Rocky Robert Reifenstuhl¹, C.G. Mull¹, D.L. LePain¹, E.E. Harris¹, D.B. Dickey²
(1) Alaska Division of Geological and Geophysical Surveys, Fairbanks, AK
(2) Petrotechnical Consultants Alaska, Anchorage, AK

Abstract: New Geologic Mapping in Cretaceous rocks of the Brooks Range foothills south of Prudhoe Bay, Alaska, USA

A recent lease sale on the National Petroleum Reserve in Alaska (NPRA) and newly announced oil discoveries in northern Alaska have renewed attention on plays outside of the Prudhoe Bay-Kuparuk area. New geophysical and drilling technology combined with pipeline proximity result in exploration for smaller plays than previously considered economic. In particular, attention is being given to potential plays in the eastward prograding clastic tongues of the Lower and Upper Cretaceous Nanushuk and Colville Groups. Some of these rocks are mapped in new 1:250,000 and 1:63,360-scale geologic maps by DGGS in the Sagavanirktok quadrangle south of Prudhoe Bay. The area is bisected by the Sagavanirktok River, Trans-Alaska Pipeline, and Dalton Highway; the mapping extends from the Arctic coastal plain south to the Brooks Range foothills. It includes the transition between the well known mid- and Upper Cretaceous shelfal rocks of the Umiat area and NPRA and their basinal counterparts in the Arctic National Wildlife Refuge (ANWR) to the east. The mapping also includes the area of the Kemik anticline, the location of a small gas discovery in the Neocomian Kemik Sandstone.

Stratigraphic correlations of the surface exposures in the foothills with subsurface wells to the north are aided by paleontologic control and a reinterpretation of the one publicly available seismic line, which extends from the foothills anticlines north to the Prudhoe Bay area. Organic and inorganic geochemistry, Ar/Ar dating, lithofacies, and petrographic studies are being carried out in addition to micropaleontology, palynology, and identification

AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana