with the morphology

of the landscape and exhumation rates, and how this can be connected to

the local climate. Using ArcGIS and remote sensing imagery including

Landsat ETM+, and GDEM 30 m resolution digital elevation models we

identified the location of glaciers across the range, and quantified several

of their key characteristics such as area, length, head/toe elevations, slope,

and ELA. When calculating the ELA of the glaciers, AA and AABR

methods were used, using a BR ratio of 1.75. ELA is related to the relative

size and altitude distribution of the accumulation and ablation zones of

each glacier, and is tied to the location of maximum glacial erosion.

Therefore, identifying these local and regional ELA variations is essential

in order to understand the overall range morphology. As ELA is controlled

by temperature and precipitation, we also relate our ELA observations to

local climate. For this study PRISM data is used to estimate the amount of

precipitation that falls throughout the range, but due to a lack of weather

stations in the area, no temperature data are available. Preliminary results

indicate that the majority of the glaciers are found on the upwind,

southeastern side of the range, which is possibly due to increased

orographic precipitation there. The largest glaciers are found straddling the

highest peaks, but it is not yet known if they are caused by the high

precipitation drawn in by the peaks, or if they themselves are promoting

the formation of high peaks by eroding material and increasing local

exhumation rates and relief production. It was also found that the high

peaks are offset to the east from the drainage divide, which suggests that

there is either aggressive headward erosion or the preservation of an older,

pre-uplift drainage basin morphology.

PALEOENVIONMENTAL ANALYSIS OF EDIACARAN FOSSIL-

BEARING FORMATIONS OF THE CATALINA DOME,

BONAVISTA PENINSULA, NEWFOUNDLAND

Mason, S.J., Narbonne, G.M., Dalrymple, R.W., Queen's University,

Kingston, ON K7L 3N6, mason@geol.queensu.ca, and O'Brien, S.J.,

Geological Survey of Newfoundland and Labrador, St. John's, NL

A1B 4J6

In 2008, Hofmann and colleagues described Ediacaran fossils from

Newfoundland's Bonavista Peninsula, exposed in a small (about 5km

diameter) dome near the town of Catalina. The strata in which these fossils

are found have been correlated with the Conception and St. John's groups

of the adjacent Avalon Peninsula, famous for the Mistaken Point

assemblage of early complex macrofossils. Detailed sedimentological

study of the Catalina Dome allows for comparison with previous

paleoenvironmental analyses of correlative Avalon Peninsula stratigraphy

in order to constrain further the nature of the basin in which the Ediacaran

biota evolved. The succession formed in a deep marine environment in a

tectonically active possible forearc basin. It is dominated by muddy

turbidites with abundant thin beds of volcanic ash; soft sediment

deformation occurs throughout the succession, due to seismicity in the

lower part, and due to slumping toward the top. This records a transition

from a basin plane to slope environment. Thick-bedded muddy turbidites

in the lower third of the succession are consistent with a previous

interpretation that turbidite ponding may have occurred due to a

topographic high to the east. A particularly sandy 94 m-thick interval not

present in the Avalon succession may have been deposited in a turbidite

channel. Compared to equivalent strata on the Avalon Peninsula, ash is

more abundant in the Catalina Dome, with thicker beds and persistence of

ash deposition to higher stratigraphic levels, likely due to a position closer

to the volcanic arc to the west. Because the ash provides the mechanism

for preservation of soft-bodied biota, and fossil assemblages are similar

between the base and the top of the succession, Hofmann et al. observed

that this succession extends the stratigraphic range of the Mistaken Point

biota. The occurrence of complex frond fossils beneath ash beds at this

stratigraphic level as well as surfaces with only the controversial discoid

taxon Aspidella that is similar to what is observed in equivalent strata on

the Avalon Peninsula supports interpretation of Aspidella as the holdfast of

otherwise unpreserved frondose organisms. Previous workers studying the

Conception and St. John's groups on the Avalon Peninsula recorded a shift

in turbidite paleocurrent direction from roughly eastward to southward,

consistent with the existing tectonic model for the basin: a transition from

convergence to strike-slip. However, the paleocurrent change occurs at a

different stratigraphic level in each area, which suggests significant

diachroneity in this transition.

OPENING THE WINDOW ON SHALLOW MARINE TO NON

MARINE PALAEOBIOLOGY IN THE EDICARAN OF AVALONIA

Matthews, J.J.

, [email protected], McIlroy, D.

and

Brasier, M.D.

1,2

Department of Earth Sciences, University of

Oxford, South Parks Road, Oxford, OX1 3AN, UK;

Department of

Earth Sciences, Memorial University of Newfoundland, St. John’s,

NL A1B 3X5

Rocks of the Avalon terrane from England and Newfoundland show many

remarkable similarities in their succession of environments, passing from

deeper marine slope deposits on the flanks of a volcanic arc, through

deltaic cycles, towards fluvial sediments and then non deposition shortly

before the end of the Ediacaran Period. Shallow marine to fluvial deposits

within the St John’s Group, in Newfoundland, have hitherto been regarded

as having a poor or even non-existent biota. This is not confirmed by our

current studies, in which we are finding remarkably preserved macrofossils

and microfossils in these rocks, which show exciting comparisons to those

of the Longmyndian in England. Of great interest in these studies is the

possibility that some of these shallow water deposits are contemporaneous

with deeper water sediments containing the more familiar rangeomorph

assemblages. These shallow marine to fluvial environments, and others

under investigation, clearly have interesting potential for palaeontological

discoveries within the Ediacaran of Avalonia.

MICROFOSSIL EVIDENCE OF AN 8000 YEAR HIATUS ON THE

CRAWFORD LAKE SHORELINE

McCarthy, F.M.G., fmccar[email protected], Drljepan, M., Brears, E.,

Krueger, A. and members of the 2011 Paleolimnology Class, Brock

University, St. Catharines, ON L2S 3A1

Crawford Lake occupies a small (~2.5 ha), deep (z

max

~24 m) basin

excavated by glacial activity from the edge of the Niagara Escarpment in

Milton. Because of its morphology, the lake is meromictic, allowing

varved sediments to accumulate in the deep basin over much of the last

millennium (Boyko-Diakonow, 1979; Dickman, 1979). In a core recovered

from the shoreline at its outflow, however, a long hiatus is recorded

between marl deposited during the early Holocene pine zone (McAndrews,

1994) and ragweed pollen-rich woody organic debris deposited since Euro-

Canadian settlement. The lower 17 cm of the 97 cm core consists of grey

calcareous clay assigned to the late Pleistocene spruce zone and a gradual

transition from buff clay to marl around 60 cm (during the early Holocene

northern pine zone) records a decline in water level during this arid

interval. Continued warming allowed southern pine to replace northern

pine ~8.2 ka BP and led to an increase in productivity in the lake that is

recorded in the planktonic and benthic microfossil record. This natural

eutrophication is probably due to evaporation and concentration of

nutrients, a response similar to that in Sluice Pond, MA (Hubeny et al.,

submitted). No sediments were deposited between ~ 7.5 ka BP and the

1880s when logging (to which the woody debris is attributed) took place.

The hydrology of Crawford Lake appears to have been sufficiently altered

by construction of the lumber mill on the south shore of the lake to allow

sediments to accumulate again at the lake’s outflow following several

millennia of drought-induced low lake levels, especially between ~4.8 and

2 ka (Yu et al., 1997).

Boyko-Diakonow, M., 1979. The laminated sediments of Crawford Lake,

southern Ontario, Canada. In: Schluchter, C., editors. Moraines and

Varves. A.A. Balkema, Rotterdam, p. 303-307.

Dickman, M.D., 1979. A possible varving mechanism for meromicitic

lakes. Quaternary Research 11, 113-124.

Hubeny, J.B. et al., submitted. Holocene stratigraphy, environmental

history and regional hydroclimate significance of Sluice Pond,

northeastern MA. Manuscript HOL-11-0143 submitted to The

Holocene.

McAndrews J.H., 1994. Pollen diagrams for southern Ontario applied to

archaeology. In: MacDonald RI (ed) Great Lakes Archeology and

Paleoecology: Exploring Interdisciplinary Initiatives for the Nineties,

Quaternary Sciences Institute, University of Waterloo, Waterloo,

Ontario, pp 179-195.

Yu, Z. et al., 1997. Middle Holocene dry climate caused by change in

atmospheric circulation patterns: evidence from lake levels and stable

isotopes. Geology 25:251-254.

METAL ZONATION AND DEVELOPMENT OF Cu-ZONES IN

VOLCANOGENIC MASSIVE SULFIDE DEPOSITS OF THE

BATHURST CAMP, NEW BRUNSWICK: AN OVERVIEW

McClenaghan, S.H.

, [email protected], and Lentz, D.R.

New Brunswick Department of Natural Resources, Geological

Surveys Branch, PO Box 50, Bathurst, NB E2A 3Z1;

Department of

Geology, University of New Brunswick, PO Box 4400, Fredericton,

NB E3B 5A3

Zn-Pb-Cu-Ag-type volcanogenic massive sulfide deposits of the Bathurst

Mining Camp (BMC) are for the most part syngenetic-exhalative in origin,

and intimately associated with laterally extensive Algoma-type iron

formations that together define the Brunswick Horizon. Based on

mineralogy and stratigraphic (footwall-hanging wall) relationships,

massive sulfides in the BMC can be divided into two principal

hydrothermal facies; 1) An exhalative Zn- and Pb-rich bedded sulfide

facies composed of pyrite, sphalerite, galena and lesser chalcopyrite; and

2) An epigenetic Cu-rich sulfide facies, commonly referred to as a basal

Cu-zone or vent complex, and comprising massive to brecciated pyrite (±

pyrrhotite) and chalcopyrite with lesser sphalerite.

The largest and most developed Cu resource in the BMC occurs at

the 329 Mt Brunswick No.12 deposit, where a Cu-enriched basal keel

underlying bedded Zn-Pb (ore) is estimated to contain 64.5 Mt grading

0.98% Cu, of which 5.4 Mt grades 1.53% Cu. Massive sulfides sampled

(n=64) from the Brunswick No.12 Cu-zone average 1.28% Cu, 1.05% Zn,

0.28% Pb, 38.0 ppm Ag, and 0.35 ppm Au, and exhibit distinct

enrichments in Bi (555 ppm), Co (1690 ppm), and Se (34.2 ppm), relative

to the bedded sulfide facies. Pyrrhotite is a significant component of the

basal Cu-zone, comprising up to 40% of the Cu zone and strongly

controlling contents of Co and Se, averaging 0.09% and 0.03%,

respectively. Sphalerite, which can exhibit extensive chalcopyrite disease,

is markedly depleted in the Cu zone and accounts for less Co (ave., 0.08%)

and Se (ave., 0.02%). Pyrrhotite barren Cu-zones in the BMC typically

exhibit lower levels of Co. The 21 Mt Murray Brook deposit has one of the

richest Cu-zones in the BMC with an estimated 2.1 Mt grading 2.0% Cu.

Yet massive sulfides sampled (n=37) from this Cu-zone (ave., 4.72% Cu)

exhibit much lower levels of Co (379 ppm). Nevertheless, these Cu-zones

display marked enrichment in Co, Se and Bi, relative to their co-genetic

Zn-Pb sulfide facies.

A proximal Cu-Co-Bi-Se signature is prevalent among Cu-zones of

the BMC and its distribution across hydrothermal facies is interpreted to

reflect high temperature zone-refining processes. This is corroborated by

the high abundance of chalcopyrite, arsenopyrite, and native bismuth all of

which have higher temperature sensitive solubilities than sphalerite and

galena, and strongly reflecting assemblages in adjacent (footwall)

epigenetic stockwork zones. Variations in mineralogy (± pyrrhotite) result

from differing ƒS

, and perhaps ƒO

conditions, during development of the

large replacement-style Cu-rich facies.

TRILOBITES FROM THE EARLY ORDOVICIAN (IBEX) OF

NORTH-EAST GREENLAND: REVISITING OLD COLLECTIONS

IN THE LIGHT OF NEW LITHO- AND BIOSTRATIGRAPHIC

DATA

McCobb, L.M.E., lucy[email protected], Department of

Geology, National Museum of Wales, Cathays Park, Cardiff, CF10

3NP, UK, Boyce, W.D., [email protected].ca, Knight, I.,

[email protected], Geological Survey, Newfoundland and

Labrador Department of Natural Resources, PO Box 8700, St. John's,

NL A1B 4J6, and Stouge, S., Natural History Museum of Denmark,

Geological Museum, Øster Voldgade 5–7, DK-1350 Copenhagen K,

Denmark, [email protected]

A 1.5 km thick succession of Early to Middle Ordovician peritidal to

subtidal carbonates is exposed in North-East Greenland, mainly on Ella Ø

and Albert Heim Bjerge. A significant trilobite collection was amassed by

John Cowie and Peter Adams during 1950s mapping of the area, but

descriptions were never published. Ongoing studies of the macro- and

microfaunas incorporate these historical collections with those made

during GEUS-led mapping and logging of the Cambrian–Ordovician

sequence in 2000/2001. The data from these expeditions has made it

possible to place the earlier trilobite collections within updated

lithostratigraphic and conodont biostratigraphic contexts.

The revised Antiklinalbugt Formation (Tremadocian) has yielded a

diverse trilobite fauna, including two new species of the dimeropygid

Tulepyge. Conodonts place the lower Antiklinalbugt Formation in the

Cordylodus intermedius Biozone, the lower upper part in the Cordylodus

angulatus conodont Biozone and the uppermost part in the Rossodus

manitouensis conodont Biozone.

The Cape Weber Formation has also been revised, and a new

formation, the Septembersø formation, erected at its base. A significant

disconformity encompassing the upper Tremadocian Stage (= Stairsian

Stage) separates the Antiklinalbugt from the overlying Septembersø

formation. The trilobites of the Septembersø formation comprise members

of the Family Bathyuridae, including, Bolbocephalus, Peltabellia, Punka,

Randaynia and a new genus.

The diverse trilobite fauna of the (revised) Cape Weber Formation

(ca. 1100 m thick) is dominated by bathyurids; at least seven other families

are represented. The trilobites indicate correlation with Strigigenalis

brevicaudata, S. caudata and Benthamaspis gibberula zones of western

Newfoundland, equivalent to Protopliomerella contracta (G

) to

Presbynileus ibexensis (I) zones of Utah-Nevada. Some trilobites in the

upper subunits of the Cape Weber Formation range into the Pseudocybele

nasuta Zone (J). This age range is supported by conodonts, which

represent the Oneotodus costatus, Oepikodus communis and O.

intermedius Biozones.

The ‘Black Limestones’, a distinctive dark grey limestone unit

developed on Albert Heim Bjerge but not Ella Ø, yielded

biostratigraphically important trilobite species, indicating a range into the

Pseudocybele nasuta Zone (J) (Cybelopsis speciosa Zone of western

Newfoundland); based on conodont evidence, the unit correlates with the

upper member of the revised Cape Weber Formation. The ‘Black

Limestones’ provide evidence for deeper water incursion onto the

carbonate platform, corresponding to the eustatic high known as the ‘Evae

transgression’.

A NEW U-Pb ZIRCON AGE AND GRAPTOLITE FAUNA FOR

THE BELLEWSTOWN TERRANE, EASTERN IRELAND, CON-

STRAIN DUNNAGE ZONE CORRELATIONS

McConnell, B., Geological Survey of Ireland, Beggars Bush, Dublin

4, Ireland, brian.m[email protected], Crowley, Q., Department of

Geology, School of Natural Sciences, Trinity College, Dublin 2,

Ireland, crowleyq@tcd.ie, Parkes, M., Natural History Museum,

Merrion Street, Dublin 2, Ireland, [email protected]

New exposures within the Ordovician Bellewstown Terrane sequence in

the Iapetus suture zone of eastern Ireland (Hilltown Formation) reveal a

graptolite fauna in shale overlying a felsic tuff. Zircons extracted from

sand-grade tuff are exclusively prismatic and primary in appearance. U-Pb

dating of the zircons by LA-ICP-MS (n=75) gives a ‘TuffZirc’ age of

474.1 +1.1-2.5 Ma (Floian: Arenig). An intra-Iapetus brachiopod fauna

from a horizon just below the dated tuff was previously assigned to the D.

artus Biozone (Darriwilian: Llanvirn) based on graptolites from elsewhere

in the Hilltown Formation, although equivalent brachiopod faunas in the

Dunnage Zone of Newfoundland are older. Characterisation of the new

graptolite fauna is ongoing and will be reported at the conference. The new

age for the tuff appears to reconcile the previous faunal age discrepancy

and allow correlation between Bellewstown and other intra-Iapetan

volcanic terranes.

NEW INSIGHTS INTO THE STRATIGRAPHIC-STRUCTURAL

RELATIONSHIPS OF COMPLEXLY FOLDED ROCKS OF THE

WOODBURN LAKE AND KETYET RIVER GROUPS, NUNAVUT,

CANADA

McEwan, B., Bethune, K.M., Riemer, W., University of Regina,

3737 Wascana Pkwy., Regina, SK S4S 0A2, [email protected]om,

and Jefferson, C.W., Geological Survey of Canada, Rm 659 – 601

Booth St., Ottawa, ON K1A 0E8

Archean to Paleoproterozoic rocks of the Rae Craton, Western Churchill

Province, have been affected by polyphase deformation and

metamorphism causing structural complexity and confusion regarding the

age and affiliation of rock units. This study aims to improve the

stratigraphic-structural understanding of Neoarchean rocks and the

Paleoproterozoic Ketyet River group through detailed mapping of four

areas in the region NNW of Baker Lake: “Nipterk Lake”, “Ukalik Lake”,

“Bar Lake” and Kiggavik, north of the uranium deposits. This will provide

better knowledge of the basement rocks to assist unconformity-related

uranium exploration marginal to the late Paleoproterozoic Thelon Basin.

In 2010 and 2011, 1:6,000 to 1:70,000 scale mapping in the first

three areas revealed that the Ketyet River group comprises thin

metaconglomerate gradationally overlain by orthoquartzite and grey pelitic

schist. At Bar Lake, sills of metagabbro within the latter may be equivalent

to the Five Mile Lake basalts, substantiating correlation to the Amer

Group. The metaconglomerate and orthoquartzite unconformably overlie

2.6 Ga quartz-K-feldspar porphyritic schist (QFP schist) and parts of the

Woodburn Lake group ranging from feldspathic metagreywacke to

komatiite. Where the metaconglomerate is absent, the base of the

orthoquartzite contains “quartz eyes” resembling those of the QFP schist.

Cross-beds at the base and top of the orthoquartzite respectively face away

from the QFP schist and toward the pelitic schist, providing control on the

younging direction. The quartzite-pelitic schist contact is gradational;

approaching the contact, decimetre-scale pebble-metaconglomerate and

centimetre-scale pelitic schist interbeds are more common, whereas above

the contact, the pelitic schist contains graded granule metaconglomerate

interbeds.

Four ductile deformational events (D

– D

) affected all of these

rocks. The first two strongly controlled the map pattern, whereas D

and

are recorded mainly at the outcrop scale as strong domainal crenulation

cleavages defined by micas in the QFP and pelitic schists. D

recumbent

isoclinal folds and thrusts caused multiple structural repetitions of the

Neoarchean and Paleoproterozoic strata. D

coaxially refolded D

structures, producing type 3 “hook” interference patterns. D

structures

were generally transposed sub-parallel to the inclined axial planes of

second generation open to closed folds (F

) cut by northwesterly directed

thrusts. At Kiggavik, relationships are similar except that F

axial planes

are moderately north-dipping rather than steeply south-dipping. Brittle

faulting related to Thelon Basin development dextrally offset basement

rocks at Bar Lake and Kiggavik, allowing definition of three structural

domains at Bar Lake that are rotated relative to one another.

Keynote 3D GIS-BASED EXPERT SYSTEMS FOR EXPLORATION

TARGETING

McGaughey, W.J., Mira Geoscience Ltd, 310 Victoria Avenue, Suite

309, Westmount, QC H3Z 2M9, johnm@mirageoscience.com

The past several years has seen a progressive, successful development and

deployment of 3D GIS-based expert systems for mineral exploration

targeting. The general principle is to combine multiple 3D earth model

elements to determine spatial locations with the statistical characteristics

diagnostic of economic mineral occurrence. The general approach is to

take as input multiple pre-computed properties and proximity relationships

interpolated on a 3D grid to compute a classified and ranked list of targets.

Typical input properties are lithology, formation, physical and

geochemical rock properties, proximity relationships of structural and

topological model objects, proximity to existing boreholes, and presence,

proximity, and classification of geophysical anomalies. Workflows have

been implemented to guide geoscientists through the complex sequence of

steps required for input data designation, characterization, quality control,

normalization, and possible re-classification. Tools from the field of 2D-

GIS spatial expert systems, largely developed and proven at the Geological

Survey of Canada in the 1980s and 1990s, have provided a solid

foundation for extension to 3D. These include the knowledge-driven

techniques of Boolean Logic, Index Overlay, Multi-Class Index Overlay,

and Fuzzy Logic, as well as the data-driven techniques of Weights-of-

Evidence.

Practical implementation of 3D expert-system methods has required

parallel advances in earth modelling. The last several years has seen

systematic progress in our ability to quantitatively interpret and integrate

geoscience data for 3D exploration targeting at regional, prospect, and

mine scales. Interpretational advances have occurred individually in each

of the sub-disciplines of geology, geophysics, and geochemistry. Our

ability to integrate these interpretations into practical targeting models,

approximately consistent with both geological reasoning and data, has

similarly advanced and delivered success at the drillbit.

PALEOPROTEROZOIC LATE-TECTONIC PEGMATITE-HOSTED

U-Th±REE-Y-Nb MINERALIZATION IN THE WOLLASTON

DOMAIN, NORTHERN SASKATCHEWAN

McKeough, M.A., mmckeough.[email protected], and Lentz,

D.R., [email protected], University of New Brunswick, PO Box 4400,

Fredericton, NB E3B 5A3

In northern Saskatchewan late-tectonic granitic pegmatites intrude Early

Paleoproterozoic Wollaston Group metasedimentary rocks and interfolded

granitoids that unconformably overlie Late Archean gneisses, all of which

have been subjected to deformation during the 1.86 to 1.78 Ga Trans-

Hudson Orogeny. The high-T metamorphic events during the THO

generated partial melting of recycled lower crustal materials, producing

syn- to late-tectonic granitoid magmas. Variably mineralized U-Th±REE-

Y-Nb–pegmatite intrusions and fracture-controlled uranium mineralization

characterizes the U-Th±REE-Y-Nb mineral showings in the Kulyk and

Eagle lakes region, within the Wollaston Domain.

The highly evolved (mineralized) pegmatites in the Kulyk and Eagle

lakes area range from simple granitic pegmatites to partially zoned,

mineralogically complex pegmatites. The complex pegmatites often have

diffuse contact margins that are hybridized as a result of bimetasomatic

interaction with the metasedimentary host rocks, and are mineralogically

heterogeneous (biotite, actinolite, diopside, magnetite, ilmenite, titanite,

pyrite, xenotime, zircon, monazite, thorite, and allanite). U-Th±REE-Y-Nb

mineralization is concentrated within these “hybrid” contact zones and

biotite metasomatic reaction zones along the pegmatite margins.

Generally, it is the concordant hybridized pegmatites that are more

mineralogically complex than the discordant pegmatites, suggesting that

the concordant pegmatites have reacted more completely with the host

rocks; this is similar to late-tectonic uraniferous pegmatites of the

Grenville Province.

Geochemical analysis of the mineralized simple granitic to

hybridized pegmatites indicate they are rare-element Nb-Y-F pegmatites,

that average 33 ppm Nb, 175 ppm Y, 670 ppm U, 320 ppm Th, 400 ppm

Zr, and 1300 ppm ∑REE. They are variably high Sr-Ba pegmatites

interpreted as anatectic melts generated from an extremely fractionated,

crustally derived A- to I-type leucogranitic magma; this setting agrees with

U-Pb geochronology of these granitic pegmatites, which constrains them

between peak to late metamorphic events ca. 1.81 Ga. Previous Pb isotopic

data from similar concordant pegmatites, to the south of the Kulyk and

Eagle lakes region, indicate they were derived from Hearne basement that

is Paleoproterozoic orogenic rock metamorphosed to granulite facies.

U, Th, REE, Y, and Nb were most likely maintained at significant

concentrations in these enriched crustal melts as they ascended, up to the

final stages of the hybrid pegmatite evolution. These hybridized

pegmatites represent a dynamic environment, in which hybridization

processes evolved during active assimilation and fractional crystallization

at the site of pegmatite emplacement, promoting the exchange of accessory

phases between multiple pegmatite injections, and resulting in saturation

of mineralizing phases, such as U, Th, and REEs, along these bimeta-

somatic hybrid border zones.

VOLCANIC AND HYDROTHERMAL RE-CONSTRUCTION OF

PILLEY’S ISLAND VMS DISTRICT, NOTRE DAME BAY

REGION, CENTRAL NEWFOUNDLAND

McKinley, C.P., [email protected], Piercey, S.J., Memorial

University of Newfoundland, Department of Earth Sciences,

Alexander Murray Building, 300 Prince Philip Drive, St. John’s, NL

A1B 3X5, Winter, L., Altius Minerals Corp., Suite 202, Kenmount

Business Center, 66 Kenmount Road, St. John's, NL A1B 3V7, and

Thurlow, J.G., 16 Hammond Drive, Corner Brook, NL A2H 2W2

Pilley’s Island in Notre Dame Bay, central Newfoundland is host to a

significant cluster of bimodal felsic Zn-Pb-Cu volcanogenic massive

sulfide (VMS) deposits within the Ordovician Annieopsquotch

Accretionary Tract (AAT). The Pilley’s Island terrane of the Roberts Arm

– Buchans belt within the AAT is dominated by altered, glassy, dacitic

breccia and volcaniclastic rocks intercalated with lesser flow banded

dacite, and mafic pillow lava and pillow breccia. The rocks of the Pilley’s

Island terrane are interpreted to have originated within a peri-Laurentian

volcanic arc/back-arc in the western Iapetus Ocean.

Recent exploration programs have identified several southeast

dipping thrust faults that offset the stratigraphy. The identification of these

faults has created a need for re-interpretation of the district’s stratigraphy,

structure, hydrothermal alteration and lithogeochemistry. Detailed

mapping and drillcore logging have allowed a reconstruction of the

volcanic stratigraphy, hydrothermal alteration and 3D visualization of the

VMS district, with considerable focus on the Bumblebee Bight/3B and

Mine area.

Pilley’s Island hosts three VMS deposits, from west to east:

Spencer’s Dock, Old Mine and Bumblebee Bight/3B. The deposits vary by

mineralization style including: 1) sub-seafloor massive pyrite replacement

deposits (Spencer’s Dock, Old Mine); 2) sea floor massive sulfide deposits

(3B, Bumble Bee Bight); and 3) breccia sulfide deposits (Bull Road

showing). The stratigraphy of each panel varies with each deposit style, for

example: 1) Spencer’s Dock Panel is dominated by contorted dacitic

flows; 2) Old Mine-3B Panel consists of mostly felsic volcaniclastics; and

3) Bull Road Panel (host to Bull Road showing and Bumble Bee Bight

deposit) is dominated by massive dacitic flows and lesser volcaniclastic

rocks.

Mapping, petrography, lithogeochemistry, and shortwave infrared-

near infrared (SWIR-NIR) spectroscopy have identified alteration haloes

around the VMS deposits. Major alteration zones, from strongest to

weakest alteration, include: illitic phengite and phengite, illitic muscovite

and muscovite, and Fe to Fe-Mg to Mg chlorite. These haloes also

correspond to increased element mobility in zones of strongest alteration,

specifically Na depletion and K-Mg-Fe enrichment. Lithogeochemistry has

also been very useful in identifying element mobility and primary

petrochemistry so as to compare and contrast different thrust panels as well

as vectoring towards prospective zones for VMS mineralization.

TECTONIC EVOLUTION OF THE ADIRONDACK PORTION OF

THE GRENVILLE PROVINCE

McLelland, J.M., j[email protected], and Selleck, B., Colgate

University, 13 Oak Drive, Hamilton, NY 13346, USA

The oldest rocks in the Adirondacks are ca. 1.4-1.3 Ga tonalites and

quartzites of the Dysart-Mt. Holly suite rifted from the Laurentian

marginal arc and exposed in the Appalachian Mesoproterozoic inliers at

least as far south as the New Jersey Highlands. They are intruded by ca.

1.25 Ga. Elzevirian granites and overlain by ca. 1.3-1.22 Ga metapelites

and marbles presumably deposited in backarc basins. Closure of the

backarc archipelago was underway by ca. 1.2 Ga and signaled the onset of

the Shawinigan orogeny whose contractional phase terminated by ca. 1.16

Ga and was followed by the emplacement of the ca. 1.16-1.14 Ga AMCG

suite. Shawinigan P,T reached amphibolite grade in the Adirondack

Lowlands and granulite grade in the Highlands resulting in regional

anatexis. Additionally, the Lowlands were thrust over the Highlands to

form a local Orogenic Lid, thus escaping granulite facies conditions of the

ca. 1.09-1.04 Ga Ottawan pulse of the Grenvillian orogeny. Evidence for

Shawinigan orogenesis extends southeast into the Appalachians.

Initial Ottawan orogenesis in the Adirondacks coincides with

termination of Hawkeye granitic magmatism at ca. 1093 Ma and was

followed by development of penetrative fabrics and nappe-like structures

throughout the Highlands. There is little preserved evidence for

magmatism or anatexis until ca. 1.05 Ga when the periphery of the present

Highlands was intruded by the A-type Lyon Mountain Granite (LMG).

Highland titanite cooling ages of ca. 1.03 Ga and monazite ages of 1.50-

1.25 Ga reflect Ottawan T ≥800°C, whereas Lowlands titanite ages of ca.

1.15 Ga and hornblende Ar/Ar ages >1.06 Ga demonstrate that this region

did not experience high grade Ottawan conditions. These data reflect the

ca. 1.05 Ga down-to-the-west faulting of the Lowlands from its perch

above the Highlands and demonstrate that it is part of the southeast

Grenville Orogenic Lid. In the eastern Adirondacks, east-side-down

faulting along a mylonitic shear zone at ca. 1.05 Ga (monazite) indicates

that the Highlands represent a late Ottawan symmetrical core complex

(gneiss dome) reflecting regional Grenville orogen collapse. Downfaulted

Orogenic Lid rocks probably lie beneath Paleozoic cover to the east. The

detachment fault zone coincides with the southward projection of the

Canadian Tawachiche shear zone. Collapse accompanied intrusion of the

1050±10 Ma LMG that reflects deep crustal melting and weakening. LMG

crosscuts early Ottawan F

structures but is folded by upright, open F

and

folds which formed during terminal Ottawan extension and collapse.

METALLOGENY OF URANIUM DEPOSITS IN THE CENTRAL

MINERAL BELT, LABRADOR, CANADA

McNeill, P.D.

, Paul.McNeill@Paladinenergy.com.au, Wilton, D.

Wilde, A.

, Barrett, S.

, Otto, A.

and Owers, M.

Paladin Energy

Ltd., 140 Water Street, St. John’s, NL A1C 6H6;

Department of

Earth Sciences, Memorial University, St. John’s, NL A1B 3X5;

Paladin Energy Ltd., 502 Hay Street, Subiaco, Western Australia

6008

The Central Mineral Belt (CMB) extends for over 250 × 75 km through

central to coastal Labrador and is underlain by a series of six

Mesoproterozoic supracrustal sequences and associated intrusive suites.

Uranium was first discovered in 1954 with subsequent exploration through

to the late 1970s and more recently since 2003. At least 180 occurrences

with a variety of forms were delineated in all units and associated

basement rocks. Since 2003, defined uranium resources in the CMB have

increased six-fold from 25 to 154 M pounds including: Michelin, (103M

lbs.) Jacques Lake (17M lbs.), C-zone (10M lbs.) and Inda (6.6M lbs.),

among others. This growth in discovery was contemporaneous with, and at

least partly dependent upon, the acquisition of large, detailed geological/

geophysical/geochemical data sets. A recent compilation of these data has

allowed for a much more detailed definition of the regional geological

setting of uranium mineralization of the CMB. Specifically, we present the

results of the compilation and review the local setting of deposits within

the context of the compilation.

THE PINGUICULA GROUP, NORTHERN YUKON: PROGRESS

IN THE PROTEROZOIC PUZZLE OF WESTERN NORTH

AMERICA

Medig, K.P.R.

, [email protected], Thorkelson, D.J.

, Turner,

E.C.

, Davis, W.J.

, Gibson, H.D.

, Rainbird, R.H.

and Marshall,

D.D.

Simon Fraser University, 8888 University Drive, Burnaby,

BC V5A 1S6;

Laurentian University, 935 Ramsey Lake Road,

Sudbury, ON P3E 2C6;

Geological Survey of Canada, 601 Booth

St., Ottawa, ON K1A 0E8

The late Meso- or early Neoproterozoic Pinguicula Group, Wernecke

Mountains, Yukon, is a siliciclastic and carbonate succession deposited on

an angular unconformity developed on the Wernecke Supergroup. Detailed

stratigraphic observations indicate that the Pinguicula Group was

deposited during overall deepening of the basin: fining-upward siliciclastic

facies of unit A are overlain by mid-slope carbonate facies of unit B,

which grade to lower slope and possibly basinal carbonate facies of unit C.

Detrital zircon geochronology from the Pinguicula Group unit A sandstone

provides information on provenance and age of the sediment deposited in

the Pinguicula basin. Neoarchean and Paleoproterozoic populations are

abundant and may be derived from the underlying Wernecke Supergroup

or the Laurentian craton. A distinctive population from the Meso-

proterozoic, between 1610 and 1490 Ma (North American Magmatic Gap),

suggests that sediment may have been derived from Australia. The

possibility of Australia as a sediment source suggests that the Pinguicula

Group may have been deposited in an intracratonic basin between the

Laurentian and Australian cratons. In addition, a single Grenvillian detrital

zircon

207

Pb/

206

Pb age (1144±25 Ma) from the Wernecke inlier raises the

possibility that the Pinguicula Group is younger than ~1150 Ma. If

additional grains of this age are found to support a statistically viable

population, and the depositional age of <1150 Ma is confirmed, then

correlations between the Pinguicula Group and other successions in

northern Canada, such as the Dismal Lakes Group, will need to be

revisited.

MODELING OF EFFECTIVE THERMAL CONDUCTIVITIES OF

POROUS MEDIA AS A FUNCTION OF TEMPERATURE IN THE

SOLID REGION

Mehmood, S., Physics Department, Quaid-i-Azam University,

Islamabad PO Box 44000, Pakistan, p[email protected]

The thermal conductivity, thermal diffusivity, and heat capacity per unit

volume of dunite rocks taken from Chillas near Gilgit, Pakistan, have been

measured simultaneously using the transient plane source technique. The

temperature dependence of the thermal transport properties was studied in

the temperature range from 303°K to 483°K. Based on the temperature-

dependent experimental data listed above, model calculations have been

performed to achieve a deeper insight into the thermodynamical behavior

of these materials within the high-temperature solid regime.

Two different models are proposed for the prediction of effective

thermal conductivities of alloy series taking into account the thermal

conductivities of the constituents, the temperature, and a fit parameter. For

such calculations, it is of special importance to choose model functions

that are both physically relevant and numerically robust. It is observed that

the values of the effective thermal conductivity predicted by the models

are in agreement with the experimentally determined thermal

conductivities by pulse heating technique within 8%.

TERRANE AFFINITIES OF CALEDONIAN ROCKS IN

SOUTHEAST IRELAND

Menuge, J.F., School of Geological Sciences, University College

Dublin, Belfield, Dublin 4, Ireland, j.f.m[email protected], Crowley, Q.,

School of Natural Sciences, Department of Geology, Trinity College,

Dublin 2, Ireland, McConnell, B., Geological Survey of Ireland,

Beggars Bush, Haddington Road, Dublin 4, Ireland, and O’Brien,

B.H., Geological Survey of Newfoundland and Labrador,

Newfoundland and Labrador Department of Natural Resources, St.

John's, NL A1B 4J6

A collage of peri-Gondwanan micro-terranes rifted from Gondwana and

accreted to Laurentia during the Caledonian – Appalachian orogeny.

Southeast Ireland occupies a key position for along-strike correlation in the

orogen, but data have been inadequate to assess correlation of peri-

Gondwanan terranes. U-Pb detrital zircon dating and Sm-Nd whole-rock

isotope analysis are useful methods for distinguishing, correlating and,

ultimately, reconstructing these dispersed fragments. These methods have

therefore been applied in southeast Ireland to clastic metasedimentary

rocks that may have been derived from pre-Caledonian crystalline

basement. Sm-Nd whole-rock isotope analysis has also been carried out on

granitic intrusions that are likely to have formed mainly from melts of pre-

Caledonian crystalline basement, or of its sedimentary derivatives.

Early Ordovician metasedimentary rocks in southeastern Ireland

have detrital zircon age spectra with dominant late Neoproterozoic ages,

typical of peri-Gondwanan sources. The Ribband Group also has a spread

of Mesoproterozoic, Palaeoproterozoic and Neoarchaean ages, typical of

Amazonian Gondwanan sources and similar to rocks from Avalonia and

Ganderia. Although there are differences in the age spectra, it is not

possible to definitively distinguish between Ribband Group samples from

either side of the Wicklow Fault Zone, a putative terrane boundary. The

Grahormack Fm (Tagoat Gp) has very sparse Mesoproterozoic and

Neoarchaean signals and small but significant clusters of

Palaeoproterozoic and Mesoarchaean ages, similar to rocks from the

Meguma terrane and possibly suggesting a source in West African

Gondwana.

Nd isotope ratios, expressed as the parameter ε

, are calculated for

400 Ma to optimize comparison between rocks of different age.

Neoproterozoic to early Devonian felsic igneous rocks from southeastern

Ireland have ε

(400 Ma) values of -7 to -1, whilst Neoproterozoic to

Ordovician sedimentary and metasedimentary rocks have ε

(400 Ma)

values of -6 to -12. These ranges compare well with the ranges exhibited

by rocks of the Gander Zone in Newfoundland and Nova Scotia. There are

no positive values of ε

(400 Ma) in the Irish rocks, in contrast to the

Avalonian of the Maritime Provinces. It is unclear whether the data for

Wales and England are significantly different to those from the Irish

samples.

HUDSONIAN URANIUM MINERALIZATION IN THE WESTERN

MARGIN OF THE TRANS-HUDSON OROGEN (SASKATCHEWAN,

CANADA): A MAJOR PROTORE FOR UNCONFORMITY-

RELATED URANIUM DEPOSITS?

Mercadier, J., G2R, Nancy-Université, CNRS, CREGU, Boulevard

des Aiguillettes, B.P. 239, F-54506 Vandoeuvre lès Nancy, France,

Annesley, I.R., JNR Resources Inc., 204-315 22

Street East,

Saskatoon, SK S7K 0G6, jnrirvine@sasktel.net, McKechnie, C.L.,

Department of Geological Sciences, University of Saskatchewan,

114 Science Place, Saskatoon, SK S7N 5E2, and Creighton, S.,

Saskatchewan Research Council, 125 Innovation Boulevard,

Saskatoon, Saskatchewan, SK S7N 2X8

The genetic model of the giant unconformity-related uranium deposits of

the Athabasca Basin is still debated; one of the main questions being the

source of the metals concentrated by the diagenetic-hydrothermal events

during the Mesoproterozoic Era (ca. 1.6-1 Ga) at the interface between the

Athabasca Basin and the underlying Archean/Paleoproterozoic basement

rocks. Currently, accessory minerals such as monazite, zircon or apatite

from the sedimentary basin and basement rocks are proposed as the

primary uranium source for these high-grade uranium deposits.

A systematic study of two areas of basement rocks located near the

eastern part of the Athabasca Basin (i.e. Way Lake and Moore Lake

properties) highlights the significant and widespread occurrences of

Hudsonian (ca. 1.82-1.76 Ga) uranium oxide mineralization in these zones.

Two types of mineralization are identified: magmatic uranium oxides

related to granitic pegmatites and high-temperature uranium oxides in

veins. The most common type occurs within granitic pegmatites, but the

highest grade occurs as veins. The two types were formed during events

related to the evolution of the Trans-Hudson Orogeny at 1820-1720 Ma.

The magmatic uranium oxides were formed by partial melting of

Wollaston Group metasedimentary rocks, with differential melt extraction

processes, melt transfer, and fractional crystallization. The origin of the

vein-type occurrences is unclear, but they seem to be related to Ca- and/or

Na-metasomatism. The uranium oxides are associated with other U-, Th-

and REE-bearing accessory minerals like monazite, zircon, and/or

uranothorite, enriching the metal contents of these UO

-bearing rocks,

which are up to 200 times (only considering U-rich pegmatites) more

enriched in U than other basement or basin lithologies. The studied rock

samples, even macroscopically fresh and located far away from any known

unconformity-related U deposit, present clear evidence of alteration with

clay minerals, alumino-phosphate-sulfate (APS) minerals and UO

dissolution, indicating the percolation of brines associated with the

formation of unconformity-related uranium deposits.

