Chapter 16 Geology of the Late Cretaceous to Cenozoic Beaufort-Mackenzie Basin, Canada

Abstract

Abstract The Canadian Beaufort-Mackenzie Basin lies on the continental margin of the Arctic Ocean and contains 14–16 km of Late Cretaceous to Recent sediment, the bulk of which is Tertiary in age. It has rifted basin margins although the southeastern margin has been overprinted by compressional structures that are contemporaneous with deposition and are part of the Cordilleran foldbelt that extends along west North America. The combination of post-rift subsidence and tectonic loading explains the thick accumulation of Late Cretaceous to Recent sediments. These sediments have been divided into several large transgressive-regressive sequences, each one dominated by the formation of delta complexes and their lateral equivalents. Sediment was supplied mostly from the rising orogenic belt on the southwestern margin of the basin. Several phases of tectonism have been recognized, each terminated by a major basin-scale unconformity. The first phase extended from the Late Cretaceous to about the Middle Eocene, the second from Middle Eocene to the Late Miocene, and the third from the Late Miocene to the present. The first two phases are dominated by compressional tectonics, although listric faults and some translational faults also formed. The third phase is characterized by the lack of any significant deformation. The basin has significant reserves of oil and gas and its potential of additional resources is high. Exploration in the basin started in the 1960s but has undergone several periods of exploration slow-down. At present there is renewed activity and undoubtedly this basin will be a major source of hydrocarbons in the future.