The bedrock geology for the Glacial Environments and Surficial Sediments (GESS) geodatabase is an amalgamation of several “Integrated Geologic Map Databases for the United States” (Dicken and others, 2008; Ludington and others, 2007; Nicholson and others, 2007-1,-2,-3; Stoeser and others, 2007). Using the LITH62 and LITH62MINO attribute values from that series of maps and the associated lithclass 6.2 code text descriptions from the geodatabase, spatial elements of that geodatabase were grouped. A new GESS attribute was created, “Litho_class,” and each spatial element was given a Litho_class value of non-carbonate sedimentary rock, carbonate rock, non-carbonate metamorphic rock, volcanic rock, plutonic rock, or unconsolidataed (material).

The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States (https://doi.org/10.5066/F7WH2N65) represents a seamless, spatial database of 48 State geologic maps that range from 1:50,000 to 1:1,000,000 scale. A national digital geologic map database is essential in interpreting other datasets that support numerous types of national-scale studies and assessments, such as those that provide geochemistry, remote sensing, or geophysical data. The SGMC is a compilation of the individual U.S. Geological Survey releases of the Preliminary Integrated Geologic Map Databases for the United States. The SGMC geodatabase also contains updated data for seven States and seven entirely new State geologic maps that have been added since the preliminary databases were published. Numerous errors have been corrected and enhancements added to the preliminary datasets using thorough quality assurance/quality control procedures. The SGMC is not a truly integrated geologic map database because geologic units have not been reconciled across State boundaries. However, the geologic data contained in each State geologic map have been standardized to allow spatial analyses of lithology, age, and stratigraphy at a national scale. A full discussion of the procedures and methodology used to create this dataset is available in the accompanying report: Horton, J.D., San Juan, C.A., and Stoeser, D.B, 2017, The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States (ver. 1.1, August 2017): U.S. Geological Survey Data Series 1052, 46 p., https://doi.org/10.3133/ds1052.

The Sediment and Aquifer Characteristics dataset includes two, grid-based polygon feature classes. The first class uses a five-kilometer grid to show the density of lithologic logs available for analysis. The second class contains attributes that characterize either Quaternary sediment in the glaciated conterminous United States or aquifer material within it. The attributes are derived from lithologic logs obtained from boreholes and wells. The polygons were delineated by a constrained, kriging-based interpolation based on the distribution of map units in the source Surficial Geologic Units dataset using a grid-based algorithm to interpolate between the point data, as defined in the processing steps.

The Sediment and Aquifer Characteristics dataset includes two, grid-based polygon feature classes. The first class uses a five-kilometer grid to show the density of lithologic logs available for analysis. The second class contains attributes that characterize either Quaternary sediment in the glaciated conterminous United States or aquifer material within it. The attributes are derived from lithologic logs obtained from boreholes and wells. The polygons were delineated by a constrained, kriging-based interpolation based on the distribution of map units in the source Surficial Geologic Units dataset using a grid-based algorithm to interpolate between the point data, as defined in the processing steps.

This data release is a compilation of the digital products from a hydrogeologic framework of the glaciated conterminous United States that were constructed to portray sediment and aquifer characteristics within this area. These digital products are described in Yager and others (2018).

This data release is a compilation of the digital products from a hydrogeologic framework of the glaciated conterminous United States that were constructed to portray sediment and aquifer characteristics within this area. These digital products are described in Yager and others (2018).

This digital data release contains geospatial data for the 1:250,000 scale geologic map of the Grand Island 1 degree by 2 degree quadrangle, Nebraska, originally published by Dreeszen and others (1973). The database includes line and polygon features depicting the extent of the Miocene Ogallala Formation and underlying Cretaceous rocks. The original map also included shaded patches indicating outcrop areas, and contour lines depicting the thickness of Quaternary deposits; these are not included in this database. The spatial data are accompanied by non-spatial tables that describe the sources of geologic information, a description of geologic map units, a glossary of terms, and a Data Dictionary that duplicates the Entity and Attribute information contained in the metadata file.

This digital data release contains geospatial data for the 1:250,000 scale geologic map of the Grand Island 1 degree by 2 degree quadrangle, Nebraska, originally published by Dreeszen and others (1973). The database includes line and polygon features depicting the extent of the Miocene Ogallala Formation and underlying Cretaceous rocks. The original map also included shaded patches indicating outcrop areas, and contour lines depicting the thickness of Quaternary deposits; these are not included in this database. The spatial data are accompanied by non-spatial tables that describe the sources of geologic information, a description of geologic map units, a glossary of terms, and a Data Dictionary that duplicates the Entity and Attribute information contained in the metadata file.

This digital data release contains spatial datasets of bedrock geology, volcanic ash bed locations, test hole locations, bedrock outcrops, and structure contours of the top of bedrock and the base of the Ogallala Group from a previously published map (Souders, 2000). The GeologicMap feature dataset contains separate feature classes for the Ogallala Group map unit (ContactsAndFaults and MapUnitPolys) and the underlying pre-Ogallala bedrock map units (ContactsAndFaults_Bedrock and MapUnitPolys_Bedrock). The VolcanicAshBedPoints feature class contains the locations of volcanic ash beds within the Ogallala Group. The contours depicting the elevation of the top of bedrock (top of Ogallala Group where present and top of pre-Ogallala bedrock where Ogallala is absent) are contained in the IsoValueLines_TopBedrock feature class. The contours depicting the elevation of the base of the Ogallala Group are contained in the IsoValueLines_BaseOgallala feature class. Contoured values are given in both feet and meters. Feature classes containing the location of test holes (TestHolePoints) and bedrock outcrops (OverlayPolys) that were used in generating the structure contour surfaces are included. 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. Surficial geologic units that are only represented as cross-sections on the original map publication, and the cross-sections themselves, are not included in this digital data release.

This digital data release contains spatial datasets of bedrock geology, volcanic ash bed locations, test hole locations, bedrock outcrops, and structure contours of the top of bedrock and the base of the Ogallala Group from a previously published map (Souders, 2000). The GeologicMap feature dataset contains separate feature classes for the Ogallala Group map unit (ContactsAndFaults and MapUnitPolys) and the underlying pre-Ogallala bedrock map units (ContactsAndFaults_Bedrock and MapUnitPolys_Bedrock). The VolcanicAshBedPoints feature class contains the locations of volcanic ash beds within the Ogallala Group. The contours depicting the elevation of the top of bedrock (top of Ogallala Group where present and top of pre-Ogallala bedrock where Ogallala is absent) are contained in the IsoValueLines_TopBedrock feature class. The contours depicting the elevation of the base of the Ogallala Group are contained in the IsoValueLines_BaseOgallala feature class. Contoured values are given in both feet and meters. Feature classes containing the location of test holes (TestHolePoints) and bedrock outcrops (OverlayPolys) that were used in generating the structure contour surfaces are included. 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. Surficial geologic units that are only represented as cross-sections on the original map publication, and the cross-sections themselves, are not included in this digital data release.