Where did the organic material come from up there?
It was formerly at a more southern latitude. The plates, they are a’changin. Antarctica was once a basin as well.
The Upper Triassic Shublik Formation is a prolific source rock for North Slope hydrocarbons, containing an average total organic carbon (TOC) content near Prudhoe Bay of 5.6%. Approximately 32 billion barrels of Shublik-sourced oil are estimated to have migrated and accumulated in North Slope reservoirs located between the Colville and Canning Rivers, assuming a 10% migration and accumulation efficiency. Potential also exists within the Prudhoe Bay Field for the Shublik to be a producing reservoir.