Geology and Petroleum Potential of the Rifted Margins of the Canada Basin
The Canada basin opened by Alaska-Canada rifting and rotational extension during Jurassic-Early Cretaceous, with a pole of rotation near the Mackenzie Delta. The Chukchi borderland is a continental fragment that separated from Arctic Alaska during or following opening of the Canada basin. Thus, three sides of the Canada basin are bordered by high-standing, conjugate rift shoulders of the Chukchi borderland, Alaska, and Canada.
Seismic data show that the passive margins of Alaska and Canada include thick sediment prisms, but the Chukchi borderland contains only a thin mantle of sediment. The thickness and age of this sediment reflect the tectonics and sediment dispersal systems of adjacent regions. Sediment generated by Brooks Range tectonism (Early Cretaceous and Tertiary) in Alaska and by Alpha Ridge volcanism (Cretaceous) and Eurekan tectonism (Tertiary) in Canada was partly accommodated by the Colville foreland basin (Alaska) and the Sverdrup basin (Canada), but most was deposited on the adjacent passive margins. The Alaska and Canada sediment prisms thicken outboard of the rift shoulder by listric growth faults that form viable petroleum traps. A thin Cretaceous-Cenozoic section on the Chukchi borderland reflects isolation from regional sediment dispersal systems.
Along the eastern Alaska-western Canada margin, the Brooks Range tectonic front during the Tertiary impinged on the rifted-margin sediment prism and formed a still-active fold-thrust belt in growth-faulted Tertiary strata. Most exploration around the rim of the Canada basin has focused on structures in this deformed margin and ~1.5 BBO and ~10 TCFG have been discovered. Additional contractional structures occur in a gravity fold belt that may be present along the entire Alaska and Canada margins of the Canada basin.
Stratigraphic and geochemical data south of the rift shoulder, regional paleogeographic reconstructions, and history of global sea level suggest three potential source-rock intervals: Lower Cretaceous (pre-Albian), Upper Cretaceous (Turonian), and lower Paleogene. Burial history modeling indicates favorable timing for generation from all three intervals beneath the Alaska and Canada passive margins, and an active petroleum system has been documented in the Canning-Mackenzie deformed margin. Assessment of undiscovered petroleum resources indicates greatest potential in the Canning-Mackenzie deformed margin and significant potential in the Canada and Alaska passive margins.
AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009