Central Nevada tungsten skarns

Region West, Southwest
Mineral systems
Deposit types
Critical minerals
Other minerals

Information leading to the delineation of this focus area

Basis for focus area Tungsten skarn district outlines from USMIN for the following: Lodi (NV00108), Pilot Mountains (NV00113), Regent (NV00117), Silver Star W veins (NV00111), and White Pine ( NV00116). Also includes areas assessed as high potential for W skarns by Lederer and others (2021).
Identified resources Identified resources and historical production of tungsten.
Production Lodi district: Victory mine (1951-1957): 102,100 short tons units WO3 (Stager and Tingley, 1988). Pilot Mountains district: Desert Scheelite mine (1947-1957): 500 short tons units WO3; Garnet mine (1941-1953): 215 short tons units WO3; Gunmetal mine (1925-1956): 23,000 short tons units WO3 (Stager and Tingley, 1988). Regent district: Nevada Scheelite (1935-1982): 310,000 short tons units WO3 (Stager and Tingley, 1988). Silver Star district: Silver Dyke mine (1916-1972): 65,000 short tons units WO3 (Stager and Tingley, 1988). White Pine district: Monte Cristo mine (1954): 194 short tons units WO3 (Stager and Tingley, 1988).
Status Pilot Mountains district: Past mining and active exploration by Thor Mining, LLC. Past mining in other districts.
Estimated resources Desert Scheelite: Indicated 8,410,000 metric tons at 0.27% WO3 for calculated contained of 18,000 metric tons W; Inferred 1,490,000 metric tons at 0.23% WO3 for calculated contained 2720 metric tons W; Garnet: Indicated 1,830,000 metric tons at 0.36% WO3 for calculated contained 5,200 metric tons W (Karl and others, 2020). Centennial deposit: Unclassified 59,600,000 metric tons with grade of 0.2%, calculated contained 17,000 metric tons W (Pennington and others, 2014).
Geologic maps Stewart and Carlson (1978), scale 1:500,000; Ross (1961), scale 1:250,000; Klepper and U.S. Geological Survey (1943), scale 1:4,675; Holmes (1950), scale 1:4,800.
Geophysical data Inadequate aeromagnetic and aeroradiometric coverage. Only the Silver Star district has adequate aeromagnetic coverage.
Favorable rocks and structures Lodi district: Intrusion of Mesozoic age intrusive plutons into Triassic age carbonate sequence resulted in sodic feldspathization. Hydrothermal activity along some contacts and shear zones resulted in scheelite mineralization (Tingley, 1986). Pilot Mountains district: Tactites formed by metamorphism of limestone by intrusion the Gunmetal stock. Regent district: Tactite; mineralization is in areas of where granodiorite intruded and metamorphosed limestone. Silver Star district: Disseminated scheelite occurs within tabular stringers in concentric replacement quartz veins, which occur as repeated fracture fillings within old fault breccia consisting of angular blocks of diorite. White Pine district: Early metasomatic alteration converted shales and carbonaceous siltstones of the upper Secret Canyon shale to hornfels after shales and calc-silicate skarn after silty carbonates. Mineralization consists of skarn-hosted Sn, Mo, Cu +/- Zn with later epithermal Au and Ag (Pennington and others, 2014).
Deposits Lodi district: Victory mine (MRDS dep_id: 10044264; USMIN Site_ID: NV00109), Smuggler mine (MRDS dep_id: 10098593), Kay Cooper Group (MRDS dep_id: 10044259); White Pine district: Monte Cristo mine (MRDS dep_id: 10107655; USMIN Site_ID: NV00114), Mt. Hamilton (Centennial) mine (MRDS dep_id: 10310557); Pilot Mountains district: Desert Scheelite mine (MRDS dep_id: 10045331; USMIN Site_ID: NV00112), Garnet mine (MRDS dep_id: 10044640), Gunmetal mine (MRDS dep_id: 10149453), Silver Dyke mine (MRDS dep_id: 100089798; USMIN Site_ID: NV0110); Regent district: Nevada Scheelite (MRDS dep_id: 10008848; USMIN Site_ID: NV00137), Rawhide mine (MRDS dep_id: 10310397), Yankee Girl mine (MRDS dep_id: 10045434), Hooper mine (MRDS dep_id: 10045435).
Evidence from mineral occurrences MRDS; USMIN.
Geochemical evidence Lodi district: Scheelite mineralization is in altered skarn, feldspathized and migmatized altered granite, and in late-stage tourmaline veins (Tingley, 1986). Pilot Mountains district: Ore minerals were scheelite, powellite, molybdenite, and sphalerite. White Pine district: An extensive alteration aureole formed in the Cambrian Secret Canyon and Dunderberg Shale Formations surrounding the Cretaceous granodiorite stock. Alteration consists of an early biotite hornfels replaced in part by a diopside-orthoclase hornfels. Skarn alteration is zoned from a garnet-dominated assemblage adjacent to the stock to a garnet-pyroxene skarn to a calcite-diopside-quartz-kspar-tremolite skarn, to distal biotite hornfels. Retrograde alteration consists of quartz-calcite-iron oxide assemblage after garnet and a subordinate quartz-calcite-epidote-iron oxide-amphibole-chlorite assemblage after garnet-pyroxene. Regent district: Scheelite mineralization occurs with garnet, epidote, diopside, quartz, calcite, limonite, chalcopyrite, and pyrite. Silver Star district: The tungsten mineral is yellow fluorescing, high Mo scheelite. See Kilbreath (1979).
Geophysical evidence Unknown.
Evidence from other sources Unknown.
Cover thickness and description Exposed at the surface.
Authors John L. Muntean.
New data needs Geologic mapping, geophysics.
Geologic mapping and modeling needs Updated geologic mapping.
Geophysical survey and modeling needs High-resolution, Rank 1 aeromagnetic and aeroradiometric surveys.
Digital elevation data needs Lidar inadequate.