Donald S. Sweetkind Jay R. Cederberg Susan G. Buto Melissa D. Masbruch Brooklyn Smout 20260122 vector digital data and raster digital data Denver U.S. Geological Survey https://doi.org/10.5066/P13BAFSV Victor M. Heilweil Lynette E. Brooks 2011 publication Reston, VA U.S. Geological Survey Heilweil, V.M., and Brooks, L.E., eds., 2011, Conceptual model of the Great Basin carbonate and alluvial aquifer system: U.S. Geological Survey Scientific Investigations Report 2010-5193, 191 p. https://pubs.usgs.gov/sir/2010/5193/ This digital dataset was created as part of a U.S. Geological Survey (USGS) regional groundwater assessment of the eastern Great Basin; the project was called the Great Basin Carbonate-Alluvial Aquifer Study (GBCAAS). The study area has a geographic extent of 110,000 square miles, predominantly in eastern Nevada and western Utah. As part of this larger study, the USGS developed digital geologic data and a three-dimensional hydrogeologic framework model (3DHFM) that defines the elevation, thickness, and extent of nine hydrogeologic units in the regional study area. The hydrogeologic framework model became the principal digital geologic input to a regional numerical groundwater flow model. A USGS report published in 2011 presented a conceptualization of the regional hydrogeology and major aquifer systems and included a description of the construction of the 3DHFM. This data release formalizes the input geologic data and model outputs as a digital dataset. Nine hydrogeologic units (HGUs) were modeled within the GBCAAS 3DHFM; six of the units describe consolidated pre-Cenozoic rocks and the other three describe Cenozoic basin-fill and volcanic rocks. The modeled HGUs include, from deepest to shallowest, a noncarbonate confining unit (NCCU) representing low-permeability Precambrian siliciclastic formations, (2) a lower carbonate aquifer unit (LCAU) representing high-permeability Cambrian through Devonian limestone and dolomite, (3) an upper siliciclastic confining unit (USCU) representing low-permeability Mississippian shale, (4) an upper carbonate aquifer unit (UCAU) representing high-permeability Pennsylvanian and Permian carbonate rocks, (5) a thrusted noncarbonate confining unit (TNCCU) representing low-permeability siliciclastic rocks incorporated in regional thrust faults, (6) a thrusted lower carbonate aquifer unit (TLCAU) representing high-permeability limestone and dolomite incorporated in regional thrust faults, (7) a volcanic unit (VU) representing outcrop areas of volcanic rocks, (8) a lower basin-fill aquifer unit (LBFAU) representing the lower one-third of the Cenozoic basin fill, and (9) an upper basin-fill aquifer unit (UBFAU) representing the upper two-thirds of the Cenozoic basin fill. The GBCAAS 3DHFM was built by extracting and combining information from digital elevation models, geologic maps, cross sections, drill hole logs, existing hydrogeologic frameworks, and geophysical data. Compared to areas with active oil and gas production, deep well data for the GBCAAS study area are generally sparse; the primary input data for the 3DHFM were map and cross section data. Input surface and subsurface data have been reduced to points that define the top elevation of each hydrogeologic unit at x,y locations; these point data sets serve as digital input to the framework models. Faults and caldera boundaries that offset or affect hydrogeologic units are provided as a separate line feature class. XYZ data from all input sources were combined and interpolated using standard grid interpolation methods. Each interpolated surface was then sampled at the centroid nodes of a polygonal cellular array of square cells at a node spacing of 1 mile in both the north-south and east-west directions. The array of polygonal cells is essentially a “flattened”, two-dimensional representation of the digital 3DHFM. The mesh of model cells have multiple attributes that describe the geometry of the regional hydrogeologic framework including x,y location, elevation, and thickness of each hydrogeologic unit. Spatial data in this digital dataset are stored in file geodatabase format and are also released as shapefiles. Data include a polygon dataset representing a hydrogeologic map of the region, a polyline dataset that contains the map traces of faults and calderas included in the 3DHFM, a second polyline dataset that contains the map traces of geologic cross sections from which HGU tops were derived, and a large point features class that contains as x,y,z data all of the geologic input data used to construct the 3DHFM. The GBCAAS 3DHFM is contained in a polygon dataset that is a polygonal array of square cells with multiple attributes. A separate folder contains raster output from the 3DHFM including elevation and thickness grids for each HGU in the 3DHFM. Also included is a raster dataset of a gravity based regional “depth-to-basement” surface compiled from previous studies that was used to represent the altitude of the pre-Cenozoic rock surface and the base of the Cenozoic sedimentary basin-fill deposits and volcanic rocks. The spatial data are accompanied by non-spatial tables that describe the