Chapter 17 - Geological History of the Late Cretaceous to Cenozoic Beaufort-Mackenzie Basin, Arctic Canada

Abstract

The Canadian Beaufort-Mackenzie Basin lies on the rifted continental margin of the Arctic Ocean and contains 14–16km of Late Cretaceous to Holocene strata. The southwestern margin is overridden by syndepositional convergent structures of the Cordilleran foldbelt of western North America. Postrift subsidence and tectonic loading together explain the thick accumulation of sediments that comprise regionally extensive transgressive-regressive sequences, each one dominated by delta complexes and their lateral equivalents. Sediment was supplied mostly from the rising orogenic belt on the southwestern margin of the basin. Three tectonic phases are recognized, each terminated by a basin-scale unconformity. The first phase extended from Late Cretaceous to middle Eocene, the second from middle Eocene to late Miocene, and the third from late Miocene to the present. The first two phases are dominated by convergent tectonics, although listric faults and some transcurrent faults also formed due to locally complex boundary conditions. The third phase is characterized by a lack of major deformation. Since the 1960s, multiple exploration cycles occurred. Though there is currently little activity, the basin contains significant reserves of oil and gas and could be a significant future hydrocarbon resource.