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GEOREF RECORD

Reconstruction of a large deep-crustal terrane; implications for the Snowbird tectonic zone and early growth of Laurentia

K. H. Mahan and M. L. Williams
Reconstruction of a large deep-crustal terrane; implications for the Snowbird tectonic zone and early growth of Laurentia
Geology (Boulder) (May 2005) 33 (5): 385-388

Abstract

The approximately 2800-km-long Snowbird tectonic zone is a well-recognized but still enigmatic feature in the western Canadian Shield. It has been interpreted as a Paleoproterozoic continental suture or an Archean strike-slip fault system, but here we suggest that the distinctive geometry of the central Snowbird tectonic zone is primarily due to the interaction of crosscutting Paleoproterozoic intracontinental thrust and strike-slip shear zones having a length of hundreds of kilometers. First, a major zone of thrust-sense shearing, coeval with early continent-continent collision between the Superior and western Churchill provinces, accommodated uplift of a large exposure of granulite facies lower continental crust. Younger strike-slip shear zones, perhaps analogous to Asian fault systems behind the Himalayan orogen, offset the thrust zone. Thus, the current geometry and distribution of deep-crustal rocks in this region represent a relatively late stage in the tectonic evolution of the western Churchill province rather than an accretionary one. Earlier structures oriented at a high angle to the Snowbird tectonic zone may record the fundamental accretionary history in this part of Laurentia.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 33
Serial Issue: 5
Title: Reconstruction of a large deep-crustal terrane; implications for the Snowbird tectonic zone and early growth of Laurentia
Affiliation: University of Massachusetts, Department of Geosciences, Amherst, MA, United States
Pages: 385-388
Published: 200505
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 32
Accession Number: 2005-034354
Categories: Structural geology
Document Type: Serial
Bibliographic Level: Analytic
Annotation: With GSA Data Repository Item 2005070
Illustration Description: illus. incl. geol. sketch maps
N58°00'00" - N61°00'00", W106°30'00" - W101°30'00"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 200519
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