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GEOREF RECORD

Montana Transform; a tectonic cam surface linking thin- and thick-skinned Laramide shortening across the Rocky Mountain foreland

James W. Sears
Montana Transform; a tectonic cam surface linking thin- and thick-skinned Laramide shortening across the Rocky Mountain foreland
Rocky Mountain Geology (December 2006) 41 (2): 65-76

Abstract

The Montana transform is here defined as the northern boundary of the Wyoming Laramide foreland. This sinistral-transpressional shear zone followed a crustal-scale structure that defined the southern margin of the Mesoproterozoic Belt basin of western Montana. The structural zone transferred clockwise tectonic rotation of the thick-skinned Wyoming foreland to clockwise rotation of thin-skinned thrust plates of the Montana thrust belt. Traction above the Farallon plate, which rotated northeastward beneath the Wyoming foreland, may have driven the rotation of the basement-involved Laramide ranges. The ancestral crustal structure that controlled the transform did not coincide exactly with a small circle of rotation about the Euler pole for the Wyoming foreland. Instead, the transform rotated eccentrically, like a cam surface, and generated sufficient sinistral transpression against the Belt Supergroup to thrust it out of its basin.


ISSN: 1555-7332
EISSN: 1555-7340
Coden: WUGGAO
Serial Title: Rocky Mountain Geology
Serial Volume: 41
Serial Issue: 2
Title: Montana Transform; a tectonic cam surface linking thin- and thick-skinned Laramide shortening across the Rocky Mountain foreland
Author(s): Sears, James W.
Affiliation: University of Montana, Department of Geosciences, Missoula, MT, United States
Pages: 65-76
Published: 200612
Text Language: English
Publisher: University of Wyoming, Dept. of Geology and Geophysics, Laramie, WY, United States
References: 66
Accession Number: 2007-010837
Categories: Structural geology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: sketch maps
N44°30'00" - N49°00'00", W116°01'60" - W104°01'60"
N32°00'00" - N65°00'00", W155°00'00" - W103°00'00"
N41°00'00" - N45°00'00", W111°04'60" - W104°04'60"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Abstract, copyright, University of Wyoming. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 200707
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