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The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 63 (1979)

Issue: 5. (May)

First Page: 822

Last Page: 823

Title: Applied Exploration Geology and Uranium Resources of Great Divide Basin, Wyoming: ABSTRACT

Author(s): W. W. Boberg

Article Type: Meeting abstract

Abstract:

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The Great Divide basin of central Wyoming has been the focus of intense uranium exploration for a decade. Over 10 million lb (4.5 million kg) of uranium oxide has been produced since 1957 from the Crooks Gap mining district in the northern part of the basin. This geologic province is estimated to contain at least 270 million lb (122 million kg) of uranium resources and is the least exploited of Wyoming basins known to contain significant deposits of uranium.

The Great Divide basin has the most complex structural, stratigraphic, and sedimentologic history of any Wyoming uranium-producing basin. These complexities have exerted significant controls on the ore-forming processes which have resulted in many variations in the characteristics of alteration features and the geometry of the uranium deposits.

The massive thickness of the Eocene Battle Springs Formation provides a host unit of up to 4,000 ft (1,200 m) at a maximum in the northern part of the basin and generally does not contain continuous shale breaks to allow for stratigraphic correlations or for the primary focusing of the ore-forming fluids. The result is a massive roll-front system which may be several thousand feet (1,000+ m) in vertical extent, a few miles wide, and tens of miles long exhibiting extreme irregularities caused by variations in both vertical and horizontal porosity and permeability as well as the structural complexities of the basin itself. Farther west and southwest, where the Battle Springs Formation intertongues with the Wasatch and Green River Formations, continuous shale beds are common, allowing fo easier stratigraphic correlations, good focusing of the ore-forming fluids, and the development of roll-front features similar to those in other Wyoming basins.

Gross roll-front features indicate pervasive alteration through most of the basin leaving scattered areas of reduced ground as islands. The roll-front trends which outline these reduced islands display a significant influence by faulting and folding in the basins and contain deposits of uranium of variable tenor scattered along the trends at various lateral and vertical positions. The gross outlines of the redox interfaces outlining the reduced islands are very complex in detail and may represent multiple individual roll fronts, each of which must be mapped separately to insure a complete understanding of the frontal development and to result in the discovery of the greatest amount of uranium possible.

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