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Mineral Resources On-Line Spatial Data

Siliceous and volcanic rocks

SILICEOUS AND VOLCANIC ROCKS-Chert, shale, quartzite, greenstone, and minor amounts of limestone. Includes units such as Valmy Formation of north-central Nevada and some rocks mapped as Palmetto Formation in northern part of Esmeralda County and adjacent parts of Mineral and Nye Counties. Locally includes rocks of Silurian and Devonian age.
StateNevada
NameSiliceous and volcanic rocks
Geologic ageOrdovician to Devonian
Original map labelOsv
CommentsSimilar in lithology to NVOs but has larger proportion of volcanics and chert. The Sonoma Range Formation is overlain by the Valmy Formation and possibly correlative with the lower part of the Valmy; it is over 3,000 feet thick but limited to Humboldt County and possibly Pershing County (Willden, 1964, Johnson, 1977). The Valmy Formation occurs in thrust sheets but has been measured at a thickness of 8,000 feet and estimated to be 20,000 to 25,000 feet thick (Stewart and McKee, 1977).
Primary rock typechert
Secondary rock typequartzite
Other rock typesshale; greenstone; limestone; conglomerate; siltstone; chemical
Lithologic constituents
Major
Sedimentary > Chemical > Chert (Bed)
Metamorphic > Quartzite
Minor
Sedimentary > Clastic > Mudstone > Shale (Bed)Includes argillite and slate.
Sedimentary > Clastic > Sandstone (Bed)
Incidental
Sedimentary > Clastic > Siltstone (Bed)Reported locally in Valmy, present in Palmetto where it may be metamorphosed to hornfels.
Sedimentary > Clastic > Conglomerate (Bed)Chert or pebble conglomerate.
Sedimentary > Carbonate > Limestone (Bed)Locally abundant, but often sparse.
Metamorphic > Greenstone (Greenschist)Altered from pillow lavas, andesitic lava, some gabbroic and pyroclastic material.
Sedimentary > Chemical > Barite (Bed)
Map references
Stewart, J.H., and Carlson, J.E., 1978, Geologic Map of Nevada: U.S. Geological Survey and Nevada Bureau of Mines and Geology, 1:500,000 (not part of any formal series, printed and distributed by the U.S. Geological Survey, G75163, reprinted, 1981, G81386).
Unit references
Stewart, J.H., and Carlson, J.E., 1978, Geologic Map of Nevada: U.S. Geological Survey and Nevada Bureau of Mines and Geology, 1:500,000 (not part of any formal series, printed and distributed by the U.S. Geological Survey, G75163, reprinted, 1981, G81386).
Stewart, J. H., 1980, Geology of Nevada: A discussion to accompany the Geologic Map of Nevada: Nevada Bureau of Mines and Geology Special Publication 4.
Stewart, J.H., and McKee, E.H., 1977, Geology, Pt. 1, in Geology and Mineral Deposits of Lander County, Nevada: Nevada Bureau of Mines and Geology Bulletin 88, p. 1-59, 3 pl.
Willden, R., 1964, Geology and Mineral Deposits of Humboldt County, Nevada: Nevada Bureau of Mines and Geology Bulletin 59, 154 p., 3 pl.
Coats, R.R., 1987, Geology of Elko County, Nevada: Nevada Bureau of Mines and Geology Bulletin 101, 112 p., 1 pl.
Albers, J.P., and Stewart, J.H., 1972, Geology and Mineral Deposits of Esmeralda County, Nevada: Nevada Bureau of Mines and Geology, 80 p., 2 pl.
Roberts, R.J., Montgomery, K.M., and Lehner, R.E., 1967, Geology and Mineral Resources of Eureka County, Nevada: Nevada Bureau of Mines and Geology Bulletin 64, 152 p., 12 pl.
Ross, D.C., 1961, Geology and Mineral Deposits of Mineral County, Nevada: Nevada Bureau of Mines and Geology Bulletin 58, 98 p., 2 pl.
Geographic coverageElko - Esmeralda - Eureka - Humboldt - Lander - Mineral - Nye - Pershing

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