Digital subsurface data from previously published contoured maps of the top of the Dakota Sandstone, Uinta and Piceance basins, Utah and Colorado

The top of the Upper Cretaceous Dakota Sandstone is present in the subsurface throughout the Uinta and Piceance basins of UT and CO and is easily recognized in the subsurface from geophysical well logs. This digital data release captures in digital form the results of two previously published contoured subsurface maps that were constructed on the top of Dakota Sandstone datum; one of the studies also included a map constructed on the top of the overlying Mancos Shale. A structure contour map of the top of the Dakota Sandstone was constructed as part of a U.S. Geological Survey Petroleum Systems and Geologic Assessment of Oil and Gas in the Uinta-Piceance Province, Utah and Colorado (Roberts, 2003). This surface, constructed using data from oil and gas wells, from digital geologic maps of Utah and Colorado, and from thicknesses of overlying stratigraphic units, depicts the overall configuration of major structural trends of the present-day Uinta and Piceance basins and was used to define the elevation of the base of a specific source-rock interval as part of the assessment. A second structure contour map of the top of the Dakota Sandstone, along with a contoured map showing the elevation of the top of the overlying Mancos Shale, was constructed from well data as part of a stratigraphic research thesis of the Douglas Creek Arch, a structural high which separates the Uinta and Piceance basins (Kuzniak, 2009). This digital dataset contains spatial datasets corresponding to the structure contour maps of the top of the Dakota Sandstone produced by the U.S. Geological Survey's petroleum assessment (Roberts, 2003) and the topical studies along the Douglas Creek Arch (Kuzniak, 2009). Both structure contour maps of the top of the Dakota Sandstone were digitized and attributed as GIS data sets so that these data could be used in digital form as part of U.S. Geological Survey and other studies of these basins. The contours depicting the elevation of the top of the Dakota Sandstone are contained in line feature classes within a geographic information system geodatabase and are also saved as individual shapefiles. Feature classes have a single attribute, elevation, that represents the contoured value. Contoured values are given in feet, to maintain consistency with the original publication, and in meters. Nonspatial tables define the data sources used, define terms used in the dataset, and describe the geologic units. A tabular data dictionary describes the entity and attribute information for all attributes of the geospatial data and the accompanying nonspatial tables.