Geology topics
Research about Humboldt County, Nevada
Source-linked reports with geographic coverage including Humboldt County, Nevada.
Element dispersion in alluvium covering gold deposits east of the Osgood Mountains, Getchell Trend, Humboldt County, Nevada: slides and text of a talk given at the Association of Exploration Geochemists' 15th International Geochemical Exploration Symposium, Reno, Nevada
The current trend in mineral exploration is to search for covered deposits. In the Great Basin, this translates into searching for ore bodies buried by alluvial cover. The exploration techniques used range from random drilling to the use of new and exciting geochemical sampling media and analytical methods. But we have a problem. Many of our geochemical techniques lack a conceptual basis (We tried it and it worked) or the original conceptual basis is now suspect (The method also works when it shouldn't). What we need is a basic understanding of what is going on in the alluvium -- the third dimension. The discovery and development of the alluvium-covered, disseminated gold deposits at Rabbit Creek, Chimney Creek, and Pinson provides us with an opportunity to gain some knowledge of the dispersion of elements in the third dimension. The work presented here is one part of a larger multi-disciplinary study of the Kelly Creek Valley by the U.S. Geological Survey in cooperation with FirstMiss Gold, Inc., Gold Fields Mining Corporation, Pinson Mining Company, and Santa Fe Pacific Mining, Inc.
Geochemical analyses of ore and host rocks, Sleeper gold-silver deposit, Humboldt County, Nevada
No abstract available.
Geologic map of the Trident Peak SW quadrangle, Humboldt County, Nevada
No abstract available.
Geology and geochemistry of the Sleeper gold-silver deposit, Humboldt County, Nevada– An interim report
No abstract available.
Geologic map of the South Jackson Mountains Wilderness Study Area, Humboldt County, Nevada
The Federal Land Policy and Management Act (Public Law 94-579, October 21, 1976) requires the U.S. Geological Survey and the U.S. Bureau of Mines to conduct mineral surveys on certain areas to determine their mineral values, if any, that may be present. Results must be made available to the public and be submitted to the President and the Congress. This report presents the results of a mineral survey of the South Jackson Mountains (NV-020-603) Wilderness Study Area, Humboldt County, Nevada. The South Jackson Mountains Wilderness Study Area is in south-central Humboldt County, approximately 50 miles northwest of Winnemucca, Nevada. The boundaries originally specified for the wilderness study area encompassed an area of 60,211 acres. The draft Environmental Impact Statement issued in 1983 by the U.S. Bureau of Land Management (BLM) identified 20,094 acres within the wilderness study area as potentially suitable for inclusion into the National Wilderness Preservation System. Subsequent (August 27, 1984) deletions by the BLM have resulted in the present study area of approximately 10,300 acres. The boundaries of the study area are approximated by the range crestline to the east and the 4,400-ft contour along the west side of the range from King Lear Peak north to the divide between Hobo and Christiorsson Canyons.
Uraniferous opal, Virgin Valley, Nevada: Conditions of formation and implications for uranium exploration
Uraniferous, fluorescent opal, which occurs in tuffaceous sedimentary rocks at Virgin Valley, Nevada, records the temperature and composition of uranium-rich solutions as well as the time of uranium-silica coprecipitation. Results are integrated with previous geologic and geochronologic data for the area to produce a model for uranium mobility that may be used to explore for uranium deposits in similar geologic settings. Uraniferous opal occurs as replacements of diatomite, or silicic air-fall ash layers in tuffaceous lakebeds of the Virgin Valley Formation (Miocene) of Merriam (1907). Fission-track radiography shows uranium to be homogeneously dispersed throughout the opal structure, suggesting coprecipitation of dissolved uranium and silica gel. Fluid inclusions preserved within opal replacements of diatomite have homogenization temperatures in the epithermal range and are of low salinity. Four samples of opal from one locality all have U-Pb apparent ages which suggest uraniferous opal precipitation in late Pliocene time. These ages correspond to a period of local, normal faulting, and highangle faults may have served as vertical conduits for transport of deep, thermalized ground water to shallower levels. Lateral migration of rising solutions occurred at intersections of faults with permeable strata. Silica and some uranium were dissolved from silica-rich host strata of 5–20 ppm original uranium content and reprecipitated as the solutions cooled. The model predicts that in similar geologic settings, ore-grade concentrations of uranium will occur in permeable strata that intersect high-angle faults and that contain uranium source rocks as well as efficient reductant traps for uranium. In the absence of sufficient quantities of reductant materials, uranium will be flushed from the system or will accumulate in low-grade disseminated hosts such as uraniferous opal.
Principal facts for a gravity survey of the Double Hot Springs Known Geothermal Resource Area, Humboldt County, Nevada
During July 1977, forty-nine gravity stations were obtained in the Double Hot Springs Known Geothermal Resource Area and vicinity, northwestern Nevada. Elevations for twenty-two stations were estimated from lake bed topographic contours. Horizontal positions for these stations were determined from topographic maps and vehicle odometer. Elevations for stations DBLD34 and DBLD35 were determined with altimeters. Positions for the remaining stations were taken from spot elevations shown on U.S. Geological Survey topographic maps at scales of 1:24,000.
