Evolution of the Arctic Alaska Sedimentary Basin

Abstract The Arctic Alaska basin occupies the eastern part of the Arctic Alaska–Chukotka microplate, which rifted from the Canadian Arctic margin during opening of the Canada Basin. Stratigraphy comprises four tectonostratigraphic sequences. (1) The Devonian and older Franklinian sequence consists of sedimentary and metasedimentary rocks deposited on the Arctic passive margin of Laurentia and in a Devonian foreland basin, and deformed during Caledonian, Romanzof, and Ellesmerian tectonism. (2) The Mississippian–Triassic Ellesmerian sequence was deposited on the Arctic rifted passive margin of Laurentia during and after opening of the Angayucham Ocean basin. Predominant sediment routing was southward in present coordinates. (3) The Jurassic–Lower Cretaceous Beaufortian sequence was deposited during rift-opening of the Canada Basin, and includes graben fill on the rift shoulder and a southward offlapping clastic wedge beneath the Alaska North Slope. (4) The Lower Cretaceous–Cenozoic Brookian sequence was deposited in the Colville foreland basin and on the Beaufort rifted margin during Brooks Range–Chukotkan tectonism. Predominant sediment routing was eastward (longitudinal) in the underfilled foreland basin, and progressively became northward in the overfilled foreland basin and on the rifted margin. The Arctic Alaska basin is a prolific petroleum province from which approximately 18 billion barrels of oil have been produced since 1977. The basin hosts the Prudhoe Bay oil field, the largest in North America.