Due to the geological similarities between the studied zones and the

basement domains from the eastern part of the Athabasca Basin, (i.e. the

Hearne Province), it is proposed that these geological domains were a

significant host of uranium protores of Hudsonian age, which provided

uranium and other metals for the metal enrichment of basinal brines and

formation of Athabasca Basin U deposits. These observations bring new

insight to the source debate for the metals in unconformity-related U

deposits, and reinforce the greater metal potential of the basement

compared to that of the sedimentary basin.

FROM SOURCES TO DEPOSITS: RECENT ADVANCES ON THE

U-MINERALIZING BRINES IN THE ATHABASCA BASIN

(SASKATCHEWAN, CANADA)

Mercadier, J., julien.m[email protected], Richard, A.,

Cathelineau, M., Boiron, M-C. and Cuney, M., G2R, Université de

Lorraine, CNRS, CREGU, Boulevard des Aiguillettes, P.P. 239,

54506, Vandoeuvre-lès-Mamcy, France

Giant unconformity-related uranium deposits were formed during the

Mesoproterozoic era, 1.6-1.0 Ga ago, in both Paleo- to Meso-Proterozoic

Athabasca Basin (Canada) and Proterozoic Kombolgie Basin (Australia).

They are precious witnesses of protracted large-scale fluid flows at the

interface between sedimentary basins and their Archean to

Paleoproterozoic crystalline basement, at conditions close to peak

diagenesis (130-220°C). Although the Athabasca Basin hosts the world’s

largest high-grade uranium deposits and consequently has been the subject

of extensive research, metallogenic models still bear important

uncertainties. The objective of this contribution is to present new insights

about the genetic model of these exceptional deposits from the study of the

U-mineralizing brines.

Origin of the mineralizing brines

The origin of the brines has been investigated based on coupled

Cl/Br and δ

Cl composition of fluid inclusions trapped in quartz-dolomite

veins and δ

B composition of Mg-tourmalines associated with U ores.

These studies have shown that the brines originate from subaerial

evaporation of seawater up to epsomite saturation (salt content of ca. 25-35

wt%) forming a Cl-Na-K-Mg-rich brines.

Fluid percolation in the basement rocks, metal uptake and brine

modifications

The original Cl-Na-K-Mg brines have percolated through the

sedimentary pile and also extensively in the underlying basement, during

tectonic reactivation, thanks to major faults and dense network of

microfractures, partly inherited from late-orogenic deformation related to

Trans-Hudson Orogen. Intensive brine/basement interaction was

responsible for major chemical and isotopic changes (O, H, C) of the

initial brines to form two chemically distinct Cl-Na-Ca-Mg-K (NaCl-rich)

and Cl-Ca-Mg-Na-K (CaCl

-rich) brines, both being highly enriched in

metals (U, Zn, Pb, Mn, Cu, Sr). Their high metal content compared to

modern sedimentary brines and metal enrichment comparable with brines

related to MVT Pb-Zn deposits supports the idea that the basement was the

dominant source for metals, and especially for U.

Conditions for the transport and deposition of uranium

The mineralizing brines have U concentrations between 1×10

-6

and

2.8×10

-3

mol.l

-1

, making them the U richest crustal fluids so far. This

exceptional U content is related to the oxidizing and acidic nature of the

brines (pH between 2.5 and 4.5) and to the high availability of U sources.

The mixing of the NaCl-rich and CaCl

-rich brines is coeval with the UO

deposition but the reductant necessary for UO

precipitation remains

enigmatic.

THE GOLD CONTENT OF VMS DEPOSITS: KEY FEATURES

AND CONTROLLING PARAMETERS, WITH IMPLICATIONS

FOR EXPLORATION IN THE APPALACHIAN OROGEN

Mercier-Langevin, P.

, [email protected], Dubé, B.

Hannington, M.

and Bécu, V.

Geological Survey of Canada, 490

Rue de la Couronne, Québec, QC G1K 9A9;

Ottawa University, 140

Louis-Pasteur, Ottawa, ON K1N 6N5

VMS deposits contain variable amounts of gold, both in terms of average

grade and total contents. The analysis of gold grades and tonnages of 513

VMS deposits of all ages worldwide revealed that a large proportion of

deposits are characterized by a relatively low gold grade (<2 g/t). The

geometric mean and geometric standard deviation appear to be the

simplest metric for identifying subclasses of VMS deposits based on gold

grade. The geometric mean gold grade is 0.76 g/t; the geometric standard

deviation is +2.70 g/t Au. Deposits with more than 3.46 g/t Au (geometric

mean plus one geometric standard deviation) are considered auriferous.

The geometric mean gold content is 4.7 t Au, with a geometric standard

deviation of +26.3 t Au. Deposits containing 31 t Au or more are

considered to be anomalous in terms of gold content, irrespective of the

gold grade. Deposits with more than 3.46 g/t Au and 31 t Au are

considered gold-rich VMS. A large proportion of the total gold hosted in

VMS worldwide is found in a relatively small number of such deposits.

The identification of these truly anomalous systems helps shed light on the

geological parameters that control unusual enrichment of gold in VMS. At

the district scale, the gold-rich deposits occupy a stratigraphic position and

volcanic setting that commonly differs from other deposits of the district

possibly due to a step change in the geodynamic and magmatic evolution

of local volcanic complexes. The gold-rich VMS are commonly associated

with transitional to calc-alkaline intermediate to felsic volcanic rocks,

which may reflect a particularly fertile geodynamic setting and/or timing

(e.g., early arc rifting). At the deposit scale, uncommon alteration

assemblages (e.g., advanced argillic) and trace element signatures are

present, suggesting a direct magmatic input in some systems.

There are over 30 VMS deposits and occurrences for which tonnage

is known in the Appalachian orogen of Newfoundland, including about 10

deposits that have reported gold grades. These VMS deposits are hosted in

distinct arc and back-arc sequences, and those hosted in the Baie Verte

oceanic tract, including Rambler-Ming, are enriched in gold relative to the

deposits of the Annieopsquotch and Penobscot sequences. Similar trends

are developed in the Bathurst Camp with the VMS deposits of the

California Lake Group being on average slightly richer than the VMS

deposits of the Tetagouche Group. This suggests that some specific rock

sequences of the Appalachian orogen are more prospective than others to

host gold-rich and auriferous VMS deposits.

COMPOSITION, PROBABLE ORIGIN, AND RECENT CORAL

FAUNA OF ENIGMATIC MOUNDS ON ORPHAN KNOLL,

NORTHWEST ATLANTIC OCEAN

Meredyk, S.P., Environmental Science Program, Memorial

University, St. John’s, NL A1B 3X9, [email protected], Piper,

D.J.W., Geological Survey of Canada Atlantic, Bedford Institute of

Oceanography, Dartmouth, NS B2Y 4A2, Edinger, E.N., Geography,

Biology, and Earth Sciences Departments, Memorial University, St.

John’s, NL A1B 3X9, and Ruffman, A., Geomarine Associates Ltd.,

PO Box 41, Station M, Halifax, NS B3J 2L4

Orphan Knoll is a foundered fragment of the North American continental

crust found in deep water off the continental margin of Newfoundland.

Orphan Knoll contains more than 250 mounds that range from 60 to 300 m

of meters tall and 1 to 3 km wide. Possible origins proposed for these

mounds have included a karstified limestone plateau, block-faulted

bedrock, bioherms or cold-seep carbonate mounds. The principal objective

of the study was to determine the composition and probable age of the

enigmatic Orphan Knoll mounds, in an effort to better understand their

possible origins. They were also studied as habitats of live deep-water

corals.

A geological and biological survey using the remotely-operated

vehicle ROPOS in July, 2010, collected bedrock samples, 3.5 kHz sub-

bottom profiles, high-definition video, CTD data, and near-bottom

multibeam bathymetry of mounds from the southeastern and northeastern

parts of Orphan Knoll, at approximate depth ranges of 2900-2400 m and

2000-1750 m, respectively. Video surveys of several mounds found

bedrock at the centre of the mound, surrounded by mixed sediment

composed of bedrock-derived talus, ice-rafted debris, and drifted

hemipelagic sediment. Rock samples from the upper layer of limestone on

top of one northeast Orphan Knoll mound were identified as mid-Miocene

thinly bedded pelagic limestone bedrock with Miocene foraminiferans

(Orbulina spp. and Globigerina spp.), interbedded with thick Mn-oxide

crusts. These limestones unconformably overlie a lower thick-bedded

limestone of unknown age. Strike and dip estimates from video suggested

SW-NW dips of ~10-45°. Mn-oxide crusts with interbedded pelagic

limestone were found at the top of several mounds. Our observations

suggest block-faulted bedrock as the most likely origin of the studied

mounds. Formation of these mounds may have been initiated through

listric faulting during Mesozoic and Cenozoic extension, and reactivated

by faulting during the Neogene and Quaternary.

Recent coral fauna of the Orphan Knoll mounds included several

gorgonians, especially Isidids, Chrysogorgia spp, Acanthogorgia sp. and

an unknown gorgonian, at least two species of antipatharians, several

species of soft corals and the solitary scleractinians Flabellum spp.,

Vaughanella margaritata, and Desmophyllum dianthus, mostly on the

shallower mounds. No colonial scleractinians were observed. Although

live D. dianthus were not highly abundant, dead D. dianthus formed a

time-averaged “coral graveyard” deposit on the eastern slope of a cliff of

one of the northeast mounds. Dominant corals on soft sediment habitats

surrounding the mound centres were several species of sea pens, soft

corals, and reclining solitary scleractinians.

EXAMINING THE GEOCHEMICAL POTENTIAL FOR USING U-

Th-Pb ISOTOPE SYSTEMS IN THE BASEMENT LITHOLOGIES

OF THE ATHABASCA BASIN TO VECTOR TOWARDS MIN-

ERALIZATION

Millar, R.

1,2

, [email protected], Annesley, I.R.

1,3

and Ansdell, K.

University of Saskatchewan, 114 Science Pl., Saskatoon, SK S7N

5E2;

Saskatchewan Research Council, 125-15 Innovation Blvd.,

Saskatoon, SK S7N 2X8;

JNR Resources, 315-22

Ave., Saskatoon,

The largest unconformity-type (U/C-type) uranium deposits in the world

are found in the Proterozoic Athabasca Basin in northern Saskatchewan,

Canada. The basin is comprised of a sedimentary rock sequence underlain

by Archean to Paleoproterozoic metamorphosed basement rocks, which

include graphitic pelitic gneisses and granitic pegmatites. Major faults

cutting these rocks, initially related to the Talston Magmatic Zone and the

Trans Hudson Orogen, were reactivated episodically and thus provided

focal points for fluid flow and mixing.

Many researchers agree that oxidized basinal brines flowed through

the basement lithologies, mixing with reducing fluids or interacting with

reduced rocks to cause uranium to precipitate. Although the source of the

uranium deposited at or near the unconformity is an unresolved and highly

debated subject, monazite is often considered a possible source because it

can contain significant amounts of U and Th within the crystal structure. If

hot, saline rich fluids interact with monazite, U and Th may become

fractionated as U is typically more mobile. This could generate U-Th-Pb

variations between altered and unaltered basement lithologies.

This research aims to provide some insight into the U-Th-Pb isotopic

system of the basement lithologies beneath the Athabasca Basin, especially

since many researchers have used anomalous radiogenic lead ratios to

detect proximity to uranium mineralization. A suite of fresh to strongly

altered graphitic pelitic gneisses and granitic pegmatites selected from the

Dawn Lake region (12.9 Mlbs @ 1.69% U

) were analyzed by HR-

ICPMS and MC-ICPMS to determine U-Th-Pb bulk chemistry isotopic

ratios. Preliminary geochemical analysis of graphitic pelitic gneiss and

granitic pegmatitic samples exhibit elevated Th/U ratios up to 18.5 from a

wide range of U (2 to 177) and Th (2 to 114) concentrations, accompanied

by anomalous

206

Pb/

204

Pb ratios as high as 200. Elevated Th/U ratios and

anomalous radiogenic Pb may indicate the presence of U-depleted Th-

bearing minerals and that U bearing fluids may have flowed through the

basement rocks.

STONEHAMMER GEOPARK; BUILDING ON ‘A BILLION

YEARS OF STORIES’

Miller, R.F., New Brunswick Museum, Saint John, NB E2K 1E5

Stonehammer Geopark, established in 2010 as North America’s first

member of the Global Geoparks Network, tells a story of Earth history by

linking together existing parks under a common brand. Stonehammer

promotes itself as ‘A Billion Years of Stories’ linking the science of

geology with the stories of people. Stonehammer is about more than rocks,

it is about making a meaningful connection between people and the Earth

in interesting and engaging ways.

Stonehammer has a complex geology exposed along rugged ocean

and river shorelines, on sparsely vegetated landscapes, and on roadways.

The scenic landscape has resulted in a rich mosaic of parks scattered

through the region, depending on geology for their beauty, but with little

interpretation of the rocks. The geopark incorporates more than sixty

significant geological and fossil locales, including more than fifteen

publicly accessible sites across 2500 square kilometers. Each place brings

a unique geological story, along with its own management, scientific,

tourism or recreation focus, creating a varied geopark. The public face of

Stonehammer Geopark includes two provincial parks, seven municipal

parks, a proposed fossil interpretation centre, and a museum. Dozens of

other outcrops on public lands display many geological features, including

significant fossil sites, from more than 100 formal geological formations

and igneous suites.

Using existing parks allows Stonehammer Geopark to make use of

built infrastructure with minimal cost required to add layers of geological

interpretation. Potential visitors to a geopark are already travelling to these

sites, including many of the 200,000 annual visitors from cruise ships.

From Precambrian stromatolites to Neogene brittlestars; island arc

volcanics to an ancient rift valley, the geopark has a range of stories to fit

almost any geologic process. The region’s long history of geologic

exploration, palaeontology and mining, much of it conducted by local

geologists, is a key feature of our interpretive program. Studying the Earth

is as much a part of the community’s history as shipbuilding, fishing,

lumbering and commerce.

RARE METAL EXPLORATION IN BRITISH COLUMBIA – A

FOCUS ON CARBONATITES AND ASSOCIATED ALKALINE

Millonig, L.M., , lm[email protected], Groat, L.A., University of

British Columbia, 6339 Stores Road, Vancouver, BC V6T 1Z4, and

Gerdes, A., Institut fuer Geowissenschaften, Goethe University

Frankfurt, Altenhöferallee 1, 60438 Frankfurt, Germany

In British Columbia a variety of geological settings are being explored for

rare metals, many of which are related to alkaline rocks. These alkaline

intrusions are associated with a continental-scale valley called the Rocky

Mountain Trench that follows a long-lived, transcurrent fault system. This

zone is informally known as the Rocky Mountain Rare Metal Belt.

A staking rush between 2008 and 2010 resulted in dozens of rare

metal projects in this belt, most of which were based on information that

had been available since the late 1980’s. These projects were fueled by the

success of Commerce Resources’ Blue River tantalum-niobium project

and reports of significant rare earth element (REE) mineralization at

Spectrum Mining Corp.’s Wicheeda project, amongst others. In this

context some companies tried to improve their exploration strategies and

deepen their understanding of the belt and its mineralization by

establishing joint ventures between industry and academia. This study

reports on several elements of such a joint venture and will discuss the

initial goal, the applied strategy and methodology, and what has been

achieved in the two years since the project was initiated.

The first step of an exploration program is often to select general

target areas by evaluating easily accessible regional databases (e.g.,

Regional Geochemical Survey stream sediment databases). Once a number

of targets have been selected, follow-up work will include field programs

and/or airborne geophysics to narrow down prospective areas. These areas

will then become the focus of intensified field work, which may include

mineralogical investigations in order to evaluate the feasibility of

processing, and drilling at a more advanced stage. However, our deeper

understanding of the many possible types of deposits is founded on the

combined results of field work and scientific studies, which try to unravel

the processes that lead to the formation of a deposit and in doing so

making it comparable to similar deposits. This research covers the various

aspects of mineralization types and also links the distribution of different

deposits to geological times and settings and will ultimately enhance

exploration efforts on local and regional scales.

The results of our study link carbonatitic and alkaline magmatism in

the Canadian Cordillera to three distinct magmatic events, but only one is

of economic interest to date. These results have implications for

exploration efforts on a regional scale, whereas geological field work and

mineralogical studies were able to identify promising areas on a local

scale.

VOLCANIC STRATIGRAPHY AND SETTING OF THE HOOD

VOLCANOGENIC MASSIVE SULFIDE (VMS) DEPOSIT,

NUNAVUT, CANADA

Mills, H.K., [email protected], Piercey, S.J., Memorial University of

Newfoundland, Department of Earth Sciences, St. John's, NL A1B

3X5, and Neill, I., MMG Resources, #555-999 Canada Place,

Vancouver, BC V6C 3E1

The Slave Province, Nunavut, contains numerous undeveloped and

underexplored volcanogenic massive sulfide (VMS) deposits. The Hood

deposit of the Hanikahimajuk Lake area, Nunavut (total resource of all

lenses - 3.8 Mt @ 2.6% Cu and 3.8% Zn), located 425 km north of

Yellowknife, NWT, remains poorly understood, in spite of intermittent

exploration for the past 40 years. The Hood deposit consists of a cluster of

lenses over a ~10 km

area hosted by the late Archean Amooga Booga

volcanic belt. Re-logging of drill core has resulted in new stratigraphic

reconstructions for the different lenses of the deposit, including the H10,

H41 and H41A lenses. Mineralization is hosted in a bimodal volcanic

sequence composed of basaltic and rhyolitic tuffs and flows. Basaltic and

diorite dykes cross-cut the volcanic rocks. The volcanic and intrusive rocks

are regionally metamorphosed to greenschist grade. Younger (~2.58 Ga)

pink granitoids have intruded all the above rocks and are associated with

quartz-K-feldspar alteration. There are variations in the lithofacies, host

rocks, and structural setting in each lens. The H10 lens is hosted in steeply-

dipping isoclinally folded sequence dominated by felsic volcanic flows.

Stratigraphy of the H41 deposits lies at a near vertical angle and

mineralized horizons occur near the contact of mafic and felsic volcanic

flows. The H41A deposit is dominated by steeply dipping mafic volcanic

rocks including abundant mafic to intermediate tuffs. Volcanogenic

massive sulfide-related alteration includes chlorite-quartz and sericite-

quartz alteration that is strong in the immediate footwall of the various

lenses and extends into the hanging wall. Mineralization in the lenses

consists of massive and semi-massive pyrite-pyrrhotite-sphalerite-

chalcopyrite and minor zones of stringer sulfides. Abundant clasts within

the ore and abundant hanging wall alteration are consistent with formation

via subseafloor replacement.

TRACING FLUID-FLOW THROUGH SPACE AND TIME:

EPIGENETIC MINERALIZATION IN THE REDSTONE

COPPERBELT

Milton, J.E., [email protected], Hickey, K.A., University of British

Columbia, Vancouver, BC V6T 1Z4, Gleeson, S.A., University of

Alberta, Edmonton, AB, and Jercinovic, M.J., University of

Massachusetts, MA, USA

The Redstone Copperbelt spans an arcuate zone of approximately 300 km

× 15 km within the Mackenzie Mountains, NWT, Canada. Neoproterozoic

strata that host copper mineralization are part of a fold and thrust belt

within the easternmost limit of deformation of the northern Cordillera. The

Coates Lake deposit, the largest discovered deposit of the copperbelt,

contains a NI-43-101 compliant historical inferred resource of 33.6 Mt @

3.92% Cu, 9 g/t Ag. The Redstone Copperbelt has many similarities to the

sedimentary rock-hosted copper deposits of the African Copperbelt or the

European Kupferschiefer “red-bed” deposits. We set out to test the

hypothesis that copper mineralization is early diagenetic by studying the

spatial and temporal aspects of fluid-flow.

Stratiform, disseminated chalcocite-bornite-chalcopyrite and copper-

bearing vein style mineralization occur in the Transition Zone between the

Redstone River Formation and the overlying Coppercap Formation.

Sulphide mineral assemblage zones are symmetric above and below

mineralized beds, indicating flow along rather than across ore horizons.

Fluid-flow relating to copper mineralization is controlled laterally by more

permeable lithologies and vertically by structures, including syn-

sedimentary faults and reverse faults. A weak foliation is developed within

ore zones and within the Redstone River Formation, likely related to

Cretaceous fold-thrust deformation across the Cordillera. This foliation

controls the orientation of copper sulphides and the presence of sulphides

in strain shadows indicates growth of some sulphides during deformation.

Element mapping of monazites in mineralized Transition Zone rocks

reveals texturally and chemically distinct Th-rich, core and Th-U-poor, rim

domains. Electron microprobe U-Th-(Pb) dating of monazite rims and

cores show that cores are detrital (>1023 ± 15 Ma) and rims are authigenic

(557-711 ± ~41 Ma). Euhedral rim-overgrowths on rounded, detrital

monazites share grain boundaries with irregular, intergranular masses of

copper sulphides. The growth of monazite rims records a fluid event,

which may relate to copper mineralization, occurring significantly after the

deposition and burial of the host rocks. Transition Zone-hosted copper

mineralization is epigenetic and it originated from low-temperature

hydrothermal or late-diagenetic processes. There are other styles of copper

mineralization present in the Redstone Copperbelt that are hosted at

younger stratigraphical intervals and encompass significant regional

unconformities. It is possible that a single, epigenetic fluid event is

responsible for copper mineralization across the copperbelt or

mineralization may be episodic in nature. The region has a prolonged

history of basin-development, fluid-flow and tectonism that has resulted in

the generation of significant amounts of copper mineralization.

CHARACTERIZATION OF THE GOLD MINERALIZING FLUIDS

AT THE VIKING PROPERTY, WHITE BAY, NEWFOUNDLAND

Minnett, M.

, Sandeman, H.

and Wilton, D.

Department of Earth

Sciences, Memorial University of Newfoundland, St. John’s, NL

A1B 3X5;

Mineral Deposits Section, Geological Survey of

Newfoundland and Labrador, Natural Resources, 50 Elizabeth Ave.,

St. John’s, NL A1B 4J6

The Viking Gold Property is a Silurian-Devonian epigenetic gold system

that has many geologic features in common with mesothermal gold

deposits. Located approximately 10 km southeast of Pollards Point, White

Bay, it is the most recently discovered gold prospect in the region and has

been intensely explored over the past four years. Mineralization consists of

coarse (up to 50 µm) blebby gold and argentiferous electrum grains within

quartz veinlets and as inclusions in associated sulphide minerals (pyrite,

galena, sphalerite, and chalcopyrite). Arsenic concentrations are low (<

100 ppm) and arsenopyrite is absent.

There are a number of gold prospects in the White Bay area of

western Newfoundland proximal to the Doucer’s Valley Fault System

(DVFS). The DVFS is a prominent north-east trending structural lineament

which juxtaposes Cambrian to Ordovician clastic and carbonate rocks of

the Labrador Group unconformably upon Neoproterozoic granitoid rocks.

The Viking vein systems appear to fill secondary splays and dilational

zones associated with movement along the DVFS. These secondary

structures likely acted as favourable environments for the passage of Au-

enriched fluids in a series of hydrothermal pulses over a ca. 150 Ma

interval of protracted sinistral strike-slip movement.

This study aims to document the nature and composition of the fluids

responsible for precipitating the structurally controlled gold mineralization

within the ca. 1030 Ma Main River Pluton. Fluid inclusion data indicate

that the ore-forming fluids were aqueous-carbonic H

O-CO

with low to

medium salinities (< 10 wt% NaCl equivalent). T

Homo

indicate that the gold

and sulphide-bearing quartz±calcite veinlets precipitated at 240-350°C

under pressures of 1200 to 3300 bars; such pressures correspond to depths

between 4.3 and 11.1 km under lithostatic load. Sulphur isotope ratios for

pyrite chalcopyrite fall within the 0 to +9‰ range characteristic of

mesothermal deposits; however, δ

S for galena were typically higher than

this range. Characterization of the orogenic fluids responsible for the

precipitation of gold mineralization at the Viking Property will enable

local and regional correlation of similar deposits within the Appalachians.

SPATIAL ANALYSIS OF SPECIES DISTRIBUTIONS FROM

MISTAKEN POINT, NEWFOUNDLAND

Mitchell, E.G., Department of Earth Sciences, University of

Cambridge, Cambridge, CB2 3EQ, UK, emilyghmitche[email protected]

Bedding-plane assemblages of Ediacaran fossils at Mistaken Point,

Newfoundland (565 Ma), are the oldest known examples of in-situ

macroscopic communities. The constituent organisms have few similarities

with living forms, making their ecology difficult to assess. To investigate

the ecology of these early communities, I analysed the spatial distributions

of the fossils on two of the key bedding surfaces, known as D and E.

Differentiated GPS was used to map out the position of 4360 fossils

on 110m

of bedding surfaces D and E, creating high resolution 3D data

sets of these two distinct ‘communities’. The resulting data sets were

analysed using two statistical approaches: 1) Bayesian network inference

to find the key interactions within the ecosystem and 2) pair correlation

functions to identify the ecological processes behind these interactions.

This work builds on previous work by Clapham et al (2003) in three

different ways. First, Bayesian network inference finds the underlying

ecological network using species abundances. Second, Bayesian analysis

only identifies primary relationships, so that each interaction found

corresponds to an underlying ecological process. Third, using pair

correlation functions it is possible to determine the distribution of the

interactions over a large spatial scale allowing the identification of

ecological process. By contrast, nearest neighbour analysis, performed by

Clapham et al, is limited to the largest distance between two species,

which is typically much smaller than the area studied.

The Bayesian analyses indicate that the fossil assemblage on E

surface had a complex web of species interactions, with all but one species

(Thectardis) interacting with at least one other, whereas the assemblage on

D showed no interactions. The higher density of species on E resulted in

density dependant interactions between species.

From our analysis of E surface, we were able to conclude Fractofusus

and Primocandelabrum form clusters of 30cm radius that are distributed

over 1m apart. This spatial pattern is interpreted as deriving from

facilitation between species at small scales and competition at large scales.

A double clustering of Ivesheadia and Fractofusus at both small (<20cm)

and large scales is interpreted as Fractofusus feeding on DOC produced by

the decay of the taphomorph Ivesheadia. The segregation of Charnia from

lobate discs across all spatial scales indicates an environmental variable

that affects each species in opposite ways. The small scale (<50cm)

clustering of Charniodiscus and Primocandelabrum was apparently due to

both species having similar requirements for establishment.

TEXTURAL EVIDENCE FOR MELT AT THE NANO-SCALE:

TRANSMISSION ELECTRON MICROSCOPY OF POLY-

ANATECTIC, META-PELITIC CONTACT AUREOLES,

NORTHERN LABRADOR

Mitchell, R.K.

, [email protected], Mason, R.

, Wirth, R.

Indares, A.

and Ryan, B.

Isotope Geochemistry and

Geochronology Research Centre, Carleton University, 1125 Colonel

By Drive, Ottawa, ON K1S 5B6;

Memorial University of

Newfoundland and Labrador, St. John’s, NL A1C 5S7;

Telegrafenberg, 14473 Potsdam, Germany, 0331 288-0;

Geological

Survey of Newfoundland and Labrador, Department of Mines and

Energy, Elizabeth Ave., St. John’s, NL A1B 4J6

Rocks from the Tasiuyak paragneiss, near Nain, Labrador, are unusual in

having reached granulite facies conditions twice: once during the Torngat

Orogeny regional metamorphism at ca. 1.8 Ga and again at ca. 1.3 Ga

during contact metamorphism, associated with multiple hot, dry intrusions

of the Nain Plutonic Suite. Regional metamorphism (9.4 kbar, 820°C)

induced biotite dehydration melting, during which some melt was lost. As

inferred from microstructural evidence, contact metamorphism caused a

second episode of partial melting. The assemblages associated with contact

metamorphism (3.5-5.5 kbar, >900°C) are controlled by the distribution of

the regional metamorphic assemblages on the scale of a single thin section

and consist of Crd-Ksp-Pl-Opx-Qtz-Bt-Ilm. Former partial melt films from

the contact-related melting event are preserved locally. Many of the

textural domains in the contact metamorphic assemblages are interpreted

to be melt-related; however, the distribution of formal partial melt films do

not account for the melt connectivity required to produce the multitude of

melt-related textures observed throughout the rock.

Transmission electron microscopy (TEM), electron diffraction

and energy dispersive X-ray spectroscopy studies of melt-related

micro-structures place constraints on the degree of partial melting and

melt connectivity during contact metamorphism, by evaluating

evidence for the presence of melt along grain boundaries in different

textural settings.

Direct evidence for former melt occurs as microstructures located on

the boundary between a K-feldspar grain remnant from the regional

metamorphism and a pocket of plagioclase-quartz symplectite, believed to

have crystallized from melt. TEM imaging revealed a row of spherical

‘bubbles’ of K-feldspar, approximately 100nm diameter, which are

interpreted to have nucleated on the regional K-feldspar grains.

Furthermore these ‘bubbles’ and the entire grain boundary are coated with

a film of K-feldspar, approximately 30nm in thickness. At the grain

boundary, both the thin film of K-feldspar and the adjacent quartz grain

extend into micro-fractures of the regional K-feldspar grain. Thin

plagioclase films and/or nano-granitic grain clusters are observed along

grain boundaries between regional K-feldspar grains and cordierite-quartz

symplectites. Feldspar grains within the nano-granitic grain clusters are

euhedral and locally twinned.

Nano-scale evidence for melt along grain boundaries, documented by

TEM imaging, supports a higher degree of melt connectivity than that

supported by the distribution of former partial melt films and confirms the

involvement of melt in the formation of many textural domains in these

rocks.

TESTING KENORLAND: EARLY PALEOPROTEROZOIC

APPARENT POLAR WANDER COMPARISON OF SLAVE AND

SUPERIOR CRATONS

Mitchell, R.N.

, [email protected], Bleeker, W.

, Hamilton, M.

and Lecheminant, T.

Yale University, 210 Whitney Avenue, New

Haven, CT 06511, USA;

Geological Survey of Canada, 601 Booth

St, Ottawa, ON K1A 0E8;

University of Toronto, 22 Russell Street,

Toronto, ON M5S 3B1

Is the early Paleoproterozoic Era characterized by a sprawling

Kenorland supercontinent or separate, though large, supercratons?

Paleomagnetism can quantitatively test the null hypothesis of a single

large Kenorland: one unified apparent polar wander (APW) reference

frame that juxtaposes cratons when accordingly reconstructed. One

caveat, true polar wander (TPW), would also yield unified APW but

cratons would not necessarily juxtapose when reconstructed to their

relative positions. Recently, a new paleomagnetic pole for the 2193 Ma

Dogrib dykes of Slave craton developed an APW path for Slave craton,

establishing that Slave and Superior cratons reconstructed far from each

other before 2 Ga (Mitchell et al., 2012). We present a new virtual

geomagnetic pole and U-Pb age (baddeleyite) of 2505 Ma for the

Pensive Lake sheet of southern Slave craton, tentatively extending the

Slave APW path back into Archean time. We find that from 2.5-2.0 Ga

Slave and Superior craton experienced nearly identical APW, advancing

the presence of either Kenorland or TPW in Paleoproterozoic time. At

face value, the large arc distance (>60˚) between Slave and Superior

cratons challenges the notion of Kenorland and would appear more

consistent with the multiple supercratons hypothesis, suggesting that

TPW may explain the unified APW. Both hypotheses, Kenorland or

TPW, are imminently testable by developing early Paleoproterozoic

APW paths for other key cratons.

PLATE TECTONICS BEFORE 2 Ga: EVIDENCE FROM PALEO-

MAGNETISM

Mitchell, R.N.

, [email protected], Bleeker, W.

, van Breemen,

, Lecheminant, T.N.

, Peng, P.

, Nilsson, M.K.M.

, Evans,

D.A.D.

Yale University, 210 Whitney Avenue, New Haven, CT

06511, USA;

Geological Survey of Canada, 601 Booth St, Ottawa,

ON K1A 0E8;

Institute of Geology and Geophysics, Chinese

Academy of Sciences, No.19 Beitucheng West Road, Chaoyang

District, Beijing, 100029, China;

Department of Earth and

Ecosystem Sciences, Lund University, Sölvegatan 12, Lund SE-223

62, Sweden

Laurentia, the core of Paleo-Mesoproterozoic supercontinent Nuna, has

remained largely intact since assembly 2.0-1.8 billion years ago [Ga]. For

earlier times, previous paleomagnetic data on poorly dated Paleo-

proterozoic mafic intrusions yielded ambiguous estimates on the amount of

separation between key cratons such as the Slave and Superior. Recent

developments in paleomagnetism and U-Pb on baddeleyite geochronology,

including new results reported herein, yield sufficiently precise data to

generate fragmental apparent polar wander (APW) paths for both Slave

and Superior cratons from 2.2-2.0 Ga. Our new APW comparison confirms

earlier speculations that processes similar to plate tectonics, with hallmark

independent relative motions between internally rigid lithospheric blocks,

were operative before the final assembly supercontinent Nuna.

AN ECLOGITE-BEARING FOLD STRUCTURE IN THE

SVECONORWEGIAN OROGEN, SCANDINAVIA

Möller, C.

, charlotte.moller@geol.lu.se, Andersson, J.

and Dyck,

Department of Geology, Sölvegatan 12, SE-223 62 Lund,

Sweden;

Geological Survey of Sweden, Box 670, SE-751 28

Uppsala, Sweden

Occurrences of Sveconorwegian eclogite within the parautocthonous belt

(Eastern Segment) are structurally bound by a major recumbent isoclinal

fold structure, which is exposed for 60 km in the present N-S-direction and

> 20 km in the present E-W direction. We interpret the structure as a non-

cylindrical, east-plunging nappe with a fold nose located below the present

exposure. The structure formed during east-directed translation.

Variably retrogressed eclogite occurs as tectonic lenses within the

fold structure. The central and northern parts of the structure are

dominated by stromatic migmatite gneiss with amphibolitized

retroeclogite, whereas the southernmost part hosts remnants of kyanite

eclogite in granulite and amphibolite facies mylonitic gneiss. 986±4 Ma

and 983±6 Ma metamorphic zircon from eclogite in northern areas are in

agreement with previous results from the southern area. Migmatization of

host gneisses at 972±8 Ma was associated with amphibolitization,

confirming previous data from southern areas.

Various gneiss units with mafic rocks outside the fold structure lack

signs of eclogite metamorphism but were metamorphosed under high-

intermediate pressure granulite and upper amphibolite facies conditions.

Moreover, a pinch-and-swell shaped, heterogeneously deformed augen

gneiss forms a tectonostratigraphic marker unit enclosing the southern and

eastern margins of the eclogite-bearing domain. This boundary thus

appears to represent a significant tectonic and metamorphic break.

The southern Eastern Segment, including the eclogite-bearing

domain, underwent near-pervasive metamorphic recrystallisation under

high-intermediate pressure granulite and upper amphibolite facies

conditions and simultaneous heterogeneous formation (D

). This

deformation involved tight to isoclinal folding of the (S

) layering,

shearing along fold limbs, and pronounced stretching in the E-W direction.

It produced isolated fold hinges enclosed by strongly strained zones on

different scales up to a few km. Asymmetric augen and porphyroclasts

indicate top-to-the-east and dextral movement.

The partial preservation of early eclogite assemblages within the fold

structure demonstrates 1) the existence of different tectonometamorphic

units in the deepest part of the Sveconorwegian Orogen, and 2) that it is

possible to identify different tectonic units despite reworking under high

metamorphic temperatures.

PALEOTECTONIC SETTING AND STRATIGRAPHY OF LOWER

PERMIAN BASALTS WITHIN THE SVERDRUP BASIN, ARCTIC

CANADA

Morris, N.J., [email protected], Beauchamp, B. and

Cuthbertson, J.P., University of Calgary, 2500 University Drive,

Calgary AB, T2N 1N4

The Esayoo Formation consists of altered Lower Permian basalts that

outcrop on northwest Ellesmere Island and northeast Axel Heiberg, within

the Sverdrup Basin, Arctic Canada. Rifting in the Sverdrup Basin initiated in

the Early Carboniferous and ceased during the Early Permian. Despite the

extensional nature of the basin, geographically widespread sub-Middle

Permian angular unconformities and extensive, yet local uplift and folding

occurred during the Early Permian, prior to Middle Permian deposition. This

suggests that compressional tectonics existed within the Sverdrup Basin

during the Early Permian; however, previous geochemical work on the

Esayoo Formation characterized these volcanics as being sourced from an

extensional tectonic regime. During the 2011 July field season, ten

stratigraphic sections of the Esayoo Formation were measured at four

locations on northwest Ellesmere Island: Borup Fiord Pass, Oobloyah Bay,

Ricker Glacier and Mount Leith. The Esayoo Formation reaches a maximum

thickness of 450 m near Oobloyah Bay, and thins west, east and north of

Oobloyah Bay with respective thicknesses of 140 m, 69 m and 75 m. Field

work at Oobloyah Bay showed that two stratigraphic levels of the Esayoo

Formation exist. The existence of two levels of the volcanic rocks, as well as

the structural evidence for compressional tectonics during this time, suggests

the Esayoo Formation may be related to the periods of tectonic quiescence

between compressional tectonic episodes. The lower Esayoo unit is bounded

below by the predominantly carbonate-rich Great Bear Cape Formation and

above by sandstones of the Sabine Bay and Assistance formations, whereas

the upper Esayoo unit lies above the Assistance Formation. Both the upper

and lower Esayoo units are overlain by thin 1 to 2 m shales that indicate

maximum flooding surfaces, which suggest contemporaneous high rates of

accommodation space generation within the basin. Further work on the

geochemistry of the Esayoo Volcanics will help piece together why intraplate

volcanism was occurring between periods of compressional tectonics when

the main phase of rifting had ceased. During the Early Cretaceous, the

Sverdrup Basin underwent renewed rifting and extensional tectonic regimes

once again became dominant. Evidence for this rifting consists of an

extensive system of cross-cutting Cretaceous sills and dykes that regionally

occur throughout the basin and a Large Igneous Province (LIP) on northern

Ellesmere Island.

DEEP WATER GEOHAZARDS AND CONSTRAINTS TO

DEVELOPMENT ALONG THE LABRADOR MARGIN

Mosher, D.C., Campbell, D.C., Saint-Ange, F. and Piper, D.J.W.,

Geological Survey of Canada - Atlantic, Bedford Institute of

Oceanography, 1 Challenger Dr., Dartmouth, NS B2Y 4A2

In support of recent renewed interest in hydrocarbon exploration along the

Labrador continental margin, its deepwater region was investigated to

document geohazards and processes that may constrain hydrocarbon

exploration and development. Between 2005 and 2011, ~7000 km

EM300 swath bathymetric data were acquired in water depths from 500 to

2500 m. Additional geophysical and geological surveys were conducted in

2005, 2006, 2008 and 2010. Legacy public and industry seismic data were

interpreted in this context as well. The resulting reconnaissance-level

assessment provides a regional geological context to assess the nature,

distribution and severity of seafloor conditions and seabed and subseabed

instabilities.

The Labrador Sea is dynamic for both oceanographic and

sedimentologic reasons. In addition to its relatively young age, subsidence

and sedimentation history, it was also only recently (i.e. < 10000 years

ago) deglaciated. The seabed along the Labrador slope is broadly divided

into trough mouth and submarine fans, canyon incision, mass transport

deposition, inter-canyon areas that include levees and sediment drift

deposits, and detached sediment drifts or spurs. Transverse troughs

(“saddles”) on the Labrador Shelf were conduits for ice streams during

glaciation and the sites of major sediment input to the basin. Erosional

gullies and valleys on the upper slope coalesce downslope to create a

heavily incised margin, locally resulting in coarse-grained sediment at or

near the seafloor in the valleys. Slope angles reach up to 7° along the

uppermost slope, particularly off of Hopedale Saddle. Similar to the

southern Canadian margin, mass transport deposits form a significant

proportion of the Quaternary sedimentary succession. Ice-rafted debris is

common in shallow piston core studies. Shallow gas and gas hydrate

bottom-simulating reflections are recognized within slope deposits. Strong

bottom currents due to the Labrador Current and Western Boundary

Undercurrent rework sediment at almost all water depths, generating

sediment wave and drift deposits. Variable foundation/drilling conditions,

boulder beds, sediment transport events, shallow gas, gas hydrates and

slope instability are, therefore, all issues of exploration concern along the

Labrador continental deep water margin.

Nd ISOTOPE MAPPING OF CRUSTAL SUTURES BETWEEN

ACCRETED TERRANES OF DIFFERENT AGES WITHIN THE

DEEPLY EXHUMED CORE OF THE GRENVILLE OROGEN IN

LABRADOR

Moumblow, R.M., moumblrm@mcmaster.ca, Dickin, A.P.,

McMaster University, 1280 Main Street West, Hamilton, ON L8S

4L8, and Gower, C.F., Geological Survey of Newfoundland and

Labrador, St. John's, NL

The geological makeup of the eastern Grenville Province is the product of

Makkovikian (1860-1790 Ma), Labradorian (1710-1600 Ma), Pinwarian

(1520-1460 Ma) and Grenvillian (1085-985 Ma) orogenesis, plus

intervening events not obviously related to orogenic activity. Much of the

crust in this region has been dated to be Labradorian or Pinwarian,

whereas, its present structural configuration was largely achieved by major

translational movement of crustal terranes during the Grenville orogeny.

