Mineral Evaluation of Part of the Gold Butte District, Clark County, Nevada. National Uranium Resource Evaluation

摘要

The mineral potential of part of the Gold Butte district, Clark County, Nevada, was investigated to supplement the evaluation of granitic rocks in the area as a probable geologic environment for uranium mineralization. This project is a part of the National Uranium Resource Evaluation (NURE) program conducted by Bendix Field Engineering Corporation for the US Department of Energy. A total of 41 stream-sediment samples and 149 rock samples were collected; the stream-sediment samples were analyzed chemically, and most f the rock samples were analyzed chemically and petrographically. The project area was restricted to Precambrian rocks, which comprise a metamorphic complex of early Proterozoic age, charnockitic rocks of early or middle Proterozoic age and ultramafic rocks and the Gold Butte Granite of middle Proterozoic age. Although the project area is not favorable for uranium deposits according to NURE criteria, an area of low resource potential for uranium, thorium, rare-earth elements and yttrium, and niobium-tantalum was assigned to the contact zone of the Gold Butte Granite. Pegmatites and aplites in the zone contain high concentrations of these elements. Two areas of moderate potential for gold and silver in quartz veins are within the project area; small-scale operations may recover these elements profitably. Titanium has a low-to-moderate resource potential, although the deposits are currently subeconomic. The titanium concentrations occur as titaniferous magnetite- and ilmenite-bearing placer sands. One small area has been assigned a low-to-moderate resource potential for vermiculite in altered ultramafic rocks. Tungsten has been assigned a low resource potential in two places within the project area; scheelite-bearing ultramafic bodies are small and scattered. Platinum-group metals and copper have no resource potential in the project area. (ERA citation 08:025623)