Rocky Robert Reifenstuhl¹

(1) Alaska Division of Geological and Geophysical Surveys, Fairbanks, AK

ABSTRACT: Tectonic Setting and Provenance, Petrography and Reservoir Characteristics of Nine Siliciclastic Sandstone Formations, Mississippian to Tertiary age, Sagavanirktok Quadrangle, Eastcentral Brooks Range Foothills and Arctic Slope, Alaska

New geologic mapping and petrography of nine siliciclastic formations reveals original provenance, tectonic setting, reservoir characteristics, and petroleum-resource information relevant to oil exploration for Prudhoe Bay satellite fields, new play-type evaluations, and surface and subsurface stratigraphic correlations. Outcrop samples are from Brookian, Beaufortian, Ellesmerian, and Franklinian sequences, ranging from Mississippian to Tertiary age, and part of the parautochthonous Paleozoic and Mesozoic mountain front and foothills belt. The foreland basin succession (Brookian) lies north of the Brooks Range fold-and-thrust belt, and prograded north, onlapping the south flank of the Beaufort sill, which separates the Colville Basin from the Canada Basin in the Arctic Ocean. Stratigraphy is part of the 1,000 km-long and 50 to 350 km-wide Colville Basin, and in the subsurface forms reservoir and source rocks for Prudhoe Bay and satellite fields. The Sagavanirktok Quadrangle has a noncommercial gas accumulation in an Early Cretaceous (Kemik Sandstone) reservoir (anticlinal trap within fold belt). To the north, uppermost Cretaceous and lowermost Tertiary deltaic sandstones provide reservoirs for huge heavy oil deposits. The Sagavanirktok Quadrangle has similar rocks suggesting further discovery potential.

Petrography indicates predominately monocrystalline quartz, a trend of increasing monocrystalline quartz with increasing age, and that Kekiktuk, Ivishak, Kemik, and Franklin Bluff have undergone more than one erosional cycle. Samples (11) plot within four tectonic provenance fields: "transitional recycled" (5: Prince Creek, White Hills Sagavanirktok, Schrader Bluff, Nanushuk, Canning), "quartzose recycled" (3: Kemik, Kekiktuk, Franklin Bluff Member Sagavanirktok Formation), "craton interior" (2: Ivishak Sandstone, Kekiktuk), or "lithic recycled" (1: Prince Creek).

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado