The southern termination of the Main Ranges and Western Ranges of the southern Canadian Rocky Mountains: Stratigraphy, structural geology, and tectonic implications.

摘要

The Tanglefoot area straddles the southern termination of the Main Ranges and Western Ranges geologic sub-provinces of the Foreland Fold and Thrust Belt of the Canadian Cordillera. The map-area also straddles a regional, east-west, cross-strike discontinuity, across which there are profound changes in the stratigraphy, sedimentary facies, and the style and orientation of the structures of the Rocky Mountains.;The stratigraphy of the Tanglefoot area is subdivided into three distinct, unconformity-bounded assemblages: the Mesoproterozoic strata, the Lower Palaeozoic strata, and the Upper Palaeozoic strata. There is a profound change in the Palaeozoic stratigraphy across the Dibble Creek fault. On the south side of the fault, the Lower Palaeozoic strata comprise a thin (118 m - 337 m), condensed succession of Middle Cambrian cratonic platform facies rocks, which unconformably overlie Mesoproterozoic strata, and are unconformably overlain by Upper Devonian cratonic platform facies strata. On the north side of the Dibble Creek fault, shaly equivalents of the Upper Devonian Fairholme Group (?), Palliser, Exshaw, and Banff Formations overlie approximately 7 km of shaly Lower Palaeozoic rocks.;The structures within the map-area are dominantly northeast-trending, and verge to the southeast, in marked contrast to the regional structural trend of the Foreland Fold and Thrust Belt. The Tanglefoot area has been subdivided into three structural domains: the Montania domain, the Tanglefoot domain, and the Hughes domain. (Abstract shortened by UMI.).