sources of geologic information, a glossary of terms, a description of model units, and a Data Dictionary that duplicates the Entity and Attribute information contained in the metadata file. This digital dataset was created as part of a U.S. Geological Survey regional assessment of groundwater availability of the eastern Great Basin as part of a national water census. This digital dataset was created as the geologic input data for numerical simulation of the hydrologic system. The compiled elevation, thickness, and spatial extent of the hydrogeologic units may be used to define the geohydrologic layering within a numerical model. The location of faults and calderas may be used to define the location of potential horizontal flow barriers in numerical simulation of the groundwater system. The intended uses of this dataset include, but are not limited to, natural resource modeling, mapping, and visualization applications. Although this Federal Geographic Data Committee (FGDC) compliant metadata file is intended to document the data set in nonproprietary form, this metadata file may include some ArcGIS-specific terminology. The hydrogeologic map spatial elements are distributed as separate feature classes within a geographic information system geodatabase and are also saved as shapefiles. Modeled unit tops and thicknesses are distributed as grids within the geodatabase and in TIF format in a separate folder. Nonspatial tables define the data sources used, the terms used in the dataset, and describe the modeled units. A tabular data dictionary describes the entity and attribute information for all attributes of the geospatial data and the accompanying nonspatial tables. This digital dataset is broadly compliant with and incorporates parts of two digital data schema, the GeMS digital geologic map data standard (U.S. Geological Survey National Cooperative Geologic Mapping Program, 2020; https://ngmdb.usgs.gov/Info/standards/GeMS/), and data schema for subsurface and 3-D data being developed by the USGS National Cooperative Geologic Mapping Program. Components used in construction of this database are explained in the Entity and Attribute section. Data source inputs used to create the dataset, cited as part of the Process Steps, are not cross-referenced using a source abbreviation within the "Data Quality" section of the metadata. Instead, cited references are tabulated in the DataSources nonspatial table, provided within the spatial geodatabase and as a stand-alone table. Citation of references in this fashion results in FGDC schema errors when the metadata are validated, however, inclusion of the large number of data sources makes the metadata file unwieldy. The nonspatial DataSources table is a part of the GeMS digital geologic map data standard and follows a published standard database schema for tabulating source material. 2011 2026 publication date Complete None planned -119.6772 -110.1123 42.7584 34.7607 ISO 19115 Topic Category geoscientificInformation None hydrogeologic carbonate alluvial aquifer systems 3D three dimensional USGS Metadata Identifier USGS:68b1d2f6d4be024847d7b95a Common geographic areas Great Basin Nevada Utah Idaho California Arizona Basin and Range basin-fill aquifers Basin and Range carbonate-rock aquifers This data set is provided by USGS as a public service. Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. Acknowledgement of the U.S. Geological Survey would be appreciated in products derived from these data. Donald Sweetkind USGS - ROCKY MOUNTAIN REGION Research Geologist mailing and physical

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Lakewood CO 80225 303-236-1828 dsweetkind@usgs.gov Project supported by funding from the USGS Water Mission Area’s Groundwater Resources Program and the USGS National Cooperative Geologic Mapping Program. Julie Simon (USGS, Denver) assisted with the compilation of data sources. Sam Johnstone and Warren Roe (USGS, Denver) provided insight and guidance on the format and attribution of digital subsurface data. Acknowledgement of the U.S. Geological Survey would be appreciated in products derived from these data. Technical review of this database was done by Jennifer Sharpe, USGS Illinois Water Science Center at UIUC,University of Illinois Data were originally developed using Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 3; ESRI ArcCatalog 9.2.4.1420. Data were finalized for this data release using Esri's ArcGIS Pro software version 3.4.2 in a native Microsoft Windows environment, Rockware's Rockworks software, and Microsoft Excel. Lynette E. Brooks Melissa Masbruch Donald S. Sweetkind Susan G. Buto 2014 publication Scientific Investigations Report 2014-5213 Brooks, L.E., Masbruch, M.D., Sweetkind, D.S., and Buto, S.G., 2014, Steady-state numerical groundwater flow model of the Great Basin carbonate and alluvial aquifer system: U.S. Geological Survey Scientific Investigations Report 2014-5213, 124 p., 2 pl. http://dx.doi.org/10.3133/sir20145213 https://doi.org/10.3133/sir20145213 D.S. Sweetkind J.R. Cederberg S.G. Buto M.D. Masbruch 2023 dataset https://www.sciencebase.gov U.S. Geological Survey Sweetkind, D.S., Cederberg, J.R., Buto, S.G., and