Digital subsurface database of previously published well tops, structural features, and contour maps of the Inyan Kara Group, Minnekahta Formation, Minnelusa Formation, Madison Group, and Deadwood Formation, Black Hills region, South Dakota and Wyoming

This digital data release presents multiple previously published elements of the structural configuration of the Black Hills regional subsurface. The original data within this geodatabase is sourced from multiple U.S. Geological Survey Open File Reports into the hydrology of the Black Hills, stored on the USGS Water Mission Area NSDI Node (Driscoll, 1992; Strobel et al., 1999; Williamson et al., 2000). Data include mapped surface exposures of faults and fold hinges, the location and depth of 1025 formation tops of the Madison Group, Minnelusa Formation, and Minnekahta Formation from water well scout tickets, isopach contours of the Madison Group and Minnelusa Formation, and structure contour maps of the top of the Deadwood Formation, Madison Group, Minnelusa Formation, Minnekahta Formation, and Inyan Kara Group. Isopach and structure contour maps were generated using a combination of formation tops and known fold and fault traces (Williamson et al., 2000). Characterizing these units in the subsurface is of value, as they have been identified as highly productive groundwater sources in the Black Hills, and prospective hydrocarbon reservoirs in the adjacent Powder River and Williston Basins (Strobel et al., 1999; Williamson et al., 2000). Geologic formation tops, fold and fault traces, isopach contours, and structure contours were digitized and attributed as GIS data sets for use in digital form as part of U.S. Geological Survey’s ongoing effort to inventory, catalog, and release subsurface geologic data in geospatial form. This effort is part of a broad directive to develop 2D and 3D geologic information at detailed, national, and continental scales. Structure contour lines and isopach contours for each formation are stored within separate IsoValueLine feature classes, while formation tops for each formation are stored as point data in separate “GenericPoints” feature classes. Fold hinge traces are stored in the GeologicLines feature class, while faults are stored in the ContactsAndFaults feature class. These are distributed within a geographic information system geodatabase and are also saved as shapefiles. Contour and point data are provided in both feet and meters to maintain consistency with the original publication and for ease of use. Nonspatial tables define the data sources used, define terms used in the dataset, and describe the geologic units referenced herein. A tabular data dictionary describes the entity and attribute information for all attributes of the geospatial data and accompanying nonspatial tables.