Folded thrust faults in the foothills of Alberta

Abstract

This paper describes the stratigraphic and geologic structure of an area in the Rocky Mountain foothills of west-central Alberta. An unusual group of low-angle thrust faults is described and analyzed. At least seven overlapping faults were recognized which range up to 30 miles in length and have an aggregate displacement of about 6 miles. They divide the incompetent Upper Cretaceous sediments into thin sheets. The faults and faulted sediments have been strongly folded. These faults are thought to have developed in an asymmetrical syncline where the structural development required more bedding-plane slippage than the strata were capable of performing and the faulting relieved the stresses involved. The faults are believed to be confined to the stratigraphic section and the major structure with which they are found associated and to die out completely with depth without producing any dislocation of Paleozoic rocks.