National uranium resource evaluation: Mesa quaddrangle, Arizona

The Mesa Quadrangle (2/sup 0/), Arizona, was evaluated to a depth of 1500 meters to identify geologic environments and delineate surface and subsurface areas favorable for the occurrence of uranium deposits. The criteria used to define uranium favorability were developed during the National Uranium Resource Evaluation program. Surface and subsurface studies were augmented by aerial radiometric surveys and hydrogeochemical and stream-sediment reconnaisance studies. The results of the investigations identified three favorable areas: older Precambrian quartz monzonite near Horseshoe Dam; the gray unit of the Dripping Spring quartzite of Precambrian age in the Sierra Ancha, Salt River Canyon, and Mescal Mountain regions; and Tertiary lake beds near Cave Creek, Horseshoe Dam, and northeastern Tonto Basin. Unfavorable environments include nearly all older Precambrian crystalline and metamorphic rocks, most younger Precambrian igneous and sedimentary rocks, parts of the Paleozoic section, igneous intrusives of Laramide age. Tertiary volcanic rocks, and late Tertiary sedimentary rocks. The eastern third of the quadrangle remains unevaluated because access was prohibited or could not be obtained in time. Environments were unevaluated in older Precambrian volcanic, sedimentary, and metamorphic rocks; the Naco and Supai Formations; Cretaceous sedimentary rocks; and many Tertiary sedimentary rocks in intermontane basins and within the southwesternmore » portion of the quadrangle because of time constraints, land access restrictions, and sparsity of subsurface data.« less