--> Structural History of Chukchi Sea Planning Area, Alaska, by Dennis K. Thurston; #91024 (1989)

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Structural History of Chukchi Sea Planning Area, Alaska

Dennis K. Thurston

In the Late Devonian(?) to Early Mississippian, the Central Chukchi basin was created by subsidence accompanied by faulting and basinward-tilting of the flanking Arctic and Chukchi platforms. This basin formed a north-trending extension of the Arctic Alaska basin of the North Slope. Subsidence of the Central Chukchi basin continued to the latest Jurassic to Early Cretaceous, resulting in deposition of over 40,000 ft of strata equivalent to the Ellesmerian sequence of the North Slope.

The formation of the North Chukchi basin and the North Chukchi high in the Early Cretaceous truncated the northern end of the Chukchi platform and Central Chukchi basin. Contemporary uplift of the ancestral Brooks Range, southeast of the Chukchi platform, created the east-trending Colville foredeep along the range's northern front. The North Chukchi basin and the Colville foredeep were separated by a passive arch, and each contains over 20,000 ft of Lower Cretaceous strata of the Brookian sequence. Continued north-directed thrusting in the Brooks Range eventually involved strata of the Colville foredeep, creating a foreland foldbelt.

North to northeast-trending transtensional faulting commenced in the Late Cretaceous-Paleogene and created numerous wrench features across the area. To the west, the northern Chukchi platform collapsed during this episode, initiating local salt(?) diapirism sourced from deeply buried Ellesmerian strata. To the north, the North Chukchi basin received an additional 20,000 ft of probable Tertiary sediments. In the south, the Colville foredeep and foldbelt were overprinted by the northwest-trending Herald arch and Herald thrust fault. Tectonic activity ceased in the Neogene.

AAPG Search and Discovery Article #91024©1989 AAPG Pacific Section, May 10-12, 1989, Palm Springs, California.