• 2 meter unenhanced GeoTIFF Sidescan-Sonar Mosaic of Virgin Basin - Lake Mead, Nevada (VBASIN_UNGEOG.TIF, geographic)

    Metadata Updated: August 16, 2020

    Lake Mead is a large interstate reservoir located in the Mojave Desert of southeastern Nevada and northwestern Arizona. It was impounded in 1935 by the construction of Hoover Dam and is one of a series of multi-purpose reservoirs on the Colorado River. The lake extends 183 km from the mouth of the Grand Canyon to Black Canyon, the site of Hoover Dam, and provides water for residential, commercial, industrial, recreational, and other non-agricultural users in communities across the southwestern United States. Extensive research has been conducted on Lake Mead, but a majority of the studies have involved determining levels of anthropogenic contaminants such as synthetic organic compounds, heavy metals and dissolved ions, furans/dioxins, and nutrient loading in lake water, sediment, and biota (Preissler, et al., 1998; Bevans et al, 1996; Bevans et al., 1998; Covay and Leiker, 1998; LaBounty and Horn, 1997; Paulson, 1981). By contrast, little work has focused on the sediments in the lake and the processes of deposition (Gould, 1951). To address these questions, sidescan-sonar imagery and high-resolution seismic-reflection profiles were collected throughout Lake Mead by the USGS in cooperation with researchers from University of Nevada Las Vegas (UNLV). These data allow a detailed mapping of the surficial geology and the distribution and thickness of sediment that has accumulated in the lake since the completion of Hoover Dam. Results indicate that the accumulation of post-impoundment sediment is primarily restricted to former river and stream beds that are now submerged below the lake while the margins of the lake appear to be devoid of post-impoundment sediment. The sediment cover along the original Colorado River bed is continuous and is typically greater than 10 m thick through much of its length. Sediment thickness in some areas exceeds 35 m while the smaller tributary valleys typically are filled with less than 4 m of sediment. Away from the river beds that are now covered with post-impoundment sediment, pre-impoundment alluvial deposits and rock outcrops are still exposed on the lake floor.

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    Metadata Date November 25, 2019
    Metadata Created Date August 16, 2020
    Metadata Updated Date August 16, 2020
    Reference Date(s) January 1, 2003 (publication)
    Frequency Of Update notPlanned

    Metadata Source

    Harvested from USGS-Harvest

    Graphic Preview

    Browse image showing overview of Virgin Basin sidescan-sonar mosaic.

    Additional Metadata

    Resource Type Dataset
    Metadata Date November 25, 2019
    Metadata Created Date August 16, 2020
    Metadata Updated Date August 16, 2020
    Reference Date(s) January 1, 2003 (publication)
    Responsible Party USGS (Point of Contact)
    Contact Email
    Access Constraints Use Constraints: The U.S. Geological Survey must be referenced as the originator of the dataset in any future products or research derived from these data. This image is available as a GEOTIFF image with an accompanying world file. To utilize this data, the user must have an image viewer, image processing or GIS software package capable of importing a GEOTIFF image., Access Constraints: NONE
    Bbox East Long -114.358236
    Bbox North Lat 36.181256
    Bbox South Lat 36.063916
    Bbox West Long -114.633747
    Coupled Resource
    Frequency Of Update notPlanned
    Graphic Preview Description Browse image showing overview of Virgin Basin sidescan-sonar mosaic.
    Graphic Preview File http://pubs.usgs.gov/of/2003/of03-320/htmldocs/icons/vbasinun.jpg
    Graphic Preview Type JPEG
    Harvest Object Id f7e69a93-949e-4555-ae58-30bef88fccac
    Harvest Source Id 00f54869-3a43-480d-a67c-0ba115f5d739
    Harvest Source Title USGS-Harvest
    Licence Although these data have been used by the U.S. Geological Survey (USGS), U.S. Department of the Interior (DOI), no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
    Metadata Language
    Metadata Type geospatial
    Progress completed
    Spatial Data Service Type
    Spatial Reference System
    Spatial Harvester True
    Temporal Extent Begin 2001-04-01
    Temporal Extent End 2001-04-26

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