National Uranium Resource Evaluation: Elko Quadrangle, Nevada and Utah

The Elko Quadrangle (1/sup 0/ x 2/sup 0/), Nevada and Utah, was evaluated to identify and delineate geologic environments favorable for the occurrence of uranium deposits. Geologic reconnaissance, radiometric surveys, and geochemical sampling programs were carried out in all identified environments in the quadrangle. Known and newly identified uranium occurrences were evaluated. All geologic environments, both favorable and unfavorable for the occurrence of uranium, were evaluated and compared to analogous environments known to contain uranium deposits. This study concludes that tuffs and sediments of the Humboldt Formation are favorable for initial-magmatic and sandstone uranium occurrences. Contact metasomatic and allogenic environments developed within the Park City limestones adjacent to the Delcer Buttes quartz monzonite are also favorable for uranium concentration. With the exception of unevaluated basins adjacent to possible igneous source rocks, all other identified geologic environments are considered unfavorable for uranium deposits.