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New high-precision U-Pb ages for the Island Lake greenstone belt, northwestern Superior Province; implications for regional stratigraphy and the extent of the North Caribou Terrane

Jen Parks, Shoufa Lin, Don Davis and Timothy Corkery
New high-precision U-Pb ages for the Island Lake greenstone belt, northwestern Superior Province; implications for regional stratigraphy and the extent of the North Caribou Terrane (in The western Superior Province Lithoprobe and NATMAP transects--Les geotraverses des projets CARTNAT et Lithoprobe de la Province du lac Superieur occidentale, John A. Percival (editor) and Herwart H. Helmstaedt (editor))
Canadian Journal of Earth Sciences = Revue Canadienne des Sciences de la Terre (July 2006) 43 (7): 789-803

Abstract

A combined U/Pb and field mapping study of the Island Lake greenstone belt has led to the recognition of three distinct supracrustal assemblages. These assemblages record magmatic episodes at 2897, 2852, and 2744 Ma. Voluminous plutonic rocks within the belt range in age from 2894 to 2730 Ma, with a concentration at 2744 Ma. U-Pb data also show that a regional fault that transects the belt, the Savage Island shear zone, is not a terrane-bounding structure. The youngest sedimentary group in the belt, the Island Lake Group, has an unconformable relationship with older plutons. Sedimentation in this group is bracketed between 2712 and 2699 Ma. This group, and others similar to it in the northwestern Superior Province, is akin to Timiskaming-type sedimentary groups found throughout the Superior Province and in other Archean cratons. These data confirm that this belt experienced a complex geological history that spanned at least 200 million years, which is typical of greenstone belts in this area. Age correlations between the Island Lake belt and other belts in the northwest Superior Province suggest the existence of a volcanic "megasequence". This evidence, in combination with Nd isotopic data, indicates that the Oxford-Stull domain, and the Munro Lake, Island Lake, and North Caribou terranes may have been part of a much larger reworked Mesoarchean crustal block, the North Caribou superterrane. It appears that the Superior Province was assembled by accretion of such large independent crustal blocks, whose individual histories involved extended periods of autochthonous development.


ISSN: 0008-4077
EISSN: 1480-3313
Coden: CJESAP
Serial Title: Canadian Journal of Earth Sciences = Revue Canadienne des Sciences de la Terre
Serial Volume: 43
Serial Issue: 7
Title: New high-precision U-Pb ages for the Island Lake greenstone belt, northwestern Superior Province; implications for regional stratigraphy and the extent of the North Caribou Terrane
Title: The western Superior Province Lithoprobe and NATMAP transects--Les geotraverses des projets CARTNAT et Lithoprobe de la Province du lac Superieur occidentale
Author(s): Parks, JenLin, ShoufaDavis, DonCorkery, Timothy
Author(s): Percival, John A.editor
Author(s): Helmstaedt, Herwart H.editor
Affiliation: University of Waterloo, Department of Earth Sciences, Waterloo, ON, Canada
Affiliation: Geological Survey of Canada, Ottawa, ON, Canada
Pages: 789-803
Published: 200607
Text Language: English
Summary Language: French
Publisher: National Research Council of Canada, Ottawa, ON, Canada
References: 41
Accession Number: 2007-002788
Categories: Structural geologyGeochronology
Document Type: Serial
Bibliographic Level: Analytic
Annotation: Includes appendix; Lithoprobe Publ. No. 1457
Illustration Description: illus. incl. sect., 1 table, geol. sketch maps
N52°00'00" - N54°00'00", W97°00'00" - W94°00'00"
Secondary Affiliation: Queen's University, CAN, CanadaUniversity of Toronto, CAN, CanadaManitoba Geological Survey, CAN, Canada
Country of Publication: Canada
Secondary Affiliation: GeoRef, Copyright 2018, American Geosciences Institute.
Update Code: 200701
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