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<DIV STYLE="text-align:Left;"><P><SPAN>This data set was created as part of a U.S. Geological Survey study, done in cooperation with the Nevada Division of Environmental Protection, to evaluate the susceptibility and vulnerability of ground water to anthropogenic contamination. A basic part of evaluating ground water is characterizing the hydrogeology of aquifer systems including the lithology and soil permeability, which partly control the susceptibility of ground water to contamination (Maurer and others, 2004). The intended uses of this data set include, but are not limited to, natural resource modeling, mapping, and visualization applications.</SPAN></P><P><SPAN>This data set consists of hydrogeology for the State of Nevada. Consolidated rocks and unconsolidated sediments are the two major hydrogeologic units. Consolidated rocks are subdivided into 8 hydrogeologic units: (1) carbonate rocks, Quaternary to Tertiary-age; (2) basaltic, (3) rhyolitic, and (4) andesitic volcanic flows; (5) volcanic breccias, tuffs, and volcanic rocks older than Tertiary-age; (6) intrusive and metamorphic rocks; (7) consolidated and semi-consolidated tuffaceous rocks and sediments; and (8) clastic rocks consisting of sandstone and siltstone. Unconsolidated sediments are subdivided into 4 hydrogeologic units: 1) alluvial slopes, (2) valley floors, (3) fluvial deposits, and (4) playas. In addition, soil permeability is provided and grouped into five descriptive categories ranging from very high to very low, which generally correspond to mapped geomorphic features such as playas and alluvial slopes. The geologic map of Nevada (Stewart and Carlson, 1978), published at a scale of 1:500,000, is the primary source of lithology used to delineate hydrogeologic units, enhanced with elevation and hydrologic data, and supplemented with Landsat Thematic Mapper imagery (Maurer and others, 2004).</SPAN></P><P><SPAN>Dataset last updated from USGS on March 24, 2015. For additional metadata, please see https://water.usgs.gov/GIS/metadata/usgswrd/XML/nv_hydgeolnv_p.xml </SPAN></P><P><SPAN>Dataset downloaded on November 3, 2021 from </SPAN><A href="https://water.usgs.gov/GIS/dsdl/nv_hydgeolnv_p.shp.zip" STYLE="text-decoration:underline;"><SPAN STYLE="text-decoration:underline;"><SPAN>https://water.usgs.gov/GIS/dsdl/nv_hydgeolnv_p.shp.zip</SPAN></SPAN></A></P></DIV> |