The geology of the 1977 offshore hydrocarbon discoveries in the Beaufort-Mackenzie Basin, N.W.T.

Wells drilled in 1977 from drillships moored in the Canadian Beaufort Sea encountered Tertiary oil- and gas-bearing sands in large synsedimentary growth structures within the Beaufort-Mackenzie sedimentary basin. Oil and gas were recovered from Eocene deep-water sands in Dome Hunt Nektoralik K-59. An Oligocene gas sand was penetrated in Dome Gulf et al. Ukalerk C-50. The Beaufort-Mackenzie sedimentary basin contains a thickness of more than 8 km of Tertiary and possible Upper Cretaceous clastic sediments. The Upper Cretaceous - Paleogene section includes two major regressive clastic sequences. Separated from them by a regional submarine unconformity, the overlying Neogene is another regressive sequence, up to 4 km thick, for which the new name Iperk Group is proposed. The Beaufort-Mackenzie basin lies at the junction of the Canada Basin and the continental margins of Alaska and northern Canada. It is believed to have formed as a result of major displacements of faults separating these crustal elements, in conjuction with strike-slip fault movements along the Canadian Cordillera and sea-floor spreading about the Alpha Ridge.