National uranium resource evaluation: Austin quadrangle, Texas

Uranium resources of the Austin Quadrangle, Texas, were evaluated to a depth of 1500 m. Criteria developed for the National Uranium Resource Evaluation program were used to delineate areas and identify environments favorable for the deposition of uranium. Uranium occurrences reported in the literature were located, described, and sampled. Geochemical anomalies interpreted from hydrogeochemical and stream-sediment reconnaissance data were also investigated and sampled in detail. Environments favorable for the deposition of uranium in the subsurface were located using electric and gamma-ray logs. This investigation identifies environments favorable for Texas roll-type uranium deposits and for uraniferous lignite deposits in the southeastern portion of the quadrangle. The environment favorable for roll-type deposits is present in fluvial sediments of the Jackson Group, the Catahoula Formation, and the Oakville Formation. The envrionment favorable for lignite deposits is present in delta-plain sediments of the Jackson Group. Nine additional stratigraphic units were evaluated as unfavorable. Ten stratigraphic units were left unevaluated.