Mineral resources of the Desatoya Mountains Wilderness Study Area, Churchill and Lander counties, Nevada

Abstract

The Desatoya Mountains Wilderness Study Area (NV030-110) encompasses 51,262 acres of the central part of the Desatoya Mountains, Churchill and Lander Counties, Nev. Of this area, mineral surveys were requested on 43,053 acres and were studied for this report. The U.S. Bureau of Mines and the U.S. Geological Survey conducted geological, geophysical, and geochemical surveys to assess the mineral resources (known) and the mineral resource potential (undiscovered) of the study area. In this report, any reference to the Desatoya Mountains Wilderness Study Area refers only to that part of the wilderness study area on which the Bureau of Land Management requested mineral surveys and is referred to as the study area. An areathat includes a tributary of Topia Creek on the east edge of the study area is assigned a moderate potential for gold and silver resources. In the northern part of the study area and in the Rock Creek and Gold Basin claim areas a low resource potential for gold and silver is indicated. The study area contains no identified mineral resources. Character and Setting The study area is in the Desatoya Mountains about 60 mi east of Fallon, Nev., and 40 mi west of Austin, Nev. (fig. 1). It includes the highest and most rugged parts of these mountains, with topographic relief as much as 3,500 ft between Desatoya Peak and the range front to the west. The west side of the mountains is precipitous; the eastern side is a dissected surface sloping gently to the east. The study area is underlain by a thick sequence of rhyolite welded tuffs and intrusive rocks mostly of Oligocene and (or) Miocene age (see appendixes for geologic time chart). These volcanic and intrusive rocks are the products of a volcano that collapsed to form a large caldera located in the central part of what is now the Desatoya Mountains. This caldera, which formed about 24 million years ago, was subsequently filled with volcanic material before being greatly modified by basin and range faulting and by erosion. Identified Resources No identified mineral or energy resources exist in the study area. Several areas with traces of gold and silver were recognized, but these occurrences do not qualify as resources. Parts of the study area are in the poorly defined Gold Basin and Eastgate mining districts. No mines are in the study area; there are seven claim groups or prospects in or within 0.5 mi of the study area boundary. Mineral Resource Potential An area in the northeastern part of the study area, near Topia Creek, has moderate mineral resource potential for gold and silver (fig. 2). This potential is indicated by gold and silver anomalies in a heavy-mineral concentrate sample and gold anomalies in two rock-chip samples. Three areas have low mineral resource potential for gold and silver. These areas are the northern part of the study area north of Cold Springs Canyon, an area near the mouth of Rock Creek Canyon, and an area east of Carroll Summit. This assessment is based on small, scattered geochemical anomalies of gold and silver. Several drainages in the central and southern parts of the study area showed weak anomalies of lead, tin, and bismuth from heavy-mineral concentrates from stream sediment.