Geology topics
Research about Nevada
Source-linked reports with geographic coverage including Nevada.
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.
Water resources data, Nevada, water year 1987
Water-resources data published herein for the 1987 water year comprise the following records: Water discharge for 86 gaging stations on streams, canals, and drains.; Discharge data for 144 peak-flow stations and miscellaneous sites, and 35 springs.; Stage and contents for 14 lakes and reservoirs.; Water levels for 304 observation wells. .; Water-quality data for 29 stream, canal, and drain sites, and 5 wells.; Precipitation totals for 12 stations. Additional water data, collected at various sites that are not part of the systematic data-collection program, are published as miscellaneous measurements. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in Nevada.
Ground-water quality in Douglas County, western Nevada
A 182% increase in population within the last 10 years in Douglas County, Nevada, has raised concerns by county officials as to the possible effects land development may have on groundwater quality. Most groundwater in Douglas County meets the State of Nevada drinking water standards. Of the 333 water samples used in this analysis, 6 equaled or were greater than the drinking water standards for sulfates, 44 for fluoride, 4 for dissolved solids, 5 for nitrate as nitrate, 12 for arsenic, 33 for iron, and 18 for manganese. Groundwater in the west-central, northern, and northeastern part of Carson Valley is influenced by geothermal water. Some areas in the county may have septic-tank effluent contaminating the groundwater. Temporal changes in most municipal wells showed no overall trend for dissolved-solids and nitrate concentrations spanning the years 1969-83. However, a municipal well in the Topaz Lake area has shown a general increases in the nitrate concentration from 1961 to 1984, but the concentration does not exceed the drinking-water standard. A future groundwater quality monitoring program in Douglas County would include periodic sampling of primary or heavily pumped wells, long-term trend wells, and supplemental wells. (Thacker-USGS)
Sedimentary biomarker and isotopic indicators of the paleoclimatic history of the Walker Lake basin, western Nevada
Walker Lake, a terminal saline lake in western Nevada, has experienced major fluctuations in its water level due to changes in the regional climate during Quaternary times. As part of a paleo-climatological study of western Nevada, we have investigated organic matter δ 13 C and C/N values and lipid biomarker contents of sediments deposited at various periods over the past 150 thousand years of lake history. Surficial sediments from two cross-lake transects contain mostly lake-derived organic matter. Diagenetic losses of organic matter are evident in deeper sediments, and the proportion of aquatic and terrigenous organic materials changes in response to variations in preservational factors. Source identification of organic matter is complicated by the probability that Walker Lake has experienced desiccation at various times in its history which impacts the degree of preservation of organic substances.
Changes in the morphometry of Las Vegas Wash and the impact on water quality
Las Vegas Wash, a natural wash east of Las Vegas, Nevada, carries stormwater, groundwater drainage, and sewage effluent from two sewage treatment plants to Lake Mean. Over 80 percent of the normal discharge of approximately 3.4 m 3 /s (120 ft 3 /s) consists of effluent from the City of Las Vegas and Clark County sewage treatment plants. Beginning in the 1950s, a large wetland area developed along the wash that supported waterfowl populations and contributed to some water quality transformations. Heavy rains and subsequent flooding in the area in 1983 and 1984 resulted in erosion and channelization that greatly reduced the wetland area within Las Vegas Wash. The reduction in wetland area shortened water travel time in the wash and affected water quality. The primary impacts on the water entering Lake Mead have been an increase in temperature, a decrease in dissolved oxygen concentration, and an increase in ammonia levels. Other physical-chemical parameters and changes in nutrient transformations are also discussed.
A 250,000-year climatic record from Great Basin vein calcite: Implications for Milankovitch theory
A continuous record of oxygen-18 (δ 18 O) variations in the continental hydrosphere during the middle-to-late Pleistocene has been obtained from a uranium-series dated calcitic vein in the southern Great Basin. The vein was deposited from ground water that moved through Devils Hole—an open fault zone at Ash Meadows, Nevada—between 50 and 310 ka (thousand years ago). The configuration of the δ 18 O versus time curve closely resembles the marine and Antarctic ice core (Vostok) δ 18 O curves; however, the U-Th dates indicate that the last interglacial stage (marine oxygen isotope stage 5) began before 147 ± 3 ka, at least 17,000 years earlier than indicated by the marine δ 18 O record and 7,000 years earlier than indicated by the less well dated Antarctic δ 18 O record. This discrepancy and other differences in the timing of key climatic events suggest that the indirectly dated marine δ 18 O chronology may need revision and that orbital forcing may not be the principal cause of the Pleistocene ice ages.
Mineral resources of the Riordans Well Wilderness Study Area, Nye County, Nevada
No abstract available.
Geologic and hydrologic investigations of a potential nuclear waste disposal site at Yucca Mountain, southern Nevada
Crustal velocity sections based on two seismic-refraction profiles are presented for the area west of Yucca Mountain, Nye County, Nevada. The Crater Flat profile is interpreted in terms of six velocity layers ranging from 1.5 to 6.1 km/s. Interpretation of the Beatty profile reveals an escarpment near the northeast edge of Bare Mountain, where Paleozoic rocks are probably down-faulted 2600 m into a volcano-tectonic depression in Crater Flat. The seismic profiles and inferred density-velocity relations have been incorporated into an east-west gravity model from Death Valley to Crater Flat, corresponding to the Beatty seismic profile. An important feature of this model is the inferred continuity of a layer interpreted as the lower plate of a regional decollement or detachment fault.
Index of granitic rock masses in the state of Nevada
A compilation of 205 areas of exposed granitic rock in Nevada was undertaken for the U.S. Department of Energy. The purpose was to obtain data for evaluating granitic rock masses as potential underground nuclear waste repositories. Information, compiled by county for areas of granitic rock exposure, includes general location, coordinates, land classification, areal extent, accessibility, composition, age, rocks intruded, aeromagnetic expression, mining activity, and selected references.
Aerial gamma-ray contour maps of regional surface concentrations of potassium, uranium, and thorium in Nevada
No abstract available.
Surficial geologic map of the Bare Mountain quadrangle, Nye County, Nevada
No abstract available.