Skip to Main Content
Skip Nav Destination
GEOREF RECORD

Seismic interpretation of the Rocky Mountain thrust front near the Crowsnest deflection, southern Alberta

N. J. Begin, D. C. Lawton and D. A. Spratt
Seismic interpretation of the Rocky Mountain thrust front near the Crowsnest deflection, southern Alberta
Bulletin of Canadian Petroleum Geology (March 1996) 44 (1): 1-13

Abstract

Interpretation of seismic profiles in the southwestern Alberta Foothills near the Crowsnest Deflection delineates along- and across-strike variations of orogenic structures in the triangle zone. The overall structural geometry is dominated by an east-verging allochthonous wedge of Mesozoic rocks, overlain by west-verging thrust sheets of Upper Cretaceous and Tertiary rocks, and underlain by undeformed Paleozoic strata. The Big Coulee Fault, which rides within the Bearpaw Formation, represents the boundary between east- and west-verging structures and is the main upper detachment of the triangle zone. Strike seismic lines reveal evidence of major lateral ramps and folding of the Big Coulee Fault. Backthrusts above the upper detachment (e.g. Co-op, Waldron and Callum Creek) die out southward near Crowsnest River and folding of these faults decreases eastward. This suggests an eastward progression in the temporal development of west-verging faults above the triangle zone. In the vicinity of the Crowsnest Deflection, a major lateral ramp occurs in the lower detachment, as it cuts up-section to the north from the Blairmore Group to the Alberta Group. This is evidence for southward thickening of the allochthonous wedge, in addition to its eastward-tapering geometry documented along the entire fold and thrust belt.


ISSN: 0007-4802
Coden: BCPGAI
Serial Title: Bulletin of Canadian Petroleum Geology
Serial Volume: 44
Serial Issue: 1
Title: Seismic interpretation of the Rocky Mountain thrust front near the Crowsnest deflection, southern Alberta
Affiliation: University of Calgary, Department of Geology and Geophysics, Calgary, AB, Canada
Pages: 1-13
Published: 199603
Text Language: English
Summary Language: French
Publisher: Canadian Society of Petroleum Geologists, Calgary, AB, Canada
References: 24
Accession Number: 1996-053689
Categories: Structural geologyApplied geophysics
Document Type: Serial
Bibliographic Level: Analytic
Annotation: Foothills Res. Project, Contrib. No. 003
Illustration Description: sects., strat. col., 2 tables, sketch map
N49°30'00" - N49°55'00", W114°30'00" - W113°30'00"
Country of Publication: Canada
Secondary Affiliation: GeoRef, Copyright 2020, American Geosciences Institute.
Update Code: 199618
Close Modal

or Create an Account

Close Modal
Close Modal