Age and composition of igneous rocks, Edna Mountain quadrangle, Humboldt County, Nevada
Six pulses of igneous activity ranging in age from Jurassic to Pliocene have been identified in the Edna Mountain quadrangle, Humboldt County, Nev. Porphyritic syenite am! quartz monzonite of Jurassic age (146-164 million years) at Buffalo Mountain are highly potassic through a wide range in SiO 2 content from olivine-bearing syenite to quartz-rich monzonite, and their composition contrasts sharply with plutons elsewhere in north-central Nevada. Granodiorite and quartz monzonite plutons of Cretaceous age (88- 106 m.y.) are chemically and mineralogically similar to other calc-alkaline plutons in north-central Nevada. Four episodes of Tertiary volcanism include rhyolite ashflow tuffs and slightly younger andesitic basalt flows and tuffs of Oligocene age, rhyolite vitrophyre of late Miocene age, and olivine basalt flows of Pliocene age. Their age and mineralogical and chemical compositions are similar to other Tertiary volcanic rocks in north-central Nevada.
Paleozoic tectonics in the Edna Mountain quadrangle, Nevada
Geologic mapping at scale 1:24,000 of the Edna Mountain 15-minute quadrangle, Humboldt County, Nev., revealed two episodes of pre-Mesozoic deformation that are difficult to reconcile with either the Antler or the Sonoma orogeny. We believe that the older episode predated the Antler orogeny and may be as old as Late Cambrian. The younger episode may have been more localized, predated the Sonoma orogeny, and was probably Late Pennsylvanian to Permian in age. Deformation related to Antler and Sonoma orogenies also occurred. These four episodes suggest that cycles of uplift, folding, faulting, and erosion began early in the development of the southern Cordillera and continued intermittently throughout Paleozoic time. West of the continental shelf was a broad subsiding basin marked by narrow troughs and elongate structural highs which emerged, matured, and diminished at different times. Waxing and waning deformation in various parts of the geosyncline acting upon local "highs" and troughs can explain the seemingly erratic distribution in north-central Nevada of different fades of time-correlative stratigraphic units and structural blocks of Paleozoic age. Telescoping of facies by thrust faulting certainly took place, but large displacements within brief periods are not essential to the validity of the explanation.
Geochemical, aeromagnetic, and generalized geologic maps showing distribution and abundance of lead, silver, gold, and copper, Goldrun Creek Quadrangle, Humboldt County, Nevada
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Geochemical, aeromagnetic, and generalized geologic maps showing distribution and abundance of molybdenum and zinc, Golconda and Iron Point quadrangles, Humboldt County, Nevada
Detailed geologic and geochemical studies of the four 7½-minute quadrangles that make up the Edna Mountain 15-minute quadrangle in Humboldt County, Nevada, were begun during the 1969 summer field season. The objectives of the project are to map the geology of this structurally complex area at 1:24,000 scale and to determine the regional distribution and abundance of metals in rocks of the area and the factors that control the distribution and abundance of those metals. Tungsten-bearing hot-spring tufa, metalliferous black shale in Ordovician rocks, base-metal and barite deposits in Paleozoic sedimentary rocks, and copper-molybdenum in granodiorite pultons of Cretaceous age occur in the Edna Mountain area. None of these deposits have been of much economic significance, although tungsten was mined for the hot-spring deposits during World War II. The numerous occurrences of mineralized ground, however, along with the broad spectrum of types of mineralization, intensity of alteration, structural complexity, and abundance of intermediate to silicic igneous intrusive rocks suggest that concealed or heretofore unrecognized mineral deposits may exist in the area. Integrated geologic, geochemical, and geophysical studies on a district-wide scale might improve our understanding of the factors that control the distribution, methods of emplacement, and spatial and genetic relationships (if any) of these different types of deposits. We hope that broad target areas or guidelines for mineral exploration in this area may be identified. This series of maps shows the distribution and abundance of mercury, arsenic, antimony, tungsten, gold, copper, lead, and silver related to a geologic and aeromagnetic base in the Golconda and Iron Point 7½-minute quadrangles. All samples are rock samples; most are from shear or fault zones, fractures, jasperoid, breccia reefs, and altered rocks. All the samples were prepared and analyzed in truck-mounted laboratories at Winnemucca, Nevada. Arsenic, tungsten, copper, lead, and silver were determined by semiquantitative spectrographic methods by D.F. Siems and E.F. Cooley. Mercury and gold were determined by atomic absorption methods and antimony was determined by wet chemical methods by R.M. O'Leary, M.S. Erickson, and others.
Geochemical, aeromagnetic, and generalized geologic maps showing distribution and abundance of gold and copper, Golconda and Iron Point quadrangles, Humboldt County, Nevada
Detailed geologic and geochemical studies of the four 7 1/2-minute quadrangles that make up the Edna Mountain 15-minute quadrangle in Humboldt County, Nevada, were begun during the 1969 summer field season. The objectives of the project are to map the geology of this structurally complex area at 1:24,000 scale and to determine the regional distribution and abundance of metals in rocks of the area and the factors that control the distribution and abundance of those metals. Tungsten-bearing hot-spring tufa, metalliferous black shale in Ordovician rocks, base-metal and barite deposits in Paleozoic sedimentary rocks, and copper-molybdenum in granodiorite plutons of Cretaceous age occur in the Edna Mountain area. None of these deposits have been of much economic signigicance, although tungsten was mined from the hot-spring deposits during World War II.