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This report presents the results of the geochemical reconnaissance sam pling in the Winnemucca 1x2 quadrangle of the National Topographic Map Series (NTMS). We collected wet and dry sediment samples throughout the 2 18,/70-km arid to semi-arid area and water samples at available streams, springs and wells. We present neutron activation analyses of uranium and trace elements and other measurements made in the field and laboratory in tabular hardcopy and microfiche format. The report includes 5 full-size overlays for use with the Winnemucca NTMS 1:250,000 quadrangle. Water sampling sites, water-sample uranium and thorium concentrations, sediment sampling sites, and sediment-sample total uranium and thorium concentrations are shown on the separate overlays. We present general geological and structural descriptions of the area, and describe the 12 known uranium occurrences. The results indicate that the uranium geochemistry of the area is diverse. High concentrations (greater than 5 ppm) of uranium in sediments are associated mainly with rhyolitic ash falls and flows and silicic intrusives. In defining areas of interest the ratio of relatively insoluble thorium to uranium was considered. The anomalies as defined are then the sediment samples containing low Th/U and high uranium concentrations. These areas consist mainly of fluvial-lacustrine units. Most known uranium occurrences were also identified by this technique. The main dumboldt River shows an irregular increase in uranium concentration downstream which may be related to agricultrual modification of the stream flow. U/Cl ratios were used to evaluate the effects of evaporative concentration. Of interest are spring and tributary waters containing high U/Cl and high uranium values. These waters mainly drain acid intrusives, silicic volcanic recks and related sediments. One such area is the Shoshone and Cortez Mountain:;. 1 deposits of mercury, lead, and zeolites. Althouqh there are numerous mining districts, there are only scattered occurrences of low-grade uranium. Twelve radioactive occurrences and p-.aerous recent uranium claims are shown on Fig. 3. This map is based on reports by Garside and Larson and 14 Beal. The uranium is found in a wide variety of environments, but most of it occurs within igneous rocks or related sediments. Host occurrences contain only uranium; two deposits contain uranium and other metals. Anomalous radioactivity is associated wi.r.h features in waterlaid tuff overlain by Tertiary rhyolite at Dacies Creek (T28N, R41E). At Lee Canyon (T30N, R52E), the Kei No. 2 claims contain uranium in siltstone, water-laid tuff, and Tertiary lake sediments. Similar occurrences exist at the Ela?k Hills claims and Deerhead claims in T32N, R52E. To the south, the Asphaltite prospect (T29N, K52E) contains uranium in strings and lenses of asphaltic pyrobituraen in northerly trending faults. The veins cut Paleozoic elastics and contain associated vanadium. Mid-Paleozoic carbonates contain autunite (?) near the foot of Cortez Canyon (T27N, R47E) in Crescent...

The authors of this report wish to recognize, with appreciation, that many persons contributed to its preparation. Among these persons are Earth Sciences Division Leader Robert N. Schock, Project Manager James F. Scheimer, and Engineering Geology Group Leader Harold C. Ganow. These individuals provided technical and administrative expertise necessary to keep project investigations on track. Dennis W. Peifer, Technician Associate provided critical logistical support and supervision of laborers and aided greatly in trench logging and preparation of drawings. Sandra Vinson and Robert R. Poulin prepared and expedited contract riocumenls, and construction inspector Bill Martz provided invaluable liaison with contractor forces and the LLNL Facilities Engineering Department. California State University, Hayward students Robert Clark, Jim Springer, and Frank Ciminesi provided capable assistance during trench preparation and logging. The cooperation and assistance of the Sandia National Laboratory, Livermore, extended through Plant Engineer William E. Thompson, is gratefully acknowledged. The authors of this report also benefited greatly from informal discussions with geoscience personnel from federal, state, and local agencies who examined the exploratory trenches and other excavations that provided essential field data for this study. These professional colleagues include:

We present the results of an orientation study of uranium concentrations in the Artillery Peak quadrangle, Arizona, a part of the Prescott 10 X 2* quadrangle of the National Topographic Map Series (NTMS). Uranium concentrations, as well as those of 25 other elements, were measured by neutron activation analysis of wet, dry, and rock samples collected throughout the region. Uranium is found in veins and disseminations in the Precambrian rocks and in carbonaceous, tuffaceous lacustrine rocks of the Tertiary Artillery Formation. Data suggest that uranium is associated with resistate mineral phases. Data also show that stream sediments samples may not be an accurate way to determine uranium concentrations in poorly exposed lacustrine deposits similar to those in the Artillery Formation. Analytical data and field measurements are presented in tabular hardcopy and fiche format; full-size overlays are included for use with the Artillery Peak NTMS Quadrangle map and show water sample sites, water-sample uranium locations, sediment sample sites, and sediment-sample total uranium concentrations.