National Uranium Resource Evaluation: Jordan Valley Quadrangle, Oregon and Idaho

The Jordan Valley Quadrangle, Oregon and Idaho, was evaluated to identify and delineate areas favorable for uranium deposits in accordance with criteria developed for the National Uranium Resource Evaluation. Surface radiometric reconnaissance and geochemical sampling were used for overall evaluation of the quadrangle. Detailed rock sampling, geologic mapping, and examination of uranium deposits and occurrences were performed in areas suspected to be favorable. The northeast part of the McDermitt caldera within the quadrangle is favorable for volcanogenic deposits associated with the ring-fracture zone. The favorable area contains the Aurora uranium deposit, the Bretz mercury mine, and the Cottonwood Creek occurrence. The Triangle Ranch area and the Snake River Plain, both in the northeast part of the quadrangle, have environments that may be favorable for uranium deposits in sandstone but are considered unevaluated due to lack of subsurface data and lack of detailed investigations. Rocks in the remainder of the quadrangle are considered unfavorable for uranium deposits because of low uranium contents, basic to intermediate compositions, or lack of favorable structures.