U-Pb geochronological investigations in the eastern Grenville

Province have been summarized by Gower and Krogh (2002). This work

established a framework for the timing of major crust forming events in

the region. However, the time of separation of crustal material from the

mantle and the spatial extents now represented by various mantle-

separation events are much less well known. In other words, a map that

represents the time of original separation of crustal material from the

mantle is lacking.

Formation-age mapping of crustal terranes can be achieved by Nd

isotope analysis of representative samples of the crust over a large

geographical region. Previous Nd isotopic data produced crustal formation

ages for the Makkovik Province (1.93-2.21 Ga), and within the eastern

Grenville Province; the Groswater Bay, Hawke River, Lake Melville and

Mealy Mountains terranes have overlapping ranges of TDM model ages

(1.97-1.90 Ga). These overlapping mean compositions suggest that these

terranes are representative of one crustal realm, probably the product of

mixing between pre-Labradorian and Labradorian crustal components.

The data from the present study provide Depleted Mantle model

(TDM) ages from within the Pinware terrane. In contrast to regions farther

north, two discrete crustal-formation age signatures are indicated. The

northern portion has Nd signatures similar to those from the Hawke River,

Lake Melville and Mealy Mountains terranes, whereas the southern

portion has ages indicating a juvenile Labradorian source. This data

suggests that Makkovik crust extends into the northern part of the eastern

Grenville Province, whereas juvenile Labradorian crust is present in

southeast Labrador. The differing signatures suggest a boundary between

the two crustal regions to be situated a few km north of Red Bay, and are

interpreted to mean that the original edge of the Makkovik continental

margin extended as far as southernmost Labrador.

NEOPROTEROZOIC-EARLY JURASSIC MAFIC MAGMATISM

IN MAINLAND NOVA SCOTIA: TRACKING THE EVOLUTION

OF MANTLE SOURCES

Murphy, J.B., Department of Earth Sciences, St. Francis Xavier

University, Antigonish, NS B2G 2W5, bmur[email protected], Dostal, J.,

Department of Geology, St. Marys University, Halifax, NS B3H

3C3, Gutiérrez-Alonso, G., Departamento de Geología, Universidad

de Salamanca, 37008 Salamanca, Spain, and Keppie, J.D.,

Departamento de Geología Regional, Instituto de Geología,

Universidad Nacional Autonoma de Mexico, 04510 Mexico D.F.

The sub-continental lithospheric mantle (SCLM) may either underlie regions

for a long period of time or may be replaced during processes such as

delamination or plume magmatism. The occurrence and timing of mantle

replacement may be identified by comparing the Sm-Nd isotopic signature of

suites of basaltic rock within the same terrane over a range of time.

In mainland Nova Scotia, the early Jurassic North Mountain Basalt

(NMB) straddles the boundary between two terranes (the Avalon and

Meguma terranes) that accreted to Laurentia during the Paleozoic. NMB is

widely recognized as the northernmost representative of the Central

Atlantic Magmatic Province (CAMP) but Sm-Nd isotopic data yield ε

Ndt

values (t=200 Ma) ranging from +0.1 to -2.7, which are typical of

derivation from the underlying Proterozoic SCLM, rather than from the

CAMP plume. Comparison with older mafic magmatic events indicates

that the SCLM is isotopically indistinguishable from that inferred to yield

Ordovician and Devonian mafic magmas in the Meguma terrane and

Neoproterozoic to Devonian mafic magmas in the Avalon terrane. These

data indicate that the same SCLM underlay mainland Nova Scotia from

Neoproterozoic to Jurassic times, and that Paleozoic tectonic events did

not significantly detach the mantle from the overlying crust. Taken

together, the Sm-Nd isotopic data for the mafic rocks form and envelope

that defines the evolution of the mantle sources beneath mainland Nova

Scotia. The data suggest that the mantle source was enriched between 0.8

and 1.1 Ga and has an average Sm/Nd ratio of ca. 0.24 (a value that is

typical of an enriched mantle source). Neoproterozoic paleocontinental

reconstructions that this mantle originated in the (Mirovoi) ocean that

surrounded the supercontinent Rodinia. More generally, the study points

out the additional insights gained by tracking mantle evolution in a given

terrane through time.

POTENTIAL GEODYNAMIC RELATIONSHIPS BETWEEN THE

DEVELOPMENT OF PERIPHERAL OROGENS ALONG THE

NORTHERN MARGIN OF GONDWANA AND THE

AMALGAMATION OF WEST GONDWANA

Murphy, J.B., Department of Earth Sciences, St. Francis Xavier

University, PO Box 5000, Antigonish, NS B2G 2W5,

[email protected], Pisarevsky, S., School of Earth and Environment

(M004), University of Western Australia, 35 Stirling Highway,

Crawley, WA 6009, Australia, and Nance, R.D., Department of

Geological Sciences, 316 Clippinger Laboratories, Ohio University,

Athens, Ohio 45701, USA

The Neoproterozoic-Early Cambrian evolution of peri-Gondwanan

terranes (e.g. Avalonia, Carolinia, Cadomia) along the northern

(Amazonia, West Africa) margin of Gondwana provides insights into the

amalgamation of West Gondwana. The main phase of tectonothermal

activity occurred between ca. 640-540 Ma and produced voluminous arc-

related igneous and sedimentary successions related to subduction beneath

the northern Gondwanan margin. Subduction was not terminated by

continental collision so that these terranes continued to face an open ocean

into the Cambrian.

Prior to the main phase, Sm-Nd isotopic studies suggest that the

basement of Avalonia, Carolinia and part of Cadomia was juvenile

lithosphere generated between 0.8 and 1.1 Ga within the peri-Rodinian

(Mirovoi) ocean. Vestiges of primitive 760-670 Ma arcs developed upon

this lithosphere are preserved. Juvenile lithosphere generated between 0.8

and 1.1 Ga also underlies arcs formed in the Brazilide Ocean between the

converging Congo/São Francisco and West Africa/Amazonia cratons (e.g.

the Tocantins province of Brazil). Together, these oceanic arc assemblages

with similar isotopic characteristics may reflect subduction in the Mirovoi

and Brazilide oceans as a compensation for the breakup of Rodinia and the

generation of the Paleopacific. Unlike the peri-Gondwanan terranes,

however, arc magmatism in the Brazilide Ocean was terminated by

continent-continent collisions and the resulting orogens became located

within the interior of an amalgamated West Gondwana.

Accretion of juvenile peri-Gondwanan terranes to the northern

Gondwanan margin occurred in a piecemeal fashion between 650 and 600

Ma, after which subduction stepped outboard to produce the relatively

mature and voluminous main arc phase along the periphery of West

Gondwana. This accretionary event may be a far-field response to the

breakup of Rodinia. The geodynamic relationship between the closure of

the Brazilide Ocean, the collision between the Congo/São Francisco and

Amazonia/West Africa cratons, and the tectonic evolution of the peri-

Gondwanan terranes may be broadly analogous to the Mesozoic-Cenozoic

closure of the Tethys Ocean, the collision between India and Asia

beginning at ca. 50 Ma, and the tectonic evolution of the western Pacific

Ocean.

RISE AND FALL OF CAMBRIAN–ORDOVICIAN TRILOBITE

EXTINCTION PATTERNS: FACIES PATTERNS AND ROLE OF

PALEOGEOGRAPHY

Myrow, P.M., Geology Dept., Colorado College, Colorado Springs,

CO 80903, pmyrow@coloradocollege.edu, Taylor, J.F., Geoscience

Dept., Indiana University of Pennsylvania, Indiana, PA 15705, and

Ripperdan, R.L., 1417 Fairbrook Drive, Des Peres, MO 63131

Cambrian biomeres and their associated stage boundaries display patterns

of trilobite extinction and radiation that took place within Laurentia in the

Late Cambrian to earliest Ordovician. Numerous hypotheses exist for these

patterns, although very high-resolution stratigraphic, sedimentological and

geochemical data are commonly lacking. Hypotheses include changes in

oxidation potential of marine water, sea surface temperatures, and eustasy.

We provide high-resolution (decimeter-scale) data from (1) strata that span

the critical interval at the top of the Ptychaspid Biomere, the last of the

Cambrian Biomeres, and the base of the Ibexian Series; and (2) deposits

that span the base of the Lower Ordovician Stairsian Stage, which also

records a biomere-like extinction. Our integrated sedimentological,

biostratigraphic, and carbon-isotope chemostratigraphic analysis of these

and other sections from the inner detrital belt of western North America

are used to contrast depositional and paleogeographic patterns of

sedimentation that evolved across the Cambrian–Ordovician boundary

interval. The older event is recorded in well developed, meter-scale,

deepening upward, subtidal cycles of shale and limestone that correlate

across a broad area of the inner detrital belt. Deposition of shale is linked

to the introduction of mud from reactivated rivers during lowstand

conditions, and upward replacement by carbonate reflects reduced

terrigenous input. Sub-meter-scale resolution of the biostratigraphic data

establishes that the horizons of faunal change (subzonal boundaries) from

within the critical interval at the top of the Ptychaspid Biomere coincide

with the upper parts of the upward-deepening cycles. Although the

biomere occurs within a third-order lowstand, precise biostratigraphic data

indicate that each component extinction occurred during the late stages of

fifth-order highstands. Thrombolitic microbial mounds, which are absent

from the critical interval, reappear at the top of the Ptychaspid Biomere. In

contrast, trilobite extinction patterns at the base of the Ordovician Stairsian

Stage do not culminate in a nadir of diversity, but instead record rapid

diversification. Such a pattern may represent the last gasp of Cambrian

extinction processes, in part due to the demise of the continent-wide

Cambrian paleogeographic pattern, including a well-developed inner

detrital belt.

MANTLE SIGNATURES IN LATE-ARCHEAN ALKALINE

MAGMATIC-HYDROTHERMAL SYSTEMS: IMPLICATION FOR

GOLD SOURCES

Nadeau, O., Stevenson, R. and Jébrak, M., Université du Québec à

Montréal / Géotop, rue President-Kennedy, Montréal, QC H2X 3Y7,

[email protected]

Field relations, trace elements and isotopic compositions as well as

radiogenic isotope dating suggest that syn- to late-orogenic, 2676 to 2688

Ma old, auriferous syenites, lamprophyres (sensus stricto) and carbonatites

of the Abitibi greenstone belt are genetically related. Chondrite-normalized

REE patterns of carbonatites, lamprophyres and syenites of the Province of

Superior are very similar. La/Yb ratios for lamprophyres and carbonatites

range from ~10 to 100 whereas those for coeval syenites show La/Yb

ratios of ~10. Preliminary results on rocks from Duquesne Au syenite

porphyry show La/Yb ratios of 10 for the syenites and 100 for the

lamprophyres. A survey of isotope data in the literature reveals ε

values

that are consistent with derivation of these suites from a depleted mantle:

+1 to +2 for lamprophyres, +2 to +3 for syenites and +2 to +4 for

carbonatites. Initial

Sr/

Sr values for these three types of lithologies also

suggest mantle sources, with values ranging from 0.70122 to 0.70135 for

the gold-bearing Lac Shortt and Dolodau carbonatites, 0.70146 for the

Kamiskotia-Montcalm area lamprophyres, and 0.70106 to 0.70136 in

clinopyroxenes of the Murdock Creek Complex syenites. Preliminary

Sr/

Sr data obtained from carbonates in lamprophyres from Duquesne

Au deposit show mantle-like values ranging from 0.70468 to 0.70530 but

also show some carbonates with more crustal values such as 0.72641.

The literature data, along with the above preliminary results allow us

to shed light on the petrogenesis of these rocks and their possible

relationship to the metallogenesis of gold deposits. It is commonly

accepted that carbonatites and lamprophyres are derived from the depleted

mantle. Lamprophyres (sensus stricto) are quenched, volatile-rich,

hypabyssal, mafic porphyric rocks that appear to interact very little with

the crust as they rise from the mantle. Radiogenic isotope data indicate that

syenites are also derived from a depleted mantle source and that they too

interact very little with the crust as they evolve. We thus propose that the

syenites were produced by fractional crystallization of lamprophyre-

carbonatite magmas in the crust. This would also provide physical

pathways for magmatic-hydrothermal activity from the mantle to shallow

level porphyries during the late Archean. In this model, gold could have

been carried from the mantle to its site of deposition in shallow level

syenitic porphyries via a mantle-derived, carbothermal fluid. This model

also finds support in the presence of carbonic-fluid-saturated, hybrid

silicocarbonatites of Lac Shortt, Abitibi.

CESSATION OF ARC-NORMAL MID-CRUST EXTRUSION AND

ONSET OF ARC-PARALLEL OROGENIC EXTENSION IN FAR

NW NEPAL HIMALAYA

Nagy, C., Godin, L. and Antolin, B.T., Queen's University, Miller

Hall, Kingston, ON K7L 3N6, carl.nagy@queensu.ca

The Grenville system is argued to be a deeply-exhumed equivalent of the

Himalayan orogen. Both orogens can be subdivided into two distinct

evolutionary phases: (1) significant crustal thickening leading to the

growth of an orogenic plateau, followed by extrusion of mid-crustal

material, and (2) cessation of arc-normal mid-crustal flow marked by the

onset of extensional faulting. Locating areas that record the transition

between these two phases can be problematic in all orogens, particularly

those deeply exhumed, such as the Grenville.

Field mapping, structural and microstructural analysis, geo-

chronology, and thermochronology confirm the existence of the Gurla-

Mandhata-Humla fault, an orogen-oblique strike-slip dominated fault in

the High Himalaya of northwestern Nepal. Detailed across-strike transects

reveal shallow-dipping mylonitic foliations and intense shallow plunging

mineral stretching lineations consistent with orogen-parallel deformation.

Furthermore, this fault system overprints the exhumed metamorphic and

anatectic core of the Himalaya and its upper bounding fault, thus

documenting the transition from arc-normal directed extrusion of mid-

crustal material to orogenic extension.

This transitionary shear zone is characterized at upper structural

levels by well-developed type-1 cross-girdle quartz c-axis fabrics and

symmetric a-axis fabrics, indicating plane strain conditions. C-axis fabrics

transition to type-2 cross girdles at ~ 1.2 km below the fault, suggesting an

ostensible contribution of constrictional strain at depth. Quartz c-axis

opening angles and quartz and feldspar recrystallization mechanisms show

a progressive increase in deformation temperatures from ~ 350°C along

the zone of maximum strain, to upwards of ~ 630°C at depths greater than

~ 5.5 km below the fault. Abundant asymmetrical fabric elements and

conjugate shear bands in conjunction with a calculated mean kinematic

vorticity number of 0.60 (c. 58% pure shear) attest to an important

contribution of pure shear. U-Th-Pb in situ monazite geochronology, U-Pb

whole rock zircon geochronology and

Ar/

Ar muscovite thermo-

chronology reveal rapid crystallization, decompression melting, and

cooling within ≤ 7 Myr. This cooling is interpreted to represent the

cessation of orogen-normal mid-crustal extrusion and the onset of orogen-

parallel upper-crustal extension.

These observations suggest this tectonic transition occurs over a

geologically short time period and is characterized by important

contributions of coaxial strain, invoking the following question: Can the

same tectonic processes that govern this transition be applied to the

Grenville and what, if at all, will these structures look like in the deeply

exhumed Grenville orogen?

CONTRIBUTIONS OF AVALONIAN NEWFOUNDLAND TO OUR

GLOBAL UNDERSTANDING OF THE EDIACARAN PERIOD

Narbonne, G.M., Geological Sciences and Geological Engineering,

Queen's University, Kingston, ON K7L 3N6, narbonne@

geol.queensu.ca

The first Ediacara-type megafossil named anywhere in the world was

Billings (1872) description of Aspidella terranovica from Duckworth

Street in downtown St. John’s. This was a bold move - Billings recognized

that Aspidella was nonmineralized, that it occurred in extraordinary

abundance in undoubted pre-Cambrian strata, and that it did not resemble

any described Phanerozoic fossils. However many of Billings’

contemporaries were less receptive to the concept of Precambrian

megascopic life, and Aspidella lapsed in obscurity as a “pseudofossil” for

more than a century until it was resurrected in 2000 as probably

representing the base of an Ediacaran frond. The discovery of even older

fossils at Mistaken Point during thesis research at Memorial University of

Newfoundland was at first even more contentious, but we now recognize

the Mistaken Point biota as the oldest representatives of the Ediacara biota

and among the oldest large and complex eukaryotes known anywhere.

Subsequent studies have shown that the Mistaken Point fossils first appear

immediately above the highest Proterozoic glacial deposits (Gaskiers

Tillite) and coincident with evidence for a massive oxidation of the deep-

sea, providing a causal mechanism for “when life got big” after 3 billion

years of mostly microbial evolution. Most of the Mistaken Point fossils

were rangeomorphs, an extinct clade of fractal organisms whose affinities

remain delightfully controversial, and who formed tiered communities

strikingly like those of modern suspension-feeding animals to extract

nutrients from the seawater. The end of the Ediacaran is formally defined

at the GSSP at Fortune Head on the Burin Peninsula, and is marked by an

increase in complex burrowing and predatory strategies that signalled the

end of the Ediacaran and the beginning of our Phanerozoic world.

THE “BRITISH COLUMBIA CALEDONIDES”: MID-PALEOZOIC

OROGENY IN THE SOUTHERN ALEXANDER TERRANE

Nelson, J.

, [email protected], Mahoney, J.B.

, Gehrels,

, Pecha, M.

, van Staal, C.

, Diakow, L.

, Karl, S.

and Angen, J.

B.C. Geological Survey Branch, Box 9333, Stn Prov Govt, Victoria,

BC V8W 9N3;

Department of Geology, University of Wisconsin

Eau Claire, Eau Claire, WI 54702 USA;

Department of

Geosciences, University of Arizona, Tucson, AZ 85721 USA;

Geological Survey of Canada, 605 Robson St., Vancouver, BC V6B

5J3;

USGS, 4200 University Dr, Anchorage, AK 99508-4626;

University of Waterloo, Waterloo, ON N2L 3G1

The Alexander terrane (AT) in southeastern Alaska is a Neoproterozoic–

Early Devonian primitive arc terrane with faunal and geochronological

affinities to western Baltica / Polar Urals. Permian faunas place it in the

northern Pacific, and it was accreted to the western Cordillera by the mid-

Jurassic. Bedrock mapping and geochronology in the lesser-known AT of

coastal NW British Columbia provide constraints on its mid-Paleozoic

tectonics. The lowest stratigraphic unit is the Cambrian-Ordovician

Descon Formation (Moira Sound unit?) (ca. 460-520 Ma) – arc-related

andesitic breccia, tuff, felsic volcanics, volcanogenic sediments and

hypabyssal rocks. It is unconformably overlain by a Devonian clastic

succession of mixed Paleozoic arc and pericratonic provenance, the

Mathieson Channel unit ( MCU). MCU includes lithic feldspathic

sandstone, local plutonic-volcanic clast conglomerate, abundant carbonate,

basalt and minor rhyolite. Detrital zircon populations from eastern MCU

near Grenville and Mathieson channels are ca 400-460 Ma, with a peak at

423 Ma, sourced primarily from Late Ordovician-Silurian plutonic rocks

like those of AT in southeastern Alaska. Farther west towards and on

Banks Island, detrital zircon spectra show both mid-Paleozoic peaks like

eastern MCU, and a set of peaks between 2.0 to 1.0 Ga, including

populations in the NAMG. Rare quartzite-clast conglomerates contain

exclusively Precambrian signatures. MCU was derived from two source

terranes: mid-Paleozoic AT arc granitoids to the east, and a pericratonic

(Baltican?) source to the west (present coordinates).

The Ogden Channel plutonic-metamorphic complex occurs as a

fault-bounded panel on Porcher Island, near the western limit of typical

Alexander stratified rocks, and east of the pericratonic Banks Island

outcrop belt. Evidence for Early Devonian tectonism is shown by epidote

amphibolite-facies metamorphism and synplutonic ductile deformation

affecting both Descon-age strata and plutonic bodies as young as ca 413

Ma, cut by post-tectonic tonalite (ca. 410 Ma). Synmagmatic shear zones

preserve evidence for sinistral and/or oblique sinis tral-reverse motion. It

may represent a mid-Paleozoic accretionary boundary between the AT and

a pericratonic fragment, while MCU represents the associated clastic

overlap. In southeastern Alaska, this Late Silurian-Early Devonian event is

termed the Klakas orogeny. Observed features of the Klakas orogeny in

NW BC - widespread shallow-water clastic-carbonate deposits of the

MCU, restricted occurrence of coeval ductilely-deformed plutonic rocks,

and sinistral strain indicators – highlight the significance of oblique

motions. This mechanism is consistent with evidence for Silurian-

Devonian sinistal transport of terranes of the northernmost Caledonides

(e.g. Pearya) westward towards the Pacific realm.

TAPHONOMY AND EARLY DIAGENESIS OF ANCIENT DEEP-

WATER SPONGE MOUNDS

Neuweiler, F., Université Laval, 1065 avenue de la Médecine,

Québec, QC 1V 0A6, Fritz[email protected]

Important components of the rock fabric of ancient deep-water sponge

mounds are: a) calcified siliceous sponges, b) a secondary cavity system,

c) various generations of infiltrated carbonate mud, d) crusts of marine

cement, e) molds of bio-opaline silica, and f) replacive silica that ranges

from microsopic traces to macroscopic chert.

Calcification of siliceous sponges (lithistid and non-lithistid

demosponges, hexactinellids), although still poorly understood, relates to

the degradation of sponge connective tissue that serves as a non-living

organic substrate for the precipitation of microcrystalline carbonate. This

kind of organomineralisation results in net-accretion and patchy

consolidation. The degree of connective tissue calcification varies from

complete, thus preserving spicular architecture and canal system, to

incomplete, hence leading to mechanical collapse in association with the

formation of a secondary (stromatacid) cavity system. Ongoing

sedimentation and benthic sediment cycling results in a highly structured

succession of infiltrated carbonate mud. Late stages of sediment

infiltration co-occurs with initial marine cement formation. The

mechanisms and controls of marine cementation in such deep-water, low-

energy environments are underexplored. The conventional view of an

actively circulating shallow marine-phreatic environment does not match

instead internal waves and/or advective fluid flow should be considered.

Dissolution of sponge spicules, an opaline-proteic composite, co-occurs

with early stages of marine cement formation. Pore-water dissolved silica

might be held in place if stagnant conditions prevail, which is usually the

case for the conditions of a condensed section (transgressive systems

tract). By contrast, pore-water dissolved silica might be rapidly lost if the

mound deposits are succeeded by a shallowing- and coarsening-upward

sequence (highstand systems tract, diffusion + advective flux). Silica

flocculation depends on acidification of pore-waters (sulfide oxidation)

and the availability of Mg-bearing carbonate substrates and might result in

important substrate-selective chertification. The time scale between sponge

taphonomy and silicification is on the order of several tens to hundreds of

thousands of years.

GEOGRAPHIC AND ENVIRONMENTAL VARIATION IN

GORGONIAN CORAL SKELETAL GROWTH RATES

Neves, B.M.

, [email protected], Edinger, E.

1,2

, eedinger@

mun.ca, sup>1Department of Biology/

Department of Geography,

Memorial University of Newfoundland, St. John’s, NL A1B 3X9

Gorgonian corals are widely distributed colonial marine organisms whose

growth forms and rates vary according to intrinsic and/or environmental

factors. They can have three types of skeleton: proteinaceous (gorgonin),

calcareous, and mixed; which have been used to assess their growth rates.

To examine which factors seem to be related to growth in these organisms

we compared published linear and radial growth rates among gorgonian

taxa, skeleton types, and along environmental gradients using

environmental data from the World Ocean Database. We analyzed growth

rates in 16 genera from the families: Acanthogorgiidae, Briareiidae,

Coraliidae, Isididae, Paragorgiidae, Plexauridae and Primnoidae in relation

to latitude, temperature, depth, salinity, nitrate and phosphate

concentrations in the depth ranges from which corals were collected.

Growth rates were significantly different among skeletal types. Linear

growth rates differed significantly among cold-water gorgonian families

and genera, but radial growth rates did not. Tropical gorgonians had

significantly higher growth rates than cold-water species. The analysis

between all samples and environmental variables showed negative

correlations with depth, phosphate and silicate concentrations (radial

growth), latitude (linear growth), and a positive correlation with salinity

(linear growth). Using data from cold-water gorgonians only in relation to

environmental variables we found a positive correlation between radial

growth and phosphate, and a negative correlation with depth. Tropical

gorgonians linear growth rates were negatively correlated with phosphate

and nitrate concentrations. The negative correlations with phosphate and

nitrate with growth rates in tropical gorgonians reflects the reliance of

these dominantly zooxanthellate animals on photosynthesis by their algal

symbionts. Conversely, the positive correlation between cold-water

gorgonian growth rates and phosphate concentrations reflects the

relationship between phosphate concentrations and particulate organic

matter (POM), the main food source for cold-water gorgonians. Production

of gorgonin depends directly on food supply, and gorgonian calcification

requires metabolic energy, as does calcification in cold-water

scleractinians. Similarly, the negative correlation between cold-water

gorgonian growth and depth probably reflects decreasing food availability

in deeper waters. Examining the influence of current strength in particular

could represent a potential source of information on the role of

environmental variables in gorgonian growth, considering that it plays an

important role in the delivery of food and in the mechanical stress

experienced by their skeletons through their lives.

IMPLICATIONS OF AND OBSERVATIONS FROM THE POST-

MINERALIZATION WEATHERING, DENUDATION, AND

BURIAL OF CARLIN-TYPE AU-MINERALIZATION

Newkirk, T.T., tnewkirk@eos.ubc.ca, Hickey, K.A., khickey@

eos.ubc.ca, Bissig, T., Dept Earth & Ocean Sciences, The University

of British Columbia, 6339 Stores Rd, Vancouver, BC V6T 1Z4;

Reiners, P.W., Dept of Geosciences, University of Arizona, Tucson,

AZ 85721 USA, reiners@u.arizona.edu; and Donelick, R.A., Apatite

to Zircon Inc., Viola, ID, USA

The economic viability of shallow depth mineral deposits is strongly

affected by their post-mineralization history. Important influences include

exhumation to near surface depths, weathering/oxidation, erosion/

resedimentation, and/or burial. The complex tectonic history at Cortez

Hills (Battle Mountain-Eureka gold trend, NE Nevada, USA) presents a

unique opportunity to study the results of each of the aforementioned

processes, which have together produced a world-class ore body. The

Cortez Hills deposit is located in the hanging wall of NNW striking Cortez

Hills fault and footwall to the NE striking Crescent Valley fault, which is

associated with Basin and Range faulting. This work lends itself to a larger

integrated study of regional spatial and temporal tectonic evolution of the

late Cenozoic Basin and Range extension.

Apatite Fission Track (AFT) and apatite (U-Th/He) (AHe)

thermochronology of samples from the footwall of the Crescent Valley

fault constrain the timing and magnitude of exhumation along the Cortez

Range. AFT data indicates that the northern Cortez Range was largely

exhumed during the mid- to Late-Cretaceous, AHe data from the southern

Cortez Range indicate two additional episodes of exhumation occurred in

this area. The first major began in the Oligocene and early Miocene and

was associated with the formation of the proto-Cortez/Pediment basins.

This event brought the Cortez Hill deposit to the surface, subjecting the ore

body to supergene modification, erosion, and resedimentation into the

newly formed Pediment/Cortez basins. The last significant episode of

exhumation occurs around 10Ma and is associated with the onset of Basin

and Range extension, and was responsible for the dissection of Oligocene

and Miocene basins in the region.

By mapping stratigraphic indicators and reconstructing the evolution

of the sedimentary basins we are able to document the post-mineralization

supergene processes that have affected the Cortez Hill ore body. We

interpret thermochronologic data and regional stratigraphic sequences to

indicate that the Cortez Hills deposit was at depths no greater than 1 km

from surface at ~34Ma. Carlin-type deposits in Nevada are generally

considered to have formed at 42-37Ma suggesting Cortez hills formed in

the near sub-surface. Oxidation and supergene modification of the deposit

began prior to the Miocene as oxidized clasts of mineralized material occur

in the Miocene Pediment Basin. Deep oxidation of the orebody, likely did

not begin until the late Miocene, after significant relief had developed and

relatively oxygenated surface water was driven down topographical

gradients from the main Cortez Range into adjacent basin through the

deposit.

COMPARING AURIFEROUS AND BARREN FLUID VEIN

SYSTEMS AT THE 007 ZONE GOLD DEPOSIT, BISSETT,

MANITOBA

Neyedley, K.J., u[email protected]ba.ca, Fayek, M., Uni-

versity of Manitoba, 125 Dysart Rd, Winnipeg, MB R3T 2N2, and

Ferreira, W., San Gold Corp., PO Box 1000, Bissett, MB R0E 0J0

The Rice Lake Greenstone Belt (RLGB) has been producing gold for

almost a century. It is the most prominent gold district in Manitoba (1.77

million oz produced). The RLGB is located approximately 230 km

northeast of Winnipeg, Manitoba, within the western Uchi Subprovince of

the Superior Province and is composed primarily of mafic to felsic

volcanic and volcaniclastic rocks of tholeiitic and calcalkaline affinity. The

007 Zone gold deposit was discovered in 2009 and has an indicated

mineral resource of 230,330 ounces of Au and inferred mineral resource of

186,980 ounces of Au (October 2010). The deposit is located within

Townsite Dacite of the Bidou Assemblage (ca. 2.72-2.73 Ga) and

mineralization occurs within quartz veins at the contact with the Shoreline

Basalt.

The objective of this project is to compare barren and auriferous vein

systems. Alteration minerals (e.g., sericite and ankerite) associated with

barren and mineralized veins are similar. Mineralized and barren veins

contained two generations of quartz: primary coarse grained quartz and

secondary fine-grained quartz. However, mineralized veins have a higher

proportion of secondary quartz relative to barren veins. Gold

mineralization is generally associated with secondary quartz. Using

Secondary Ion Mass Spectroscopy (SIMS), in situ oxygen and sulphur

isotopic analysis of the two generations of quartz and pyrite were obtained

from auriferous and barren samples. Primary quartz from mineralized

samples gave higher δ

O values (average 11.07 ± 2.90 ‰) than the barren

primary quartz (average 7.74 ± 1.77 ‰). However, secondary

recrystallized quartz in both barren and mineralized samples generally

gave higher δ

O values relative to primary quartz. δ

O values of

secondary quartz from barren samples are generally lower (average 9.26 ±

3.38 ‰) than secondary quartz from the auriferous veins (average 12.93 ±

2.79 ‰). Pyrite from auriferous veins has slightly higher δ

S values (1.81

± 1.02 ‰) relative to pyrite from barren veins (-1.56 ± 2.21 ‰). The

sulphur isotopic composition of pyrite is consistent with a magmatic

source of sulphur.

Based on petrography, the alteration mineral assemblage is related to

the primary quartz and is not associated with gold mineralization.

However, the higher δ

O value of secondary quartz that is associated with

gold suggests that the auriferous fluid had a distinct δ

O value relative to

barren fluids. Therefore, it is possible to distinguish between barren and

auriferous systems using the δ

O values of quartz and to a lesser extent

the δ

S values of pyrite.

OROGENIC Ni-Cu-PGE: CA-TIMS U-Pb ZIRCON GEOCHRON-

OLOGY OF THE GIANT MASCOT ULTRAMAFIC INTRUSION,

BRITISH COLUMBIA - PRELIMINARY RESULTS

Nixon, G.T., BC Geological Survey, Ministry of Energy and Mines,

PO Box 9333 Stn Prov Govt, Victoria, BC V8W 9N3,

[email protected], Friedman, R.M., Scoates, J.S., Dept. of

Earth and Ocean Sciences, The University of British Columbia, 6338

Stores Road, Vancouver, BC V6T 1Z4, and Ames, D.E., Geological

Survey of Canada, 750-601 Booth St, Ottawa, ON K1A 0E8

The Giant Mascot mine (1958-1974), the only past-producer of nickel in

British Columbia, is situated in the Coast Mountains approximately 20km

north of Hope. The mine produced over 4Mt of ore from 22 distinct pipe-

to tabular-shaped bodies grading 0.77 wt % Ni and 0.34 wt % Cu along

with minor cobalt, silver, gold and an unknown quantity of platinum-group

elements. The magmatic sulphide ores are hosted by the Giant Mascot

ultramafic intrusion (~3 × 2 km) comprising mainly pyroxenite, peridotite

and dunite. A discontinuous hornblendite rim separates the ultramafic

intrusion from the mid-Cretaceous, dioritic Spuzzum Pluton, except to the

east where it lies in contact with Late Triassic, amphibolite-grade

metasedimentary rocks (Settler schist). The origin of the ultramafite and

contact relationships with the Spuzzum diorite are controversial: previous

interpretations include an early ultramafic cumulate phase of the Spuzzum;

a fragment of Late Paleozoic ophiolite (Cogburn Assemblage) engulfed by

the Cretaceous pluton; or a raft of cumulates belonging to the Late Triassic

Wrangellia flood basalt province.

New CA-TIMS U-Pb zircon geochronology of Giant Mascot

pyroxenite and Spuzzum diorite has been used to evaluate these competing

hypotheses. A sample of Giant Mascot pyroxenite gives an age of

93.04±0.06 (2σ) Ma based on five concordant and equivalent

206

238

dates. Another sample from the same pyroxenite unit collected 100m away

yields a spread of

206

238

Pb dates (88-119 Ma) with results on or close to

concordia, and one significantly discordant grain with a

206

238

Pb date of

216 Ma. A regression through this latter grain, anchored through 93 Ma,

suggests that it may contain an inherited core as old as 1.4 Ga. The spread

of ages both older and younger than the accepted age of 93 Ma for the

pyroxenite is interpreted to result from older inheritance in some grains

combined with incomplete removal of Pb loss even though all zircon

grains were subjected to chemical abrasion. A diorite collected close to the

margin of the pyroxenite gives a U-Pb zircon age of 95.47±0.13 Ma based

on a weighted average of three concordant and overlapping

206

238

dates which is interpreted as a maximum age for the diorite, and is similar

to previous dates reported for the Spuzzum Pluton. Although preliminary,

our geochronological results indicate that the Giant Mascot ultramafic

body is mid-Cretaceous in age and apparently younger than the Spuzzum

Pluton, and clearly eliminate an ophiolitic origin or affinities with the

Wrangellia flood basalt province.

THE FUTURE OF GLOBAL GEOPARKS IN NORTH AMERICA

Nowlan, G.S., Geological Survey of Canada, 3303 - 33

Street NW,

Calgary, AB T2L 2A7, gnowlan@NRCan.gc.ca

A Global Geopark is a defined area with geological heritage of

international significance. Key sites in a geopark may be protected under

local, regional or national legislation, as appropriate. Within the geopark

some sites are used to promote the sustainable development of the local

communities who live there, through education and geotourism. The

Global Geopark brand is supported by UNESCO but it is not a formal

program. However, the UNESCO General Assembly voted in late 2011 to

establish a task group to examine what it would take to make Global

Geoparks into a formal program; this task group will be formed in early

2012. Stonehammer Global Geopark in southern New Brunswick was

established as North America’s first Global Geopark in 2010. This geopark

is based on the billion year history represented within it (Proterozoic to

Recent with only the Jurassic missing) and the strong historical connection

100

to science in the nineteenth century. It has been flourishing ever since and

regularly catches the eye of Canadian and American media. It won an

Innovation Award from the Tourism Industry Association of Canada in

2011 drawing further attention to the idea of geoparks. This is a great start

for geoparks in North America and the Canadian National Committee for

Geoparks is working hard to encourage other communities to adopt the

concept and develop proposals. The committee has prepared guidelines for

the establishment of geoparks in Canada that are based closely on those for

Global Geoparks, but reflect the Canadian context. It has worked closely

with U.S. counterparts to ensure that the guidelines for the two countries

are as similar as possible, with the long-term goal of establishing a North

American Geopark Network that would be self-governing. The committee

has received expressions of interest from communities in many parts of

Canada and has been working to make the concept of geoparks better

known across the country. Explaining and distinguishing the geopark

concept is crucial because North Americans are used to the long-

established array of federal, provincial (state) and municipal parks, which

contrast markedly with the concept of a geopark. The future for geoparks

in Canada looks bright, but it will take time to establish new ones.

Stonehammer Global Geopark has given us an excellent example to

follow.

RESULTS OF AN AIRBORNE BIOGEOCHEMICAL SURVEY

OVER BURIED URANIUM AND RELATED MINERALIZATION

AT THE JACQUE’S LAKE AREA, LABRADOR

Nyade, P.K., [email protected], Wilton, D.H.C., Longerich, H.P., Dept

of Earth Sciences, Memorial University, St. John's, NL A1B 3X5,

Thompson, G., College of North Atlantic, Burin Campus, Burin Bay

Arm, NL A0E 1G0, and McNeill, P., Aurora Energy Ltd., St. John’s,

NL A1C 6H6

The recent positive uranium market outlook has rekindled interest in

uranium exploration. Renewed exploration activities involving the

reevaluation of previously known deposits and/or the search for new

deposits, has pushed prospecting into more challenging terrains such as

areas covered by unmineralized cap rock, or buried beneath transported

overburden such as glacial fluvial outwash. The mineralized bedrock in the

Labrador Central Mineral Belt (CMB) and in particularly, the Jacques

Lake area, is buried beneath thick layers of recently deposited glacial till

and peat. These materials present a challenge to exploration because they

effectively obscure direct observation of mineralized outcrops and

accompanying alteration haloes. The area also has rugged topography with

dense coniferous forest cover, lacks access roads, and is characterized by

long and extreme winter weather conditions with very high precipitation.

Successful evaluation of uranium resources requires cost effective and

efficient exploration strategies capable of detecting buried mineralization.

This study used airborne helicopter sampling of black spruce twigs (7

– 10 year growth), black spruce stem bark, and shoots of Labrador Tea.

Samples were collected at 100 m intervals along ten 1.6 km long, NW-SE

transects that lay over, and perpendicular to the bedrock radiometric

uranium anomaly that constitutes the Jacque’s Lake deposit. Black spruce

twigs had maximum uranium concentrations of 60 ppb, whereas the

ground level samples recorded mean concentrations close to their

individual limits of detection with a few elevated concentrations ranging

from 10 – 18 ppb. Elevated uranium concentrations in the treetop samples

coincided with the airborne magnetic and radiometric uranium anomalies

of the Jacques Lake deposit. Additional elevated biogenic uranium

anomalies were located outside the radiometric anomaly at the

northeastern and southeastern edges of the property. Geochemical

relationships (pathfinder elements) between U and Pb, Ag, Cu and Be in

the tree samples were also established.

COMMUNITY ANALYSIS OF THE TULIP BEDS (BURGESS

SHALE) – PRELIMINARY REPORT

O'Brien, L.J., Department of Ecology & Evolutionary Biology,

University of Toronto, 25 Willcocks Street, Toronto, ON M5S 3B2,

[email protected], and Caron, J.B., Department of Natural History,

Royal Ontario Museum, 100 Queen's Park, Toronto, ON M5S 2C6

Burgess Shale-type deposits provide critical clues about the early evolution

and ecology of metazoans directly in the aftermath of the Cambrian

Explosion. The Burgess Shale itself has been intensively studied, but our

understanding of ecological patterns at the scale of entire fossil

assemblages and communities remains limited. This study quantitatively

examines the Tulip Beds locality on Mount Stephen. This locality is

slightly older in age and more distal in stetting than the Walcott Quarry

and this allows examination of changing patterns in evolutionary time at a

small regional scale. Almost 9,000 specimens representing about 90

species have been examined from the Tulip Beds so far. Like at the

Walcott Quarry the arthropods and sponges dominate in terms of number

of species and relative abundance of specimens, although the most

abundant taxon, Siphusauctum gregarium, is a problematic organism only

known from the Tulip Beds. Preliminary observations suggest marked

differences in species identity per phyla. These patterns, which will be

explored in greater details during the course of this ongoing doctoral

project, will hopefully shed some light on the structure and function of the

Burgess Shale biota in different temporal and geographical settings.

EVOLUTION OF THE ARCHEAN SLAVE CRATON: INSIGHTS

FROM SEDIMENTARY BASINS AND THEIR DETRITAL

ZIRCONS

Ootes, L., [email protected], Miskovic, A., NWT Geoscience

Office, Box 1500, Yellowknife, NT X1A 2R3, Heaman, L.M.,

Department of Earth and Atmospheric Sciences, University of

Alberta, Edmonton, AB T6G 2E3, Bennett, V., Geomantia

Consulting, 33 Roundel Rd., Whitehorse, YT Y1A 3H4, and

Hewton, M., Department of Earth Sciences, Simon Fraser University,

8888 University Dr., Burnaby, BC V5A 1S6

The growth of a craton is recorded by episodes of juvenile magmatism.

