COLLAPSE STRUCTURES NEAR SASKATOON, SASKATCHEWAN, CANADA

Abstract

A structural depression herein called the "Saskatoon. Low" is apparent on structural maps drawn on the top of the Lea Park Formation–Upper Colorado Group, on the bedrock surface, and on the uppermost till surface. The structure was probably formed by collapse as a result of the removal of salt from the Elk Point Group. The structure presumably comprises numerous individual fault blocks, which are bounded by high-angle step faults. The structure may have started to form during deposition of the Bearpaw Formation. It was well developed, however, at the time of the advent of Pleistocene glaciation and continued to develop until late Pleistocene time. The final collapse is radiocarbon dated at about 12 000 years ago.