The Shublik Formation within the project area is an unconformity-bounded assemblage of carbonates and clastics of Middle and Late Triassic age. It is characterized by two distinct facies: nearshore depositional environments to the north, and deeper water and organic-rich facies to the south. The formation ranges in thickness from zero at its feather edge on Yukon Coastal Lowland to a few hundred metres at the headwaters of Ogilvie River. The northern and eastern erosional limits of the Shublik, as well as those of the upper Paleozoic formations immediately beneath it, follow a curvilinear trace, outlining the fundamental, ancient and persistent shape of the Cordilleran miogeocline and, in turn, the structural grain of the Laramide and earlier deformations imposed upon it. The overstepping of the Shublik onto progressively older formations from southwest to northeast, in addition to the erosional truncation of the Shublik at the sub-Jurassic disconformity, means that the southeastward continuation of the Permian and Triassic hydrocarbon reservoirs at Prudhoe Bay do not reach into mainland Canada and may not be present beneath the continental shelf of southern Beaufort Sea.