The reworking and destruction of cratonic material through time may be

preserved as detritus in sedimentary basins. As detrital zircon U-Pb dating

and Lu-Hf isotopic tracing have become the ‘fossil’ record of Precambrian

environments, key stratigraphic horizons and their zircons can enable the

decoding of Archean lithospheric evolution. Presented here is previously

reported and unpublished detrital zircon U-Pb ages (SHRIMP, LA (MC)

ICP-MS, and ID-TIMS) from three distinct sedimentary sequences within

and on the Archean Slave craton, forming a dataset in excess of 5000

individual analyses. The oldest unit is quartzite from the ca. 2820 Ma

Central Slave Cover Group (CSCG) that rests unconformably on

Mesoarchean basement throughout the central and western part of the

craton. The second is the ca. 2660 and <2640 Ma Package I and II

greywacke-mudstone turbidites that are ubiquitous throughout the Slave

craton. The <2600 Ma conglomerates (e.g., Jackson Lake, Keskarrah

formations) are important stratigraphic horizons in the craton, but currently

there is only limited U-Pb detrital zircon data available. The third horizon

is Paleoproterozoic quartzite preserved unconformably on Archean

basement at the eastern edge of the Wopmay orogen.

We have screened the compilation to only include data with

concordance between +15% and -5%, errors <50 Ma (1σ) and ages older

than their constrained depositional age (younger ages are interpreted to

be isotopically out of equilibrium). For the precise ID-TIMS ages, we

augmented error margins to a minimum of ±7.5 Ma (1σ) to be more

consistent with the analytical uncertainty of the microbeam techniques

(reported errors greater than ±7.5 were not modified). Data is plotted by

stratigraphic horizon and in the Neoarchean and Paleoproterozoic

sedimentary units we remove any ages in the dataset older than the next

oldest stratigraphic horizon to relieve the effects of recycling and

dilution. The major episodes of crustal growth recorded in the CSCG are

at 3.65-3.20 Ga, 3.18-3.16, 2.98-2.94, 2.90, and 2.85-2.82 Ga. Within

the Package I-II turbidites the major zircon populations are at 2.74 Ga,

2.72-2.70, 2.68-2.66, and 2.64-2.63 Ga. The Wopmay quartzite contains

significant zircon populations at 2.63 Ga, 2.61, 2.60-2.59, and 2.57 Ga.

The largest populations in the Mesoarchean data are at 3.15 Ga and 2.94

Ga and in the Neoarchean at 2.70 Ga, 2.68-2.66 Ga, and 2.59 Ga. Within

our assigned parameters, only three grains older than 3.90 Ga have been

identified.

101

Keynote THE ROLE OF TERRESTRIAL ANALOGUE

ACTIVITIES IN A GLOBAL SPACE EXPLORATION PROGRAM

Osinski, G.R., Centre for Planetary Science and Exploration,

University of Western Ontario, London, ON N6A 5B7, gosinski

@uwo.ca

These are exciting times for planetary exploration. The robotic exploration

of the Solar System continues at an unprecedented pace with active

missions extending from Mercury to Pluto. Over the past decade, Canada

has contributed several high-profile instruments for specific robotic

planetary missions, including the meteorological station on the Phoenix

Mars lander and the Alpha Particle X-Ray Spectrometer instrument on the

Mars Science Laboratory “Curiosity” rover. The CSA has committed to

support the Mars Atmospheric Trace Molecule Occultation Spectrometer

instrument to fly on the 2016 Mars Trace Gas Orbiter and advanced plans

are underway for a lidar instrument contribution to the OSIRIS-REx

asteroid sample return mission scheduled for later this decade. Future

planetary exploration, as described in the Global Exploration Strategy, will

increasingly be through a series of partnerships and collaborations targeted

at the Moon, asteroids and Mars. Robotics is expected to be a key

technology Canada will contribute as part of this effort. In addition, in

order to prepare for future missions and to position Canada as a major

partner, terrestrial analogue activities offer a high profile and uniquely

Canadian contribution to the global space exploration program.

Terrestrial analogues are places on Earth that approximate the

geological, environmental and putative biological conditions on Mars and

other planetary bodies, either at the present-day or sometime in the past.

They are obviously important for purely scientific reasons, for comparative

planetary geology and for astrobiology. However, and perhaps most

importantly, terrestrial analogues are important for various aspects of

“exploration”. They can be used to train the next generation of planetary

scientists, engineers, managers, and astronauts; to test and develop

technologies and techniques for future missions; and to provide unique

education and public outreach opportunities that can engage the public

while developing actual flight opportunities. Critically, terrestrial analogue

activities represent a critical niche that Canadians are known for on the

international stage. The role of analogue studies in planetary exploration is

expanding and gaining importance as we prepare for future exploration

missions and it is critical that Canadian academia, industry, and

government work together to ensure that Canadians remain at the forefront

of such activities.

In this Invited contribution, I will provide a brief overview of the

history of terrestrial analogue activities in Canada and beyond, outline

some of the unique Canadian analogue sites, and provide a vision for a

renewed Canadian analogue program that can provide a stepping stone

towards a global space exploration program.

THREE YEARS OF CONTINUED GROWTH: THE EDUCATION

AND OUTREACH PROGRAM AT THE CENTRE FOR

PLANETARY SCIENCE AND EXPLORATION

Osinski, G.R., Gilbert, A., August, T., Mader, M., McCullough, E.,

Pontefract, A., Shankar, B. and Singleton, A., Centre for Planetary

Science and Exploration, The University of Western Ontario,

London, ON N6A 5B7, [email protected]

The Centre for Planetary Science and Exploration (CPSX) at The

University of Western Ontario (Western) continues to develop a

comprehensive education and outreach program focusing on planetary

science and exploration. With funding from the Canadian Space Agency

and Western, the program strives to: 1) use planetary science as a way to

raise general interest in science, 2) increase awareness of career

opportunities in planetary science and exploration research, 3) offer

educational resources to teachers, and 4) train graduate students in

education and outreach practices.

The CPSX education and outreach program has sustained extensive

growth over its first three years. This is due to a number of factors

including the hiring of a full-time education and outreach coordinator,

increasing the number of partnerships with other organizations such as

Let’s Talk Science, the London Children’s Museum, and the Thames

Valley District School Board Itinerant Gifted Program, continued

development of a wide-range of interactive presentations and activities,

and offering new large-scale events such as a full-day high school

symposium, hosting an exhibit at the Children’s Museum, and the

introduction of a weekly radio program on astronomy.fm.

As the program enters its fourth year, many new activities and

initiatives are being developed, including two large-scale projects. The

Interactive Mapping of the Planets (IMaPS) program – which recently

received funding from an NSERC PromoScience grant - will consist of

multiple inquiry-based workshops, a web-based activity using Google

Earth, Moon, and Mars, pre-prepared kits to be sent out to teachers in rural

and remote areas, and a summer camp offered in association with Sports

Western. Funding is also being sought for a program that would bring

primary- and secondary-school teachers on field research excursions so

they may learn first-hand the importance of field-work in planetary and

earth sciences.

INDICATOR MINERAL AND TILL GEOCHEMICAL

SIGNATURE ASSOCIATED WITH THE PINE POINT Pb-Zn

MISSISSIPPI VALLEY-TYPE (MVT) DEPOSITS, NORTHWEST

TERRITORIES, CANADA

Oviatt, N.M., [email protected], Gleeson, S.A., University of

Alberta, Edmonton, AB T6G 2E3, Paulen, R.C., McClenaghan,

M.B., Geological Survey of Canada, 601 Booth Street, Ottawa, ON

K1A 0E8, and Paradis, S., Geological Survey of Canada, Sidney, BC

V8L 4B2

This study was initiated to determine the till indicator mineral and

geochemical signature of the world class Pine Point Pb-Zn MVT deposits

and is part of the Geological Survey of Canada’s R&D of indicator mineral

methods for base metal exploration. Mineralized bedrock and metal-rich

till samples were collected from 5 of the more than 100 deposits in the

district. Indicator minerals recovered from mineralized bedrock samples

include sphalerite, galena and pyrite, as well as barite and anglesite. The

majority of these grains occur in the 0.5 to 1.0 mm fraction. Till on the

bedrock surface proximal to the O28 deposit contain ~35,000 sphalerite

grains and ~53,000 galena grains/10 kg sample, in all size fractions, while

samples collected from sample pits at surface proximal to the deposit

contain 0 to 3 grains of each mineral.

Ice-flow data consist of striation measurements recorded from

bedrock surfaces in the immediate sample area as well across the region.

These data indicate an earliest sustained ice flow direction to the southwest

(~230°) with an intermediate phase to the northwest (~300°) followed by

the last phase, during deglaciation, to the west- southwest (~250°).

Previous regional surficial mapping in the Pine Point area had identified

only the latest ice flow to the west-southwest, which formed the

streamlined landforms in the region.

Pathfinder elements in the <0.063 mm till fraction include Pb, Zn and

Fe, and to a lesser extent Cd and Ba. Zinc and Pb concentrations are

highest in till directly down-ice (southwest) of the O28 deposit. Elevated

Zn values in till range up to 3497 ppm while Pb values are up to 2015

ppm. The highest values for all pathfinder elements occur along the

bedrock surface down-ice of the O28 orebody. Some values are higher to

the northwest, indicating additional dispersal or reworking by the second,

northwest trending ice-flow.

PROTEROZOIC GEOMAGNETIC FIELD GEOMETRY FROM

MAFIC DYKE SWARMS

Panzik, J.E., joseph.panzik@yale.edu, Evans, D.A.D., Yale

University, 210 Whitney Avenue, New Haven, CT 06511

North America is home to many large dyke swarms. The vast areal

coverage of these dyke swarms, commonly emplaced in a few million

years, are ideal for investigating the nature of the global geomagnetic field

geometry and testing the reliability of the time-averaged geocentric axial

dipole (GAD) assumption, which is relied on critically for pre-Mesozoic

continental reconstructions and paleoclimatic inferences from

paleomagnetism. We have been testing the GAD assumption and localized

non-dipole components, by compiling paleomagnetic remanence

directional variations within the Matachewan (2.45 Ga), Mackenzie (1.27

Ga) and Franklin (0.72 Ga) dyke swarms. Our analysis varies the

quadrupole and octupole values of the generalized paleolatitude equation

to determine a minimal angular dispersion and maximum precision of

102

paleopoles from each dyke swarm. As a control, paleomagnetic data from

the Triassic-Jurassic (0.20 Ga) central Atlantic magmatic province

(CAMP) show the sensitivities of our method to non-GAD contributions to

the ancient geomagnetic field. Within the uncertainties, CAMP data are

consistent with independent estimates of non-GAD contributions derived

from global tectonic reconstructions (Torsvik & Van der Voo, 2002).

Current results from the three Proterozoic dyke swarms all have best fits

that are non-dipolar, but they differ in their optimal quadrupole/ octupole

components. Treated together under the hypothesis of a static Proterozoic

field geometry, the data allow a pure GAD geodynamo within the

uncertainty of the method. Global volcanic rocks within the age range of 0-

5 Ma will be used as another test for the robustness of this method. Current

results were performed using Fisherian statistics, but Bingham statistics

will be included to account for the ellipticity of data.

THE PETROLOGICAL EVOLUTION OF THE REE-ENRICHED

A-TYPE GRANITES OF THE LATE PALEOZOIC WENTWORTH

PLUTON, COBEQUID HIGHLANDS, NOVA SCOTIA

Papoutsa, A., angeliki_papoutsa@hotmail.com, Pe-Piper, G.,

Department of Geology, Saint Mary’s University, Halifax, NS B3H

3C3, and Piper, D.J.W., Geological Survey of Canada, Bedford

Institute of Oceanography, PO Box 1006, Dartmouth, NS B2Y 4A2

The Wentworth Pluton in the Eastern Cobequid Highlands consists

principally of metaluminous to peralkaline A-type granite (~362 Ma), a

large part of which was remelted by a major gabbro intrusion (~357 Ma).

Magmatic minerals like allanite-(Ce), chevkinite-(Ce), zircon, and

hingganite-(Y) and post-magmatic mineral phases, such as REE-epidote,

samarskite, aeschynite-(Y), fersmite, thorite, and hydroxylbastnäsite-(Ce),

were identified.

The presence of fluorine, kept the rare metals in solution and

changed the behavior of the REE, increasing the solubility of monazite and

xenotime and thus the rare earths and rare metals remained in the

magmatic system for prolonged periods. The fractionation of allanite-(Ce)

and chevkinite-(Ce) led to a magma enriched in HREE, from which

hingganite-(Y) crystallized during late magmatic stages. The remelting of

the early granite led to fluorine and sulfur release in volatile phases, which

circulated with hydrothermal fluids, thus mobilizing the REEs and rare

metals. Reduction of fluorine activity during the late to post-solidus

crystallization resulted in the precipitation of HREEs and rare metals in

samarskite, thereby enriching the residual hydrothermal fluids in LREEs.

Post-magmatic LREE-minerals such as hydroxylbastnäsite-(Ce) either

replaced earlier minerals or precipitated from these hydrothermal fluids.

Carbonate fluids involved in a late regional hydrothermal circulation along

the Cobequid-Chedabucto fault (320-315 Ma) resulted in titanium mobility

and the formation of titania minerals and probably of aeschynite-(Y).

Modelling of batch partial melting of a feldspar-dominated rock,

such as a tonalite, with a REE composition similar to that of the

Neoproterozoic quartz diorites of the region, shows that the resulting melt

would have REE concentrations similar to those of the Wentworth

granites. Partial melting of tonalitic rocks in the lower crust would produce

alkaline granitic magmas, such as the A-type granites of the Wentworth

Pluton.

The geochemistry of the Wentworth granites indicates that the REE-

enrichment can be of magmatic origin. This is further supported by the

unusual REE-mineral assemblage, which records a sequence from

magmatic REE-silicates to post magmatic oxides. The complex geological

history of the pluton provides a unique opportunity to correlate the

formation of these minerals to different stages of pluton evolution and

record the transition of an enriching system from magmatic to mainly

hydrothermal.

FLUCTUATIONS IN PRECAMBRIAN ATMOSPHERIC AND

OCEANIC OXYGEN LEVELS: A NEW PRECAMBRIAN

PARADIGM EMERGING?

Partin, C.A.

, [email protected], Bekker, A.

, Planavsky,

, Gill, B.C.

, Li, C.

, Podkovyrov, V.

, Maslov, A.

, Konhauser,

K.O.

, Love, G.D.

and Lyons, T.W.

University of Manitoba,

Winnipeg, MB;

University of California, Riverside, USA;

Virginia

Polytechnic Institute, Blacksburg, VA, USA;

China University of

Geosciences, Wuhan, China;

Russian Academy of Sciences, St.

Petersburg, Russia;

Russian Academy of Sciences, Ekaterinburg,

Russia;

University of Alberta, Edmonton, AB

The Precambrian atmosphere and oceans are traditionally thought to have

undergone a progressive increase in oxygen content after ~2.4 Ga. This

progressive transition from anoxic conditions to more oxidizing conditions

is assumed to have occurred in two incremental steps, one at the beginning

and one at the end of the Proterozoic Eon. This paradigm is changing.

Enrichments of the redox-sensitive element uranium in organic matter-rich

shales through time shows that the Earth’s surface oxidation had a much

more dynamic and unexpected history. The initial rise of atmospheric

oxygen ~2.4 billion years ago was followed by a dramatic decline to less

oxidizing conditions during the mid-Proterozoic, beginning after the

cessation of the Lomagundi excursion, ~2.05 Ga. The subsequently

established steady-state redox state persisted for nearly one billion years,

ending with a second event in the latest Neoproterozoic. Utilizing the

ubiquitous geological shale record, the U record demonstrates

unprecedented temporal resolution to reveal Earth’s dynamic path to its

present well-oxygenated state. We present evidence for a precipitous rise

and (previously unrecognized) fall in atmospheric oxygen early in the

Proterozoic, which is in direct contrast to conventional models predicting a

unidirectional oxygen rise. With this new paradigm in mind, future models

will need to reexamine the links between the co-evolution of biology and

chemical composition of the Precambrian oceans.

BASIN EVOLUTION OF THE PALEOPROTEROZOIC PENRHYN

AND PILING GROUPS: IMPLICATIONS FOR TECTONIC

EVOLUTION AND PALEOGEOGRAPHIC RECONSTRUCTION

Partin, C.A.

, [email protected], Corrigan, D.

, Wodicka,

and Bekker, A.

Dept. of Geological Sciences, University of

Manitoba, Winnipeg, MB R3T 2N2;

Geological Survey of Canada,

615 Booth Street, Ottawa, ON K1A 0E9

Tectonic processes that operated in the western Churchill province during

the Paleoproterozoic can be revealed by the study of sedimentary basins

that developed over the Rae and Hearne cratons and filled during and prior

to the Trans-Hudson Orogeny (THO). To that end, the Penrhyn and Piling

groups offer a window into understanding the tectonic mechanisms that led

to basin initiation, subsidence, and closure during the opening of the

Manikewan ocean and protracted continent-continent collision of the THO.

Geological, geochemical, and geochronological investigation of the

Penrhyn and Piling groups, on Melville Peninsula and Baffin Island,

respectively, was carried out under the Geo-Mapping for Energy and

Minerals (GEM) Program.

An understanding of the evolution of the Penrhyn and Piling basins

(including mechanisms and timing of basin initiation, sediment sources,

and mechanisms and timing of basin closure) is important when

reconstructing the tectonics and paleogeography of the surrounding

microcratonic blocks at that time. The recognition of extension-related

mafic and ultramafic volcanism in the Piling Group helps to elucidate

tectonic regimes associated with early stages in the THO. The Piling basin

shows a transition from a passive margin to an extensional continental

back-arc basin, and finally to a foreland basin during the collision with the

Meta Incognita microcraton presently located on southern Baffin Island.

Subsidence of the Penrhyn basin, in turn, was influenced by far-field

tectonic stresses, likely associated with those occurring in the Piling basin.

Both the Penrhyn and Piling strata show a ca. 1.9 Ga arc-derived detrital

zircon population, in addition to Archean and older Paleoproterozoic

zircon populations, though Penrhyn strata record only a minimal influence

of these younger zircons, suggesting a more distal source of arc-derived

detritus. Both basins began to close between ca. 1.9 and 1.89 Ga in

response to Meta Incognita docking. Combining revised stratigraphy and

results from geochronology and geochemistry of the Penrhyn and Piling

groups together allows for an integrated synthesis of the basin evolution

and evaluation of potential metal endowment of these basins.

103

AWARUITE - A NICKEL DEPOSIT CONCEPT: GEOLOGICAL

TARGETS AND EXPLORATION STRATEGIES IN NEWFOUND-

LAND

Patey, B., Devereaux, A., Winter, L., Altius Resources Inc., PO Box

8263, Station "A", St. John's, NL A1B 3N4, and Wilton, D.,

Department of Earth Sciences, Memorial University of

Newfoundland, St. John's, NL A1B 3X5

Awaruite is a nickel-iron alloy mineral, with the formula Ni

-3Fe, that

forms through the breakdown of nickel-bearing olivine or sulphide in the

extremely low oxygen and sulfur conditions produced during

serpentinization of ultramafic rocks. Although ore deposits of awaruite are

conceptual at this stage and no economic deposits are currently known,

exploration for such mineral deposits is ongoing across Canada. Awaruite

generally occurs in low concentration (<0.25%) in many ultramafic rocks,

but the strongly magnetic and high density characteristics of the mineral

may allow for relatively simple extraction, ultimately producing a

concentrate suitable for production of stainless steel yet bypassing the

smelting process. Moreover, the geology of many ultramafic bodies,

notably the large volume of the units and the relative homogeneity,

suggests that large deposits suitable for open pit mining techniques may

exist. Finally, as awaruite and the ultramafic rocks it occurs in have very

low sulphide contents, acid mine drainage is not likely to be an issue.

An exploration program has been designed based on the distinctive

mineralogical characteristics of awaruite. The program consists of a first

phase of systematic till and stream sediment sampling and regional rock

sampling over selected areas. Rock samples are sawed making the

awaruite more readily identifiable with a microscope or the naked eye.

Tills and stream sediment samples are processed to yield heavy mineral

concentrates and subsequent magnetic separates. Grain mounts are then

examined with a petrologic microscope where a count of the awaruite

grains is measured. Grain counts are plotted on maps to indicate areas that

have the greatest abudance of awaruite for further follow up. Geochemical

plots of the samples using elements such as Ni and other elements are

helpful but less reliable due to the multiple Ni-bearing phases that may

exist. Hence, petrological observations are critical as to determine both the

presence and the qualitative aspects of the awaruite occurrences, such as

grain size and whether the awaruite is monominerallic or part of multi-

phase systems (eg., mixed awaruite-silicates-sulphides). In this regard, we

have used SEM-MLA analysis to provide a more rigorous analysis of

awaruite bearing samples. As this exploration model is in its infancy,

despite much technical success to date, further improvements to the

methodology are anticipated.

DIFFERENTIATION OF NEOARCHEAN FROM

PALEOPROTEROZIC BASALT IN THE URANIFEROUS AMER

AND WHITEHILLS BELTS, NORTHEAST THELON REGION,

NUNAVUT

Patterson, J.

, [email protected], Jefferson, C.W.

Kjarsgaard, B.A.

, Pehrsson, S.

, McEwan, B.

, Calhoun, L.

Bethune, K.

, White, J.

and Tschirhart, V.

Fellow, Science

College, Concordia University, Montreal, QC H3G 1M8;

Geological

Survey of Canada, 601 Booth Street, Ottawa, ON K1A 0E8;

University of Regina, 3737 Wascana Pkwy., Regina, SK S4S 0A2;

Department of Earth Sciences, University of New Brunswick,

Fredericton, NB E3B 5A3;

MAGGIC, School of Geography & Earth

Sciences, McMaster University, 1280 Main St. W., Hamilton, ON

L8S 4K1

Distinction of Paleoproterozoic from Neoarchean mafic volcanic units in

the Amer and Whitehills fold and thrust belts has been challenged by

complex structures, yet developing unique criteria to characterize them is

critical to unraveling those structures. Mapping these belts under the

Geomapping for Energy and Minerals Program aims to improve

knowledge of basement geology for exploration of basement hosted

uranium and lode gold deposits in the northeast Thelon Basin region.

Greenschist to amphibolite facies mafic metavolcanic rocks within the

Paleoproterozoic portions of these belts have variably been interpreted as

single or multiple extrusive events during the Paleoproterozoic, or as

structurally intercalated Neoarchean basalt. Analysis of new and heritage

map data from many sources has shown that field criteria can clearly

distinguish a range of Neoarchean volcanic rocks from products of a single

Paleoproterozoic mafic event with a crustally contaminated continental

tholeiite signature.

The Neoarchean basalt is an aphyric and very finely crystalline,

integral component of 2.6 Ga and older suites ranging from komatiite

through komatiitic basalt and high-Mg tholeiite to quartz-feldspar-phyric

rhyolite. The Neoarchean suites include granitoid to pyroxenitic intrusive

components and the volcanic units are interlayered with metagreywacke

and banded chert-magnetite iron formation. The aeromagnetic expression

of the basalt to rhyolite phases is negative whereas the ultramafic rocks

and iron formations are powerful, complex highs. The Neoarchean igneous

rocks unconformably underlie basal conglomerate and/or schistose facies

of the early Paleoproterozoic quartzarenite in both the Whitehills and

Amer belts.

The Paleoproterozoic tholeiite flows are invariably plagioclase

phyric, have amygdules filled with calcite and rimmed by epidote, and

commonly overlie dolomitic mafic tuff. Gabbro sills locally intrude

underlying rocks and the tuff. The basalt gradationally overlies dolostone

in some places; in others the underlying and overlying schist contains

graphite, feldspathic and lithic meta-sandstone to -mudstone with

disseminated magnetite. In the Amer Belt, randomly oriented rip-ups of

dolostone within the metabasalt demonstrate their depositional inter-

relationship. The basalt and the stratigraphically close, magnetite-bearing

fine clastic rocks form strong, relatively continuous linear magnetic highs.

This assemblage stratigraphically overlies laterally extensive, magnetically

low quartzarenite, separated in the Whitehills belt by polymict

metaconglomerate. Geochronology of several sills within the

Paleoproterozoic sequences, and extensive new geochemical analyses are

testing the compositional distinctions summarized above; whether the

2153 ± 4 Ma Schultz Lake metagabbro is a deeper expression of the

Paleoproterozoic tholeiite event; and if these units are related to the 2.19

Ga Tulamelu / MacQuoid dyke swarm.

INFLUENCE OF PALAEOGEOGRAPHY ON VMS DEPOSIT

FORMATION AND PRESERVATION

Pehrsson, S.

, [email protected], Eglington, B.M.

[email protected], Evans, D.A.D.

, Huston, D.

and Rogers,

Geological Survey of Canada, 601 Booth St, Ottawa, ON K1A

0E8;

University of Saskatchewan, Saskatoon, SK S7N 4K8;

Yale

University, New Haven, CT, USA;

Geoscience Australia, Canberra,

Australia

Understanding the processes leading to the amalgamation of crust in the

past has always been hampered by the disseminated nature of information

and by a lack of technology to draw together data in formats suitable for

systematic study. The IGCP 509 project initiated some databases which

have facilitated the structured compilation of global data and new

technologies have become available to reconstruct and illustrate past

palaeogeographies in a GIS environment. The reconstructions utilise

published palaeomagnetic data, augmented by regional structural vergence

direction information which permit the ‘explosion’ of crustal domains at

times dictated by geology and geochronology. Known ore deposits,

lithostratigraphy and sample locations move with the continental

fragments so that one can ‘watch’ the processes and events as they change

in time and space.

Nuna was formed by closure of the Manikewan Ocean from 2.2 to

1.8 Ga. Diachronous accretion occurred from 2.2 to 1.95 Ga, starting in the

southern parts of Nuna and progressing northwards. Orogenic gold

deposits formed in the collisional zones of southern Nuna at the same time

that VMS mineralisation was occurring further north. A second phase of

accretion from 1.95 to 1.88 Ga is evident in Laurentia and Baltica as other

crustal blocks joined proto-Nuna. Many of the major, global Ni-Cu-PGE

and VMS deposits formed during this stage. Final closure of the

Manikewan Ocean occurred from 1.88 Ga to 1.60 Ga and subduction

switched from a dominantly interior domain to the peripheral, western

margin of Laurentia.

In a similar pattern, Palaeozoic VMS mineralisation in eastern North

America (New Brunswick) and in Scandinavia are preserved on either side

of the pre-Caledonian Iapetus ocean. Mineralization occurred in exten-

sional settings associated with multiple island arcs, subsequently accreted

104

to Laurentia and Baltica. Palaeogeographic reconstructions suggest that

both the New Brunswick and Norwegian VMS deposits formed along-

strike in a single major accretionary island arc system which may also be

traced into Ireland, illustrating the potential use of palaeogeographic

investigations for greenfields exploration.

Both the Nuna and Iapetus examples exhibit mineralization

associated with the closure of interior oceans. Additional, regional features

such as ocean basin palaeogeography may have influenced seawater

chemistry and VMS preservation. Iapetus and its marginal/successor

basins had a restricted east – west orientation that favoured development of

a stratified water column. A similar orientation for Nuna's Manikewan

Ocean and numerous cratonic blocks and microcontiental fragments

highlights that particularly productive VMS periods may reflect the

geometry of supercontinent amalgamation.

PETROLOGIC–GEOCHEMICAL EVOLUTION OF THE

URANIUM MINERALIZED PEGMATITES OF THE UNGAVA

BAY, NORTHERN QUEBEC

Pelletier, P.A., Université du Québec à Montréal, 201 avenue du

President-Kennedy, Montréal, QC H2X 3Y7, pierrealexandrepelletier

@hotmail.com, Jébrak, M., Université du Québec à Montréal,

Département des sciences de la Terre et de l’Atmosphère, 201

avenue du President-Kennedy, Montréal, QC H2X 3Y7, Cuney, M.,

Université Henry Pointcarré, Boulevard des Aiguillettes, BP 239

Nancy, France, and Lulin, J.M., Exploration Azimut Inc, 110 rue De

La Barre, bureau 214, Longueuil, QC J4K 1A3

A new uranium district has recently been discovered in the Rae Province

in the Superior Craton. The region was explored for uranium-bearing

pegmatites, emplaced between an Archean basement and a Proterozoic

cover. These deposits and those of Areva to the north (Cage area) are often

compared with those of Rossing. The metamorphic basement is

dominantly tonalitic. The cover is mainly a quartz-feldspar gneiss, rich in

femic minerals and sulfides with local occurrences of metabasic rocks,

marbles, calc-silicates and graphitic schists.

Two types of mineralized pegmatites are recognizable by their

mineralogy, petrology and geochemistry and structural setting. The Puqila-

type pegmatites are characterized by a laccolithic shape and a high

proportion of rounded feldspars in a matrix of biotite, quartz, apatite and

zircon. The uranium minerals are uraninite, uranothorite or uranium-rich

mobilisate between the minerals. The Aqpiq-type pegmatites are more

dyke-like and are characterized by a very quartz-rich matrix, with minor

amounts of Fe-Mg minerals, variable feldspar contents and high

concentrations of monazite, blue apatite and uraninite. Scanning electron

microscope analysis show apatite-bastnaesite alteration halos around the

monazite crystals, which indicate the influence of F-rich fluids. Other non-

mineralized pegmatites containing tourmaline, garnet and apatite also

occur in the vicinity of the mineralized types.

The pegmatites are generally weakly peraluminous, garnet bearing ones

(Agpik) are the most peraluminous, and some are slightly metaluminous

indicating interaction with the Ca-rich lithologies during their injection or

emplacement. REE geochemistry of the pegmatites suggests that monazite

has a strong control over REE patterns with large fractionation of the light

and heavy rare earths elements and a strong negative europium anomaly.

Seagull-like REE patterns in some pegmatites indicate a tetrad effect caused

by the F-rich fluids. REE patterns also show that the Aqpiq-pegmatites are

much more richer in REE, than the Puqila-Type.

The geometric relationships suggest that the formation of these

pegmatites results from the early emplacement of Puqila-Type pegmatites,

followed by the extraction of a melt corresponding to the Aqpiq-type

pegmatites with variable interaction with enclosing lithologies. Uranium

enrichment in the pegmatites of the Ungava Bay corresponds to a forming

a polyphased event related to local partial melting and limited

differenciation.

LATE GLACIAL TO HOLOCENE ENVIRONMENTAL HISTORY

OF EASTERN KAMCHATKA PENINSULA, THE NORTH

PACIFIC

Pendea, I.F.

, [email protected], Ponomareva, V.

, Bourgeois,

, Korosec, G.

, LaSelle, S-P.

, Ponkratova, I.Y.

, Ferguson, C.

Fraser, R.

, Keeler, D.

and Zubrow, E.B.W.

Lakehead University -

Orillia Campus, Department of Interdisciplinary Studies, 500

University Avenue, Orillia, ON, L3V 0B9V;

Institute of

Volcanology and Seismology, Piip Boulevard 9, Petropavlovsk-

Kamchatsky, 683006, Russia;

Department of Earth and Space

Sciences 351310, University of Washington, Seattle, WA 98195-

1310, USA;

Department of Anthropology, State University of New

York at Buffalo, 380 MFAC-Ellicott Complex, Buffalo, NY 14261-

0026;

North International University, Portovaya str. 13 Magadan

685030, Russia

We present a 14,000 year-old pollen and tephrostratigraphic record - the

longest to date in the Kamchatka Peninsula – and used this to infer

vegetation and climate dynamics as well as eruptive history around the

eastern seaboard of the peninsula. The Late Glacial environment was

characterized by wet tundra while the Late Glacial – Holocene transition

was probably drier and equally treeless. The Early Holocene landscape is

marked by the expansion of shrubs, mainly alder but also dwarf birch and

dwarf pine. The arrival and expansion of trees in Kamchatka took place

around 8000 cal BP and these are represented by Betula ermanii forests.

The absence of conifers is a distinct feature of the eastern seaboard of the

peninsula and contrasts with Central Kamchatka where conifers were an

important part of the regional vegetation during this period. The Middle

Holocene is defined by a warmer climate with strong oceanic influence

and the dominance of the Betula ermanii forests, while the Late Holocene

is marked by relative climatic instability between cool and wet periods,

when forests retreat and shrub vegetation expands considerably, and

warmer periods characterized by an opposite trend. The eruptive history of

eastern Kamchatka, inferred from high-resolution radiocarbon dating of

tephra layers, is characterized by at least 20 major eruptions, most of them

originating from the proximal Shiveluch- Kliuchevskoi volcanic group.

Tephra deposition had a major impact on wetland plant communities and

to a lesser extent on upland vegetation.

EARLY CRETACEOUS VOLCANISM IN THE SCOTIAN BASIN

SYNCHRONOUS WITH RIFTING OF THE NORTH ATLANTIC

OCEAN

Pe-Piper, G., Bowman, S.J., Saint Mary’s University, Halifax, NS

B3H 3C3, [email protected], and Piper, D.J.W., GSC Atlantic, BIO,

Dartmouth, NS B2Y 4A2

Early Cretaceous volcanism is widespread in the eastern part of the Scotian

Basin, synchronous with and spatially related to the prolonged rifting

between the Grand Banks and Iberia that began in the Tithonian and gave

way to normal sea-floor spreading at the beginning of the Albian. The

stratigraphy of volcanic rocks in wells was re-evaluated and their

volcanology refined by study of cuttings and well logs. Principally

Hauterivian volcanic rocks on the SW Grand Banks and principally Aptian

volcanic rocks in the Orpheus Graben are the result of Strombolian type

eruptions. More extensive Hawaiian type flows have been mapped from

seismic profiles on the SW Grand Banks, derived from local volcanic

basement highs with a positive magnetic anomaly, and accumulating in

small Hauterivian rift basins. Subaerial basalt flows in Orpheus graben

wells are of mid Aptian age and extended to the paleoshoreline at the

Hesper wells. They were derived from Scatarie Bank to the north, which

has a positive magnetic anomaly and known Cretaceous mafic dykes.

Cretaceous detrital zircon is widespread in the Scotian Basin,

together with detrital lithic clasts and feldspars of apparent subvolcanic

origin. U-Pb laser ablation ICPMS dating of shows two clusters of dates at

~105 and ~120 Ma, but their stratigraphic position suggests that the

determined dates are ~10 Ma too young and the true ages correspond to

late Aptian and Barremian. Zircon grain size (~130 µm) implies fluvial

transport rather than air fall. Two magnetic anomalies similar to, but east

of, Scatarie Bank might be the sources of the Barremian volcanic material.

In the central Scotian Basin, fluid inclusions in and the C-isotope

composition of carbonate cements indicate a period of flow of hot (<

175°C and <23 wt % NaCl) basinal brines in the Aptian–Albian. Although

no direct link with volcanism is known, the timing of these hydrothermal

fluids corresponds to a period of regionally high heat flow in the Northern

Appalachians, that resulted in high vitrinite reflectance in the lower

Chaswood Formation and widespread paleomagnetic resetting.

105

DETRITAL ZIRCONS FROM A LATE PALAEOZOIC

ACCRETIONARY COMPLEX OF SW IBERIA (VARISCAN

BELT): HISTORY OF CRUSTAL GROWTH AND RECYCLING

AT THE RHEIC CONVERGENT MARGIN

Pereira, M.F., IDL, Departmento de Geociências, ECT, Universidade

de Évora, Portugal, [email protected], Drost, K., Department of

Earth Science and Centre for Geobiology, University of Bergen,

Norway, Chichorro, M., CICEGe, Faculdade de Ciências e

Tecnologia, Universidade Nova de Lisboa, Portugal, Silva, J.B., IDL,

Departamento de Geología, Faculdade de Ciências, Universidade de

Lisboa, Portugal, and Solá, R., - LNEG, Unidade de Geologia e

Cartografia Geológica, Portugal

In this study we present new U-Pb ages of detrital zircons from

greywackes and quartzites of the Pulo do Lobo Anticline (PLA) that have

been interpreted to represent a Late Paleozoic accretionary complex in SW

Iberia. The PLA separates the Ossa Morena Zone, which has a North-

Gondwana affinity throughout Late Ediacaran and Early Paleozoic times,

from the South Portuguese Zone, which is considered to be underlain by

Laurussia basement. The PLA stratigraphy most likely represents a

synorogenic basin that records the closure of the Late Paleozoic Rheic

Ocean and the amalgamation of Pangaea. The youngest formations of the

PLA contain upper Devonian microfossils.

The results obtained indicate that the detrital zircons from the PLA

represent a wide range of Precambrian and Paleozoic crystallization ages.

Recycling of older sedimentary units of the Late Ediacaran active margin

(Cadomian/Pan-African orogenies) as well as of the Early Paleozoic rifting

and passive margin (Rheic Ocean) stages, accounts for the older

populations with North-Gondwana affinity (Cambrian, Neoproterozoic,

Paleoproterozoic and Archean, with a gap of Mesoproterozoic-age).

However, the Mesoproterozoic detrital zircon ages found in the

greywackes of the Pulo do Lobo Formation (< 7%) that do not correspond

to any substantial source within North-Gondwana, could come from

recycled sedimentary deposits or from denudation of Grenville-age

basement (Laurussia?). The more recent formations present in the northern

limb (Ferreira-Ficalho Group) of the PLA show a significant age cluster in

the upper Devonian (c. 378 Ma), whereas on the southern limb (Chança

Group), samples have from base to top of the stratigraphic sequence: a

minor age cluster in the middle Devonian (c. 390 Ma), a significant age

cluster in upper Devonian (c. 380 Ma) and very significant age cluster in

the upper Devonian (c. 372 Ma). The presence of middle-upper Devonian

detrital zircons in combination with very low abundances of

Mesoproterozoic detrital zircon suggests that the PLA sedimentary rocks

were not derived from exotic sources but rather have a North-Gondwanan

origin. The zircon population in the interval c. 390-380 Ma has no

identified corresponding magmatic or stratigraphic source in SW Iberia.

Considering that, during the development of the upper Devonian basins of

SW Iberia, Laurussia basement was not exposed and that there was no

magmatic arc on the North-Gondwana margin, we suggest that the c. 390-

380 Ma detrital zircons are most probably derived from denudation of a

(intra-oceanic) magmatic arc related to the closure of the Rheic Ocean.

THE ATOMIC STRUCTURE AND HYDROGEN BONDING IN

WILCOXITE, FROM RICO, COLORADO

Peterson, R.C., Department of Geological Sciences and Geological

Engineering, Queen’s University, Kingston, ON K7L 3N6, Peterson

@geol.queensu.ca

Wilcoxite MgAl(SO

)

F•17H

O is a secondary sulfate mineral that occurs in

hydrothermal systems containing significant amounts of fluorine. The

mineral sample was collected from abandoned mine workings east of Rico

Colorado. Wilcoxite occurred within a timber crib that protected the material

from direct exposure to rain and snow but not from changes in the humidity

and temperature of the atmosphere. It is remarkable that this highly hydrated

mineral has remained stable under these conditions. Cell dimensions are a =

6.644(1) Å, b = 6.749(2) Å, c = 14.892(3) Å, α = 79.664(4) °, β = 80.113(4)

°, γ = 62.487(3) °, V = 579.6(2) Å

, P-1. The atomic structure of wilcoxite

consists of isolated sulfate tetrahedra, magnesium-containing octahedra and

aluminum-containing octahedra connected through hydrogen bonding

involving additional water molecules. Wilcoxite has 1.5 water molecules per

sulphur tetrahedron that do not participate in the formation of an aluminum

or magnesium-containing octahedra. The water molecules held within the

epsomite (MgSO

•7H

O) structure are lost if the relative humidity drops

below 50% at 298K. In fact hexahydrite (MgSO

•6H

O) loses water to form

starkeyite (MgSO

•4H

O) at 40% RH at 298K. The fact that wilcoxite, with

such a high water content, is stable when the magnesium sulfate with which

it coexists has become starkeyite indicates that these water molecules are

more tightly bonded within the wilcoxite structure. If epsomite crystals are

warmed slightly they slowly become translucent and then an opaque white

powder. Wilcoxite, however, behaves quite differently. Williams and

Cesbron (1983) describe this break down. “If a hot or bright light source is

employed, crystals dissolve in their own waters of crystallization”. Wilcoxite

does not dehydrate but melts when warmed. This behaviour is similar to the

incongruent melting of meridianiite on warming above 2° C. The details of

the hydrogen bonding within these structures will be discussed.

