U-Pb ages of uranium ores in the Church Rock uranium district, New Mexico

Journal Article · Wed Dec 01 04:00:00 EST 1982 · Econ. Geol.; (United States)

DOI:https://doi.org/10.2113/gsecongeo.77.8.1942· OSTI ID:6181473

Ludwig, K R; Fishman, N S; Reynolds, R L; Rubin, B

Examines samples from the largest US uranium-producing region in order to determine ages of mineralization of different orebodies. Uranium from this area has come mainly from arkosic and subarkosic sandstones of the Upper Jurassic Morrison Formation. Several lines of evidence suggest that ages range from Late Jurassic or Early Cretaceous to at least as young as Tertiary. Geologic observations indicate that the oldest (primary) orebodies are tabular in shape and rich in amorphous organic material, whereas the youngest orebodies tend to be poor in amorphous organic material, display roll-front geometry, and are commonly spatially associated with Laramide or younger faults. Both types of ore were formed by relatively lowtemperature, dilute fluids that were essentially ground water in nature. Concludes that the 0- to 1-m.y. U-Pb apparent ages of the United Nuclear Corporation Church Rock Mine relate to redistribution, by roll-front processes, of earlier-formed ores by oxidizing Pleistocene ground waters, perhaps those that resulted in the present-day limonitic zone of the Westwater Canyon Member. Suggests that the 10-m.y. apparent age of sample KM-17-1 may represent an earlier phase of redistributed ore formation, perhaps related to the Tertiary oxidation front that resulted in the present-day hematitic zone of the Westwater Canyon Member.

• Research Organization: U. S. Geological Survey, Box 25046, M. S. 963, Denver, Colorado 80225
• OSTI ID: 6181473
• Journal Information: Econ. Geol.; (United States), Journal Name: Econ. Geol.; (United States) Vol. 77:8; ISSN ECGLA
• Country of Publication: United States
• Language: English

Related Subjects

050200* -- Nuclear Fuels-- Exploration-- (-1987)
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
AGE ESTIMATION
CHEMICAL REACTIONS
FEDERAL REGION VI
GEOLOGIC AGES
GEOLOGICAL SURVEYS
GROUND WATER
HYDROGEN COMPOUNDS
MESOZOIC ERA
MINERALIZATION
NEW MEXICO
NORTH AMERICA
ORES
OXIDATION
OXYGEN COMPOUNDS
ROCKS
SAMPLING
SANDSTONES
SEDIMENTARY ROCKS
SURVEYS
URANIUM ORES
USA
WATER