New and Redefined Cretaceous Formations in Western Part of Northern Alaska

The Nanushuk group is redefined in the Utukok-Corwin area, where the group consists of two formations, the Kukpowruk (new), and the Corwin (redefined). The dominantly marine Kukpowruk formation consists largely of shale, siltstone, and sandstone; it overlies and intertongues with the upper part of the Torok formation. The Corwin formation is dominantly non-marine, and consists largely of shale, siltstone, sandstone, conglomerate, and coal; it overlies and intertongues with the upper part of the Kukpowruk formation, and is overlain by the Prince Creek formation of the Colville group.