GOSSAN HILL, VICTORIA ISLAND, NORTHWEST

TERRITORIES: AN ANALOGUE FOR MINE WASTE REACTIONS

WITHIN PERMAFROST AND MINERAL PERSISTENCE IN THE

SUB-SURFACE OF MARS

Peterson, R.C., Department of Geological Sciences and Geological

Engineering, Queen’s University, Kingston, ON K7L 3N6,

[email protected], and Williamson, M-C., Geological

Survey of Canada, 601 Booth Street, Ottawa, ON K1A 0E8

Gossan Hill is located within the Minto Inlier on northwestern Victoria

Island, Northwest Territories (N 71.36697° W 114.95155°). From above,

the hill stands out because of the topographic relief of 75m and the orange-

brown colour of the surficial rocks. The hill is underlain by inter-bedded

carbonate and sulfate-evaporite sedimentary rocks of the Kilian formation

in the upper part of the neoproterozoic Shaler Supergroup. The

sedimentary rocks were intruded by diabase sills of the 723 My Franklin

igneous event which crop out ~1km to the south of Gossan Hill. The

surface of the hill is marked by areas of concentric colour zonation up to 3

meters across, with light grey centers surrounded by a yellow-orange ring

which is, in turn, surrounded by a red-orange colour that covers the rest of

the surface of the hill. Trenches dug into these areas reveal that the central

zone contains quartz and pyrite ± native sulfur in a loose aggregate of

sand-sized grains. This is surrounded by a zone dominated by gypsum and

quartz with some jarosite. Beyond this, the surrounding surface consists of

quartz, hematite and amorphous iron oxides. The radial arrangement of the

mineral assemblage indicates an increase in oxidation of sulfur from the

center outward. Analysis of isotopic composition of the sulfur is underway

to assess the involvement of bacteria in the formation of the Gossan Hill

deposit. The soft friable nature of these deposits and the topographic relief

of the hill indicate a post-glacial (Pleistocene) age of formation. Crustal

flexure, as the result of isostatic rebound after the loss of the ice sheet,

could have created fluid migration pathways from the sulfate-evaporite

deposits in the lower part of the Kilian Formation. Permafrost has

maintained this disequilibrium mineral assemblage since the cessation of

fluid flow. Extraction of the permafrost ice from the central zone yields a

liquid with a pH of 2.0. The observed long-term persistence of pyrite

encased within the acidic permafrost indicates that oxidation and

dissolution reactions common in mine waste are slowed if not stopped in

such an environment. Water ice just below the Martian surface would also

preserve such mineral disequilibrium for very long periods of time. No

region exists on Earth where ice has existed continuously for millions of

years, but on Mars, some sub-surface ice may be very old and could be a

repository of ancient fluid compositions and reactive mineral assemblages.

REGIONAL POTASSIC ALTERATION CORRIDORS SPATIALLY

RELATED TO THE 1750 Ma NUELTIN SUITE IN THE

NORTHEAST THELON BASIN REGION, NUNAVUT – GUIDES

TO URANIUM, GOLD AND SILVER?

Peterson, T.D.

, [email protected].ca, Scott, J.M.J.

, Jefferson,

C.W.

and Tschirhart, V.

Geological Survey of Canada, 601 Booth

Street, Ottawa, ON K1A 0E8;

Carleton University, Ottawa, ON;

McMaster University, Hamilton, ON

Shallow granitic intrusions commonly generate mineralized, hydro-

thermally altered zones in porous roof rocks. Typically the alteration

involves potassic metasomatism, which can be revealed as enhanced K/Th

106

and K/U ratios in airborne gamma ray maps. 1.75 Ga Nueltin granite

plutons in the Dubawnt-Baker-Aberdeen lakes area are subvolcanic,

intruding co-magmatic rhyolitic carapaces of the Pitz Formation. A north-

opening triangle of enhanced K/Th extends from the Pamiutuq intrusion at

Tulemalu Lake (65O) toward Mallery Lake, and a corridor of enhanced

K/Th extends north from Dubawnt Lake (65N). These domains coalesce

south of Abderdeen Lake (66B,C) at an east-west high-K domain.

Although large exposures of Pitz Formation and Nueltin granite constitute

portions of these domains, broad tracts with high K/Th have no obvious

relation to silicic intrusions.

The Geomapping for Energy and Minerals Program has

demonstrated that the 65O triangle contains previously known basaltic

intrusions (McRae Lake Dyke and an unnamed intrusion east of it) and

newly recognized hi-Ti basalt flows within the Pitz Formation (SE of

Tebesjuak Lake, in 650, on Thelon River south of Beverly Lake, and at

Mallery Lake), all correlated with the mafic trigger that generated silicic

Nueltin/Pitz magmas. Two sets of dykes correlated with the Pitz basalts

(~015° parallel to the McRae Lake dyke, and ~075° parallel to the Thelon

Fault) are prominent in the high K/Th domain in 66B. We postulate that

regional potassic metasomatism is a result of alteration driven by the

basaltic phase of the Nueltin event, which is unusually prominent in these

domains, with local enhancement by Nueltin granites.

Geochronological tests of this hypothesis are in progress at the

University of Manitoba. Fluorite from the Au-Ag deposit at Mallery Lake,

located above the roof of a Nueltin pluton near its contact with Pitz

Formation basalt, has been dated by Nd-Sm isochron at 1434 ± 60 Ma.

Uraninite at Kiggavik, which has a close spatial association with

hypabyssal Nueltin bodies, has been dated by a U-Pb method at 1.4 Ga;

this age is also represented in Athabasca Basin uranium deposits. The

driver for the 1.4 Ga event is uncertain, but it must reflect a crustal scale

disturbance which has no known relation to igneous activity in these areas.

We speculate that at Kiggavik, this age represents low T resetting of an

original higher-grade metasomatic event in wall rocks of the Nueltin Suite

which is proposed as an exploration guide to U-Au-Ag deposits.

ZIRCON U-Pb, Hf AND O ISOTOPE CONSTRAINTS ON

GROWTH VERSUS RECYCLING OF CONTINENTAL CRUST IN

THE GRENVILLE OROGEN, OHIO, USA

Petersson, A.

, [email protected], Scherstén, A.

Andersson, J.

, Fisher, C.M.

, Whitehouse, M.J.

and Hanchar, J.M.

Department of Geology, Lund University, Sölvegatan 12, SE-223 62

Lund, Sweden;

Geological Survey of Sweden, Box 670, SE-751 28

Uppsala, Sweden;

Department of Earth Sciences, Memorial

University of Newfoundland, St. John's, NL A1B 3X5;

Laboratory

for Isotope Geology, Swedish Museum of Natural History, Box 50

007, SE-104 05 Stockholm, Sweden

Combined U-Pb, O and Hf isotope data in zircon allows discrimination

between juvenile and recycled crust, and is therefore a useful tool for

understanding formation and evolution of the continental crust. The crustal

evolution of basement rocks in central North America (Laurentia) is poorly

constrained as it is almost entirely overlain by a Palaeozoic cover. In order

to improve our understanding of the evolution of this region we present U-

Pb, O and Hf isotope data from zircon in drill-core samples from the

subsurface basement of Ohio. The Hf isotopic data provide evidence for

juvenile crust formation at ~1650 Ma followed by continued reworking of

a single reservoir. 1643 ±54 Ma igneous zircon in pegmatite provides

evidence of a late Palaeoproterozoic continental reservoir within the

Grenville province. This 1650 Ma reservoir was tapped in a second

igneous event at ~1450 Ma and subsequently reworked during the

Grenvillian orogeny. The ~1650 Ma crust formation model age and

presence of ~1650 Ma magmatic rocks suggests an eastward extension of

the Mazatzal province and makes it a possible protolith to the subsurface

basement of Ohio and surrounding Mesoproterozoic (i.e. Grenville-age)

rocks. The eastward extension of this ~1650 Ma crustal reservoir into Ohio

requires a revision of the crustal boundary defined by Nd isotopic data to

be located further east, now overlapping with the Grenville front in Ohio.

The easternmost sample in this study is derived from a more depleted

reservoir however, which limits the extent of >1.5 Ga basement in

subsurface Ohio and defines the location of the crustal boundary.

Syn-orogenic magmatism at ~1050 Ma suggests an extrapolation of

the Interior Magmatic Belt to incorporate Ohio.

During Grenvillian metamorphism, zircon recrystallisation occurred

in the presence of heavy δ

O fluids increasing the δ

O value of

metamorphic zircon, which also appears to have been in Lu-Hf equilibrium

with the surrounding host rocks.

THE NATURE OF REE MINERALIZATION IN THE MISERY

SYENITIC INTRUSION (QUÉBEC)

Petrella, L., laura.petrella@mail.mcgill.ca, Williams-Jones, A.E.,

McGill University, 3450 University Street, Montréal, QC H3A 2A7,

Goutier, J., Géologie Québec, 70 Boul. Québec, Rouyn-Noranda, QC

J9X 6R1, Walsh, J. and Guay, P., Quest Rare Minerals, 65 Queen

Street West, Toronto, ON M5H 2M5

The Misery Syenitic Intrusion, located 200 km east of Schefferville,

Québec, is host to an interesting, recently discovered REE-Zr-Nb prospect,

which locally contains up to 8.56 wt% TREO, 3.05 wt% ZrO

, and 0.72

wt% Nb

. The intrusion is conspicuous on aeromagnetic maps as a well

defined, ring-shaped anomaly. It was emplaced within the Mistastin

Batholith, a large Mesohelikian age igneous body, which intrudes

Paleoproterozoic rocks of the Churchill Province. A recent U-Pb

radiometric determination on zircon from the intrusion yielded an age of

1409.7 ± 1.2 Ma (David and Dion, 2011).

The core of the intrusion is largely covered by Misery Lake. Country

rocks consist of coarse-grained potassic granite characterized by some

rapakivi texture and the presence of fayalite. The contact between this

country rock and Misery Syenitic Intrusion is gradational. The dominant

lithology outside the lake is a coarse-grained syenite composed of

idiomorphic perthite with 1 to 10 volume % mafic minerals, comprising

fayalite, annite (iron rich biotite), hedenbergite and ferrohornblende. The

accessory minerals are quartz, iron oxides (magnetite, titanomagnetite and

ilmenite), zircon, fluorite, apatite, britholite, gittinsite and allanite. Other

syenites have been observed near the centre of the intrusion (medium-

grained syenite, fine-grained syenite and ferrosyenite). Their textures are

different but the mineral proportions are similar, except for the

ferrosyenite, which contains up to 50 volume % mafic minerals and

exhibits a cumulate texture with either fayalite or hedenbergite. This unit

seems to form a layer in the intrusion. The geochemical characteristics of

the various lithologies in the Misery Syenitic Intrusion suggest that the

syenites are alkaline; they are characterized by a very high Fe/(Fe+Mg)

ratio (0.8 to 1). Textures in which hedenbergite was replaced by

ferrohornblende indicate that the oxygen fugacity of the system increased

during subsolidus alteration.

The REE mineralization is concentrated mainly in iron oxide-rich

lenses, pods and veins as the mineral britholite ((Ce,Ca,Th,La,

Nd)

(SiO

,PO

)

(OH,F)) or in apatite cumulates, which have been partly

replaced by britholite. However, some rare metal mineralization also

occurs within evolved pegmatitic syenite in the form of cumulate zircon,

pyrochlore ((Na,LREE,Ca)

(F,OH)), allanite ((Ce,Ca,Y)

(Al,Fe)

(SiO

)

(OH)), gittinsite (CaZrSi

), and REE-fluorocarbonates. Except

for zircon and pyrochlore, these minerals are secondary and represent the

hydrothermal transport of the rare metals from an as yet unidentified

source. Our preliminary observations indicate that magmatic and

hydrothermal processes were both involved in rare metal concentration.

OVERVIEW OF VOLCANOGENIC MASSIVE SULFIDE (VMS)

DEPOSITS OF THE CENTRAL MOBILE BELT, NEW-

FOUNDLAND APPALACHIANS

Piercey, S.J., Department of Earth Sciences, Memorial University of

Newfoundland, 300 Prince Philip Drive, St. John's, NL A1B 3X5,

[email protected], and Hinchey, J.G., Geological Survey of

Newfoundland and Labrador, PO Box 8700, St. John's, NL A1B 4J6,

[email protected]

The Newfoundland Appalachians host >40 volcanogenic massive sulfide

(VMS) deposits with >100,000t, with an aggregate geological resource of

~112 million tonnes. Deposits are hosted in numerous groups of rocks

ranging from Cambrian to Ordovician, and have formed within volcanic

arc, arc rift, and back-arc basin assemblages within the Dunnage zone.

Deposits are of five classes: 1) mafic type – Cu(Zn)-rich deposits hosted

107

by ophiolitic rocks (e.g., Little Deer); 2) bimodal mafic type - Cu-Zn-rich

deposits hosted by bimodal sequences dominated by mafic rocks but

hosted in felsic rocks (e.g., Ming, Rambler); 3) bimodal felsic types – Zn-

Pb-Cu-rich deposits hosted by bimodal sequences dominated by felsic

volcanic rocks (e.g., Buchans, Lemarchant); 4) felsic siliciclastic Zn-Pb-

Cu-rich deposits hosted in felsic volcaniclastic-rich sequences with

abundant shale and iron formation (e.g., Boomerang); and 5) hybrid VMS-

epithermal deposits where deposits have features similar to both VMS and

epithermal ore systems (e.g., Ming 1806 zone, Bobby’s Pond and Daniel’s

Pond).

There has been considerable exploration for VMS deposits in the

Newfoundland Appalachians resulting in new discoveries in the last

decade (e.g., Boomerang deposit, new zones at Lemarchant, Ming, and

Little Deer). New research has also resulted in scientific advances

including: 1) recognition of the importance that stratigraphic environment

plays in the emplacement mechanisms of different ore systems (e.g.,

subseafloor replacement versus exhalation); 2) recognition of the

importance of magmatic fluids in the genesis of precious metal rich VMS

systems; 3) the importance of shales in the localization of mineralization in

volcaniclastic-rich environments; 4) better documentation of the ore

mineralogy and trace metal budgets of Newfoundland ore systems; 5)

utilization of field portable technology (e.g., TerraSpec) to better

understand the mineralogy of alteration associated with mineralization;

and 6) microanalytical work to better understand the sources of S, Pb, and

other ore metals within the deposits. Although the Newfoundland

Appalachians has experienced significant exploration and VMS deposit

research, numerous questions remain unanswered and provide the fuel for

many years of research and future exploration.

SUBSEAFLOOR REPLACEMENT ORIGIN FOR THE

BOUNDARY VOLCANOGENIC MASSIVE SULFIDE (VMS)

DEPOSIT, TALLY POND GROUP, CENTRAL NEWFOUNDLAND,

CANADA

Piercey, S.J., Department of Earth Sciences, Memorial University,

300 Prince Philip Drive, St. John’s, NL, A1B 3X5,

[email protected], Squires, G., Teck Resources Ltd., Duck Pond

Operations, Duck Pond Operations, PO Box 9, Millertown, NL A0H

1V0, [email protected], and Brace, T., Cornerstone Resources,

26 Kyle Ave., Mount Pearl, NL A1N 4R5, brace@crigold.com

The Boundary volcanogenic massive sulfide (VMS) deposit (0.50 Mt @

3.5%Cu, 4% Zn, 1%Pb, 34.00g/t Ag), Tally Pond Group, Victoria Lake

Supergroup, central Newfoundland, Canada represents one of the best

preserved subseafloor-replacement style VMS deposits in the northern

Appalachian Orogen. The deposit is hosted within a late Cambrian (~510

Ma) volcanic sequence consisting predominantly of rhyolitic flows and

associated volcaniclastic rocks. The deposit consists of a footwall

dominated by rhyolitic lapillistones, tuffs, and lesser rhyolite flows and in-

situ rhyolite breccias. The hanging wall consists of massive, quartz-

bearing, flow banded, lobe and breccia facies rhyolite. The deposit occurs

at the contact between these two units and consists of pyrite, chalcopyrite,

and lesser sphalerite that have partially to fully replaced the footwall

lapillistone and tuff units. The sulfides contain abundant clasts of the

surrounding host rocks, including chlorite-sericite-quartz altered rhyolite

lapilli and ash. Hydrothermal alteration consists of variably intense

chlorite with lesser sericite and quartz alteration. Chlorite alteration occurs

in both a discordant form, likely representing hydrothermal upflow zones,

and as blankets that parallel the volcanic stratigraphy, likely representing

alteration associated with replacement. Sericite and quartz occur in the

hanging wall in similar geometric form, but more distal from

mineralization. The hanging wall rhyolite flows (where present) also

contain moderate to intense, pervasive, quartz and sericite alteration. Both

the hanging wall and footwall are characterized by strong Na

O-Sr

depletions, K

O-MgO-Fe

-Ba-enrichments, and enrichments in base

metals and volatile metals (e.g., Hg, Tl). The presence of abundant

remnant wallrock/host rock clasts within the ore, intricate sulphide

replacement of porous tuff laminations and sand dykes, replacement fronts

in host lithofacies, and intense alteration in both the footwall and hanging

wall (where the hanging wall is present) of the deposit are all features

consistent with formation of the bulk of the deposit via subseafloor

replacement, a genesis style originally posited by industry geologists. The

Boundary deposit likely formed as a result of cooling of metal bearing

VMS fluids, mixing with ambient seawater and pore water/entrained

seawater within the volcanics at a permeability interface between young,

unlithified, highly permeable footwall volcaniclastic rocks and relatively

impermeable hanging wall rhyolitic flows. This permeability boundary

was likely an important feature in stimulating subseafloor replacement

within the deposit.

GEOLOGY, LITHOGEOCHEMISTRY, AND IN-SITU S AND Pb

ISOTOPE GEOCHEMISTRY OF HYDROTHERMAL SEDI-

MENTARY ROCKS FROM THE DUCK POND VOLCANOGENIC

MASSIVE SULFIDE (VMS) DEPOSIT, TALLY POND GROUP,

NEWFOUNDLAND APPALACHIANS

Piercey, S.J., spiercey@mun.ca, Layne, G.D., Department of Earth

Sciences, Memorial University, 300 Prince Philip Drive, St. John's,

NL A1B 3X5, Piercey, G., CREAIT Network, Bruneau Centre for

Research and Innovation, Memorial University, St. John's, NL A1C

5S7, Squires, G., Teck Resources Ltd., Duck Pond Operations, PO

Box 9, Millertown, NL A0H 1V0, [email protected], and

Brace, T., Cornerstone Resources, 26 Kyle Ave., Mount Pearl, NL

A1N 4R5, [email protected]

Pyrite- and pyrrhotite-rich mudstones are a common element throughout

the Tally Pond Group, Victoria Lake Supergroup, central Newfoundland

many of which are spatially associated with volcanogenic massive sulfide

(VMS) mineralization. At the Duck Pond VMS deposit, the Upper Block,

despite not hosting the deposit or having significant mineralization,

contains abundant hydrothermal mudstones. These mudstones are

dominated by laminated, variably carbon-bearing mudstones with layers of

pyrrhotite and pyrite with lesser chalcopyrite, spalerite, and galena. The

mudstones occur as 10-30cm wide beds atop of variably epidote-quartz-

chlorite altered pillow lavas. The mudstones have anomalous base metals,

volatile metals, and high Fe/Al values consistent with deposition from

metalliferous fluids. However, they have high Y/Ho (>>27), Ce/Ce*<1,

and Eu/Eu*<1, indicating deposition from lower temperature fluids that

have likely interacted significantly with seawater (i.e., Fe-oxide particles

scavenging REE+Y from seawater). Paragenetically constrained in situ S

isotope data on pyrite, pyrrhotite, and chalcopyrite obtained via secondary

ion mass spectrometry (SIMS) indicate complex mixing between

biogenically-derived sulfur from bacterial sulfate reduction of seawater

sulfate and hydrothermal sulfur derived from thermochemical sulfate

reduction of seawater sulfate. In-situ Pb isotope data for galena in

hydrothermal sediments overlap Pb isotope values for both bulk rock Pb

and in-situ Pb values for galena in the Duck Pond ores, lie between the

orogene and upper crust Pb isotope growth curves, and are consistent with

derivation from upper crustal sources along the margin of Ganderia.

Despite not hosting significant mineralization, the geological,

geochemical, and isotopic features of the Duck Pond mudstones indicate

that they have a hydrothermal origin, albeit a low temperature origin, and

suggests that there may be potential for VMS mineralization in the Upper

Block at Duck Pond and correlatives regionally within the Tally Pond

Group.

PETROLOGY AND GEOCHRONOLOGY OF THE TAY RIVER

PLUTONIC SUITE, SOUTHEAST YUKON

Pigage, L.C., Yukon Geological Survey, Box 2703 (K102),

Whitehorse, YT Y1A 2C6, lee.pigage@gov.yk.ca, Crowley, J.L.,

Department of Geosciences, Boise State University, 1910 University

Drive, Boise, ID 83725-1535, USA, Roots, C.F., Geological Survey

of Canada, 2099 2

Avenue, Whitehorse, YT Y1A 1B5, and Abbott,

J.G., Yukon Geological Survey, Box 2703 (K-10), Whitehorse, YT

Y1A 1B5

A southeast-trending belt of mid-Cretaceous granitic plutons from central

Alaska across the Yukon have been classified by age, physical

characteristics, mineralogy, whole rock composition and oxidation state.

Suites within this belt include the Tombstone, Mayo, Tungsten, Tay River,

transitional Tungsten-Tay River, Anvil and Hyland. Plutons in the Coal

River map area at the southeast end of the belt belong to the Tay River

suite, a coherent belt 465 km long and approximately 120 km wide.

108

Granodiorite to quartz monzodiorite 99-95 Ma predominate. The dacitic

South Fork volcanic calderas north of Ross River hamlet are coeval.

During mapping in 2009 and 2010 several previously unrecognized

intrusions were located following regional aeromagnetic anomalies. Most

stocks are small and roughly circular, ranging from 335 m to 8400 m in

diameter. Three larger intrusions to the north extend into the map area. All

are grey-weathering, fine- to medium-grained, unfoliated to slightly

foliated, biotite ± hornblende quartz monzodiorite to granodiorite.

Texturally the intrusions include equigranular and porphyritic variants.

Equigranular variants locally have K-feldspar megacrysts. Porphyritic

variants are typically crowded with plagioclase phenocrysts up to 5 mm

across in a fine-grained, grey matrix. Hornblende, biotite, and minor quartz

also occur as phenocrysts in the porphyritic phases.

U-Pb dates were obtained by the isotope dilution thermal ionization

mass spectrometry method with chemical abrasion (CA-TIMS) of single

zircon grains. Five or six grains were analyzed from each of eight samples.

All analyses are concordant and

206

Pb/

238

U dates from six samples are

equivalent within each sample. Weighted mean U-Pb zircon dates from

eight plutons range from 99.80 ± 0.03 to 97.70 ± 0.03 Ma (97.70 ± 0.03,

97.83 ± 0.03, 98.20 ± 0.03, 98.26 ± 0.03, 98.34 ± 0.03, 98.52 ± 0.03, 99.38

±0.03, 99.80 ± 0.03 Ma). The results suggest slightly younger ages are to

the south (0.5 Ma over 10 km).

Mid-Cretaceous plutonism in southeast Yukon reflects a back-arc

area of the continental crust above an east- to northeast-dipping subduction

zone located to the west. The Tay River suite marks the position of back-

ark plutonism and volcanism between 97 and 100 Ma. The plutonism then

shifted eastward and ceased at ~90 Ma.

THE MAIN SOURCES OF METALS AND SULFUR IN ARCHEAN

– EARLY PROTEROZOIC ORE DEPOSITS

Pilchin, A., Universal Geoscience & Environmental Consulting

Company, 205 Hilda Ave., #1402, Toronto, ON M2M 4B1,

[email protected]

The absolute majority of Archean – Early Proterozoic ore deposits contain

Cu, Ni, Cr, Co, Pb, Fe, Zn, Hg, Au, Ag, platinum group elements (PGE),

etc, as native metals and compounds (primarily sulfides). Ore deposits

contain different combinations of major metals along with mining by-

products. There are numerous mineralizations and small mostly non-

economic ore deposits of Early and Middle Archean age, but much greater

deposits of Late Archean and Early Proterozoic.

During early stages of magma-ocean solidification, the atmosphere

was composed of layers of SO

, HCl, HF, CO/CO

and H

O stratified by

density (σSO

≈292 kg/m

, σHCl≈454 kg/m

, σHF≈566 kg/m

, σCO≈314

kg/m

and σCO

≈135 kg/m

, and σH

O≈60 kg/m

at temperature 1273 K

and pressure ≥35 MPa) and generating partial pressures of ≤5.44 MPa,

≤2.72 MPa, ≤4.35 MPa, ≤2.99 MPa, and ≥27 MPa, respectively. During

crustal/lithospheric cooling, the surface interacted with such leaching

agents as SO

(S0, SO

and H

at lower temperatures), HCl and HF,

before their redistribution into the earth and formation of the water-ocean.

Based on analysis of ratio of sedimentary to magmatic deposits thicknesses

of Barberton Greenstone Belt, South Africa and Pilbara Craton, Australia,

water-ocean formation took place between 3.42 and 3.26 Ga. It was mostly

formed by ~3.2 Ga when the early Earth atmosphere’s sulfur-layer was

completely redistributed, evidenced by formation of significant amounts of

barites. During the Hadean – Early Archean, most highly reactive metals

(alkali, alkaline earth, etc.) were leached from surface and near-surface

rocks as part of the redistribution of HCl-, HF- and sulfur-layers yielding a

concentration of least reactive metals. The main metals of Archean – Early

Proterozoic ore deposits have a resistance to mineral acids, which

considerably increases when they form alloys (Ni-Cu-, Fe-Ni-, Cu-Zn-

based alloys, etc.), especially by alloying with Au and PGE. Komatiite

magmatism provides excellent conditions for the formation of such alloys.

The main sources of sulfur after its redistribution are related to the

decomposition of certain sulfides and sulfates at high temperatures. Felsic

magmas cause limited decomposition and formation of sulfur-poor ore

deposits; while komatiites and Mg-rich basalts cause almost complete

decomposition of sulfides and sulfates, with release of sulfur during

komatiite magmatism peaks in ~2.8-2.7 Ga (second generation of sulfur)

and ~1.9 Ga (third generation of sulfur). Absence of water-ocean in the

Hadean – Early Archean means absence of hydrothermal activity, which

led to concentration of great amounts of important metals and formation of

significant ore deposits starting from Late Archean.

AN EXAMINATION OF AWARUITE (Ni

Fe) FORMATION

DURING SERPENTINIZATION OF THE PIPESTONE POND

COMPLEX IN THE ATLANTIC LAKE AREA, CENTRAL

NEWFOUNDLAND

Piller, M.P., m.piller@mun.ca, Wilton, D.H.C., Memorial University

of Newfoundland, St. John's, NL A1C 5S7, and Winter, L., Altius

Minerals Corp, Box 8263 Station A, Suite 202, 66 Kenmount Rd, St.

John's, NL A1B 3V7

There are several well exposed ultramafic complexes in Newfoundland,

some of which have been important to mineral exploration and mining

activities for decades. These ultramafic bodies have undergone variable

degrees of serpentinization: low grade, retrograde metamorphism during

which the Fe-Mg silicates olivine and pyroxene break down to form one of

the serpentine-family of minerals and magnetite. Strongly reducing

conditions produced by the release of H

during magnetite formation can

provide the conditions amenable to the formation of Ni-rich mineral

phases such as the nickel-iron alloy awaruite (Ni

Fe). The stoichiometric

nature of Ni-minerals formed during serpentinization is also influenced by

the amount of sulphur available in the system. Awaruite forms under

reduced conditions in the absence of sulphur from the hydrous-

metamorphic remobilization of nickel from olivine and/or the breakdown

of primary sulphides such as pyrrhotite and pentlandite.

The scope of this project is i) to document awaruite and associated

nickel-bearing mineral phases in the Atlantic Lake area of the Pipestone

Pond Complex, central Newfoundland, and ii) to constrain the geological

conditions under which Ni-Fe alloys form. Petrographic and SEM-MLA

analyses were utilized to locate awaruite and define its associated mineral

assemblages. XRF data of the serpentinized lithologies indicate greater

nickel contents present than those that could solely be sequestered in

sulphides, and probably in silicate phases. Sequential acid digestions are

being conducted to identify whether the nickel source for awaruite was

produced through the breakdown of either olivine or sulphides or a

combination of both. By providing some insight on the controls of on

awaruite formation, this research will be used to help guide exploration for

Ni-Fe alloy minerals.

GEOCHEMICAL ALTERATION AND STRUCTURAL INTER-

PRETATION AS AN EXPLORATION VECTOR AT THE LAC

CINQUANTE URANIUM DEPOSIT, NUNAVUT, CANADA

Pilles, E.

, [email protected], Bridge, N.J.

, Ward, J.

, Berry, A.

Jiang, D.

, Potter, E.

, Pehrsson, S.

and Banerjee, N.R.

[email protected],

Department of Earth Sciences, University of

Western Ontario, London, ON, N6A 5B7;

Kivalliq Energy

Corporation, Suite 1020 – 800 West Pender St., Vancouver, BC V6C

2V6;

Geological Survey of Canada, 601 Booth Street, Ottawa, ON

K1A 0E8

The Lac Cinquante uranium deposit is located in the Hearne Subprovince

of the Western Churchill Province. The deposit is hosted within an

Archean greenstone belt that is unconformably overlain by the northeast

trending Angikuni sub-basin of the Paleoproterozoic Baker Lake basin in

the western Churchill Province. Uranium mineralization at Lac Cinquante

consists of a 43-101 compliant inferred mineral resource estimate of

1,779,000 tonnes grading 0.69% U

, making Lac Cinquante Canada’s

highest grade uranium deposit outside the Athabasca Basin. Mineralization

is hosted within a zone of strong tectonic transposition. Specifically it

occurs as pitchblende in discrete veins along or at small angles with the

transposition foliation and in tensional gash veins cutting the transposition

at high angles. Mineralization also occurs weakly in Paleoproterozoic

basal conglomerates. In this study we present results for oxygen stable

isotope analyses of silicate whole-rock samples, and examine surface and

sub-surface features to determine the structural controls on the deposit.

Through integration of these techniques we investigate the implications for

fluid flow, alteration, and mineralization of the main ore zone at Lac

Cinquante.

109

Oxygen stable isotope analyses are effective in documenting zones of

increased low-temperature fluid flow which resulted in hydrothermal

alteration associated with the main zone of mineralization. Oxygen stable

isotope analyses of silicate whole rock samples have identified 20 – 50

meter wide alteration envelopes where values are elevated by almost 2‰

within, and surrounding, the main zone. Several tuffaceous units not

associated with the current main zone also show anomalous enrichments

up to 2.5‰. Additionally, 1‰ enrichment halos can be traced around

structural zones in the basaltic basement rocks.

Mineralization forms linear, shallow west-plunging ore shoots within

the Lac Cinquante and Western Extension prospects, and steeply east-

plunging ore-shoots within the Eastern Extension. The orientation of these

ore-shoots potentially corresponds to the intersection of hematite-stained

tensile fractures trending 050° and high-strain zones trending 110°, which

are proposed to reflect areas of increased fluid flow.

Combined, structural interpretation and geochemical analysis can be

utilized as an exploration vector to define future drill targets. This strategy

can be further applied to historic drill core to identify possible near misses

during past drilling as well as geophysical targets in the region not directly

associated with the main zone mineralization.

GEOMETRY OF THE APPALACHIAN TECTONIC WEDGE IN

THE ST. LAWRENCE ESTUARY AND ADJACENT AREAS

Pinet, N., Lavoie, D., Duchesne, M.J., Geological Survey of Canada,

490 rue de la Couronne, Quebec, QC G1K 9A9, npinet@nrcan.gc.ca,

Keating, P. and Dumont, R., Geological Survey of Canada, 615 rue

Booth, Ottawa, ON K1A 0E9

In Quebec, the St. Lawrence Estuary roughly follows the Appalachian

deformation front. Its northwestern shore predominantly consists of Late

Proterozoic Grenvillian metamorphic rocks with a few outliers of

Ordovician autochthonous carbonate – siliciclastic rocks of the St.

Lawrence platform, whereas Early Paleozoic sedimentary rocks that

belong to the Appalachian tectonic wedge occur along its southeastern

shore. In detail, however, the submarine boundaries between the

Grenvillian basement, the St. Lawrence platform and the Appalachians

were not precisely documented.

A recent aeromagnetic survey adds significant constraints on the

geometry of the Appalachians. Magnetic data in the St. Lawrence Estuary

highlight a belt of relatively long (15-30 km) wavelength positive

anomalies reaching 100’s nT above the regional field and take the form of

disconnected ovoid anomalies separated by faults.

Maps that enhance short wavelength magnetic anomalies associated

with near-surface sources allow tracing the generally NE-trending offshore

extent of the Appalachian-St. Lawrence Platform boundary, which

includes a ENE segment in the northern part of the studied area. Within the

Appalachian wedge, WSW-trending faults are documented on the basis of

truncation of short wavelength anomalies. These faults trend obliquely

compared with the main structural grain and extent onshore where their

significance and length were underestimated in previous field mapping

programs. These structures that were previously mapped as ‘short’ second-

order structures correspond to deformation zones up to 90 m wide with

kinematic indicators (C-S structures, asymmetric folds; slickensides, drag

folds and strike separation of passive markers) demonstrating right-lateral

motion.

Additional constraints on the geometry are provided by seismic

reflection profiles collected on the south shore, both parallel and

perpendicular to the estuary. The maximum depth of the base of the

Appalachian tectonic wedge may be estimated from these profiles that

mainly image seismic markers within the St. Lawrence Platform

succession.

Keynote HOW GEOLOGICAL FRAMEWORK EXPLAINS THE

DISTRIBUTION OF GEOHAZARDS, GEOCONSTRAINTS AND

GEOINSIGHTS FOR OFFSHORE DEVELOPMENT IN THE

DEEP-WATER EASTERN CANADIAN MARGIN

Piper, D.J.W., Geological Survey of Canada (Atlantic), Bedford

Institute of Oceanography, PO Box 1006, Dartmouth, NS B2Y 4A2

A geohazard is “A geological state that represents or has the potential to

develop further into a situation leading to damage or uncontrolled risk.” In

offshore development, geohazards are of four inter-related types: (1)

seabed interaction with moving water and ice; (2) slope instability; (3)

pore-pressure phenomena; and (4) seismicity. In offshore development,

geoconstraints are aspects of geology that have substantial economic

consequences, even if there is no damage, such as strength properties of

the seabed and boulder beds. Geoinsights are the use of geological

information to solve environmental issues in other disciplines, such as

near-bottom dispersal of pollutants by bottom currents and habitat for

vulnerable marine ecosystems. Assessment of all these geological issues is

built on an understanding of the regional geological framework. First-order

control of seismicity, petroleum basin sedimentation and tectonics, and

regional seafloor gradients are a direct consequence of the rifting and sea-

floor spreading history of the margin. These parameters in turn influence

most of the major categories of geohazards. Assessment of enhanced risk

of seismicity or pore-pressure geohazards in particular regions should

trigger enhanced regulatory response. Geological issues associated with

the uppermost part of the geological column are strongly influenced by the

peculiarities of glacial and post-glacial geological processes. Seabed

morphology and sediment types that affect shallow drilling conditions are

largely a consequence of processes at glacial maxima. The observed

distribution of submarine slides of different types is strongly influenced by

shallow morphology and geology, but their frequency does not appear

responsive to geological setting, implying an important role for seismicity.

Modern sedimentation processes in submarine canyons are poorly

understood, as is their influence on geohazards. The value of a regional

perspective on these geological issues will be illustrated with type

examples, as well as how experience in one region can be applied to

another region in the light of differences in geological framework.

PROTEROZOIC REDOX CONDITIONS AND EVOLUTION

Planavsky, N.J. and Lyons, T.W., Dept. of Earth Sciences, University

of California, Riverside, CA 92521, USA, [email protected]

The chemical composition of the ocean changed dramatically with the

oxidation of the Earth’s surface, and this process has profoundly

influenced the evolutionary and ecological history of life. The early Earth

was characterized by a reducing ocean-atmosphere system, while the

Phanerozoic Eon (<542 million years ago) is known for a stable and

oxygenated biosphere conducive to the radiation of animals. The redox

characteristics of surface environments during the Earth’s middle age (1.8

to 1 billion years ago) are less well known, but over the past decade it has

been commonly assumed that the mid-Proterozoic was home to a globally

sulfidic (euxinic) deep ocean. Here, we will present evidence that anoxic

and Fe(II)-rich conditions were both spatially and temporally extensive

across diverse paleogeographic settings in the mid- Proterozoic ocean.

Further, we will explore the how the Earth transitioned from this reducing

state that characterized most of the Precambrian to the oxidized state

typical of the Phanerozoic.

SERPENTINIZATION OF MANTLE PERIDOTITE IN THE BAY

OF ISLANDS OPHIOLITE: IMPLICATIONS FOR THE ORIGIN

OF LIFE

Pollock, J., Department of Earth Sciences, Mount Royal University,

Calgary, AB T3E 6K6, [email protected]

Life arose on Earth about 4 billion years ago and has flourished ever since.

In contrast to the present nitrogen and oxygen-rich atmosphere on Earth,

the atmosphere on primitive Earth was composed primarily of carbon

dioxide, hydrogen and water vapor. For life to have emerged in this

environment on the early Earth, a sustained source of chemical energy that

could drive metabolism by chemosynthetic organisms was vital. The

serpentinization process is proposed as the likely source of that energy.

The Bay of Islands Complex is a well preserved ophiolite complex

comprising rocks of the oceanic crust and mantle located in western

Newfoundland. The mantle peridotite from the complex exposed on the

mountains of the Tablelands is composed largely of the minerals olivine

[(Mg,Fe)

SiO

] and pyroxene [(Ca,Mg,Fe)

] which are in chemical

disequilibrium at the Earth’s surface and react with H

O and CO

in near

surface environments producing Mg–HCO

type waters. Reaction of Mg–

silicates and these Mg–HCO

waters out of contact with the atmosphere

consumes H

and leads to the precipitation of magnesite and dolomite. The

110

waters formed from these reactions are progressively richer in Ca and OH

are supersaturated with respect to brucite, serpentine and diopside, and

have a high pH of c. 12. When these Ca–OH

type waters flow near the

surface and mix with Mg–HCO

waters and the atmosphere, they

precipitate calcite and dolomite in near surface veins and carbonate cement

in unconsolidated sediments and travertine. The Ca–OH

type waters are

incompatible with minerals in adjacent country rocks and form a Ca–rich

metasomatic zone or rodingite assemblage along the contact.

The oxidation of iron through metamorphism of olivine (Fe

) to

magnetite (Fe

) during serpentinization occurs at temperatures <200°C

and provides a readily available source of electrons to create a highly

reducing environment leading to the reduction of water to H

and abiotic

production of hydrocarbons. Similar elevated abiogenic hydrocarbon

concentrations have been reported from submarine ultramafic hosted

systems in which geological, chemical and biological processes are

intimately interlinked and support dense microbial communities. The

conditions associated with serpentinization of ultramafic rocks by meteoric

waters are analogs for potential early biochemical ecosystems on both

Earth and other telluric planets, and could be a common means for

producing a broad array of microorganisms that may represent the earliest

chemolithoautotrophic life forms on Earth.

CAMBRIAN-ORDOVICIAN SUCCESSIONS AND DETRITAL

ZIRCON GEOCHRONOLOGY OF NORTH WALES AND NOVA

SCOTIA: TERRANE INTERACTIONS BETWEEN GANDERIA

AND MEGUMIA

Pothier, H.D., hpothier@ualberta.ca, Waldron, J.W.F., DuFrane,

S.A., Department of Earth and Atmospheric Sciences, University of

Alberta, 1-26 Earth Sciences Building, Edmonton, AB T6G 2E3,

Schofield, D.I., British Geological Survey, Columbus House,

Greenmeadow Springs, Tongwynlais, Cardiff, CF15 7NE, Wales,

UK, Barr, S.M., Department of Earth and Environmental Science,

Acadia University, 12 University Ave., Wolfville, NS B4P 2R6,

White, C.E., Nova Scotia Department of Natural Resources, Mineral

Resources Branch, 1701 Hollis Street, Founders Square, 3

Floor,

Halifax, NS B3J 3M8

The Harlech Dome and St. Tudwell's Peninsula, in North Wales, and the

Meguma Terrane of southern Nova Scotia, in Atlantic Canada, preserve

similar sedimentary successions of Cambrian age. All three areas display

thick early Cambrian continental-derived sandstone turbidites, overlain by

early to middle Cambrian alternating mud-rich and sand-rich units in

which manganese is locally concentrated. The manganiferous interval is

everywhere marked by a diverse and abundant assemblage of trace fossils,

including locally abundant Teichichnus. Above, the successions comprise

anoxic, organic-rich turbidites, shallowing upward into paler, early

Ordovician mudstone and siltstone with the graptolite Rhabdinopora.

Meguma detrital zircon assemblages display strong peaks in the late

Neoproterozoic (common to many peri-Gondwanan terranes) and in the

Paleoproterozoic (2.0 - 2.2 Ma), suggesting derivation from the Eburnean

orogens of West Africa. Detrital zircons from the Harlech Dome reveal

closely similar clusters of ages. Within the limited constraints of the

available biostratigraphic and geochronologic data, major changes in

environment occurred synchronously in the two successions in the

Cambrian. These areas show much greater similarity to each other than to

Cambrian successions in now-adjacent "Avalonia", suggesting proximity

between the Harlech Dome and Megumasuccessions on the margin of

Gondwana. The two areas are included in the domain "Megumia", which

was dispersed during subsequent Appalachian/Caledonian movements.

In the Ordovician the histories diverge. The highest parts of the Nova

Scotian succession record shallowing conditions with shelf sedimentation

extending through the Early Ordovician, whereas the Welsh successions

are overlain with angular unconformity by Tremadocian volcanic rocks,

and then by Floian sandstone and younger Ordovician volcanic rocks. In

the Welsh successions a strong component of Mesoproterozoic zircon

indicates that the basin was juxtaposed with Ganderia in the

Monian/Penobscot events in the Early Ordovician.

