Canadian Arctic–Beaufort Sea Rifted Margin Tectono-Sedimentary Element, SE Canada Basin

Abstract

Abstract The Canadian Arctic–Beaufort Sea Rifted Margin (CARM) Tectono-Sedimentary Element (TSE) is located on the continental shelf and slope that lie to the west of the Canadian Arctic Archipelago and to the north of the Mackenzie Delta. The TSE comprises the rift succession deposited on the eastern and southern margins of the Amerasia Basin, coincident with the opening of this basin. The TSE strata range in age from the latest Triassic (Rhaetian) to Early Cretaceous (Albian). A major unconformity marks the base of the TSE, with underlying rocks consisting of moderately to highly deformed Proterozoic and Lower Paleozoic rocks that are regarded as basement. The TSE is overlain by the Canadian Arctic Prograded Margin (CAPM) TSE, with the boundary being a significant unconformity in landward areas. Well data are limited to the Beaufort–Mackenzie area, and reflection and refraction seismic data indicate that the succession is up to 4 km thick. The TSE is divided into four structural domains, with deformation increasing to the north. The Beaufort–Mackenzie Domain is dominated by extensional structures, with later contractional structures present in its western portion. The Southern Domain is extensional and characterized by normal faults with tilted fault blocks. The structure of the Central Domain is similar to that of the Southern Domain but may include broad folds formed during the Paleogene Eurekan Orogeny. The succession in the Northern Domain is likely to be strongly folded and cut by thrust faults of the Eurekan Orogeny. Cretaceous extrusive and intrusive basic rocks, related to magmatism in the northern Amerasia Basin, are present in both the Central and Northern domains. Petroleum source rocks, of both lacustrine and marine origin, may be present in the Jurassic portion of the succession and marine shales in the Lower Cretaceous succession. The potential for structural and stratigraphic traps in widespread sandstone units of alluvial fan to marine slope origin is high. The remote location of the TSE, however, makes it likely that it will not be a target for petroleum exploration in the foreseeable future.