{"accessLevel": "public", "bureauCode": ["010:12"], "contactPoint": {"@type": "vcard:Contact", "fn": "Erick Burns", "hasEmail": "mailto:eburns@usgs.gov"}, "description": "The pmtop_f grid represents the modeled elevation of the top of the Older Bedrock geomodel unit \nat a 500 foot resolution. It is one grid of a geomodel that consists of eleven grids and a spatial \nextent polygon shapefile.  As part of a U.S. Geological Survey Groundwater Resources Program \nstudy, a three-dimensional geomodel was constructed for approximately 53,000 mi2 of the \nColumbia Plateau in Washington, Oregon, and Idaho. This geomodel was constructed to define \nthe general aquifer system geometry for use in a regional numerical groundwater flow model. \nSimplifications and assumptions consistent with this ultimate goal and the uncertainty in the \navailable data were made. The geomodel units consist of Miocene age Columbia River Basalt \nGroup strata and younger alluvial overburden covering approximately 44,000 mi2. Data were \ncompiled from numerous databases and detailed studies completed during the past three \ndecades. These data include stratigraphic interpretations made on more than 13,000 wells \nand a contiguous compilation of surficial geology and structural features spanning the study \narea. These data were simplified and used to construct piecewise-smooth trend surfaces that \nrepresent upper and lower subsurface geomodel unit boundaries in this complex folded and \nfaulted terrain.  The smoothness of the surfaces implicitly represents uncertainty in prediction \nof each surface resulting from data gaps, errors in borehole interpretations, errors in mapped \ncontact locations, and uncertainty in the shape of the paleo-surface upon which flood basalts \nwere emplaced. Using a rule-based algorithm, surfaces were then recombined to construct a \nfully three-dimensional model with a 500-foot grid resolution that is consistent with the data \nand for which error estimates may be made. The modeling process yielded improved estimates \nof unit volumes, refinement of location of large structural features, and identification of features \nthat may be important for ongoing groundwater studies.", "distribution": [{"@type": "dcat:Distribution", "accessURL": "https://doi.org/10.5066/P91WF0TV", "description": "Landing page for access to the data", "format": "XML", "mediaType": "application/http", "title": "Digital Data"}, {"@type": "dcat:Distribution", "description": "The metadata original format", "downloadURL": "https://data.usgs.gov/datacatalog/metadata/USGS.01505df1-a2a6-48ab-9b16-77616fcfdc2b.xml", "format": "XML", "mediaType": "text/xml", "title": "Original Metadata"}], "identifier": "http://datainventory.doi.gov/id/dataset/USGS_01505df1-a2a6-48ab-9b16-77616fcfdc2b", "keyword": ["CPRAS", "Columbia Plateau", "Columbia Plateau Regional Aquifer System", "Columbia River Basalt", "Columbia River Basin", "Idaho", "Oregon", "Pacific Northwest", "USGS:01505df1-a2a6-48ab-9b16-77616fcfdc2b", "Washington", "geomodel", "inlandWaters", "older bedrock"], "modified": "2020-11-17T00:00:00Z", "publisher": {"@type": "org:Organization", "name": "U.S. Geological Survey"}, "spatial": "-121.844957854, 44.261075488, -115.367389272, 48.419366654", "theme": ["geospatial"], "title": "Modeled Top of the Older Bedrock Geomodel Unit (pmtop_f)"}