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Modeled Thickness of the Overburden Geomodel Unit (obthk_f)

Metadata Updated: July 24, 2024

The obthk_f grid represents the modeled thickness of the Overburden geomodel unit at a 500 foot resolution. It is one grid of a geomodel that consists of eleven grids and a spatial extent polygon shapefile. As part of a U.S. Geological Survey Groundwater Resources Program study, a three-dimensional geomodel was constructed for approximately 53,000 mi2 of the Columbia Plateau in Washington, Oregon, and Idaho. This geomodel was constructed to define the general aquifer system geometry for use in a regional numerical groundwater flow model. Simplifications and assumptions consistent with this ultimate goal and the uncertainty in the available data were made. The geomodel units consist of Miocene age Columbia River Basalt Group strata and younger alluvial overburden covering approximately 44,000 mi2. Data were compiled from numerous databases and detailed studies completed during the past three decades. These data include stratigraphic interpretations made on more than 13,000 wells and a contiguous compilation of surficial geology and structural features spanning the study area. These data were simplified and used to construct piecewise- smooth trend surfaces that represent upper and lower subsurface geomodel unit boundaries in this complex folded and faulted terrain. The smoothness of the surfaces implicitly represents uncertainty in prediction of each surface resulting from data gaps, errors in borehole interpretations, errors in mapped contact locations, and uncertainty in the shape of the paleo-surface upon which flood basalts were emplaced. Using a rule-based algorithm, surfaces were then recombined to construct a fully three-dimensional model with a 500-foot grid resolution that is consistent with the data and for which error estimates may be made. The modeling process yielded improved estimates of unit volumes, refinement of location of large structural features, and identification of features that may be important for ongoing groundwater studies.

Access & Use Information

Public: This dataset is intended for public access and use. License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

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Metadata Created Date June 1, 2023
Metadata Updated Date July 24, 2024

Metadata Source

Harvested from DOI EDI

Additional Metadata

Resource Type Dataset
Metadata Created Date June 1, 2023
Metadata Updated Date July 24, 2024
Publisher U.S. Geological Survey
Identifier USGS:707dacdc-072a-4b43-8a78-4fe4595df315
Data Last Modified 20201117
Category geospatial
Public Access Level public
Bureau Code 010:12
Metadata Context
Metadata Catalog ID
Schema Version
Catalog Describedby
Harvest Object Id c425c01d-7b98-40b8-a1f6-8495af6c1b31
Harvest Source Id 52bfcc16-6e15-478f-809a-b1bc76f1aeda
Harvest Source Title DOI EDI
Metadata Type geospatial
Old Spatial -121.844957854,44.261075488,-115.367389272,48.419366654
Publisher Hierarchy White House > U.S. Department of the Interior > U.S. Geological Survey
Source Datajson Identifier True
Source Hash 797f96c8d8838cc3a24ee8534b3b951afb8f1db3e521df1aec1612e56defe2d1
Source Schema Version 1.1
Spatial {"type": "Polygon", "coordinates": -121.844957854, 44.261075488, -121.844957854, 48.419366654, -115.367389272, 48.419366654, -115.367389272, 44.261075488, -121.844957854, 44.261075488}

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