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The AAPG/Datapages Combined Publications Database

CSPG Bulletin

Abstract


Journal of the Alberta Society of Petroleum Geologists
Vol. 7 (1959), No. 8. (August), Pages 183-183

Ninth Annual Field Conference Abstracts

Geology of the Western Front Ranges South of Bow River, Alberta [Abstract]

J. L. Usher

ABSTRACT

The Front Ranges sub-province of the Rocky Mountains along Bow River Valley is bounded on the east and west respectively by the McConnell and Castle Mountain thrust faults. It comprises, from east to west, the Fairholme, the Cascade-Rundle, the Norquay-Sulphur-Goat, the Sawback-Bourgeau, and the Pilot-Fatigue Ranges. Excepting the latter, each range is underlain by a major thrust fault; the Pilot-Fatigue Range is closely tied to the Sawback-Bourgeau Range, the two being separated by the Brewster Creek syncline, and the Fatigue thrust fault which has variable but not excessive stratigraphic throw. Topographically the two ranges are distinct.

The stratigraphic section includes the Middle and Upper Cambrian, Lower Ordovician, Upper Devonian, Mississippian, Permian, Triassic, and Jurassic. Pre-Devonian rocks are exposed on all ranges except the Norquay-Sulphur-Goat Range; there the Devonian Fairholme group forms the hanging wall of the Sulphur fault, and the foot wall rocks are overturned quartzites of the Rocky Mountain group and not the hitherto reported Ordovician Mt. Wilson quartzite. Middle and Upper Cambrian formations on the Rundle and Sawback Ranges have previously been described; the author recognizes five mappable Upper Cambrian rock units in the Sawback-Bourgeau Range and refers to them by letters A, B, C, D, and E, abeyant to future unravelling of Upper Cambrian stratigraphy and nomenclature in Main Ranges type sections.

Upper Devonian formations increase in thickness westward. The Fairholme group is in carbonate facies in the Cascade-Rundle Range, the Norquay-Sulphur Range, the Sawback Range and in the north end of the Bourgeau Range. South of Mt. Allenby the Fairholme group becomes shaly and the Alexo formation loses a thick middle carbonate member to become a uniform succession of quartzitic siltstones and silty dolomites. A similar succession occurs in the Pilot-Fatigue Range.

The Alexo formation thickens to 400 feet in the west and is composed of dolomite, fine quartzites, and silty dolomites. The Palliser formation thickens to 1,850 feet in the westernmost Front Range.

Mississippian rocks thicken westward; the Exshaw formation may reach 70 feet. The lower Banff formation contains much black shale and chert. Permian and Triassic rocks are present on back slopes of all ranges except the Pilot-Fatigue Range. Jurassic rocks occur in the upper Spray River Valley on the lowest back slope of Goat Range.

End_of_Record - Last_Page 183-------

ACKNOWLEDGMENTS AND ASSOCIATED FOOTNOTES

Shell Oil Company of Canada, Ltd., Calgary

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