Description: 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.
Service Item Id: 62e71c600e9a47bc9df916aced58d0fc
Copyright Text: The State Geologic Map Compilation of the Conterminous United States was developed by the U.S. Geological Survey Mineral Resources Program (MRP). The project owes its success to numerous MRP staff who compiled the Preliminary Integrated Geologic Map Databases for the United States (PIGMD) as well as the foundational geologic mapping work completed by U.S. State Geologic Surveys and academia.
Description: This line dataset (PP1770_ thickness_sand_LKA_con.shp) consists of contours of equal silt-plus-sand thickness, in feet, for the lower Arapahoe aquifer (model layer 10) of the Denver Basin aquifer system, Colorado. A point dataset was generated in ArcGIS 9.2 (Environmental Systems Research Institute, Inc., 1999-2004) from the CDWR Denver Basin geophysical log database (Brian Ahrens, Colorado Division of Water Resources, written commun., 2003), and the point data were contoured using an either an ordinary kriging method or an inverse-distance weighted method available in ArcGIS, depending on which method resulted in the least error. Percent-sand values were derived by dividing the silt-plus-sand thickness values from total aquifer thickness, and the percent-sand values were subsequently used as multiplier arrange for hydraulic conductivity and specific-yield values in a in a three-dimensional groundwater-flow model of the Denver Basin (Paschke, 2011). See the "Supplemental Information" section of this metadata for more detailed descriptions of the datasets, their application, and references.
Description: Levandowski and others (1973) presented structural maps of the Lyons Formation in producing oil fields.
Service Item Id: 62e71c600e9a47bc9df916aced58d0fc
Copyright Text: Levandowski, D.W., Kaley, M. E., Silverman, S.R., and Smalley, R.G. 1973 Cementation in Lyons Sandstone and its Role in Oil Accumulation, Denver Basin, Colorado: The American Association of Petroleum Geologists Bulletin 57(11), p. 2217-2244.
Description: This line dataset (PP1770_alt_base_LKA_con.shp) consists of contours of equal base altitude, in feet, for the lower Arapahoe aquifer of the Denver Basin aquifer system, Colorado. A point dataset was generated in ArcGIS 9.2 (Environmental Systems Research Institute, Inc., 1999-2004) from the Colorado Division of Water Resources Denver Basin geophysical log database (Brian Ahrens, Colorado Division of Water Resources, written commun., 2003), and the point data were contoured using either an ordinary kriging method or an inverse-distance weighted method available in ArcGIS, depending on which method resulted in the least error. This resulting dataset was then used to define the base altitude of the Arapahoe confining unit (model layer 9) in a MODFLOW-2000, three-dimensional groundwater-flow model of the Denver Basin (Paschke, 2011). See the "Supplemental Information" section of this metadata for more detailed descriptions of the datasets, their application, and references.
Description: This line dataset (PP1770_alt_base_KLF_con.shp) consists of contours of equal base altitude, in feet, for the Laramie-Fox Hills aquifer of the Denver Basin aquifer system, Colorado. A point dataset was generated in ArcGIS 9.2 (Environmental Systems Research Institute, Inc., 1999-2004) from the Colorado Division of Water Resources Denver Basin geophysical log database (Brian Ahrens, Colorado Division of Water Resources, written commun., 2003), and the point data were contoured using either an ordinary kriging method or an inverse-distance weighted method available in ArcGIS, depending on which method resulted in the least error. This resulting dataset was then used to define the base altitude of the Arapahoe confining unit (model layer 9) in a MODFLOW-2000, three-dimensional groundwater-flow model of the Denver Basin (Paschke, 2011). See the "Supplemental Information" section of this metadata for more detailed descriptions of the datasets, their application, and references.