{
    "tag": 16448,
    "title": "Interpretation of the Surficial Geology of Lake Mead Based on Sidescan-Sonar Imagery, Topography and Sediment Thickness (LAKEMEAD_INTERP.SHP)",
    "pubdate": "2009",
    "sername": null,
    "series_name": null,
    "issue": "2009-1150",
    "publish": null,
    "publisher_name": null,
    "onlink": "https:\/\/cmgds.marine.usgs.gov\/catalog\/whcmsc\/open_file_report\/ofr2009-1150\/lakemead_interp.shp.faq.html",
    "format": null,
    "email": null,
    "descript": "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.  The region covered by the reservoir had been mapped prior to construction of the dam, however there had been little study of how the lake-floor region had changed since impoundment.  To address this question, sidescan-sonar imagery and high-resolution seismic-reflection profiles were collected throughout Lake Mead by the U.S. Geological Survey (USGS) in cooperation with researchers from University of Nevada Las Vegas (UNLV).  These data allow a detailed mapping of the surficial geology of the lake's floor 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 while alluvial deposits and rock outcrops are still exposed on the lake floor away from the former river beds.",
    "lang": null,
    "journal": null,
    "pwid": null,
    "originator": [
        {
            "name": "Twichell, David C.",
            "role": "Author"
        },
        {
            "name": "Cross, VeeAnn A.",
            "role": "Author"
        }
    ],
    "index_term": [
        {
            "thcode": 2,
            "code": "470",
            "name": "geophysics",
            "scope": "Branch of geology studying the physical characteristics and phenomena of the earth and its atmosphere."
        },
        {
            "thcode": 2,
            "code": "474",
            "name": "geospatial datasets",
            "scope": "Collections of related digital information that are geographically referenced."
        },
        {
            "thcode": 2,
            "code": "2090",
            "name": "lakebed characteristics",
            "scope": "Characteristics of the bottom of inland bodies of water."
        },
        {
            "thcode": 2,
            "code": "2079",
            "name": "scientific interpretation",
            "scope": "Application of scientific judgment as to the meaning of observations or models. Use for interpretations that are provided in formats similar to data, such as geospatial data."
        },
        {
            "thcode": 15,
            "code": "008",
            "name": "geoscientificInformation",
            "scope": "Information pertaining to earth sciences, for example geophysical features and processes, geology, minerals, sciences dealing with the composition, structure and origin of the earth's rocks, risks of earthquakes, volcanic activity, landslides, gravity information, soils, permafrost, hydrogeology, groundwater, erosion"
        },
        {
            "thcode": 15,
            "code": "012",
            "name": "inlandWaters",
            "scope": "Inland water features, drainage systems and characteristics, for example rivers and glaciers, salt lakes, water utilization plans, dams, currents, floods and flood hazards, water quality, hydrographic charts, watersheds, wetlands, hydrography"
        }
    ],
    "place_term": [],
    "image": [],
    "fan": []
}