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The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 52 (1968)

Issue: 3. (March)

First Page: 566

Last Page: 567

Title: New Petroleum Prospects, Shallow and Deep Bering Sea: ABSTRACT

Author(s): David W. Scholl, David M. Hopkins, H. Gary Greene, Edwin C. Buffington

Article Type: Meeting abstract

Abstract:

Recent geological and geophysical investigations by the United States Geological Survey and cooperating institutions have outlined three areas of possible interest for petroleum prospecting in the Bering Sea: (1) intrashelf basins, (2) an outer-shelf sediment-draped basement high, and (3) a continental borderland, Umnak Plateau, seaward from the continental slope.

1. Although the possibility of subshelf oil deposits has long been recognized in the thick sequence of Cenozoic sediments underlying Bristol Bay, published geophysical data seemed to indicate that elsewhere the shelf is underlain by only a thin blanket of Cenozoic sedimentary deposits overlying a basement of crystalline

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line and deformed sedimentary rocks of Mesozoic and older ages. However, the writers' seismic-reflection studies reveal that large areas of the shallow Bering shelf are underlain by intrashelf basins containing several thousand feet of Cenozoic deposits. For example, at least 3,000 ft of sedimentary section overlies basement in western Norton Sound. Nunivak, St. Lawrence, and the Pribilof Islands are basin-bounding structural highs; these may be flanked by oil-bearing Cenozoic deposits.

2. Reflection records reveal that the outer edge of the shallow Bering shelf is underlain by a discontinuous basement high. The basement is composed in part of well-indurated sedimentary rocks of probable Mesozoic age. Cenozoic strata are draped over the shelf-edge basement high and bury the landward-facing flank, which is thought to be the scarp of a normal fault in some areas. The high may be of some interest to petroleum geologists but possible stratigraphic and structural traps within the overlying Cenozoic section are more obvious locations for petroleum prospects.

3. Deep-water drilling techniques ultimately will be required to explore adequately the petroleum possibilities of Umnak Plateau--the borderland which lies at a depth of 6,000 ft in the triangular area formed by the intersection of the Bering continental slope and the Aleutian ridge. The plateau is underlain by at least 5,000 ft of Cenozoic deposits that have accumulated over a differentially downwarped part of the basement platform underlying the shelf. The structure of the plateau is broadly domical, but moderate folding and faulting have deformed its edges; thus the flanks of the plateau may be the best location for future petroleum prospecting.

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