Masbruch, M.D., 2011, Three-dimensional hydrogeologic framework for the Great Basin carbonate and alluvial aquifer system of Nevada, Utah, and parts of adjacent states: U.S. Geological Survey data release, https://doi.org/10.5066/P9EOA8PK https://doi.org/10.5066/p9eoa8pk No formal attribute accuracy tests were conducted, however areas of uncertainty can be identified using spatial data field attributes of LocationConfidenceMeters, ExistenceConfidence, IdentityConfidence, and ValueConfidence. Verification was done by interactive on-screen review. Attribute accuracy of the output elevation and thickness grids is dependant on model output. Detailed descriptions and analysis for these data is available in Appendix 1 of the Conceptual model of the Great Basin carbonate and alluvial aquifer system (see larger work citation for details) Tests of valid values were performed throughout processing. Model elements and topology relationships between model units were checked as needed. Data set is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record and associated nonspatial tabular files carefully for additional details. Conclusions drawn from this information are the responsibility of the user. This dataset is the result of raster calculation and interpolation using multiple data sources with varying scales, quality, and accuracy. Detailed descriptions and analysis for these data is available in Appendix 1 of the Conceptual model of the Great Basin carbonate and alluvial aquifer system (see larger work citation for details) Errors resulting from the quality of the source maps, the automation processes, and the scale resolution can impact the accuracy of the data. Errors resulting from the quality of the source map and automation processes are unknown. Horizontal positional accuracy is deductively estimated at 1000 meters. This dataset represents the modeled altitude of the top of hydrogelogic formations in the GBCAAS study area. The data were derived from raster calculation and interpolation using multiple data sources with varying scales, quality, and accuracy. The vertical accuracy varies spatially and is dependant on the data source and performance of the interpolator used. Vertical accuracy of the data is estimated as 100 meters. Set up model grid for use as HFM_ModelGrid Polygon feature class: A GIS was used to develop a "fishnet" polygon array as a polygon feature class representing the model grid. Polygonal cell structure was created for the study area using a GIS and populated with an initial set of attributes such as row and column identifiers. The model grid consists of 509 rows, 389 columns. Model grid rows are oriented in an east-west direction, with row numbers increasing to the south; model grid columns are oriented in a north-south direction, with column numbers increasing to the east. Model grid spacing is 1 mi in both the north-south and east-west directions. The study area spans 110,000 square miles across five states, but most of the study area is in western Utah and eastern Nevada. 2007 Edit DEM in preparation for sampling to the HFM_ModelGrid Polygon feature class: Using a GIS, a 30-meter digital elevation model (DEM) was sampled at cell centroids to populate a land surface elevation value for each cell in the HFM_ModelGrid Polygon feature class. DEM values were hand-edited in a GIS to that stream routing and gradients for surface flows were correct. DEM values were hand edited, using the National Hydrography Dataset and aerial imagery as validation to ensure that the streams were routing in the correct place. DAS143, National Elevation Data (NED) 2007 Simplify geologic map to hydrogeologic units for use in ContactsAndFaults line feature class and MapUnitPolys Polygon feature class: Using a GIS, a state geologic map compilation was projected to the study’s projected coordinate system and clipped to the study area boundary. Geologic map polygons were attributed with corresponding hydrogeologic units (HGUs) based on regional geologic knowledge and reference to previous hydrogeologic studies of the region. Boundaries were dissolved between adjacent HGUs to create a hydrogeologic map of the study area. In a GIS, polygons were converted to polylines and label points. Geospatial data and nonspatial tables were checked for completeness and topologic consistency; polygon slivers or overlaps were eliminated during topologic checks. DAS106, Geologic map databases for the western states 2007 Extract XYZ points from the HGU map for use as model input data within ModelElementValuePoints Point feature class: Using the hydrogeologic map within a GIS, points were hand digitized at mapped contacts between hydrogeologic units, XY coordinates were assigned from map projection, elevation values were assigned by sampling the digital elevation model at each digitized point. The XYZ data were exported as files that were used as a data source for grid interpolation for each HGU. DAS106, Geologic map databases for the western states 2007 Compile faults and caldera boundaries for use in GeologicLines Line feature class A GIS was used to extract fault line and caldera boundary