Structural Geology Interpreted from AEM Data - Folded Terrain at the Foothills of Rocky Mountains, British Columbia

Abstract

This study presents an interpretation of newly collected AEM data from the Peace Region, British Columbia, Canada. Through careful data processing and interpretation we demonstrate the potential for AEM methods to map traditional structural geology such as folds and thrust structures. The study area covers about 1,960 km2, and based on a dense grid of flight lines, a conceptual structural geological model has been developed. The geology of the region generally comprises Cretaceous rocks which are gently folded and displaced by shallow westerly dipping thrust faults. Alternating clay content of the stratigraphic formations in the area makes them detectable by the AEM data. Our structural model presents a sedimentary regime affected by gentle deformation and thin-skinned thrust faulting. We are able to resolve several anticlines, synclines and thrust faults. The main thrust fault is east-dipping, thus counter to the regional Laramide orogenic trend and likely represents a backthrust from a subcutaneous structure (triangle zone). We suggest a decollement level to be situated in or just below the clay-rich Buckinghorse Formation.