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Co-sponsored by
Geological Society of America
- and -
Goldcorp Inc.

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Late Archean Crust: Magmatism and Tectonics of the Abitibi Subprovince, Canadian Shield

19-25 July 2008

Abitibi granite-greenstone belt and Kapuskasing structural zone • Ontario and Québec, Canada

Keith Benn
University of Ottawa, 550 Cumberland St., Ottawa, Ontario K1N 6N5,
Phillips C. Thurston
Laurentian University, Sudbury, Ontario P3E 2C6

Field Excursion Leaders:
Keith Benn
University of Ottawa, 550 Cumberland St., Ottawa, Ontario K1N 6N5,
R. Daigneault
Université du Québec à Chicoutimi, 555 boulevard de l'Université, Chicoutimi, Québec G7H 2B1
H. Gibson
Laurentian University, Sudbury, Ontario P3E 2C6
J.A. Percival
Geological Survey of Canada, 600 Booth St., Ottawa, Ontario K1A 0E8
Phillips C. Thurston
Laurentian University, Sudbury, Ontario P3E 2C6


The registration fee is US$1,500, based on double occupancy. This fee will cover lodging for six nights (19-24 July), food, local travel and field trip expenses. Airfare is not included. Some financial assistance will be available for eligible students.

Important Deadlines

2 May 2008:  Indication of interest to be received. Invitations to participants will be sent with a request to complete the official registration form.
22 May 2008:  Deadline for payment of registration fee.

You are invited to express your interest to participate in a Field Forum that will offer a unique opportunity to study the origins and evolution of one of Earth's major Late Archean terranes. The Field Forum will include visits to exposures of Late Archean lower, middle, and upper crust, ranging from granulite grade to subgreenschist grade. The meeting will also include visits to two major greenstone-hosted mining camps.

Discussions will benefit from the abundant geological, geophysical, geochemical, and geochronological data sets that have been, and continue to be, assembled during the two decades since the Abitibi-Grenville lithoprobe transect.

The ~1.6 × 105 km2 Abitibi granite-greenstone belt is part of the southern Superior Province, a region of the North American craton that was formed during one of Earth's major periods of crustal growth. The principal subjects of this proposed Field Forum are the formative processes and crustal architecture of the Late Archean Abitibi granite-greenstone belt, including its middle and lower crust, as exposed in the Kapuskasing structural zone and within antiformal hinge zones within the greenstone belt. The Field Forum will also provide the geological and tectonic contexts of major precious and base metals deposits.

The five-day forum will take us to key outcrops of different crustal levels and allow us to debate the following issues at the exposures and during the evenings:

  • Lower crust: granulite-grade metamorphism and migmatites. Was there more than one granulite event? What tectonic processes were responsible for the metamorphism, and when did the lower crust form?
  • Mid-crust: tonalite-trondhjemite-granodiorite (TTG) gneiss and plutons. Evidence for multiple events of TTG magmatism and structural reworking.
  • Volcanology, stratigraphy, and structure of the upper crustal greenstones and of the major gold and base metals mining camps hosted by the greenstones.
  • Geodynamic origins and magmatic evolution of the Late Archean crust. In what geodynamic environment did the crust form? What are the implications of plume-related and subduction-related magmatism in the same belt?
  • Production and reworking of TTGs. What do the distinct TTG events tell us about formation of the crust?
  • Late Archean orogeny and structural evolution at all crustal levels. How did the 40-km-thick crust form? Is the Abitibi a collage of imbricated tectonic terranes, or does it represent a single, large tectonic terrane? What are the implications for Late Archean crustal accretion arising from each of those two models?

Lectures by the field trip leaders will set the scene for the Field Forum and for each day's field excursion. Invited speakers will present and lead discussions on important topics of Archean geodynamics and tectonics in the evenings as well.

Expression of Interest

You can inform the organizing committee of your interest by sending an e-mail to Keith Benn, . Please indicate your area of specialization and affiliation, and let us know if you are a graduate student. When responding, please indicate your level of interest (i.e., definitely wish to participate, likely participant, possible participant). The forum is limited to 50 participants, and the deadline to indicate interest is 2 May 2008. Registration and fees are still to be determined.

Preliminary Program
19 July Arrival in Sudbury, Ontario. Evening seminar: Overview of the Abitibi Subprovince. Ice breaker.
20 July Tonalite and granodiorite magmatism and reworking in the middle crust, Kenogamissi complex.
21 July Lower crust granulites and migmatites in the Kapuskasing structural zone.
22 July Stratigraphy and structure of the Timmins gold mining camp.
23 July Porcupine-Destor fault zone, its structure and tectonic significance.
24 July Volcanology of the Rouyn-Noranda mining camp.
25 July Participants can fly out from Rouyn-Noranda or travel back to Sudbury.

This Field Forum will immediately follow the Goldschmidt Conference in Vancouver on 13-18 July 2008.

Cosponsored by The Geological Society of America and Goldcorp Inc.