Beaufort–Mackenzie Tectono-Sedimentary Element

Abstract

Abstract The Beaufort–Mackenzie Tectono-Sedimentary Element (TSE) is a post-rift sequence of the Canada Basin that consists of Late Cretaceous–Pleistocene sedimentary strata with a maximum thickness of over 12 km. The tectonics of the Canada Basin formation and the Cenozoic contractional deformation associated with the Cordilleran Orogeny jointly shaped and controlled the architecture and the depositional systems of the TSE. In the west, contractional deformation prevails, whereas in the east extensional deformation dominates, and gravitational deformation associated with growth faults is prominent in the far north. Early successions of Cenomanian–Early Maastrichtian age are composed of thin but commonly organic-rich muds (Boundary Creek, Smoking Hills and Mason River sequences) that were deposited on the continental margin. The main phase of sedimentation started in the Late Maastrichtian with the deposition of a series of large progradational delta complexes, which migrated oceanwards from the SW margin in the Paleogene to the central part of the TSE in the Pliocene in response to the rising Cordilleran orogen in the SW. Coal seams and gas-prone terrestrial-derived organic-rich interbeds in the Cenozoic sequences are the main source rocks for gas generation, whereas organic-rich marine shales in Cretaceous sequences are probably the source rocks for oil generation. The Beaufort–Mackenzie TSE is a proven petroleum province with many significant discoveries and a large undiscovered resource potential in oil, gas and methane hydrate.