Frontier areas and exploration techniques. Frontier uranium exploration in the South-Central United States

Selected areas of the South-Central United States outside the known U trends of South Texas have a largely untested potential for the occurrence of significant U mineralization. These areas, underlain by Tertiary and older sediments, include parts of Texas, Oklahoma, Arkansas, Louisiana, Mississippi and Alabama. The commonly accepted criteria employed in U exploration are applicable to these frontier areas but special consideration must also be given to the atypical geologic aspects of such areas as they may apply to relatively unique types of U mineralization or to the development of special exploration criteria for common types of roll-front and fault-and dome-related uranium mineralization. The procedures used in evaluating frontier areas should be based on comprehensive evaluations involving: (1) location and analysis of potential source rocks (e.g., intrusive igneous rocks, bentonitic sediments, unique complexes, etc.); (2) definition of regional variations in the potential host sediments (e.g. marginal marine to nonmarine environments of deposition); (3) review of all available radiometric data in Tertiary or older rocks; (4) local groundwater sampling; (5) widely spaced reconnaissance (or stratigraphic) drilling, coring and borehole geophysical logging to define favorable sedimentary facies and to establish the specific lithologic character of the sediments; and (6) detailed petrographic evaluation of all available samples to define the environment of deposition and diagenetic history of ''favorable'' sediments. If procedures produce favorable results, an expanded exploration program is justified. Depths up to 3,000 feet should be anticipated if up-dip information is favorable. Selected areas are discussed that have: (1) favorable source and host rocks;(2) favorable age; (3) favorable regional and local structure; and (4) radiometric characteristics favorable for U mineralization of potentially economic grade and reserves in the areas