Bedrock geology, Ramparts River southeast, Northwest Territories, NTS 106-G southeast

Abstract

The southeast Ramparts River map area (NTS 106-G/SE) covers part of the northern Mackenzie Mountains and Peel Plateau, Northwest Territories. Bedrock exposures in the area include carbonate and siliciclastic strata ranging from Neoproterozoic (Tonian) to Cretaceous age. These strata were deformed in Cretaceous to Eocene time by folding and contractional faulting associated with Cordilleran deformation. Major structures include the Deadend fault, Tawu anticline, Stony anticline, and Shattered Range anticline. A set of minor pre-Cordilleran extensional faults is preserved within Neoproterozoic strata of the Mackenzie Mountains Supergroup, and are locally associated with diabase or gabbro dykes assigned to the Gunbarrel magmatic event (~780 Ma). Truncation of Neoproterozoic units beneath the sub-Cambrian unconformity indicates tilting or folding of strata before Cambrian time. A second major unconformity between Devonian and Cretaceous strata is marked by low-angle truncation of Paleozoic strata beneath Cretaceous units.