ALTERATION MAPPING IN IOCG SYSTEMS: FAB LAKE CASE

STUDY

Potter, E.G., Geological Survey of Canada, Ottawa, ON, epotter

@NRCan.gc.ca, Montreuil, J-F., Institut National de la Recherche

Scientifique, Québec, QC, and Corriveau, L., Commission

géologique du Canada, Québec, QC

Building on a lengthy heritage of mineral exploration and production of

vein-type uranium and silver deposits, the Great Bear magmatic zone

(GBmz) is now known to have a very high potential for undiscovered

magnetite- and hematite-group iron oxide copper-gold (IOCG) deposits

and affiliated iron oxide-apatite and albite-hosted uranium systems.

Detailed mapping of the Fab Lake hydrothermal system was undertaken,

east of the community of Gamètì, NT, to test the applicability of an

alteration to brecciation and mineralization evolution model developed

under the GEM IOCG/Multiple Metals project. The Fab system was

selected due to its relative simplicity, numerous mineral showings, ease of

accessibility and restricted spatial extent. Alteration was mapped by

systematically documenting alteration type, style, mineral paragenesis,

breccias, cross-cutting relationships and determination of K (%), eTh

(ppm) and eU (ppm) concentrations and volumetric magnetic

susceptibility.

The alteration footprint of the Fab IOCG system has now been

defined over an area of almost 10 by 5 km, with the long axis trending in a

southeast-northwest direction. Within this area, field mapping identified

seven alteration assemblages: 1) high temperature albite and albite-

amphibole±magnetite; 2) amphibole-magnetite±apatite and amphibole-

magnetite-K-feldspar; 3) K-feldspar; 4) K-feldspar-magnetite±hematite; 5)

chlorite; 6) hematite; and 7) low temperature epidote-K-feldspar-quartz.

These alteration assemblages are manifested by the development of

incipient to pervasive alteration, veins, hydrothermal breccias and transient

to intense, texture-preserving and texture-destructive replacements of the

host rocks. All of the historic mineral showings (U-Cu) fall within zones

characterized by intense, texture destructive alteration comprising multiple

episodes of high temperature albite/albite-amphibole (Na and Na-Ca-Fe)

and amphibole-magnetite±apatite/amphibole-magnetite-K-feldspar (Ca-Fe

and Ca-Fe-K) overprinted by K-feldspar-magnetite±biotite (K-Fe)

assemblages.

The conceptual alteration to brecciation and mineralization model is

key to understanding the alteration assemblages documented in the Fab

IOCG system. These assemblages record the build-up of a magnetite-

group IOCG system: early high-temperature Na/Na-Ca-Fe and Ca-Fe/Ca-

Fe-K alteration, overprinted by high temperature K-Fe alterations and

incipient to well-developed hydrothermal breccias. As field observations

indicate that lower-temperature K-Fe alteration associated with hematite-

group IOCG systems is only weakly developed, the Fab Lake region is

most prospective for magnetite-group types of IOCG mineralization.

While petrographic studies are planned to complement field

observations, these initial field observations clearly document the ability of

the alteration to brecciation and mineralization zoning model to overcome

the inherent complexity of these hydrothermal systems and provide field

evaluations of their maturity and fertility.

BORATE MINERALS; HILGARDITE, VEATCHITE AND

VOLKOVSKITE FROM MARINE EVAPORITE DEPOSITS OF

NEW BRUNSWICK; NEW DATA AND GEOLOGICAL INTER-

PRETATION

Poulin, R.S.

, [email protected], Grice, J.

and Hattori, K.

Department of Earth Sciences, University of Ottawa, Ottawa, ON

K1N 6N5;

Canadian Museum of Nature, PO Box 3443, Stn D,

Ottawa, ON K2P 1E4

Chemical composition, and optical and X-ray crystallographic data were

collected for borate minerals; hilgardite (Ca

Cl•H

O), veatchite

(Sr

](OH)]

B[OH]

•H

O, and volkovskite, (KCa

[OH]

Cl•4H

O) primarily from the Sussex mine (Penobsquis) and Millstream

deposits, New Brunswick. Hilgardite and veatchite both possess polytypes,

an important area of study in crystallography. Polytypism is unique to

111

layered structured minerals and can provide information relevant to

conditions of crystal growth. For hilgardite, with three polytypes (-1A, -

3A, - 4M), from two different locations, the Sussex mine and Millstream

deposit in New Brunswick, were examined. These three polytypes show

different X-ray powder diffraction (XRPD) patterns. The patterns of -1A

and -3A polytypes indeed show differences in the d values ranging from

5.5 to 5.8 Å and from 3.1 to 3.2 Å. In the latter range, polytype -1A

displays one single peak, whereas polytype -3A shows multiple peaks. The

XRPD pattern of polytype -4M varies greatly from the -1A and -3A

structures due to an increase in symmetry and cell dimensions. For

veatchite, three polytypes have been identified by Grice (2012). Among

three, two polytypes were examined; veatchite-2M from the Sussex mine,

New Brunswick, veatchite-1M from Reyershausen, Germany and

veatchite-1A from Emet, Turkey. These three are expected to show

different XRPD patterns and our study of polytypes -1A and -2M

confirmed clear differences between the two. Differences in d-values (Å)

are observed in the ranges from 5.2 to 5.6, from 3.2 to 3.3 and from 2.7 to

2.9. The emergence of additional peak(s) in these select ranges confirms

the prediction from XRPD patterns calculated from the structure

determinations. Thus XRPD can be used directly to determine which

polytype is present without involving crystal structure analysis. Knowing

the polytype can be used as an indicator of the hosts’ environment (Grice

2012). In the present study a crystal structure refinement of volkovskite

confirms the basic model of Rastsvetaeva et al. (1992). Greatly improved

data allows for a refinement of H positions that is used to elucidate H-

bonding, a factor critical in better understanding of crystal structure of

borate minerals and the development of efficient extraction techniques of

boron. The volkovskite structure obtained in this study is applicable to

many layered borates, such as biringuccite, nasinite and gowerite as

previously studied by Grice et al. (1999).

GEOCHEMICAL ANOMALIES IN SURFACE MEDIA AND

UPPERMOST SANDSTONES OVERLYING THE CONCEALED

PHOENIX URANIUM DEPOSIT, ATHABASCA BASIN, CANADA

Power, M., Hattori, K., Department of Earth Sciences, University of

Ottawa, Ottawa, ON K1N 6N5, mp[email protected], and Sorba,

C., Denison Mines Corp., 200-230 22nd St East, Saskatoon, SK S7K

0E9

The Wheeler River Property, host of Denison Mine’s Phoenix uranium

deposit, is situated near the southeastern rim of the Athabasca Basin in

northern Saskatchewan. Discovered in 2008, the deposit currently has an

indicated resource of approximately 35 million lbs U

. Mineralization

occurs as mainly monominerallic uraninite within four pods termed the A,

B, C and D ore zones. This deposit has no surficial expression, and occurs

near the unconformity between the crystalline basement rocks and

overlying Athabasca sandstones at approximately 400 meters depth. The

surficial environment, within the region of discontinuous permafrost,

consists of gently rolling hills covered by glacial till and moraines, with

overburden varying in thickness from 25 to 100 m. In September 2011, we

initiated a study to evaluate whether geochemical anomalies related to

such a deeply seated deposit exist in surface media or the overlying

sandstones. A total of 226 soil samples (humus, B, E, and C-horizon) from

59 sites along 3 transects over the “A” and “B” ore zones were collected

approximately 10 meters apart. In addition, traverse sampling was done to

determine “background values” in the study area setting.

Geochemical analyses of the samples revealed the presence of strong

U, Mo, Co, Ag and W anomalies in humus, B-horizon soil and uppermost

sandstones not only overlying the A and B zones, but also over a nearby

northeast-trending “WS Hanging Wall” Shear Zone. Peak to background

ratios were up to 6 times (5.7 ppm) for U, 5 for Mo (4.8 ppm), 4 for Co

(5.2 ppm) 20 for Ag (0.98 ppm) and 18 for W (100 ppm), respectively, in

the various surface media. The geochemical anomalies in the surface

media and the uppermost sandstones over the shear zone suggest that the

fault is acting as a conduit for upward movement of fluids from the

deposit. This fluid movement and resulting geochemical expression in

surface media provides excellent exploration tools for deeply seated

unconformity-related uranium deposits in Proterozoic sedimentary basins.

The 5.7 ppm U anomaly by aqua regia digestion method of the

humus layer yielded among the strongest and most robust geochemical

anomalies, and therefore is recommended as the leach of choice in this

well-drained area of the Basin.

BIOCHEMICAL COPPER (HEMOCYANIN) IN THE MIDDLE

CAMBRIAN ARTHROPOD MARRELLA

Pratt, B.R., Pushie, M.J., Pickering, I.J. and George, G.N.,

Department of Geological Sciences, University of Saskatchewan,

Saskatoon, SK S7N 5E2, [email protected]

The Burgess Shale, a fossil Lagerstätte famous for its diversity of

advanced Cambrian animals, onlaps a submarine fault scarp cutting the

margin of a drowned carbonate platform in southeastern British Columbia.

We conducted reconnaissance synchrotron X-ray fluorescence imaging of

a handful of specimens belonging to several taxa. This technique has an

advantage over conventional elemental mapping with the electron

microprobe in that much smaller quantities can be detected. We focussed

on Marrella splendens Walcott 1912. This small trilobite-like arthropod

has an elaborate, non-mineralized exoskeleton and, where well preserved,

typically exhibits a dark stain emanating from the head region or the tip of

the thorax. This stain represents a body fluid—most likely blood—that was

expelled upon death or that leaked out early during decay.

Our analysis revealed that Fe and S concentrations, for example, are

especially high in the fossils, indicating precipitation of diagenetic pyrite

influenced by decay. Most other elements show no preferential

distribution. However, elevated concentrations of Cu, as chalcopyrite,

were observed in the four specimens of Marrella scanned, mostly confined

to the dark stain, but essentially not in other taxa or the matrix.

We interpret this Cu enrichment as the remnants of Cu-containing

blood, hemocyanin. Hemocyanin occurs widely in mollusks and

arthropods, especially chelicerates and crustaceans, and it is utilized for

transporting oxygen in the respiratory cycle. It was likely present in other

Burgess Shale animals, but because they were not so blood-rich, most of

the Cu was recycled back into the water column during biodegradation

instead of lingering long enough in the sediment to be fixed by bacteria

into chalcopyrite.

Because hemocyanin is a less efficient oxygen-binding protein

(compared to Fe-containing hemoglobin) but a far better transport

mechanism than simple diffusion, it is reasonable to suppose that Marrella

lived in well-oxygenated waters. Its exceptional blood-rich nature might

have allowed it extra vigour of movement than other members of the

community. It also may have allowed Marrella to tolerate exposure to

reducing fluids that may have issued from submarine springs at the base of

the fault scarp.

TECTONOSEDIMENTOLOGY

Pratt, B.R., University of Saskatchewan, Saskatoon, SK S7N 5E2,

[email protected]

Students can hunt hither and yon in textbooks for basic information on the

role of earthquakes and tsunamis in sedimentology and good illustration of

the variety of telltale structures, but chances are they will come up empty-

handed. For example, the index of Facies Models 4 (2010) contains only a

few entries in which these are mentioned just in passing. Why is this? Are

senior textbook authors reluctant to incorporate what might strike them as

unconventional interpretations, awaiting some magic moment of validation

and acceptance? Is it because these features are not considered important

or common in the rock record? Or have authorities deemed ‘seismites’ and

‘tsunamites’ impossible to distinguish from slump and storm deposits

respectively, so just fuggedaboudit?

Meanwhile, for more than a decade, research on ancient seismically

deformed and tsunami-generated deposits has been proceeding vigorously.

Deformation features ranging in size from millimetres to kilometres in

scale have been well characterized and reliably interpreted from all manner

of settings and geological ages. Certain coastal deposits, impact-related

facies, and anomalous beds in subtidal shelf successions have been

fingered as tsunami-generated. Modern events underscore their

commonplace occurrence. Indeed, the case could be made for earthquakes

and tsunamis as the default explanations in place of gravity and storms in

certain situations.

Sedimentologists studying the rock record work backwards,

combining lithological observations with hydraulic and mechanical

112

principles, modern analogues, biological attributes, laboratory simulation

and mathematical modelling. These are all in operation in tectono-

sedimentology. Naturally, interpetation is still bedevilled by unknowns and

plenty of controversy is enjoyed. Nonetheless, the implications are legion,

for tectonosedimentology opens new windows on syndepositional fault

activity, sediment rheology, shoreline configuration, paleoclimate,

paleoceanography, diagenesis, fluid flow and so on.

GEOLOGICAL HERITAGE PROTECTION IN IRELAND: THE

WORK OF THE IRISH GEOLOGICAL HERITAGE PRO-

GRAMME OF THE GEOLOGICAL SURVEY OF IRELAND

Preteseille, S., [email protected], and Gatley, S. Geological

Survey of Ireland, Beggars Bush, Haddington Road, Dublin 4

The Geological Survey of Ireland (GSI) achieved recognition of geology

as an intrinsic part of the heritage definition through the Heritage Act

1995.

GSI subsequently set up the Irish Geological Heritage Programme

(IGHP) in 1998 to document the wealth of geological heritage, and

recommend appropriate protection measures in the Republic of Ireland,

based on European best practice. The programme is a partnership between

GSI and the National Parks and Wildlife Service (NPWS), who has the

statutory authority to designate sites as Natural Heritage Areas (NHA).

16 themes were identified to best evaluate and categorise sites of

geological heritage interest. Panels of experts were set up to recommend

the best representative sites within each theme and they identified about

1200 sites.

The original aim of IGHP was to document and achieve designation

of sites of national and international importance as NHA through NPWS,

and sites of local and regional importance as County Geological Sites

(CGS) through local authorities. The Wildlife (Amendment) Act provided

the statutory basis for NHA in 2000 and the National Heritage Plan (NHP)

recognised the value of CGS and GSI’s work in 2002.

Due to ongoing limited resources in NPWS and the priority given to

European designated sites, NHA designations have been largely shelved.

Documentation of sites has instead been pursued through the CGS

system. This is achieved through county audits in which site boundaries

are surveyed and their status assessed. Audits are largely funded by the

Heritage Council, thereby fulfilling its responsibility to address the

geological part of heritage. Audits are carried out and completed following

GSI/IGH guidelines to ensure continuity and quality control. Data are then

integrated in the planning system of the local authority, thereby helping

planners to make informed decisions. They also have the responsibility to

include policies, with GSI’s advice; ensuring geological heritage is

protected from inappropriate development (as per NHP).

IGHP also coordinates, in GSI, submissions to consultations received

for Environmental Impact Assessments and advises on mitigation

measures for geological heritage sites, when applicable. IGHP has

published collaborative guidelines with the Irish Concrete Federation

aimed at helping all quarry operators to follow best practice in addressing

geological heritage issues.

Derived products from these audits include travelling exhibitions and

booklets to help raise awareness of a county’s geological heritage, and data

are also provided to support Geoparks, geotourism and educational

initiatives.

LESSONS LEARNT FROM AN IRISH GEOPARK: THE COPPER

COAST GEOPARK, COUNTY WATERFORD, IN SOUTH EAST

IRELAND

Preteseille, S., [email protected], and Gatley, S., Geological

Survey of Ireland, Beggars Bush, Haddington Road, Dublin 4

Located in rural South East Ireland, the Copper Coast joined the European

Geoparks Network as one of its earliest members in 2001, and remains its

smallest territory. The local communities identified the unspoilt landscape,

varied geology and mining heritage as their unique selling point to attract

visitors to their otherwise undervalued tourism destination. The Geological

Survey of Ireland was one of the first partners to support the project.

Geological sites of international importance benefited from the

initiative as they were included in the county development plan as an

integrated part of the local heritage, insuring their protection against

inappropriate development. The local authority put measures in place to

protect those sites exposed to coastal erosion.

The Geopark’s activities and educational resources helped to develop

awareness of the linkages between geology and people’s everyday life,

through various means but notably by tapping into the local knowledge,

and thereby increasing a sense of place and pride.

Successful European funding bids in partnership with other Geoparks

provided much needed financial support, allowing recruitment of staff and

infrastructure to be put in place. Once on the map, the Copper Coast brand

name gained recognition, triggering business opportunities for inspired

entrepreneurs. The Geopark might not be the sole reason for business

success, but it contributes additional income. There may not be an influx

of tourists overnight and understanding of the needs of the targeted

markets is required. Partners on board, including tourism bodies, can help

in channelling visitors.

With the Geopark acting as a facilitator, the communities feel

empowered; fundraising events take place and services delivered to the

communities improve. Twinning activities bring people together beyond

geology, with exchanges with other European countries and further afield,

on a cultural and business basis.

Can this be replicated in rural Newfoundland? Possibly, but it will

require a lot of effort. In supporting world-class geology, interested

communities will have to find adequate support and guidance to launch the

project. Sustained financial support is necessary as cash flow is often an

issue. Employed staff are required to avoid exhausting the good will of

volunteers. Bringing relevant partners in geology, heritage, education,

tourism, management, finance and marketing on board at an early stage

gives weight to the project. It will require long-term commitment and faith,

but with increasing international recognition of the Geopark status,

Newfoundland can benefit from a wider market including tapping into its

Irish connections.

A DYNAMIC SULPHATE RESERVOIR AT THE START OF THE

CRYOGENIAN

Prince, J.K.G.

, [email protected], Rainbird, R.H.

Wing, B.A.

, Dix, G.R.

and Thomson, D.

Ottawa-Carleton

Geoscience Centre and Carleton University, Ottawa, ON K1S 5B6;

Geological Survey of Canada, Ottawa, ON K1A 0E8;

McGill

University, Montreal, QC H3A 2A7

The Cryogenian (850Ma-635Ma) is one of the most enigmatic periods of

Earth’s history; glacial deposits and isotopic data from this time period

suggest that the entire Earth may have been completely covered by ice at

least two times. Much recent work has focused on the late Cryogenian and

the complex life associated with the subsequent Ediacaran (635-542Ma).

However, the initial conditions for this suite of earth system changes have

so far received much less attention. Here we investigate the marine sulphur

cycle at the beginning of the Cryogenian in order to constrain atmospheric

and environmental conditions. The size of the marine sulphate reservoir is

thought to respond to atmospheric oxygen concentrations. Neoproterozoic

evaporite deposits are rare and are not easily preserved, however the upper

Shaler Supergroup of Victoria Island, NWT, Canada is host to two

evaporitic formations, the Minto Inlet formation (>250m thick) and the

Kilian formation (>500m thick). The evaporite units are separated by

approximately 500m of carbonate-dominated strata of the Wynniatt

Formation. We use the variability in the S-isotopic composition of sulphate

evaporites to assess changes in the size of the early Cryogenian marine

sulphate reservoir and by association atmospheric oxygen concentrations.

Deposition of the two evaporite units was synchronous with the

break-up of Rodinia and the restricted basins where evaporite deposition

took place were tectonically controlled shallow rifts. The Minto Inlet and

Kilian Formations have similar sedimentary characteristics indicating

deposition in shallow subaqueous to subaerial environments with

characteristic high frequency alternation between sulphate rich evaporites

and carbonate. However the Kilian Formation is richer in stromatolitic

limestone and siliciclastic sediment while the Minto Inlet Formation

preserves thick successions of bedded white gypsum/anhydrite.

During the 2010 and 2011 field seasons, we measured and logged 11

stratigraphic sections through these intervals and sampled them at high

resolution (3m intervals). The S isotopic data from the two formations

113

suggest large scale environmental changes during their deposition. The

marine sulphate reservoir and by association concentrations of atmospheric

oxygen were relatively large during the deposition of the Minto Inlet

evaporites but both had shrunk considerably during the deposition of the

Kilian evaporites. A decrease in oxygen concentrations would have a

profound effect on the carbon cycle, increasing organic carbon burial and

therefore decreasing atmospheric CO

which is an important greenhouse

gas. We propose that a decrease in p

at the start of the Cryogenian was a

catalyst for plunging the earth into the snowball glaciation.

PROVENANCE AND PALEOGEOGRAPHY OF THE UPPER

PALEOZOIC AND LOW MESOZOIC SUCCESSIONS OF THE

VERKHOYANSK PASSIVE CONTINENTAL MARGIN

Prokopiev, A.V., Diamond and Precious Metal Geology Institute,

Siberian Branch, Russian Academy of Sciences, 39 Lenin Av.,

Yakutsk, 677980, Russia, prokopiev@diamond.ysn.ru, Miller, E.L.,

Stanford University, Braun GeoCorner Bld. 320, 450 Serra Mall,

Stanford, CA 94305, USA, Toro, J., West Virginia University, 98

Beechurst Ave., 330 Brooks Hall, PO Box 6300, Morgantown, WV

26506-6300, USA, and Harris, D.B., West Virginia University, 98

Beechurst Ave, G42 Brooks Hall, Morgantown, WV 26506-6300,

USA

Based on U-Pb isotope geochronology of detrital zircons, paleogeographic

reconstructions of clastic provenance in the Verkhoyansk passive

continental margin for Late Paleozoic and Mesozoic time show that

sediment was transported by a large paleo-Lena river system that existed in

the eastern North Asian craton for over 200 Ma. The main sources were

granitoids of the Central Asian foldbelt, Angara-Vitim batholith, granitoids

of East Sayan and northern Pribaikalia, the Siberian platform basement

uplifts, and the Aldan shield. The clastic material was also supplied into

the distal part of the passive margin (In’yali-Debin synclinorium and

Kular-Nera terrane) from the south sourced from the South Verkhoyansk

and the Okhotsk terranes. This indicates that the Triassic and Jurassic

rocks composing the In’yali-Debin synclinorium and Kular-Nera terrane

respectively were deposited in the distal part of the Verkhoyansk

paleobasin rather than on the margin of the Kolyma-Omolon

microcontinent as was thought before. This casts doubt on the existence of

the Oimyakon ocean separating the Kular-Nera slate belt and the In’yali-

Debin synclinorium and the assumption that the In’yali-Debin

synclinorium made part of the Kolyma-Omolon microcontinent and is

there fore exotic to North Asia.

GREY-ZONE ALTERATION AT THE MIDWEST A

UNCONFORMITY-TYPE URANIUM DEPOSIT, NORTHERN

SASKATCHEWAN

Quirt, D.H., AREVA Resources Canada Inc., PO Box 9204,

Saskatoon, SK S7K 3X5, [email protected]

The “grey reduced alteration zone” related to many unconformity-type

uranium deposits has been interpreted from drill core observations to be a

“chlorite-illite ± sooty pyrite” alteration zone. Around the Midwest A ore

body at, the grey zone is the most proximal to the ore zone of three host-

rock alteration zones (bleached, quartz dissolution, grey) present in the

sandstone.

However, the mineralogy of grey-zone alteration is more complex.

Sooty aggregates of fine-grained hematite are locally present and are often

associated with hydrothermal quartz overgrowth material. Coarse-grained,

basket-weave illitic matrix clay, likely diagenetic-hydrothermal and

hydrothermal alteration of precursor kaolin-illite matrix clay, often

contains abundant very fine-grained anhedral anatase and/or APS minerals.

The illitic clay is variably overprinted by cloudy coarser-grained chlorite

grains and very coarse-grained, pore-filling chlorite clots are locally

present. The anatase and APS are mostly removed during chloritization,

while scattered grains of very fine-grained anhedral pyrite occur in the

matrix clay, primarily the chlorite. The grey coloration of the sandstone is

due to the presence of variable proportions of hematite, anatase, APS,

pyrite, and chlorite.

Geochemically, the grey zone is enriched in uranium and related

mineralization elements like Pb, Bi, V, Mo, Ni, Co, As, Sb, Cu, Zn, Ag,

mid-heavy REE+Y, and several major oxides (Al

, K

O, TiO

, Fe

MgO). Uranium and lead are variably elevated, while sulphide-related

elements (Pb, Cu, Mo, Zn, Ag, S), arsenide-related elements (Ni, Co, As,

Sb), and APS-related elements (Sr, LREE, P) are also typically elevated,

commonly up to 10 times greater than background values that are typically

in the single-digit ppm range, or lower.

The elevated major oxides mostly represent increases in total clay

content (Al

up to ~10%) at the expense of detrital quartz. The grey

zone is argillized: variably illitic (K

O) and chloritic (MgO, Fe

) clay.

Hematite and pyrite (Fe

), anatase (TiO

), and APS minerals (P

) are

present in variable amounts.

The Midwest A grey alteration zone is a bleached zone that is

variably, but at best weakly, mineralized. It, at the same time, contains

oxidized (hematite) and reduced (pyrite) components. It displays a

geochemical signature similar to that observed for many other

unconformity-type uranium deposits suggesting that it is syn-

mineralization in timing.

A WIDE-ANGLE SEISMIC SURVEY OF THE HECATAEUS

RIDGE, SOUTH OF CYPRUS: A MICROCONTINENTAL BLOCK

FROM THE AFRICAN PLATE DOCKED IN A SUBDUCTION

ZONE?

Rahimi, A., Welford, J.K., Hall, J., Memorial University of

Newfoundland, St. John’s, NL A1B 3X5, Louden, K., Dalhousie

University, Halifax, NS, and Hübscher, C., University of Hamburg,

Hamburg, Germany

Cyprus lies at the southern edge of the Aegean-Anatolian microplate,

caught in the convergence of Africa and Eurasia. Subduction of the

African plate below Cyprus has probably ceased and this has been

attributed to the docking in the subduction zone of the Eratosthenes

Seamount microcontinental fragment on the northern edge of the African

plate. In early 2010, on R.V. Maria S. Merian, we conducted a wide-angle

seismic survey to test the hypothesis that the Hecataeus Ridge, another

possible microcontinental block lying immediately offshore SE Cyprus,

might be related to an earlier docking event. The upper crust of Cyprus is

dominated by ophiolites, with seismic velocities of up to 7 km/s. A wide-

angle seismic profile along Hecataeus Ridge was populated with 15

Canadian and German ocean-bottom seismographs at 5 km intervals and

these recorded shots from a 6000 cu. in. air gun array, fired every 100 m or

so. Rough topography of the seabed has made picking of phases and their

modelling a demanding task. Model results will be presented: preliminary

results show no evidence of true velocities approaching 7 km/s below the

Ridge. We suspect from this that Hecataeus Ridge is indeed derived from

the African plate and is not characteristically ophiolitic Cyprus (upper

plate) crust.

SAMPLING LAURENTIA REVISITED: SHRIMP DETRITAL

ZIRCON GEOCHRONOLOGY OF SANDSTONES FROM THE

AMUNDSEN BASIN OF NORTHWESTERN CANADA

Rainbird, R.H., rrainbir@nrcan.gc.ca, Rayner, N., Geological Survey

of Canada, Ottawa, ON K1A 0E8, and Thomson, D., Dept. of Earth

Sciences, Carleton University, Ottawa, ON K1S 5B6

One of the first multi-grain U-Pb detrital zircon geochronology studies was

published 20 years ago using sandstones from the early Neoproterozoic

Shaler Supergroup of northwestern Canada. At that time, 25 zircon grains

from 3 samples were analyzed by ID-TIMS. The conclusions of that study

were speculative, suggesting that most grains were transported from the

Grenville orogen, more than 3000 km to the southeast, by a pan-

continental river system. Since, there has been an explosion of research in

this field, owing largely to the advent of new instruments and techniques

for analyzing large numbers of grains, quickly and cheaply. Some of this

research included analysis of correlative sedimentary successions in North

America and abroad, which largely supported the original hypothesis.

Recent field mapping through the GSC’s Geo-mapping for Energy and

Minerals program has allowed us to re-sample and re-analyze the Shaler

Supergroup via modern techniques to: 1) test the original hypothesis; 2)

understand observed stratigraphic changes in provenance in greater detail,

and 3) establish maximum depositional ages (MDA) for key stratigraphic

horizons. In this study, we analyzed >400 zircon grains from 10 samples

using SHRIMP. Quartz-arenites from throughout the ~4000m-thick

114

section, including (in ascending stratigraphic order) the Escape Rapids,

Nelson Head, Fort Collinson, Wynniatt, Kilian and Kuujjua formations.

An arkose from the unconformably underlying Husky Creek Formation, in

the Coppermine Homocline, has a MDA of about 1230 Ma and exhibits an

age profile that suggests reworking of underlying successions, such as the

Coppermine River, Hornby Bay and Goulburn groups. The lowermost

sample from the Escape Rapids Formation has similar provenance to the

Husky Creek, but the upper Escape Rapids displays a wholesale change to

mainly 1600-1400Ma sources. Many of these grains are euhedral

indicating local provenance, but zircon-bearing rocks of this age are

unknown in this region, suggesting a non-Laurentian source. A fluvial

sandstone from the overlying Nelson Head Formation preserves

northwesterly paleocurrents and characteristically well-rounded grains of

Grenvillian age (1400-1000Ma). The Fort Collinson Formation is a marine

sandstone with similar provenance to the Nelson Head, suggesting

reworking (MDA~900Ma). The lower Wynniatt Formation sample shows

almost no Grenvillian signature and a dominant mode at 1870Ma, (Great

Bear magmatic zone?), possibly indicating a tectonic event with associated

sedimentary by-pass of Grenvillian detritus. The upper Wynniatt (identical

to the Nelson Head) and overlying fluvial Kuujjua formations signal a

rejuvenation of the Grenvillian source (strong 1080 peak; MDA~780Ma)

and/or recycling of underlying units.

INTEGRATED SEDIMENTOLOGICAL, STRATIGRAPHIC,

GEOCHEMICAL AND PALEONTOLOGICAL STUDIES OF THE

SHALER SUPERGROUP IN THE MINTO INLIER OF

NORTHWESTERN VICTORIA ISLAND, NORTHWEST

TERRITORIES, CANADA

Rainbird, R.H.

, Prince, J.

, Thomson, D.

, Krapež, B.

, Bédard, J.

Pratt, B.R.

, Rayner, N.

, Turner, E.

, Lafond, G.

, Bekker, A.

Creaser, R.

, Planavsky, N.

, Hallmann, C.

, van Acken, D.

and

Wing, B.

Geological Survey of Canada, Ottawa, ON, K1A 0E8;

Carleton University, Ottawa, ON K1S 5B6;

Curtin University of

Technology, Perth, WA, Australia;

Geological Survey of Canada,

Québec, QC G1K 9A9;

Department of Geological Sciences,

University of Saskatchewan, Saskatoon, SK S7N 5E2;

Department

of Earth Sciences, Laurentian University, Sudbury, ON P3E 2C6;

Department of Geological Sciences, University of Manitoba,

Winnipeg, MB R3T 2N2;

Dept. Earth & Atmospheric Sciences,

University of Alberta, Edmonton AB T6G 2E3;

Dept. of Earth

Sciences, University of California, Riverside CA 92521 USA;

MARUM, University of Bremen, 28359 Bremen, Germany;

Dept.

Earth & Planetary Sciences, McGill University, Montreal, QC

A re-examination of the Neoproterozoic (late Tonian-Cryogenian) Shaler

Supergroup was conducted during the summers of 2009, 2010 and 2011 as

part of the GSC’s Geo-mapping for Energy and Minerals (GEM) Program.

The Shaler Supergroup, up to 4km-thick, includes fluvial sandstones and

deltaic siltstones, shallow-marine carbonates and shales and both basinal

and supratidal sulphate evaporites. Strata are intruded by diabase sills and

capped by flood basalts of the ~720Ma Franklin igneous event. Facies

analysis and sequence stratigraphy suggest deposition within a relatively

shallow epicontinental basin or epeiric sea (Amundsen Basin) that was

periodically connected to an exterior ocean. Fieldwork included

measurement of stratigraphic sections, detailed sampling of outcrop and

drillcore and geological mapping. Studies focused in the western half of

the Minto Inlier, on Victoria Island, where only the upper half of the

stratigraphic section is exposed. Thematic studies of the Shaler Supergroup

include: U-Pb detrital zircon geochronology, Re-Os geochronology,

sequence stratigraphy and sedimentology, stable isotope

chemostratigraphy, trace element geochemistry, organic biomarker

analysis, and micro-paleontology. Ten sandstone samples were collected

for detrital zircon analysis from the complete succession to assess

provenance and to establish minimum depositional ages for key

stratigraphic units. Re-Os analysis of organic-rich shales will establish

depositional ages of units where U-Pb analysis cannot be accomplished.

Stable isotopes of C, O and S are being analyzed to produce secular

evolution curves for correlation with other sections and to assess both

global and local evolutionary changes in sea-water chemistry. Analysis of

redox-sensitive trace elements such as V, Mo, U and Fe speciation analysis

are being conducted to assess the redox state of the ocean at the time of

deposition. Organic matter from shales and carbonates is being extracted to

recover sedimentary lipids that can be used as molecular fossils to provide

insight into past organismic diversity (e.g. evolution of algae and early

metazoans). This work will be done in conjunction with extraction and

identification of microfossils (e.g. organic-walled cyanobacteria and

acritarchs) from shales and carbonates. Initial results from these studies

will be summarized on this poster. Data and interpretations generated from

this project will be compared with similar studies being conducted

elsewhere in northwestern Canada (e.g. Mackenzie, Ogilvie and Wernecke

Mountains inliers), with further comparisons to similar-age sedimentary

sections in Siberia, and Australia in order to test tectonic plate

reconstructions of the ancient supercontinent, Rodinia.

STRUCTURE AND STRATIGRAPHY OF THE DIETER BASIN,

SAKAMI RIFT, PALEOPROTEROZOIC OF QUÉBEC, CANADA

Ramaekers, P., 832 Parkwood Drive S.E., Calgary, AB,

[email protected], Catuneanu, O., University of Alberta, Edmonton,

AB, and McElroy, R., Fission Energy Corp., Kelowna, BC

The Sakami basins consist of two parallel sets of northeast trending basins

that are remnants of early Proterozoic rifts. The Dieter Basin measures 10

by 50 km, with the basin axis parallel to the trend of the set, to the NE.

Internally, deposition was from WNW to ESE in a series of compartments,

suggesting deposition as a segmented transtensional rift. The basin was

deformed by the New Québec Orogen, and again by the Grenville Orogen,

increasing the chance that it has a complex internal structure, and that a

simple half-graben model may have only local applicability.

Two sets of dykes cross the basin: a NS trend that crosses the basin at

nearly right angles, and a NE trending set that parallels the depositional

axes of the basin segments.

The Dieter Basin sediments have previously been divided into a clay-

rich Lower- Sakami and a sand-dominated Upper Sakami Formation. The

Lower Sakami is based by thin fluvial conglomerates of local derivation

from the NW, N, and NE. These are overlain by a 400 m thick silt and

mudstone to marl sequence with paleocurrents to the NE, axial to the basin

segments, but transverse to the preserved overall basin outline. The

mudstones contain playa facies with bacterial mats, and traces of

evaporites. The Upper Sakami is a thick, coarse-grained largely eolian

quartz-rich sandstone, with grain-size distributions similar to other rift

basin eolian sandstones with proximally derived sand. The eolian cross-

sets are very thick, at times over 20 m, and were formed by large

transverse dunes, with the result that bedding planes are rarely visible, and

that crossbedding has in the past been mistaken for bedding. Thus, the

sedimentary environment of the Upper Sakami has been controversial, and

the estimated thickness of the unit may have been greatly overestimated (1

rather than 4 km, assuming a half-graben cross-section).

As in other rift systems, the sedimentary fill varies greatly between

coeval basins depending on the intensity of faulting and the geometry of

the faults during basin development. The next Sakami rift basin to the west

has a smaller percentage of eolian sediments, a much larger debris flow

component, and an apparently internal rather than a marginal setting for

the lacustrine deposits.

Uranium mineralization is found in the playa facies of the Lower

Sakami.

Keynote PALEOPROTEROZOIC TO PHANEROZOIC

STRUCTURAL AND STRATIGRAPHIC DEVELOPMENT OF THE

ATHABASCA REGION, NORTHERN SASKATCHEWAN,

CANADA

Ramaekers, P., MF Resources Inc., Calgary, AB, [email protected],

and Catuneanu, O., University of Alberta, Edmonton, AB

The Athabasca Basin and surrounding area of northern Saskatchewan,

Alberta and the Northwest Territories represents crustal fragments

involved in 2 or 3 episodes of collisional tectonics and basin formation

between 1.93 and 1.4 Ga.

During the Taltson transpressional orogeny (1.99 to 1.92 Ga),

representing docking of the Buffalo Head terrane, and the passing of the

Slave Craton to the northeast, early ca. 1.96 Ga backarc basins (Waugh

Group) were overlain by a foreland basin around 1.93-1.92 Ga modified by

115

transtensional effects resulting in the preserved pull-apart basin fragments

collectively known as the Nonacho, Thluicho Lake, and Burntwood

groups. Deep burial and alteration to greenschist grade may have

continued during the Snowbird Tectonic event or collision around 1.91-

1.90 Ga. Unroofing, in places to the present erosional level occurred

during the early phases of the Trans-Hudson Orogen (1.86-1.83 Ma)

followed by deposition of the coarse clastics to lacustrine deposits of the

Martin Group (ca. 1.82 Ga) in what may be Laramide type basins. In the

late stages of the THO main event in northern Saskatchewan, the docking

of the Sask Craton, the Athabasca Group Fair Point Fm was deposited in a

late THO foreland in the Jackfish Basin perhaps in front of the main THO

western thrust belt, or as another Laramide-type basin. Sequence 2 of the

Athabasca Group (Read, Manitou Falls Fms) formed in escape basins

perhaps during the late stages of the final Superior Hearne collision. The

upper sequence in the Athabasca Basin is correlative to the Dismal Lakes

Group of the Hornby Bay Basin, perhaps to the Dessert Basin west of

Slave Lake, the basal Belt-Purcell sequences in S B.C., and may reflect a

continental scale extensional event that may have proceded to rifting,

forming a first western margin to North America around 1.40 Ga, to be

followed in the Late Precambrian by rifting during the Windermere event

at 0.7 Ga.

Structures from these events left their record in the Athabasca Basin

area, and structures formed up to and including deposition of upper

Athabasca Sequence 2 were rejuvenated during formation of Sequence 3.

These structures were the main loci of hydrothermal systems that

emplaced the unconformity U orebodies.

Structures related to the Windermere rifting may have determined the

present northern and southern basin limits in the Paleozoic. Burial and

tilting during the Cretaceous and Laramide orogenies depressed the

western side of the Athabasca basin significantly.

MULTIELEMENT GEOCHEMISTRY OF OUTCROP SAMPLES,

DIAGENETIC MAPS, STRUCTURE AND BASIN DEVELOPMENT

OF THE ATHABASCA BASIN, PROTEROZOIC, SASKATCHEWAN

Ramaekers, P., MF Resources Inc., Calgary, AB, [email protected],

Bosman, S. and Card, C., Saskatchewan Geological Survey, Regina,

A 59 element geochemical data set of 634 non-mineralized outcrop

samples of Athabasca Group clastics has been analyzed using Principal

Component Analysis (PCA). The vast majority of samples are quartz

arenites at present, but were derived from depositional lithologies ranging

from sublithic arenites to arkose. Samples have been assigned to

stratigraphic units and deposystems based on an analysis of over 1000

outcrops and hundreds of corelogs involving a re-evaluation of the

EXTECH IV stratigraphic results. This enables a more precise

characterization of the variation of the composition of the units, as well as

an evaluation of the alteration processes in different parts of the basin.

Major PCA components may be interpreted as reflecting source

areas, LREE fractionation associated with phosphate diagenesis, Mg and K

clay suites, metal (including U) concentration in Fe-Mn rich zones, HREE

fractionation, and quartz veining with Cu and Co.

Heavy minerals are indicated as a main source of REE and U with

different suites characterizing Manitou Falls and Lazenby Lake to Locker

Lake gravels and the various Manitou Falls deposystems. Quartz-rich

samples with Cu and Co and Fe, Mn-rich samples with anomalous weakly

held metals are more common near the major Snowbird fault systems and

in Sequence 3, suggesting more intense alteration below the Wolverine

Point aquitard. High LREE values are associated with P and may reflect

source area, and/or an early diagenetic stage. HREE fractionation seems

most common near major fault systems and in the Lazenby Lake strata,

deposited just prior to the time of first U ore emplacement and the major

basin deepening during deposition of the overlying McFarlane Group at ca.

1.5 Ga. It is noticeably absent in this data set (which avoided mineralized

zones) in the general area of the U orebodies. Coupled with known HREE

enrichment in hydrothermal ores, this suggests depletion zones.

The distribution of samples with high factor scores for these

components provides basin wide source sediment composition and

diagenetic maps. Factor score distribution when considered with isopachs,

paleocurrents, reactivated basement and basin development structures

provide insight to the hydrothermal systems that emplaced the U orebodies

of the basin, their location, intensity, and development of depletion zones.

CALCIC GARNETS: AN IMPORTANT REPOSITORY FOR REE

ELEMENTS IN CARBONATITES

Reguir, E.P.

, [email protected].ca, Chakhmouradian, A.R.

Bouabdellah, M.

, Kchit, A.

, Yang, P.

and Rich, A.

