Geology and Petroleum Potential of the Rifted Margins of the Canada Basin

David Houseknecht¹ and Kenneth Bird^2
1U.S. Geological Survey, Reston, VA
²U.S. Geological Survey, Menlo Park, CA

Canada basin opened by Alaska-Canada rifting and rotational spreading during Jurassic - Early Cretaceous, with a pole of rotation near the head of the Mackenzie Delta. The continental Chukchi borderland separated from Arctic Alaska during or following opening of the Canada basin. Thus, the Canada basin is bordered on three sides by conjugate rift shoulders of the Chukchi borderland, Alaska, and Canada. These evolved into passive margins that are sparsely explored except in the Mackenzie Delta.

Alaska and Canada passive margins have thick sediment prisms whereas the Chukchi borderland does not. The thickness and age of these sediment prisms reflect the tectonic history and sediment dispersal systems of adjacent regions. Sediment generated by Brooks Range orogenesis (Early Cretaceous and Cenozoic) in Alaska and by Alpha-ridge volcanism (Cretaceous) and Eurekan orogenesis (Cenozoic) 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 sediment prisms thicken outboard of the rift shoulder by growth faults, which provide viable petroleum traps. Compressional structures occur in eastern Alaska and the Mackenzie Delta, where the Brooks Range orogenic front migrated onto the passive margin during the Cenozoic. Contractional structures occur in a gravity fold belt that may be present along the entire Alaska-Canada passive margin.

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, but insufficient burial along the margin of the Chukchi borderland.

AAPG International Conference and Exhibition, Cape Town, South Africa 2008 © AAPG Search and Discovery