Abstract: Uranium Potential in the Texas Gulf Coastal Plain

By

Kendell A. Dickinson
U.S. Geological Survey 
P.O. Box 25046, Denver Federal Center, Denver, Colorado 80225

The potential for large new uranium deposits in the Tertiary rocks of the Texas gulf coastal plain is greatest in the deeper subsurface in an area southeast of the known deposits in Karnes, Live Oak, and Duval Counties, extending to the vicinity of the present coast. This area, favorable because of the thick Catahoula Tuff (Miocene) section and the geologic history of paleo-aridity, has not been extensively explored below depths of about 100 m and may yield several new large deposits.

This assessment of the uranium potential is based on the assumption that any new deposits will be geologically and geochemically similar to those known in the area, other types are not considered. Various evidence, both geologic and geochemical, indicates that the Catahoula Tuff is the ultimate source of uranium for these deposits. The Whitsett Formation (upper Eocene), the Catahoula Tuff, and the Oakville Sandstone (Miocene) are the principal uranium host rocks in the south Texas coastal plain. The outcrop area of these formations and related rocks from Gonzales and DeWitt Counties southwestward to the Rio Grande river has been thoroughly explored on the surface and to a depth of about 100 m and probably will not produce any large deposits not already known to the industry.

The part of the coastal plain northeast of Gonzales and DeWitt Counties is less promising because the Catahoula is much thinner and may contain less volcanic ash in this area. Furthermore, paleoclimates, like the present climate, may have been less arid to the northeast, creating conditions geochemically less favorable for the formation and preservation of large uranium deposits. Some small deposits are known from this area and others will probably be found.

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