University of

Manitoba, Winnipeg, MB, R3T 2N2;

University of Oujda, Oujda,

Morocco

Calcic garnets are a relatively common accessory phase in carbonatites,

and, where present, tend to sequester significant proportions of such

economically important trace elements as Y, lanthanides, Nb, Zr, Th and

U. Whereas the major-element composition of these minerals has been

reasonably well studied, their trace-element chemistry has not. In this

study, we examined Ca-Fe-Ti garnets from calcite carbonatites at Oka

(Canada), Tamazert (Morocco), Magnet Cove (USA) and Afrikanda

(Russia). Their composition ranges from 0.94 Ti atoms per formula unit,

apfu) to Ti-richschorlomite at Afrikanda ( 0.2 apfu Ti (Oka).

Theandradite (Magnet Cove and Tamazert) to andradite with examined

samples differ in their trace-element composition. The material from the

Oka Nb deposit is enriched in Nb (500-720 ppm), Ta (105-200 ppm) and

Mn (7750-9130 ppm), and contains the lowest levels of U, Zr and Hf (<

12, 1660 and 10 ppm, respectively) among the studied samples. The

highest abundances of Zr, Hf and Sc (up to 20000, 250 and 460 ppm,

respectively), and the lowest levels of V (< 580 ppm) are observed in the

Afrikanda schorlomite. Both Afrikanda and Oka garnets are enriched in

REE (1400-1900 ppm) relative to those 600 ppm). The latter two samples

are stronglyfrom Magnet Cove and Tamazert ( zoned. The Magnet Cove

andradite exhibits irregular zoning in back-scattered electrons, with high-

AZ zones enriched in REE, Ti, Zr, Nb, Ta, U, Sr, Mn and V. Overall, the

Magnet Cove andradite has the lowest levels of Nb (65-330 ppm), Sr (< 20

ppm) and Th (< 9 ppm) relative to three other localities. The Tamazert

sample is characteristically enriched in V (up to 3300 ppm), Th (up to 57

ppm), U (up to 30 ppm) and Zn (up to 440 ppm). The Tamazert andradite

is unusual in showing strong sector-controlled distribution of rare

elements. The relatively Ti-rich {121} sectors contain higher levels of

highly-charged cations (including Nb, Ta, Zr, Hf, REE, Th and U) relative

to the {110} sectors. Niobium, U and Th exhibit the greatest degree of

inter-sector fractionation (×1.4 or greater). This type of compositional

zoning has not been previously recognized in garnets and can be explained

by differences in bond strength between Ca

and Fe

on the one hand and

highly-charged cations on the other. To summarize, our data show that, in

some carbonatites, the bulk of rare-element budget is concentrated in

garnet and, hence, not amenable to recovery.

ULTRAFERROUS SILICATE MAGMATISM AND IMMIS-

CIBILITY: EVIDENCE FROM THE BUSHVELD COMPLEX,

SOUTH AFRICA

Reid, D.L., Laidler, N., Cross, C., Department of Geological

Sciences, University of Cape Town, South Africa, david.reid

@uct.ac.za, Veksler, I. and Keiding, J., German Research Centre for

Geosciences, Potsdam, Germany

Iron-rich ultramafic pegmatites occur as replacement bodies throughout

the layered sequence of the upper Critical Zone in the western Bushveld

Complex, South Africa. Morphology and size very considerably, but sub-

vertical veins and pipes are most common, often expanding outwards into

sub-concordant sheets, particularly in the plagioclase rich cumulates under

chromitite seams. Several petrographic types have been recognized

throughout the interval from the UG1 footwall to the Merensky Reef at

several platinum mines, ranging from wehrlites through a spectrum of

gabbroic lithologies, several of which may be intimately associated with

granite pegmatite. Dominant minerals include ferroaugite (Mg# >50),

fayalitic olivine (Fa

50-70

), calcic plagioclase (> An

) and magnetite, with

minor biotite, base metal sulphides (po, py, ccp), alkali feldspar and

quartz. Textures and grain sizes are extremely variable, ranging from

medium grained granular to megacrystic pyroxene prisms up to 40cm in

length.

116

The combination of highly variable textures and grain sizes,

extremely irregular morphologies and field relations with the host layered

sequence, as well as the unusual mineral assemblages, all demand a

complex replacement origin rather than a simple intrusive magmatic

emplacement. It is concluded that the suite represents the products of

liquid immiscibility that occurred in highly differentiated Fe-rich basaltic

magmas responsible for the Upper Zone. Migration of the melts lead to

their interaction with the Critical Zone, where the ultraferrous melt fraction

reacted with the layered cumulates, producing the wehrlite – gabbro suite,

while the felsic fraction either crystallised as granite pegmatite but

sometimes remained mingled with its Fe counterpart and subsequently

crystallized as hybrid or zoned assemblages.

PARAGENESIS OF THE CENTENNIAL UNCONFORMITY-

RELATED URANIUM DEPOSIT AND THE POTENTIAL FOR

IGNEOUS DRIVEN HYDROTHERMAL ACTIVITY IN THE

ATHABASCA BASIN

Reid, K.D., Ansdell, K., University of Saskatchewan, 114 Science

Place, Saskatoon, SK S7N 5E2, kdr[email protected], Jiricka, D.,

Witt, G., Cameco Corporation, 2121-11

St. West, Saskatoon, SK

S7M 1J3, and Potter, E., Geological Survey of Canada, 601 Booth

St., Ottawa, ON K1A 0E8

The Centennial unconformity-related uranium deposit in the south-central

Athabasca Basin has a complex paragenetic history which differs, in some

aspects from similar deposits in the basin. The paragenetically earliest

uraninite appears to be broadly coeval with the diagenetic illite-sudoite-

dravite-APS assemblage. However, the deposit is intruded by diabase,

which is petrographically and chemically similar to the regionally

extensive 1270 Ma Mackenzie dyke swarm. The dykes at the Centennial

deposit provide a time constrain not observed at many other deposits in the

basin. Clinochlore, euhedral quartz, carbonate and pyrite were precipitated

after the diabase and overprint the earlier diagenetic assemblage. Chlorite

geothermometry of the earlier sudoite indicates temperatures during

diagenesis and mineralization likely reached 200°C whereas the later

clinochlore formed at temperatures as high as 320°C probably due to

additional heat provided by the intrusion. The latest alteration feature is the

ubiquitous development of kaolinite along fractures and pervasively

through the ore zone.

The paragenesis developed by other workers for the high-grade

McArthur River unconformity-related uranium deposit and the ‘apparently

barren’ Wheeler River Zone K is very similar to that observed at

Centennial with clinochlore, euhedral quartz, carbonate and sulphide

forming late relative to the diagenetic/primary mineralization assemblage.

Fluid inclusions associated with late euhedral quartz at McArthur River

reveal temperatures higher than those associated with diagenesis.

Similarly, the composition of late clinochlore at Wheeler River indicates

higher temperatures than the earlier developed diagenetic sudoite.

Therefore, similar to Centennial, both areas record a period when

temperatures were elevated after diagenesis and primary uranium

deposition during the development of the later clinochlore, euhedral

quartz, carbonate and sulphide assemblage. In addition, recrystallized

uraninite and illite, and isotopically disturbed U-Pb and Ar-Ar systems at

the two locations yield ages close to that of the Mackenzie dykes.

These observations imply that hydrothermal activity initiated by

igneous events, such as the Mackenzie dykes, may be more widespread in

the basin, even where dykes are not directly observed. Future studies in the

Athabasca Basin should recognize the possibility that igneous activity may

have played an important role in developing some of the post-

mineralization alteration, including precipitation of sulfide minerals which,

if formed around a uranium deposit may have aided in preservation.

ARCHEAN KOMATIITIC VOLCANISM OF THE PRINCE

ALBERT GREENSTONE BELT, MELVILLE PENINSULA,

NUNAVUT, CANADA

Richan, L., lx_richan@laurentian.ca, Gibson, H.L., Mineral

Exploration Research Centre, Laurentian University, 935 Ramsey

Lake Rd., Sudbury, ON P3E 2C6, and Houlé, M.G., Geological

Survey of Canada, 490 Couronne St., Québec City, QC G1K 9A9

Komatiitic rocks represent a significant portion of the ca. 2970 Ma Prince

Albert Greenstone Belt (PAGB), a semi-continuous, northeast-trending

metavolcanic and metasedimentary supracrustal Archean greenstone belt,

outcropping on the eastern side of Committee Bay within the Rae Carton

of the western Churchill Province, Nunavut. The present study focuses on

one of the best-preserved komatiitic sequences within the PAGB on

Melville Peninsula.

Spinifex textured and massive komatiitic flows of the PAGB were

erupted onto a subaqueous pillowed mafic volcanic succession during an

episode of extension. Localized, coarse, framework supported breccias

containing both clasts of komatiites and basalts indicate early down

faulting and the development of synvolcanic structural basins. During, or

immediate following basin development renewed komatiitic volcanism

was channelized within these basins resulting in thick, massive,

undifferentiated flows that thin toward the channel margins, which are

defined by flanking spinifex-textured lava lobes. Renewed subsidence and

down faulting allowed the accumulation of felsic, mafic and komatiitic

volcaniclastic deposits within a restricted fault-bounded basins, which

developed on the surface of the channelized komatiitic flows. The

komatiitic volcaniclastic deposits are ultramafic in composition and have

been extensively altered to chlorite, amphibole, talc, and carbonate

minerals; textures and the morphology of microscale particles are rarely

preserved. The tuffs are largely massive or plane-bedded, and are

uniformly fine-grained. Their fine grain size, their extensive nature (up to

2km), and their substantial thickness (up to 10m), coupled with a

uniformly komatiitic composition indicating that they consist of particles

of only one composition (single provenance), are consistent with an origin

through explosive komatiitic volcanism. The komatiitic volcaniclastic

lithofacies occur at two stratigraphic intervals indicating that they are a

product of a least two pyroclastic eruptions. The komatiitic tuffs are

conformably overlain by mafic and komatiitic flows and a thick succession

of felsic volcaniclastic deposits. Subsequent deformation, including at least

two phases of folding and faulting have folded and dissected the

succession.

Although no significant sulphide mineralization was recognized, the

along strike extension of the komatiitic succession to the north contains the

newly discovered Adamson River Nickel showing. Samples collected from

this occurrence returned values of up to 8.0% Ni, 1.8% Cu, and 2.2% Co.

CLAY ALTERATION AND URANIUM MINERALIZATION

ALONG THE KIGGAVIK ANDREW LAKE STRUCTURAL

TREND, (NUNAVUT, CANADA)

Riegler, T., HydrASA / ERM, University of Poitiers, CNRS UMR

6269, Bâtiment B08, Rue Albert Turpin, 86022 Poitiers cédex,

[email protected], Beaufort, D., HydrASA, University

of Poitiers, CNRS UMR 6269, Lescuyer, J-L. and Wollenberg, P.,

AREVA Resources Canada Inc.

The Kiggavik project (previously named Lone Gull), located 70km West

of Baker Lake, Nunavut is a major uranium exploration project in the

Canadian arctic. It hosts several significant uranium deposits (Kiggavik,

End and Andrew) as well as very prospective areas, with an overall

uranium content of approximately 58 000t U of historical resources

delineated in the 70’s and 80’s along the SE border of the Thelon basin.

117

The Paleoproterozoic Thelon sandstones and the unconformity surface

between the metamorphic basement and the sedimentary cover have been

eroded. Uranium mineralization are hosted in the Neoarchean basement

rocks in the vicinity of regional N080° fault showing specific features of

alteration and crystallization such as thick quartz veining corridors,

hydraulic breccias, strong hematization, and plurimetric zones of clay

alteration.

Clay alterations are spatially controlled by secondary structures

related to the main East-West fault trend and generally host the uranium

mineralization. At the scale of the whole structural trend, the alteration

paragenesis is composed of illite ± sudoite ± hematite ± aluminum

phosphates sulfates minerals (APS). Such a paragenesis is similar to those

identified in uranium deposits related to paleoproterozoic unconformities

in the Athabasca basin (Canada) or the Alligator River (Australia).

The altered rocks surrounding the uranium mineralization contain

two populations of phyllosilicates, both of them containing similar types of

phyllosilicate (dioctahedral micas or illite and chlorites) but with distinct

crystallographic and chemical properties. The first assemblage is attributed

to the regional retrograde metamorphic stage while the second is related to

the hydrothermal alteration associated to the mineralization event. From

our investigation on these phyllosilicates it results that the crystal structure

of phyllosilicates can been used to map alteration halos using the X-ray

diffraction data (crystallinity along c-axis, polytypes). On another hand the

crystal-chemical characterization of the hydrothermal phyllosilicates

replacing the metamorphic ones evidence a strong release of ferrous iron

during the mineralogical reaction. This last point is fundamental regarding

the occurrence of hematite in alteration zones and points out the potential

effects of iron redox state in the control of uranium precipitation during the

hydrothermal event.

KIMBERLITES AS CONDUITS THROUGH MANTLE AND

LOWER CRUST: ZIRCON FROM BRAUNAS 3 KIMBERLITIC

PIPE, BRAZIL

Rios, D.C., Davis, D.W., Dept. of Geology, University of Toronto,

22 Russell St., Toronto, ON M5S 3B1, debora.[email protected],

Santos, I.P.L., Silveira, F.V., Geological Survey of Brazil, Brasilia,

DF, 70830-000, Davis, W.F., Geological Survey of Canada, 601

Booth St., Ottawa, ON K1A 0E8, Conceicao, H. and Rosa, M.L.S.,

University of Sergipe, Brazil

Serrinha Nucleus (SerN) is an Archean granite-greenstone terrain located

in the São Francisco Craton (SFC) of northeastern Brazil. SerN

lamprophyres and gold are in temporal and spatial association with 2.1 Ga

potassic-ultrapotassic syenites. Enrichment on LILE and strong depletion

of some HSFE suggest a subduction-modified source. This metasomatized

mantle shows LREE concentrations typical of lamproitic rocks. The

Braunas kimberlitic field comprises 30 kimberlite pipes and dykes, most

diamondiferous, which intrude the south area of the TTG Nordestina

Batholith (NB, 2.16 Ga). A Neoproterozoic age (~0.6-0.7 Ga) was

suggested by Ar-Ar data.

Geochemical data on Braunas 3 (Nelio’s) pipe are comparable to

average kimberlitic rocks, although lower in TiO

and P

, and higher in

. Contamination, either by weathering or xenoliths, is a common

problem in the interpretation of kimberlite geochemical data and SerN

kimberlites show a contamination degree of 1.8 (Clements parameters).

The heavy mineral concentrate includes apatite, zircon and carbonate. We

recovered more than 300 zircon crystals, which are clear, transparent to

translucid, euhedral to rounded. They range from short to long prisms and

from colorless to pink and brownish small to large crystals. U-Pb SHRIMP

data for 6 large crystals result in a concordant and consistent age of

2162±11 Ma, which is coincident with the age of NB. LA-ICP-MS (58

crystals) data obtained from distinct populations show a wide range of

xenocrystic ages, grouped in four main periods: 2.06 to 2.11 Ga (33 zrs.);

2.15 to 2.40 Ga (13 zrs.); 2.5 to 3.20 Ga (8 zrs.); 3.25 to 3.44 Ga (3 zrs.).

One zircon was dated at 0.57 Ga. Most of the crystals were assimilated

from the underlying crust/mantle by the kimberlite during its ascent. They

represent the diversity of Precambrian processes/magmas in SerN area and

additional work is need to better understand the ages/rocks not exposed at

surface. The age of the single Neoproterozoic crystal is probably the

emplacement age for Braunas pipe.

Only a few Paleoproterozoic kimberlitic rocks have been described

worldwide, eg. Ghana. The close spatial relationship with lamprophyres

(with lamproitic signature), syenites, and gold formed during the ~2.1 Ga

ultrapotassic alkaline event in SerN, as well as the predominance of ~2.11

Ga xenocrysts may be important regional characteristics favouring later

kimberlite emplacement. Other lamprophyres/kimberlites are been

discovered in spatial association with syenites in Bahia state but no other

Neoproterozoic event has thus far been recognized in the SerN/Archean

nuclei of SFC.

GEOTOURISM IN URBAN ENVIRONMENTS: SALVADOR, THE

FORMER CAPITAL OF BRAZIL

Rios, D.R., University of Toronto, 22 Russell St., Toronto, ON M5S

3B1, debora.rios@utoronto.ca (CAPES/CNPq/FAPESB/UFBA),

Pinto, A.B.C., University of Minho, Portugal (CNPq/Erasmus

Mundus), Brilha, J.B.R., University of Minho, Portugal, and Rosato,

C.S.O., Federal University of Bahia/Secretaria de Industria,

Comercio e Mineracao, Brazil (CAPES/FAPESB)

Salvador plays an important role in the history of Brazil, as it was the first

economic and political capital of the Country. Its exuberant and diverse

natural assets attract thousands of visitors. A maritime approach revel the

splendor of All Saints’ Bay in the scenic surroundings of a geological

fault. Many other natural aspects contribute to our proposal of Salvador as

a place for Earth Sciences promotion. It is located on the Salvador-

Esplanada belt, part of the Sao Francisco Craton. Three main geological

domains are exposed: (i) a horst of Precambrian rocks, the “Salvador

High”; (ii) Mesozoic-sedimentary rocks represented by the Tucano-

Reconcavo basin, the “Salvador Low”; and (iii) Tertiary-Quaternary

sediments - creating kilometers of clear and calm blue-warm-water

beaches - related to sea-level fluctuations and climatic changes. This work

categorizes four geosites, describing and integrating them to geocultural

sites to create an urban Geotouristic guide. They include: (1) The

Salvador-Fault - a 74 meters high scarp that extends for almost 6 km; (2)

the Mont-Serrat conglomerates; (3) the Abaete Lagoons, including an

extensive area of white-sand dunes; and (4) mafic-dykes exposed from

Farol da Barra to Forte beaches, recording Brazil-Africa extension.

Associated Geocultural areas include: (1) historical and magnificent

buildings - located in the Pelourinho, a World Heritage Site by Unesco - in

which gold and precious stones were used along with rocks as

ornamental/dimensional materials; (2) the Geological Museum of Bahia,

(3) the Garcia d’Avilla Castle, with medieval characteristics that are

singular on the American continent, and (4) the base for Projeto Tamar,

that saved more than two million sea turtles from extinction. The oldest

city in Brazil hosts a high populational density (>2.5 million habitants), a

rich gastronomy and architecture, a mixing of cultures and increasing

violence, ranking Salvador as one of the 50’s more violent cities in the

World. This initiative aims the sustainable development, increasing the

(geo)educational standards for the young generation of Brazilians. The

Geoheritage valuation and the creation of didactic materials are some of

the possible strategies to change the future. By protecting this rich

geological and cultural patrimony, Geotouristic initiatives will ensure the

development of high quality tourism projects, promoting Earth Sciences

education, and preventing destruction of unique geosites. Hope this

initiative will put in evidence the importance of Geoconservation and to

promote the concept of Geodiversity in Brazil, while giving the World an

opportunity to meet our rich Geoheritage.

COLLAPSED OROGENIC PLATEAU IN THE MESOPRO-

TEROZOIC GRENVILLE OROGEN – CRITICAL MARKER IN

EVOLVING PROTEROZOIC TECTONIC STYLE?

Rivers, T., Department of Earth Sciences, Memorial University, St.

John's, NL A1B 3X5, [email protected]

Evidence for the former existence of an orogenic plateau in the Grenville

Province has become increasingly compelling over the last decade or so.

Apart from the large size of the orogen, the long duration of orogeny, and

the presence of high T mineral assemblages that formed at mid crustal

levels, more recent support comes from the ‘hot nappe’ numerical models

of large hot, long-duration orogens (LHOs) that appear to reproduce many

118

of the features of the Grenvillian mid crust, and from new interpretations

of geological observations that point to widespread orogenic collapse.

Orogenic collapse, which implies the former existence of an orogenic

plateau, is indicated by the juxtaposition of different levels of orogenic

crust along normal-sense shear zones, giving rise to a crustal-scale horst

and graben architecture. The horsts are underlain by exhumed orogenic

mid crust and have the form of core complexes with sub-horizontal

gneissic fabrics and granulite-facies assemblages that formed at 850 ± 50

°C and depths of ~30 km. The grabens preserve the down-dropped

orogenic lid composed of high-level orogenic crust with steep to vertical

pre-Grenvillian fabrics that lack evidence for penetrative Grenvillian

strain, and in which peak Grenvillian temperatures were <500°C.

Formation of an orogenic plateau is contingent on the presence of

crust and lithosphere of approximately double thickness prior to collapse,

as in the Himalaya-Tibet Orogen. The existence of a plateau requires that

the doubled crust and lithosphere be strong enough to support their own

weight for a finite time before collapse is initiated. In the Grenville

Orogen, crustal thickening took place by thrusting over a period of ~50

Ma, eventually leading to thermal and melt weakening at mid-crustal

levels, thereby initiating orogenic collapse. This architecture contrasts with

that of ultra-hot orogens (UHOs) of Paleoproterozoic age, described

recently in the literature, in which despite their large size and long

duration, crustal doubling does not appear to have occurred. Instead UHOs

are characterised by large regions of approximately isobaric, low pressure–

high temperature metamorphism, distributed homogeneous thickening, and

no evidence for orogenic collapse, all features implying that the

lithosphere was thin and weak and a orogenic plateau was not developed.

This contrast in structural style between UHOs in the Paleoproterozoic

and LHOs in the late Mesoproterozoic may be a cryptic signal of planetary

cooling and rheological strengthening of the crust and lithosphere, with the

Grenville Orogen perhaps being the first (and biggest?) example of an orogen

with a plateau in its hinterland in Earth history.

EVOLUTION OF THE GNEISSIC MID CRUST BENEATH AN

OROGENIC PLATEAU - INSIGHTS FROM THE GRENVILLE

PROVINCE

Rivers, T., Memorial University, St. John's, NL A1B 3X5

[email protected]

The wide range of levels of Ottawan (~1090-1020 Ma) orogenic crust

exposed at the erosion surface in the hinterland of the Grenville Province

has recently been interpreted in terms of collapse of a former orogenic

plateau. Collapse is indicated by the juxtaposition of the gneissic mid crust

(P ~ 1000 ± 100 MPa) with the uppermost crust (Ottawan Orogenic Lid,

OOL; P ≤ 400 MPa), and by the crustal-scale architecture in which the

exhumed orogenic mid crust occupies large core complexes and the down-

dropped OOL occupies adjacent basin-shaped grabens. Orogenic upper

crust, with peak pressures between ~400-1000 MPa is under-represented at

the erosion surface.

Exhumation of the granulite-facies mid crust during collapse was

associated with widespread, but variable post-peak modification of its

metamorphic, structural and igneous character. Important effects observed

in the field include: (i) decompression and retrograde reactions; (ii) SE-

plunging stretching lineations parallel to those formed during thrusting, but

defined by post-peak retrograde assemblages; (iii) asymmetric

porphyroclasts and inclusions with SE-side-down sense of rotation; (iv)

small-scale ductile to brittle, normal-sense shear zones and faults; (v)

evidence for vertical flattening and orogen-parallel extension; and (vi)

emplacement of leucogranitic and pegmatitic dykes, sills and small

plutons. Collectively these features indicate the mid crust was shortened

vertically (i.e., flattened), extended horizontally in two directions, and

dilated by magma addition as pressure and temperature declined and

mineral assemblages re-equilibrated during exhumation.

Moreover, on the basis of the grade and timing of peak

metamorphism at different crustal levels, specifically granulite facies in

the mid crust at ~1090-1050 Ma, amphibolite facies in the upper crust at

~1050-1020 Ma, and heating to ≤ 500 °C in the uppermost crust adjacent

to the OOL at ~1020-980 Ma, exhumation of the hot mid crust brought it

into contact with progressively higher crustal levels, which underwent

prograde metamorphism by conductive heating as a result.

These results collectively suggest that collapse of the Ottawan

orogenic plateau took place over ~50 Ma, comparable to the duration of

Ottawan crustal thickening and prograde metamorphism in the mid crust.

Moreover, they also imply that all crustal levels beneath the former

orogenic plateau, including the gneissic mid crust, were profoundly

modified during orogenic collapse. Recognition that the post-peak

modification of mid-crustal rocks encodes an integral part of their tectonic

history has been largely overlooked in the past, but is essential for a

complete understanding of their complex evolution.

CHARACTERIZATION OF INDICATOR MINERAL AND TILL

GEOCHEMICAL SIGNATURES OF THE KIGGAVIK URANIUM

DEPOSIT, NUNAVUT

Robinson, S.V.J.

, [email protected], Paulen, R.C.

Layton-Matthews, D.

, McClenaghan, M.B.

, Jefferson, C.W.

, Quirt,

and Wollenberg, P.

Queen's University, Kingston, ON;

Geological Survey of Canada, Ottawa, ON;

Areva Resources

Canada Inc., Saskatoon, SK

In 2010, a drift prospecting study was initiated at the Kiggavik uranium

deposit under the Geomapping for Energy and Minerals Program. The

objective of this study was to determine the till indicator mineral and

geochemical dispersal characteristics within the zone affected by the

migration of the Keewatin Ice Divide of the Laurentide Ice Sheet.

Mineralized bedrock and surface till samples (n=71) were collected

directly overlying, up-ice and at distances of (50 m, 100 m, 200 m, 500 m,

1 km, 2 km, 3 km, 5 km, 10 km) in a fan-shaped pattern down-ice from the

deposit with respect to the dominant NNW, NW, and W ice flows.

Petrographic work on mineralized bedrock confirmed the fine-

grained mineralogy (<0.1 mm) of the Kiggavik mineralization and

discovered Pb-rich apatite (~10-50 µm), rimmed by uraninite, in strain

shadows parallel to a well-developed phyllosilicate fabric. These features

have led to the current development of a method to observe the heavy

mineral concentrate of the <0.063 mm till fraction, which better reflects

the grain size of ore minerals at the deposit, providing a representative

indicator mineral suite for drift prospecting.

Sand-sized heavy mineral concentrations (HMC: 0.25 mm – 2 mm)

of pyrite, chalcopyrite, and apatite are elevated in samples down ice of the

deposit. Furthermore, gold grains may potentially be used as an indicator

because there is an average of 14 grains per 10 kg sample (max = 114),

exceeding the 7 gold grain per 10 kg sample obtained in an earlier regional

study.

Till geochemistry was determined for both the <0.063 mm and

<0.002 mm fractions to examine geochemical partitioning of U and its

pathfinder elements. Results of samples directly above and down-ice of

Kiggavik have higher concentrations of U, Mo, Au, Bi, Ag, Cu, and V

compared to regional and local up-ice samples. These elements have

moderate positive correlations with U and elevated concentrations up to a

distance of 2 km down-ice of the deposit. Higher concentrations of these

elements are observed in the finer fraction of till, reflecting the fine-

grained mineralogy of the Kiggavik ore. The Kiggavik main zone is the

only deposit to subcrop within the region, therefore the geochemical

dispersion documented likely originates from this deposit.

A MID-DARRIWILIAN SUPER VOLCANO IN NORTHERN NEW

BRUNSWICK, RAPID CLIMATE CHANGE AND THE START OF

THE GREAT ORDOVICIAN BIODIVERSIFICATION EVENT

Rogers, N., Geological Survey of Canada, 601 Booth Street, Ottawa,

ON K1A 0E8, [email protected], and van Staal, C.R., Geological

Survey of Canada (Pacific), Vancouver, BC V6B 5J3

The mid-Darrilwilian (c. 466 Ma) Flat Landing Brook Formation of the

Bathurst Mining Camp (BMC), northern New Brunswick, constitutes the

remnants of a supervolcano of comparable size and eruption rates with the

largest known silicic volcanic provinces (i.e., Taupo; Yellowstone). The

Flat Landing Brook Formation felsic volcanic rocks consist of aphyric to

sparsely feldspar-phyric, dacitic to rhyolitic lavas, pyroclastic flows and

volcaniclastic breccias that are interbedded with locally extensive basalt

lenses and very minor light grey siltstone, red jasperitic shale and iron

formation. Although the Flat Landing Brook Formation volumetrically

dominates the polydeformed collage of dominantly volcanic sequences

119

that constitute the BMC, it was for the most part deposited very rapidly

(probably over less than 2 m.y.). Accurate estimates of the volume of

ejected material are impossible due to the combined effects of

deformation, erosion and unconformable cover sequences, and similarly

the number and duration of discrete eruptive events cannot be determined.

However, comparisons with more recent volcanic sequences, given that

geophysical models determine that the formation locally extends to at least

10 km deep and the dominance of pyroclastic deposits, imply eruptive

events amongst the largest in earth’s history.

Tectonic models determine that the BMC was formed on a series of

relatively small crustal fragments contained within the predominantly

"oceanic", late Floian to Sandbian Tetagouche - Exploits back-arc basin

that formed behind the Victoria - Popelogan arc during closure of the main

tract of Iapetus. The Flat Landing Brook felsic volcanic rocks formed by

high-temperature partial melting of crust that was granulitized during

partial melting that produced the underlying, c. 472-468 Ma Nepisiguit

Falls Formation. This high temperature, second stage partial melting was

induced following ridge subduction and slab window formation.

Though coeval bentonites occur in the South American Pre-

Cordillera and elsewhere, no Flat Landing Brook distal deposits are

recognised, as palaeogeographic constraints preclude substantial volcanic

debris from reaching areas of platformal sedimentation where preservation

is more likely. Flat Landing Brook volcanism is coincident with the

Darriwilian 4a-4b stage boundary, rapid sea-level drop, global karst

formation, a pronounced negative carbon isotopic spike and climatic

cooling to modern-like conditions. This time period also marks the

beginning of the Great Ordovician Biodiversification Event (GOBE). The

causal trigger for the GOBE is contentious, but the temporal correlation

with Flat Landing Brook volcanism dictates that it should be considered a

plausible cause for climate change and biodiversification.

INVESTIGATING NEW METHODS TO DETECT HIDDEN

INTRUSION RELATED MINERALISATION

Rogers, N., Plouffe, A., McClenaghan, B., Geological Survey of

Canada, 601 Booth Street, Ottawa, ON K1A 0E8, nrogers@nrcan.

gc.ca, and Anderson, B., Geological Survey of Canada (Pacific),

Vancouver, BC V6B 5J3

Targeted Geoscience Initiative 4 (TGI 4) is a 5 year Government of

Canada program to conduct thematic, knowledge-driven ore systems

studies aimed at discovering future resources through more effective

targeting of buried mineral deposits.

Intrusion related (e.g., porphyry) deposits are the most important

sources for Cu, Mo, W and Sn, along with Au, Ag, and PGEs. Porphyry

deposits are large, low- to medium-grade deposits in which mineralisation

is hosted within and immediately surrounding distinctive intrusive phases

within larger intrusive complexes that commonly have a complex and

prolonged emplacement history. The metallogenic contents of intrusion

related deposits are diverse, reflecting a variety of tectonic settings.

The purpose of this project is to develop more effective exploration

criteria to identify and evaluate fertile intrusive mineralizing systems at

depth and/or that are hidden beneath surficial deposits. In order to achieve

this studies are being undertaken at sites associated with the Triassic-

Jurassic porphyry deposits of the BC interior and for the array of

mineralised Canadian Appalachian Siluro-Devonian intrusions, for which

the fundamental geoscience knowledge is often lacking.

The alteration halos and vein systems associated with intrusion

related mineralization can represent a much larger exploration target than

the actual economic orebody itself. In the right circumstances alteration

and other vectors can be applied to identify hidden deposits. A common

problem facing Cordilleran and Appalachian exploration is how to detect

mineralised sequences through the extensive surficial coverage.

Consequently research activities are focussing on surficial geochemistry,

biogeochemistry, up-flow of volatiles, indicator mineral dispersal and the

geophysical characteristics of intrusion related deposits. Indicator mineral

dispersal is well established for diamond exploration, but has the potential

to be applied to other mineralising systems within glaciated terrains.

Furthermore, utilising mineral trace element fingerprinting, it might be

possible to develop methods for common phases. Also as trees collect

various elements through their roots, the chemistry of their bark can be

used as a natural probe into the subsurface to help pinpoint buried mineral

deposits and increase the effectiveness of deep mineral exploration.

LATE CAMBRIAN TO MIDDLE ORDOVICIAN GASTROPOD

FAUNAS OF WESTERN NEWFOUNDLAND

Rohr, D.M., drohr@sulross.edu, Measures, E.A., Department of

Earth and Physical Sciences, Sul Ross State University, Alpine, TX

79832, USA, Boyce, W.D., [email protected], and Knight, I.,

[email protected], Geological Survey, Newfoundland and

Labrador Department of Natural Resources, PO Box 8700, St.

John’s, NL A1B 4J6

Gastropods and other mollusks are relatively common and diverse in the

platform carbonate rocks of western Newfoundland. Sinuopea, the oldest

gastropod known here occurs in the shallow-water, Late Cambrian Petit

Jardin and Berry Head formations. Sinuopea has been reported from

Greenland through Newfoundland and eastern North America and at least

as far west as New Mexico.

The cosmopolitan genus Lecanospira is common in the Watts Bight

Formation and the lower and middle members of the Boat Harbour

Formation (Tremadocian). Lecanospira nerine is tiny and closely

associated with algal mounds in one horizon in the middle member, but

larger species are the rule.

Several long-ranging genera occur in the Barbace Cove Member of

the (uppermost) Boat Harbour Formation and the Catoche Formation

(Floian), including Euconia, “Lytospira” and Plethospira. Euomphalopsis,

several species of Maclurites (shells and opercula), and Polhemia are

known only from the Catoche Formation. These genera are common in

Missouri and as far west as Nevada. Malayaspira occurs in the upper part

of the Barbace Cove Member and continues into the Middle Ordovician

strata. “Billings Second Operculum” (probably belonging to Maclurites) is

found in the Catoche Formation, Arctic Canada, and possibly Scotland.

Gastropod opercula are particularly well preserved in western

Newfoundland because of their preferential silicification. Species of

Ceratopea (both shell and opercula) have shorter ranges within the

Barbace Cove Member of the Boat Harbour Formation and the Catoche

Formation. Ceratopea billingsi opercula also occur in the Durness Group

of Scotland. Ceratopea species’ opercula are known from Scotland,

Greenland, Newfoundland and the U.S. Appalachians to New Mexico.

Shells attributed to Ceratopea have also been found in western North

America.

Opercula of Ceratopea unguis and Teiichispira odenvillensis are

locally abundant in the Aguathua Formation. Ceratopea unguis is

restricted to eastern North America including Arkansas, Missouri,

Oklahoma, and Texas. Teiichispira odenvillensis opercula are more

widespread, and they are known from western Canada, Malaysia, and

Australia.

In contrast to the Early Ordovician gastropods of mostly eastern

North American affinities, the Middle Ordovician (Whiterockian) species

from the Table Point Formation are part of the Toquima-Table Head fauna

of brachiopods, trilobites and gastropods that occurs in a carbonate belt

that was peripheral to the trans-equatorial Ordovician North American

continent and other areas in Europe and Asia. Among the gastropods

present are large Hormotoma, Lytospira, Maclurites (shell and opercula),

Malayaspira

, Monitorella, Straparollina, as well as other cosmopolitan

genera.

CONSTRAINING THE DURATION OF THE RAPITAN

GLACIATION USING Re-Os GEOCHRONOLOGY – IMPLI-

CATIONS FOR BASINAL AND GLOBAL OCEAN PROCESSES

Rooney, A.D.

, alan.rooney@durham.ac.uk, Macdonald, F.A.

Selby, D.

, Strauss, J.V.

, and Dudas, F.

Department of Earth

Sciences, Durham University, Durham, DH1 3LE, UK;

Department

of Earth & Planetary Sciences, Harvard University, Cambridge, MA

02138 USA;

Department of Earth, Atmospheric & Planetary

Sciences, Massachusetts Institute of Technology, Cambridge, MA

02139 USA

The lack of geochronological data hinders attempts to constrain the onset

and duration of the Rapitan glaciation and to correlate associated

stratigraphic units on a basin-wide scale. The Windermere Supergroup is a

120

overlying the Rapitan Group, the post-glacial Twitya Formation consists of

an ~30-100 m thick ‘cap’ of organic-rich carbonates overlain by nearly 2

km of black and green shale, siltstone, and sandstone turbidites. A ~20 m

thick interval of the Coppercap Formation along with two intervals (1 m

and 10 m thick) of the Twitya Formation was sampled for Re-Os

geochronology and Os isotope stratigraphy.

The Re-Os geochronology of the pre-glacial Coppercap Formation

and the post-glacial Twitya Formation, coupled with existing U-Pb zircon

dates, constrains the onset and cessation of Rapitan glaciation. The Os

isotope stratigraphy from the pre-glacial Coppercap Formation reveals that

the water column had an unradiogenic composition, whereby input from

mantle sources e.g., hydrothermal vents and alteration of oceanic crust

together with weathering of rift-related volcanics, dominated over riverine

input. In contrast, the Os isotope signature from the post-glacial Twitya

Formation reveals an increasingly radiogenic signal resulting from a

dominantly riverine influx to the post-glacial global ocean. Together, the

geochronology and Os isotope datasets yield crucial constraints on the

duration of the Rapitan glaciation and provide insights into weathering

regimes prior to and immediately after a Neoproterozoic glaciation.

NEW VMS EXPLORATION POTENTIAL TO THE SE OF NEVES-

CORVO MINE, IBERIAN PYRITE BELT, PORTUGAL

Rosa, D.R.N.

, C.M.C.

, [email protected], Rosa, C.J.P.

Pereira, Z.

, Andersen, T.

and Oliveira, J.T.

, Matos, J.X.

GEUS,

Copenhagen, Denmark, Inverno;

Laboratório Nacional Energia

Geologia (LNEG), 2610-999 Alfragide, Portugal;

LNEG, 4466-956

S. Mamede Infesta, Portugal;

Dept. Geosciences, Univ. Oslo,

Norway;

LNEG, 7801-902 Beja, Portugal

WITHDRAWN

VANADIUM MINÉRALIZATIONS IN THE BELL RIVER

ARCHEAN LAYERED IGNEOUS COMPLEX, MATAGAMI,

QUÉBEC

Roudaut, S., [email protected], Jébrek, M., Goulet, N.,

Université du Québec à Montréal, CP888, Succ. Centre-Ville,

Montréal, QC, Derosier, C., Apella Ressource Inc., Vancouver, BC,

and Taner, M.F., Taner & Associates Inc., Ottawa, ON

The Bell River Complex is a large layered intrusion dated at 2725 Ma,

located in the Matagami mining camp in the northern part of the Abitibi

Subprovince. The complex consists of gabbronorite - anorthosite at its

base, overlain by a layered gabbronorite zone containing layers with Fe-Ti-

V oxides, and topped by a zone of granophyres. The oxides occur in the

upper part of the complex.

The gabbronorite zone containing the oxides displays polarity to the

north. It comprises mesogabbronorites with disseminated titaniferous-

vanadiferous magnetite and layers of massive, semi-massive and

disseminated titaniferous-vanadiferous magnetite and ilmenite, as well as

leucogabbros and anorthosites locally injected into the other facies. The

oxide zones can be up to 400 m thick and individual layers are centimetric

to decimetric. Layers are several primary magmatic sequences directly

related to fractional crystallization. A late magmatic brecciation phase is

present at the summit of the layered zone. In the magmatic breccia zone,

the matrix consists of magnetite-bearing pegmatites, plagioclases,

chloritized pyroxenes and quartz and is also characterized by

pseudospinifex textures in the giant (up to 1 m) pyroxenes.

Average grades in the layered zone reach 27.3% Fe, 39.04% Fe

6.55% TiO

and 0.42 % V

. Overall orientation is east-west with a

subvertical dip to the north. The oxide zones are cut by thrust faults

striking N130° with a variable dip to the north, interpreted as the products

of the collision between the Abitibi and Opatica subprovinces, and by a

network of conjugate dextral (NW-SE) and sinistral (northeast- southwest)

strike-slip faults likely related to the Grenville orogeny. Chloritization of

the pyroxenes indicates greenschist facies metamorphism.

Main oxide minerals are ilmenite and titanian magnetite. Ilmenite

grains are homogeneous and have low V contents. Titanian magnetite

grains are inhomogeneous, consisting of trelliswork of ilmenite lamellae in

Ti-poor, V-rich magnetite (less than 2 wt. % TiO

and to 1.41 wt. % V

Thus, magnetite is the principal ore mineral of vanadium. Vanadium is

present in the crystalline structure of magnetite where V

ions replace Fe

ions. The origin of the oxide layers could be explained by fractional

crystallization of an open to oxygen saturated Fe-Ti-V liquid. The

pegmatites in the breccia zone display evidence of high abundance of

volatils, heavy mineral density segregation during the multi-phase opening

of the breccias and evidence of sudden cooling.

