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The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 63 (1979)

Issue: 4. (April)

First Page: 692

Last Page: 693

Title: Roll-Type Uranium Occurrence at Dennison-Bunn Claim and Possibility of Uranium Deposits in Eastern Part of San Juan Basin, New Mexico: ABSTRACT

Author(s): Jennie L. Ridgley

Article Type: Meeting abstract

Abstract:

Uranium at the Dennison-Bunn claim, south of Cuba, New Mexico, along the east margin of the San Juan basin, occurs in stacked fluvial-channel sandstones interbedded with gray-green mudstones of the Westwater Canyon Sandstone Member of the Morrison Formation of Jurassic age. Although all the sandstone units are mineralized, the greatest concentration of uranium occurs in the uppermost sandstone unit. The uranium deposits are low to medium grade, range from 0.001 to 0.07% U3O8, and are irregularly distributed along the margins of intertonguing oxidized and unoxidized sandstone. The configuration indicates that these are roll-type uranium deposits and that they formed at the interface between oxidizing and reducing solutions.

The host rocks dip 45° west into the basin. Reconstruction of the tectonic and sedimentologic history along the eastern margin of the basin suggests that conditions favorable for the solution, transportation, and deposition of uranium probably occurred from Late Cretaceous into Eocene time. Uranium in the mineralizing solutions may have originated from within the Morrison Formation or may have been leached from the Paleocene Ojo Alamo Sandstone or Nacimiento Formation, or from the Eocene San Jose Formation which once covered the area.

Similar uranium deposits occur in the Morrison Formation at the Goodner lease, north of Cachana Spring. The presence of oxidized sandstone in the Morrison

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Formation along the outcrop belt from Cachana Spring north to Cuba suggests that additional uranium deposits may exist at the boundaries of oxidized and unoxidized sandstone in the subsurface along the eastern margin of the San Juan basin.

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Copyright 1997 American Association of Petroleum Geologists