Meso–Cenozoic evolution of the southwestern Chukchi Borderland, Arctic Ocean

A regional stratigraphic framework is developed for the North Chukchi Basin and southern margin of the Chukchi Borderland based on a grid of 2D multi-channel seismic reflection profiles tied to exploration wells on the U.S. Chukchi Shelf. The northern flank of the North Chukchi Basin displays a 16 km succession of mainly Cretaceous and Cenozoic strata that progressively onlaps an unconformity (Au) on the southern margin of the Borderland. Rocks beneath the unconformity are inferred to represent (A) crystalline basement that may have affinity to the Peary terrane, (B) deformed growth strata that may be related to Carboniferous to Jurassic strata on the Chukchi Shelf, and (C) seaward dipping reflections (SDRs) likely related to oceanic igneous rocks or exhumed mantle beneath the North Chukchi Basin. The SDRs indicate that the southwestern margin of the Borderland is a rifted continental margin and loosely constrained age control suggests that rifting occurred between Middle Jurassic and earliest Cretaceous.