RECENT ADVANCES IN GEOPHYSICS AND GROUND

PENETRATING RADAR

Ruffell, A., School of Geography, Archaeology & Palaeoecology,

Queen’s University, Belfast, Northern Ireland, BT7 1NN,

[email protected]

From the macro (worldwide, hundreds of kilometres) to the micro (a few

centimetres), the application of geophysics to forensic investigations has

been growing steadily. At the large scale, forensic seismology has been

particularly useful in the analysis of large explosions, be these terrorist-

related, or accidents that require a legal investigation. Analysis of the

shock waves recorded on the world seismology network allowed

geophysicists to determine that the Russian nuclear submarine (the Kursk)

suffered two explosions, one small, followed by one large, the latter being

the reactor itself. Similar analysis showed the Nairobi and Dar-es-salam

bombings to be coincidental in time, requiring the sort of exact planning

only a highly proficient terrorist group (such as Al Qaeeda) could carry

out. At the meso-scale of kilometres to hundreds of meters, geophysical

techniques such as electrical resistance tomography, shallow seismics and

121

ground penetrating radar have been used to map large burials like mass

graves (Bosnia, Iraq, Rwanda), animal slaughter burials (foot and mouth

crises) and illegal toxic waste (Italy, Canada, Ireland). Conventional uses

of magnetometry, resistivity and ground penetrating radar continue in

searches for buried cadavers, weapons, explosives, contraband and drugs.

What is new with these techniques is their application in unusual

environments such as searching coastal locations, water bodies, and within

buildings (such as child remains buried in walls), all of which will be

reviewed.

RESERVOIR CHARACTERIZATION AND GEOPHYSICAL

WIRELINE ANALYSIS OF THE EARLY JURASSIC

GORDONDALE SHALE MEMBER OF THE LOWER FERNIE

FORMATION, NORTHEAST BRITISH COLUMBIA

Ryan, F.J., Dept. of Earth Sciences, Memorial University of

Newfoundland, St. John's, NL A1B 3X5, v66fjr@mun.ca

As many geologists would agree, shale successions do not show great

variability in hand sample, outcrop or drill core, and oftentimes their

wireline log response is overlooked as any variation is considered

insignificant. Shale gas reservoirs, however, are becoming increasingly

important as energy demands increase worldwide, and oil becomes harder

to extract. Hence, it is important to more fully understand mudstone and

siltstone lithology and petrophysical character. Recent research has shown

that shales are more heterogeneous than their hand specimen appearance.

My study aims to prove that meaningful lithofacies and reservoir quality

characteristics can be exposed through petrophysics and wireline analysis.

The organic rich early Jurassic Gordondale shale (GDN) of the

Lower Fernie Formation located in north-eastern B.C., continuing through

western Alberta, was used as a natural laboratory for this investigation. In

particular, well 200D088H094A1300’s full suite of wireline logs and drill

core was examined and cross referenced with thin section microscopy, and

SEM. The variety of scales used to investigate the lithology of the GDN

was crucial to delineate proper petrofacies, and explained the great log

variability it boasts. The analysis resulted in distinct three petrofacies, with

minor sub-petrofacies, including carbonate inferring we can characterize

wells without core with more accuracy and confidence.

Additionally, the study suggests by using the bulk density log, with

some idea of lithology, we can calculate a 1:1 relationship between the

bulk density and total organic carbon (TOC) with 86% accuracy for this

well. Hence, the model could be used to estimate TOC throughout the

formation. The more cored wells in the area where TOC can be calculated

to more precise the model will become, of course.

In the future, quantitative x-ray diffraction modelling will be

conducted to further validate how we can infer fine-grained lithology using

wireline character examination.

REGIONAL CONTACT METAMORPHISM: A PRODUCT OF

SLAB ROLL-BACK IN ACCRETIONARY OROGENS?

Ryan, P.D., Earth and Ocean Sciences, National University of

Ireland, Galway, Ireland, paul.rya[email protected], and Wintsch,

R.P., Indiana University, Bloomington, IN 47401, USA

The discovery that metamorphic zircons in a contact aureole of one of

several regionally extensive NW-dipping intrusive granodioritic sheets in

the Tananao complex, eastern Taiwan have the same ~86 Ma age as those

intrusions (Wintsch et al., 2011) suggests that virtually all of the

“regional” high-grade metamorphism, here termed the Nanao Event, was

caused by coalescing contact aureoles around these sheets. This

interpretation contrasts with earlier interpretations than suppose that this

metamorphism was caused by the still active collision of the Luzon arc

with the continental margin of SE China, the “Taiwan orogeny” (e.g.

Simose et al., 2007). We test the geodynamic plausibility of such a model

using a 2D transient finite element thermal model which assumes that the

granodioritic sheets were discoid with a diameter equivalent to their strike

length and, as anatexis occurs in the contact aureoles, with initial

temperature of 750°C. The model begins at 90 Ma with the present erosion

level at 15 km, a depth consistent with biotite grade regional metamorphic

conditions, with staurolite + kyanite (no andalusite) aureole assemblages,

and with metamorphic pressure estimates of 4-5 kbar. We model

emplacement both [1] as sills in sub-horizontal strata with NW subsequent

tilting and [2] as NW dipping sheets in previously tilted strata. Case 1

produces a significant increase in metamorphic field gradient from west to

east that is not observed, suggesting tilting of the entire section occurred

during Early Cretaceous loading and pre-dates emplacement.

Emplacement of tilted sheets raises initial temperatures along a 25 km

transect from <420°C between the sheets to >490°C regionally, and to

~600°C near the contact aureoles. The model also produces uplift and

cooling curves from 85 to 6 Ma consistent with Cenozoic thermo-

chronologic data. Horizontal sections through the model space predict

concave up PT gradients in the contact aureoles as opposed to the concave

down gradients typical of burial metamorphism. Regional geological

considerations suggest that this mid-Cretaceous magmatism was associated

with roll-back of the Izanagi plate during regional mid-Mesozoic

subduction along an active Chinese continental margin. Our interpretation

of coalescing contact aureoles is consistent with similar metamorphic belts

elsewhere in accretionary orogens.

NEW U-Pb AGES FOR GABBROIC MAGMATISM WITHIN THE

RAMAH GROUP, NORTHERN LABRADOR: IMPLICATIONS

FOR PALEOPROTEROZOIC EXTENSION IN NAIN CRATON,

AND METALLOGENY

Sahin, T., [email protected]onto.ca, Hamilton, M.A., University

of Toronto, Toronto, ON M5S 3B1, Sylvester, P.J. and Wilton,

D.H.C., Memorial University, St John's, NL A1B 3X5

Archean gneisses of the North Atlantic craton in northern Labrador are

unconformably overlain by three principal Paleoproterozoic supracrustal

remnants – the mostly clastic Snyder/Falls Brook Group, the dominantly

volcanic Mugford Group, and, furthest north, the chiefly sedimentary

Ramah Group.

Ramah Group is an ~1700m thick cover sequence of lowermost

siliciclastic quartzite and sandstone, capped by a distinct supratidal

dolomite horizon, together defining a west-facing shallow shelf sequence,

overlain by euxinic, pyritic shales and mudstones and pyrite-chert

associations (Nullataktok Formation). Upwards, this unit passes through a

mixture of carbonate debris flow breccias, and then into voluminous

turbiditic sandstones. Sills of diabase or gabbro intrude most sedimentary

units, but are extensive within the upper formations. The sills typically

exhibit chilled margins, and are transgressive to their host sediments. Sills

reach up to ~100 m in thickness, though many are only a few meters thick,

in many places with good igneous textures and primary layering features

preserved. At least one thick gabbro sill is internally differentiated, with a

central ultramafic portion. The entire sequence of sedimentary rocks and

sills was deformed together and (locally) metamorphosed to amphibolite

facies, as part of an east-verging fold-and thrust belt on the east margin of

Torngat Orogen, reaching peak temperatures near 1.78 Ga. Deposition of

Ramah Group has thus been bracketed only between its late Archean (ca.

2.5 Ga), Nain craton-derived detrital zircons, and Torngat deformation.

We have dated both gabbroic and ultramafic compositional variants

of Ramah sills, from samples collected from thick sheets intruding the

Nullataktok Formation. ID-TIMS U-Pb baddeleyite analyses yield

identical ages of emplacement (within error) at 1888 ± 5 and 1887 ± 4 Ma.

These represent the first precise U-Pb dates for extension-related mafic

magmatism of this age in the North Atlantic craton in Labrador, and

provide a new minimum age for the host Ramah Group sediments. Mafic

magmatism of this age is unknown in the Greenland portion of the craton,

but is well represented in the Circum-Superior belt, including the ca. 1883

Ma Molson dyke swarm and Fox River sill of Manitoba (Molson Igneous

Events), the 1890-1870 Ma Raglan-Expo-Katiniq sills of the Cape Smith

belt, Ungava, and the 1884-1874 Ma mafic-ultramafic magmatism of the

Labrador Trough.

By analogy with contemporaneous Circum-Superior sediment-sill

complexes (Thompson, Birchtree, Raglan-Expo), Ramah Group may have

potential for magmatic Ni-Cu-PGE sulfide deposits.

122

GEOLOGICAL IMPLICATIONS OF GEOPHYSICAL SURVEYS

IN THE FORTYMILE MINING DISTRICT, YUKON–TANANA

UPLAND, EAST-CENTRAL ALASKA

Saltus, R.W., [email protected], Desczc-Pan, M., Day, W. and O'Neill,

J.M., U.S. Geological Survey, Denver, CO, USA 80225-0046

The Fortymile mining district, located in the eastern Yukon–Tanana

Upland of east-central Alaska has a long history of mineral exploration,

but its geologic history and mineral potential are still under active

investigation. Much of the bedrock is obscured by Quaternary surficial

deposits and vegetation. Geophysical data are crucial in interpreting the

concealed geology and mineral resources in the district. Regional

geophysical data compilations, as well as several detailed airborne

geophysical surveys (magnetics and multi-frequency electromagnetics)

and some surface measurements are available for portions of the district.

The detailed surveys (400 m flight-line spacing, 30 m flight height) were

collected by the State of Alaska, Division of Geological and Geophysical

Surveys.

At regional scale (1:1,000,000), magnetic and gravity data indicate

several crustal features. For example, a fundamental density and magnetic

susceptibility break trends N-NE through Black Mountain, an area of gold

prospects in the Goodpaster mining district, just west of the Fortymile

district. Within the Fortymile district itself, the crust is significantly more

dense and magnetic in a core region surrounding early Mesozoic intrusions

including the Taylor Mountain batholith. The surrounding crust (including

broad regions of late Mesozoic and Cenozoic intrusions) is lower density

and largely devoid of magnetic minerals.

At more local scale (1:63,360) the magnetic anomaly data are

particularly sensitive to intrusive, metamorphic, and structural geologic

boundaries. Airborne electromagnetics can be inverted to estimate surficial

and shallow (to about 100 m) electrical resistivity. This shallow resistivity

is sensitive to the presence of water and to some conductive minerals.

Depth inversion of the airborne electromagnetics provides guidance in the

understanding of shallow structures including faults thought to be

important to localization of mineral trends in the area.

Two different generations (both pre- and post- detailed geophysical

surveys) of 1:63,360 geologic maps are available for the Eagle A1 and A2

quadrangles. The differences between the two maps are testament to the

benefit of detailed geophysical data for geologic mapping.

New USGS mapping at 1:63,360 scale in the western Fortymile

district has utilized the new detailed magnetic and electromagnetic surveys

for the continuation of faults and other structures under cover. Especially

important are revelations of complex structural details along the

Kechumstuk fault that are reflected in both the magnetics and the shallow

resistivity inversions and that are spatially associated with minimal

prospects.

GEOCHEMISTRY OF THE 780 Ma GUNBARREL IGNEOUS

EVENT OF NORTHWEST LAURENTIA

Sandeman, H.A., Government of Newfoundland and Labrador

Natural Resources, Geological Survey, PO Box 8700, St. John’s, NL

A1B 4J6, Ootes, L., NWT Geoscience Office, Box 1500,

Yellowknife, NT X1A 2R3, Cousens, B., Department of Earth

Sciences, Carleton University, 1125 Colonel By Drive, Ottawa, ON

K1S 5B6, and Killian, T., Yale University, 210 Whitney Ave, New

Haven, CT, USA

The Gunbarrel igneous event of western North America consists of

gabbroic sills, sheets, and dykes that have been shown, via U-Pb

baddeleyite geochronology, to have crystallized at ca. 780 Ma. These

occur as widely separated units that intrude Neoproterozoic strata in the

Canadian Cordillera, Paleoproterozoic and Archean rocks in the Wopmay

orogen/western Slave craton, and Archean rocks in the Wyoming craton.

Gunbarrel rocks have well-defined paleomagnetic poles indicating

crystallization in a near-equatorial position and are considered continental

tholeiites derived from a mantle plume (centered southwest of Queen

Charlotte Islands in present-day coordinates) associated with

fragmentation of Laurentia. A modern and robust mineral chemical,

lithogeochemical, and Sm-Nd dataset, from the Tsezotene sills in the

northern Cordillera and the Hottah Sheets of Wopmay orogen, with

additional data from the Christmas Lake dyke of the Wyoming craton are

discussed.

Mineral chemical and petrographic data (plagioclase and

clinopyroxene) from chill margins indicate repeated and turbulent mixing

of geochemically and thermally similar primitive magmas in large

chambers. Thick, large intrusions exhibit large major element variations,

whereas thin dykes and sills have restricted compositions. The

incompatible trace elements and the Sm-Nd isotopic data is remarkably

homogeneous, particularly considering the samples were obtained from

distinct geological terranes separated by up to 2500 km. Nevertheless,

systematic petrochemical differences between units reveals that each is

likely derived from a distinct, primitive magma having mildly differing but

internally consistent trace element variations.

Trace element ratios demonstrate that the intrusions preserve

evidence for contributions of varying proportions of depleted MORB

(DMM) and enriched MORB (EMM) asthenospheric sources with smaller

proportions of a LILE- and LREE-enriched lithospheric component. The

nature of the lithospheric component is not constrained, but Sm-Nd

isotopic data from the intrustions indicate that it may represent either

Mesoproterozoic or older lower crust (T

= ~1600 Ma), or perhaps

continental lithospheric mantle that was LILE- and LREE- metasomatized

via subduction zone recycling of Mesoproterozoic or older continental

material. The Gunbarrel event may record the interaction of a

Neoproterozoic mantle plume with a Mesoproterozoic subduction-

modified mantle on the west side of Laurentia.

THE STATE OF KNOWLEDGE FOR SOME NEWLY RE-

COGNIZED AND REVITALIZED GOLD EXPLORATION

TARGETS, NEWFOUNDLAND AND LABRADOR

Sandeman, H.A.

, hamishsandeman@gov.nl.ca, Conliffe, J.

, Wilton,

D.H.C.

and Sparkes, G.W.

Mineral Deposits Section, Geological

Survey Branch, Department of Natural Resources, Government of

Newfoundland and Labrador, St. John's, NL A1B 4J6;

Department

of Earth Sciences, Memorial University, St. John’s, NL A1B 3X5

The primary objective of gold metallogenic research by the Mineral

Deposits Section, Geological Survey Branch, since 2008 has been focused

thematic investigations on a variety of new, or recently rejuvenated, gold

exploration targets. Each of these studies represents a collaborative

initiative involving government, industry and commonly university

partners. Recently the Research and Development Corporation (RDC) of

the Government of NL initiated “GeoEXPLORE 2011-2013” a scientific

research program to enhance geosciences R&D capacity through

academic, industry and government collaboration in support of mineral

and petroleum exploration and development in NL. Our gold deposit

research team was successful in receiving funding to aid continued

research on these and other gold exploration targets, particularly in central

Newfoundland.

To date the research team has initiated investigations into the origin

and setting of five previously undocumented gold exploration targets in the

province. These include: (1) the Aucoin Prospect of the Nain Province,

Labrador; (2) the Jaclyn Deposit in the Victoria Lake Supergroup of the

central Mobile belt; (3) the Mosquito Hill and adjacent (4) Brady deposits

of the east central Mobile belt; and (5) the Viking Prospect of the

Grenvillian Long Range Inlier. These gold targets now have a critical mass

of geoscientific information that was previously lacking including: robust

lithogeochemical data; paragenetic observations; sulphur isotopic data on

sulphide minerals; fluid inclusion data for associated quartz veins; and

radiogenic isotopic geochronology on host rocks and alteration. The

research team is presently finalizing data collection and compilation for

these deposits.

A number of other recently discovered, or older, gold prospects are

also being examined in order to provide key information on their settings,

character and age of mineralization. These include: the Staghorn Prospect

of the southwesternmost Exploits subzone of the central Mobile belt; the

Leprechaun deposit in the western Exploits subzone; and a number of

precious metal targets with epithermal character hosted by rocks of the

western Avalon Zone. This contribution briefly outlines the current

knowledge base with respect to the lithotectonic setting and character of

123

mineralization at each of these gold targets and discusses avenues and

methodologies for future research.

MICROBIAL ALTERATION OF IMPACT GLASS

Sapers, H.M., [email protected], Banerjee, N.R., Osinski, G.R.,

University of Western Ontario, 1151 Richmond Road, London, ON

N6A 5B7, Preston, L.J., Open University, Walton Hall, Milton

Keynes, UK, MK7 6AA, and Schumann, D., McGill University, 845

Sherbrooke Street West, Montreal, QC H3A 2T5

The initial catastrophic biological effects of hypervelocity impacts are well

established. However, a growing body of evidence suggests that meteorite

impact events also have beneficial effects particularly for microbial life.

This has lead many to suggest that impact craters may have been important

habitats for life on early Earth. Although impact craters are uncommon on

present day Earth, (~50 000 km

globally), they are ubiquitous on rocky

and icy bodies within the solar system often comprising the dominant

geological features. Furthermore, impact flux was twice as high on the

Archaean Earth during the Late Heavy Bombardment Period coinciding

with the earliest evidence of life on Earth. Any hypervelocity impact into a

water-rich target on a solid planetary body has the potential to generate

hydrothermal system. Post-impact hydrothermal systems expand the

potential environments for microbial colonization to environments without

endogenous volcanic heat sources to drive hydrothermal activity. Our

examination of impact glass from the Ries impact structure, Germany, has

revealed the presence of putative microbial alteration. Given the probable

ubiquity of impact glasses in post-impact environments throughout the

Solar System, it is important to understand the biological components and

potential of such systems. We have used a multi-analytical approach to

assess the biogenicity of the tubular features in the Ries glasses. Their

complex morphology (spiraling, bifurcation, avoidance, lack of

intersection) has been studied extensively using both optical and scanning

electron microscopy (SEM). Using SEM based Energy Dispersive

Spectroscopy we have shown the presence of a depletion zone indicative

of biological processing surrounding the tubules. Fourier Transform

Infrared Spectroscopy has identified the presence of organic compounds

spatially associated with the tubules and absent in crystallite regions.

Synchrotron near edge fine structure (NEXAFS) spectroscopy at the C K-

edge also indicates the presence of organically bound carbon in the glassy

matrix surrounding the tubules, but absent in the matrix hosting only

crystallites. NEXAFS spectroscopy at the Fe L2 and L3 –edges indicates

distinct patterns of Fe speciation in the tubules not present in the Fe-rich

abiotic quench crystallites. Impact cratering is a significant and ubiquitous

geological process on terrestrial bodies in the Solar System as well as on

the early Earth, as such the discovery of biogenic features in impact glass

has profound implications for early life on Earth and the early evolution of

life on Earth as well as for life on other terrestrial planets.

GRAIN SIZE FRACTION AND NUMBER OF GRAINS

REPRESENTATIVE OF IRON OXIDE COMPOSITION IN TILL

SAMPLES: THE SUE-DIANNE DEPOSIT AREA, NORTHWEST

TERRITORIES, CANADA

Sappin, A-A., anne-aurelie.sappin.[email protected], Dupuis, C.,

Beaudoin, G., Département de géologie et de génie géologique, 1065

avenue de la Médecine, Université Laval, Québec, QC G1V 0A6,

and McMartin, I., Geological Survey of Canada, 601 Booth Street,

Ottawa, ON K1A 0E8

The magnetite to hematite-group Cu-Ag-(Au) Sue-Dianne IOCG deposit,

located in the southern part of the Great Bear magmatic zone within the

Bear Structural Province of the Canadian Shield, was chosen as a test site

to optimize preparation methods for electron microprobe analysis of the

ferromagnetic fraction of till samples. The objectives are to determine the

optimum grain size fraction and number of grains to measure the

composition of magnetite and hematite in the ferromagnetic fraction of till

samples. Eight till samples were selected to provide a cross-section from

up-ice, proximal to, and down-ice from the Sue-Dianne deposit. For each

till sample, the ferromagnetic fraction was sieved in three size fractions: 1)

<0.25 mm; 2) 0.25-1 mm; 3) 1-2 mm. The intermediate fraction (0.25-1

mm) was subdivided into sub-samples containing about 200, 100, 50, and

10 grains. The ferromagnetic fractions include magnetite, titano-magnetite,

ilmenite, hematite, and other non-ferromagnetic oxides, silicates, and

sulfides. At the deposit, hematite is the dominant oxide, whereas up-ice

and down-ice of the deposit magnetite and titano-magnetite are the

dominant oxides. The grains of the <0.25 mm size fractions are difficult to

analyze with the microprobe because their size is too small to obtain

accurate results. The 1-2 mm size fraction typically contains less than 110

grains such that analytical results are difficult to compare between

samples. The 0.25-1 mm size fraction contains a large number of grains at

all sample locations. The time and cost of analyzing 200 grains of the 0.25-

1 mm size fraction limits the number of samples that can be routinely

analyzed. Our results show that sub-samples from the 0.25-1 mm size

fraction, containing circa 100 grains, yield a representative composition of

magnetite contained in till samples. The mineral proportions in the sub-

samples from the coarse and the intermediate fractions with 50 and 10

grains are variable and, generally, not consistent with the proportions

determined for the 100 and 200 grains intermediate fractions. Sub-sample

summary statistics of the composition of magnetite show that ca. 100

grains subsamples give the most reliable results. In the Ni/(Cr+Mn) vs.

Ti+V and Ca+Al+Mn vs. Ti+V discriminant diagrams, the average

magnetite composition of sub-samples from the coarse fraction, and from

the 50 and 10 grains intermediate fraction show significant variations,

supporting the use of the 100 grains intermediate fraction as the most

appropriate sub-fraction to represent the average iron oxide composition of

a sample.

3D LITHOFACIES MODELLING OF DEFORMED VOLCANO-

GENIC MASSIVE SULPHIDE (VMS) ORE SYSTEMS

Schetselaar, E., Geological Survey of Canada, 615 Booth Street,

Ottawa, ON K1A 0E9, and McGaughey, J., MIRA Geoscience Ltd.,

#309 – 310 Victoria Avenue, Westmount, Montreal, QC H3Z 2M9

A 3D modelling study is presented for mapping the lithofacies architecture

of the thrust-imbricated VMS-hosting mine horizon in Flin Flon, Canada

using Wheeler’s Time-Stratigraphy concept. The 3D modelling workflow

of Paradigm’s SKUATM software proceeds by modelling the volume of

the faulted and folded mine horizon on a curvilinear grid. It then uses a

coordinate transformation to remove the influence of geological structure

on lithofacies interpolation. It subsequently applies the inverse of this

coordinate transformation to map lithofacies on the curvi-linear grid to

represent lithofacies in the finite deformed state.

The Flin Flon VMS deposits are hosted in rhyolite flow, rhyolite

breccia and bedded tuff lithofacies of the Millrock member. The footwall

of the ore system shows an abrupt lateral transition in lithofacies from

intact pillowed basalt flows in the south to a thick volcaniclastic-

dominated succession consisting of megabreccia, pillow fragment breccia

and lapilli tuff towards the north across the margin of an intra-arc rift basin

or cauldron. The regional structure is controlled by E-dipping D

thrust

faults that broke-up D

N-trending fold structures and imbricated

volcanic and volcaniclastic rocks of the Flin Flon arc assemblage and

sedimentary rocks of the Missi Group. This thrust-imbricate structure was

subsequently deformed by S-dipping ductile thrust faults (D

) that re-

imbricated the mine horizon and ore system in a northerly direction.

The first step in 3D modelling was to build a seamless fault network

from mapped surface traces, structural field data, underground mine

surveys and seismic data. Only the D

thrust fault segments in which D

thrust faults sole were included in this fault network, since their layer-

parallel configuration does not provide constraints to model offsets of the

mine horizon along them. Once the fault block model was generated, the

faulted-curvilinear grid could be modelled from lithostratigraphic

constraints that define its top and bottom. Categorical kriging of six

lithofacies from generalized outcrop and drill core samples was applied to

interpolate the lithofacies property on the 3D curvilinear grid.

The resultant 3D lithofacies model provides insight into the rifted

volcanic arc setting in which the sulphide ore was deposited and elucidates

how the ore-hosting horizon was deformed by thrust faulting. Furthermore,

the lithofacies grid model serves as a stratified container for generating

lithochemical property models that can be used for spatially characterizing

ore forming processes, such as hydrothermal alteration. In addition, we

demonstrate how the 3D lithofacies modelling approach can contribute to

exploration targeting.

124

ANTHROPOGENIC (MAN-MADE) MATERIALS IN SOIL

Schneck, W.M., Microvision Northwest-Forensic Consulting, Inc.,

6220 W. Skagit Ct., Spokane, WA 99208, USA

Soil is derived from a multitude of different materials from weathered

bedrock including rock fragments and minerals, secondary material

transported from other locations, namely colluvium an alluvium and

organic matter from plants and animals. This presentation will focus on the

characterization of manufactured materials commonly found in soil using

polarizing light microscopy and scanning electron microscopy-energy

dispersive spectroscopy. Many of the products discussed will include

concrete, brick, wallboard, insulation, wood-plastic composites,

combustion products, fibers, glass, asphalt and wood. Several case studies

will be included to establish the investigative value in identifying the

origin of man-made materials in soil.

VERTICAL VS HORIZTONAL ARCHEAN TECTONICS: A

STUDY OF THE NORTH CARIBOU GREENSTONE BELT, NW

ONTARIO

Schneider, D.A., Van Lankvelt, A., Kalbfleisch, T., Duff, J., Hattori,

K., University of Ottawa, Ottawa, ON K1N 6N5, and McFarlane, C.,

University of New Brunswick, Fredericton, NB E3B 5A3

The North Caribou Greenstone Belt (NCGB) is in the centre of the North

Caribou Terrane (NCT), at the nucleus of the western Superior Province

(WSP). A persistent problem plaguing the Archean field geologist is that

regionally penetrative planar structures measured at the surface are

typically subvertical; whereas, with seismic studies, only structures at

shallow angles can be imaged. Our mapping along the NCGB confirms a

dominant planar vertical fabric (foliation, upright fold axes), with gentle to

moderate plunging lineations (fold axes, intersection lineations), a notable

lack of strong L-tectonites, and occasional steep lineations in iron

formations of the greenstone belt. This has implicated a primary horizontal

tectonic regime responsible for the assembly and architecture of the NCT.

Built on a >3.0 Ga basement, a dominant 2.87-2.85 Ga back arc-type

volcano-plutonic tonalite sequence was formed near or on a thinned NCT

margin. New LA-ICPMS in situ zircon U-Pb ages from St ± Al

SiO

± Bt-

bearing metasediments are similarly 2.86 Ga, suggesting metamorphism

synchronous with, if not a consequence of, elevated temperatures due to

magmatism. This phase of crustal growth maybe the only vertical tectonic

aspect in the NCT evolution as plutons and batholiths were assembled.

Peak amalgamation within the WSP occurred c. 2.75-2.72 Ga in a series of

discrete docking events with the NCT above a doubly-vergent subduction-

type setting. Preservation of the pervasive 2.87-2.85 Ga ages suggest the

NCT remained relatively cold and rigid during peak accretion and new

2.73 Ga U-Pb zircon rim and titanite ages record a metamorphic event

coeval with volumetrically small re-melting episodes of more evolved

granodioritic to granitic compositions. Continued accretion along the

southern margin resulted in localized deformation and hydrothermal flow

within the NCGB as inferred by c. 2.66-2.63 Ga Sm-Nd garnet and Pb-Pb

accessory mineral ages within zones of intense strain. Ar-Ar ages of biotite

and amphibole from central NCGB and new total-Pb in situ monazite ages

from the North Caribou-Totogan Shear Zone yield c. 2.45 Ga ages, which

likely correspond to an upper greenschist facies (400-500°C)

tectonothermal pulse and structural reactivation nearly 200 m.y. after the

latest stage of tectonism. Lithoprobe workers proposed the flat-lying

geometry and inferred amphibolite composition of the imaged mafic slab

beneath the WSP is consistent with Archean subduction models and can be

used to explain the predominance of TTG suites in the Archean. The

growing dataset of geochronology from the WSP is resolving a 400 m.y.

long Andean- / Cordilleran-type margin, and the deformation pattern is

consistent with that of horizontal tectonics.

EVIDENCE FOR NON-CYLINDRICAL IAPETUS SUBDUCTION

FROM CONTRASTING ORDOVICIAN TECTONIC INTER-

PRETATIONS FROM SOUTHERN BRITAIN AND CENTRAL

NEWFOUNDLAND

Schofield, D.I., British Geological Survey, Cardiff, UK, CF15 7NE,

[email protected], Leslie, A.G., British Geological Survey, Edinburgh,

UK, EH9 3LA, and Waldron, J.W.F., University of Alberta,

Edmonton, AB T6G 2ES

In both southern Britain and central Newfoundland the Penobscottian

Orogeny is thought to record horizontal translation of upper plate, back arc

elements onto the peri-Gondwanan foreland in response to a shallow,

advancing Iapetan subduction zone. On the island of Anglesey, NW Wales

this is recorded by metamorphism and southeast-directed translation of a

sedimentary succession comprising Gander-like sandstone-dominated units

overlain by mudstones with tuffaceous units, thrust onto a Neoproterozoic

granite-gneiss complex. The Anglesey accretionary complex preserves an

overstepping Middle Ordovician foreland basin succession that records

continued south-directed translation with a strong sinistral transcurrent

component that persisted until at least Early Silurian times and was

reactivated during probably Early Devonian, Acadian-age tectonism. This

is interpreted to reflect persisting oblique shallow subduction in this

segment of Iapetus with major basin subsidence and Late Ordovician

volcanism on mainland Wales developed in a continental pull-apart

setting.

Continued upper plate compression in Wales contrasts strongly with

the central Newfoundland and other northern Appalachian successions.

There, post-Penobscottian roll-back and upper plate extension led to

development of a broad Exploits back arc that appears to only have

become inverted during diachronous Silurian, Salinic tectonism.

We propose two possible mechanisms to explain these differences in

post-Penobscottian tectonic styles. Firstly, subduction of low-density

oceanic lithosphere in the southern British segment compared to central

Newfoundland. This could have resulted from diachronous subduction of

Iapetan spreading ridge. In this model early ridge subduction outboard of

Anglesey would sustain shallow subduction and Iapetan transform faults

could be reactivated as slab tears to accommodate roll-back in the nearby

Newfoundland segment. This model is challenged by the apparent duration

of shallow subduction in Wales as, intuitively, ridge subduction would be

short-lived and roll-back would follow on afterward.

Alternatively, shallow subduction could result from higher relative

plate velocity in southern Britain. This could reflect heterogeneous strain

along a linear oceanic plate boundary. Southern Britain was however,

proximal to a potential oceanic triple point and the strongly oblique, or

transform, Tornquist –facing margin. Hence, aspects of more complex

paleageographies incorporating strongly curvilinear margins such as in the

Caribbean or Western Pacific are more likely.

THE PRIME MERIDIAN FOR MOLECULAR CLOCKS: WHEN

DID LIFE BEGIN?

Schopf, J.W., University of California, Los Angeles, CA, USA,

90095-1567, schopf@ess.ucla.edu

Despite the fact that the fossil (including the molecular biomarker) record

can provide evidence only of the first known occurrence of metabolic

novelties or major evolutionary innovations — a necessarily minimum

estimate of their actual time of origin — the benchmarks revealed by this

record, the only direct evidence of the timing of such events, are pivotal in

calibrating molecular phylogenies and inferred rates of evolutionary

development. Foremost among such benchmarks is the beginning of life

itself, evidence relating to the timing of which has been a subject of recent

controversy that is now resolved.

Diverse, abundant, carbonaceous microscopic filaments described by

Schopf in 1993 from the ~3,465-Ma-old Apex chert of Western Australia

are recorded in many textbooks as the oldest fossils known. In 2002,

however, the biogenicity of these sinuous microbe-like filaments was

questioned by Brasier et al., the existence of these filaments ascribed to

graphite thought to be derived from organics produced by abiotic Fischer-

Tropsch-type syntheses in a submarine hydrothermal setting. This

nonbiologic interpretation is erroneous — recent studies establish that the

filaments are authentic fossil microbes and that the Apex organic matter is

assuredly biogenic.

Consistent with paleobiologic evidence from other geologic units

3,200 to 3,500 Ma in age — carbon isotopes, stromatolites, and

microfossils (including those in other hydrothermal deposits) — Raman

imagery and confocal laser scanning microscopy (CLSM) show that the

125

Apex fossils, like a great many other chert-permineralized filamentous

Precambrian microbes, are three-dimensional, cylindrical, and composed

of organic-walled cells that exhibit well defined cell lumina. Raman

establishes that they are composed of biogenic kerogen, not abiotic

graphite. CLSM data rule out their introduction by permeating organic

fluids. And the CHONSP-composition and functional-group chemistry of

the Apex organic matter documented in 2009 by De Gregorio et al.

indicate "that the Apex microbe-like features represent authentic biogenic

organic matter."

Other non-biological interpretations of the Apex fossils also fail. The

solid mineral crystallites laboratory-synthesized in 2003 by García-Ruiz et

al. lack the transverse cell walls and biological cellularity of the Apex

microbes, and the clay mineral pseudofossils reported in 2009 by Pinti et

al. as well as the hematite-infilled veinlets described in 2010 by Marshall

et al. are not relevant to interpretation of the demonstrably carbonaceous

Apex filaments.

This problem is solved. The Apex fossils are demonstrably biogenic.

Microbial life was thriving on Earth 3,500 Ma ago, but its assuredly earlier

actual time of origin has yet to be established.

HANS HOFMANN'S CONTRIBUTIONS TO PRECAMBRIAN

PALEONTOLOGY

Schopf, J.W., University of California, Los Angles, CA, USA 90095-

1567, [email protected]du

One of the foremost Precambrian paleontologists in the history of science,

Hans J. Hofmann (1936-2010) was a Fellow of the Royal Society of

Canada and recipient of the Geological Association of Canada's Billings

Medal (1980), the Royal Society's Willet G. Miller Medal (1995), and the

U.S. National Academy of Science's Charles Doolittle Walcott Medal

(2002). A pioneer in studies of Precambrian life, Hans filled in the

evolutionary gap between the more recent fossil record and the oldest

evidences of life and contributed more to the discovery and understanding

of especially ancient, Archean, microbe-formed stromatolites than any one

who has ever lived.

HRTEM AND XRD CHARACTERIZATION OF ILLITE/

SMECTITE (I/S) DIAGENESIS IN THE JEANNE D'ARC BASIN

OFFSHORE NEWFOUNDLAND, CANADA

Schumann, D.

, [email protected], Hesse, R.

, Sears,

S.K.

and Vali, H.

1,2

Department of Earth & Planetary Sciences,

McGill University, 3450 University Street, Montreal, QC H3A 0E8;

Facility for Electron Microscopy Research, McGill University, 3640

University Street, Montreal, QC H3A 0C7

An X-ray diffraction (XRD), high-resolution transmission electron

microscopy (HRTEM) and conventional transmission electron microscopy

(CTEM) study using octadecylammonium (nC=18) cation exchange has

been applied to the clay-mineral separates (2.0-0.5, 0.5-0.1, and <0.1 µm

fractions) of argillaceous rocks of increasing burial depth from the Jeanne

d’Arc Basin, offshore Newfoundland, in order to study the smectite to illite

(S→I) reaction during burial. Two wells were sampled: the North Ben

Nevis (NBN) P-93 (2025 m, 2730 m) and Adolphus (AD) D-50 (2035 m,

3135 m). XRD patterns of the EG-solvated fine fractions resemble patterns

of R0 randomly interstratified and R1-ordered I/S mixed-layer clay

minerals. Lattice-fringe images of clay minerals in ultrathin sections

treated with nC=18 cations document the multiphase nature of the clay

mineral assemblages in all size fractions. The coarse and medium size

fractions consist of low- and high-charge smectite-group minerals,

expandable and non-expanded illite, vermiculite, mica, kaolinite, and

chlorite. The <0.1 µm fractions of the shallow samples consist of low- and

high-charge smectite-group minerals, a vermiculite-like phase and minor

amounts of newly formed small packets of illite, which increases in

abundance with depth of burial. Conventional TEM images of Pt-C

replicas show a change in particle morphology with increasing depth of

burial. Irregular, flake-like particles dominate in NBN P-93 at 2025 m and

AD D-50 at 2035 m, while at greater depths (NBN P-93 at 2730 m and AD

D-50 at 3135 m) a larger proportion of lath-like or equidimensional

particles are observed. The HRTEM observations also reveal the absence

of distinct R0 and R1 I/S mixed-layer phases which appear as an artefact

of XRD analyses. Instead, three 2:1 layer silicate phases can form short

rectorite-like (R1) sequences. Most common are smectite-group minerals

that contain tetrahedral sheets with charge distributions that cause low-

charge and higher-charge 2:1 silicate layers to alternate. Expandable illite

and vermiculite are two other phases that may contain polar 2:1 silicate

layers and therefore can form short rectorite-like sequences. The

diagenetic evolution of smectite and illite in the depth interval of the

Jeanne d’Arc Basin that was investigated should be considered as

sequences of multiple discrete 2:1 clay-mineral phases that dissolve and

recrystallize from solution in overlapping zones of burial depth and not as

a single, continuous and progressive reaction series as traditionally

assumed.

DIVERSE MESOSCOPIC MANIFESTATIONS OF LATE-

OTTAWAN, MID- TO UPPER-CRUSTAL, OROGEN-PARALLEL

SHEAR, GRENVILLE PROVINCE OF SOUTHEAST ONTARIO

Schwerdtner, W.M.

, fried.schwerdtner@utoronto.ca, Zeeman,

B.T.

1,2

, Rivers, T.

, Ahmed, M.

, Yang, J.F.

and Lu, S.J.

University of Toronto, Department of Geology, Toronto, ON M5S

3B1;

Lassonde Institute for Mining, Toronto, ON M5S 3E3;

Memorial University, Department of Earth Sciences, PO Box 4200,

St. John's, NL A1B 3X5;

Flint Energy, 260-2257 Premier Way,

Sherwood Park, AB T8H 2M8

In the Central Gneiss Belt (CGB) and adjacent Composite Arc Belt (CAB),

Grenville Province of Ontario, the regional dip of lithotectonic boundaries

and the main foliation (S) is <35° toward the east or southeast. Associated

elongation lineations (L) are typically down-dip. Assuming that S marks

the XY plane of the strain ellipsoid (main ductile deformation) then its YZ

plane dips steeply to the west or northwest. In the CAB boundary zone and

adjacent domains, YZ-parallel sections through three kinds of mesoscopic

structures attest to orogen-parallel components of ductile shear and, by

implication, triaxial regional strains. The structures are: (1) naked or

winged ovoidal porphyroclasts that are discordant to S, (2) quasi-

cylindrical segments of gentle or open, asymmetric buckle folds in which

S is the folded surface and hinge lines are parallel to L, and (3) discordant

brittle-ductile dislocations such as m-scale faults, sheared contacts of

weakly deformed pegmatite dikes or narrow high-strain zones. These

structures appear to have developed consecutively, and represent post-

peak-metamorphic stages of Ottawan deformation.

With respect to ovoidal porphyroclasts (1), the obliquity between the

foliation trace and the major diameter of ovoids in the YZ plane seems to

be due to shear-induced rotation about the lineation direction. However,

the shear sense is commonly equivocal, especially where feldspar

porphyroclasts are naked or have σ-wings at one end and δ-wings at the

other. Concerning the buckle folds (2), the vast majority have S-

asymmetry and therefore attest to an orogen-parallel regional component

of sinistral ductile shear. Discordant brittle-ductile dislocations (3) are

particularly common in the Bancroft and Barry’s Bay regions. In YZ

sections through dislocation walls, the offset or deflection of prominent

folia attests to orogen-parallel shear components, but the regional-shear

sense remains to be determined.

In summary, results of our recent work suggest that orogen-parallel

shear components contributed significantly to the later stages of regional

Ottawan deformation in southeastern Ontario. This supports our contention

that regional strains were triaxial, at these stages, both in the exhumed mid

crust and the upper crust, and thus that it is problematic to investigate late

phases of the Ottawan orogenic evolution through use of two-dimensional,

plane-strain models.

GEOCHEMISTRY OF THE PROTEROZOIC NUELTIN-MCRAE

SUITES, WESTERN CHURCHILL PROVINCE

Scott, J.M.J., Carleton University, Ottawa, [email protected]m,

Peterson, T.D. and Jefferson, C.W., Geological Survey of Canada,

601 Booth Street, Ottawa ON K1A 0E8

Shallow granitic intrusions commonly generate mineralized, hydro-

thermally altered zones in porous roof rocks. Typically the alteration

involves potassic metasomatism, which can be revealed as enhanced K/Th

and K/U ratios in airborne gamma ray maps. 1.75 Ga Nueltin granite

plutons in the Dubawnt-Baker-Aberdeen lakes area are subvolcanic,

intruding co-magmatic rhyolitic carapaces of the Pitz Formation. A north-

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