features for the study area from published digital source data. The GIS was used to edit and attribute the vector dataset. Fault line and caldera boundary features were clipped to study area boundary and projected to the GBCASS study projected coordinate system. Polylines were saved in a GIS for use during interpolation of data for each HGU. DAS107, Great Basin geoscience data base DAS108, Digital geologic map of Utah DAS109, Hydrostructural map of the Death Valley ground-water basin DAS110, Tectonic map of the Death Valley ground-water model area DAS111, Geologic map of parts of the Colorado, White River, and Death Valley groundwater flow systems DAS113, geologic map of the Lake Mead 30' X 60' quadrangle DAS114, Stratigraphy of the volcanic Oligocene Needles Range Group DAS115, Eocene through Miocene volcanism in the Great Basin DAS116, Synextensional magmatism in the eastern Great Basin DAS117, Ash-flow tuffs and paleovalleys in northeastern Nevada DAS118, Tertiary volcanic rocks Thomas Range and northern Drum Mountains DAS119, Geologic map of the Fortification Range UT DAS120, Cenozoic volcanic geology of Nevada DAS121, Geologic map Colorado, White River, and Death Valley groundwater flow systems DAS123, Thomas, Keg, and Desert calderas UT DAS124, Calderas of the Marysvale volcanic field DAS125, Geologic map of the Ursine-Panaca Summit-Deer Lodge area DAS126, Death Valley region tectonic map 2007 Creating geologic data from cross sections for use as model input data within ModelElementValuePoints Point feature class: The contacts between HGUs were manually picked from 245 cross sections compiled from 99 separate sources and used as input data within ModelElementValuePoints Point feature class for developing the 3D-hydrogeologic framework. References for each of the cross sections used are available as a separate Excel file distributed with the Conceptual model of the Great Basin carbonate and alluvial aquifer system report (see larger work citation for details). Source geologic maps were georectified using a GIS and the cross section trace digitized; for digital map data, cross section polylines were projected to the GBCASS study projected coordinate system and stored in a GIS. A series of points was digitized along the cross section trace and x,y coordinates were obtained at each point from the map projection. A raster image of each cross section was scaled and georeferenced in a GIS along the cross-section trace from the source map. Geologic units on each cross section were assigned to the HGUs defined for the GBCAAS study area. A vertical stratigraphic “column” was created at each digitized point along the cross-section trace where the altitude of the top surface of each HGU point represented in cross section was interpolated from the cross section vertical scale and recorded. Note: no source abbreviations are shown below. See instead the list of cross section sources released as auxiliary file to GBCAAS conceptual model report, USGS SIR 2010-5193, (see larger work citation for details). 2007 Compilation of depth-to-basement information, for use in building an elevation surface representing the basin of the Cenozoic section; base of 3DHFM model unit LBFAU: “Depth to basement” data from regional gravity studies represent the gravity defined boundary between less dense deposits and underlying consolidated rocks. Gridded output from these studies were merged and the resulting grid used to delineate the boundary between the pre-Cenozoic basement rocks and the Cenozoic volcanic and sedimentary basin-fill deposits. Using a GIS, the Great Basin-wide depth-to-basement surface for Arizona, California, Nevada, and Utah of Saltus and Jachens (DAS132) was merged with depth-to-basement surface for Idaho (DAS133) and three three other regional studies, including data from the central and western Basin and Range (DAS134), the Death Valley region (DAS136), and geophysical framework investigations in east-central Nevada and west-central Utah (DAS135). In areas where the detailed studies overlapped the regional Saltus and Jachens (DAS132) data, the original Saltus and Jachens data were replaced with the more recent data using a common 500 square-meter grid cell size. The depth-to-basement surface was compared to the surficial hydrogeologic map polygons and grid elevations were modified so that the depth-to-basement surface altitude was equal to the sampled DEM altitude where pre-Cenozoic rocks outcrop on the hydrogeologic map. The final merged map was resampled using a 2.59 square kilometer (1 square mile) grid cell size to be consistent with the hydrogeologic map. Within the GBCAAS 3DHFM, the merged “depth-to-basement” surface is used to represent the altitude of the pre-Cenozoic rock surface and the base of the Cenozoic sedimentary basin-fill deposits and volcanic rocks (base of 3DHFM model unit LBFAU). DAS132, Saltus and Jachens; Great Basin depth to basement DAS133, Idaho depth to basement DAS134, central Nevada depth to basement DAS135, eastern NV-western UT depth to basement DAS136, Death Valley regional groundwater system depth to basement 2007 Compile well data for use as model input data within ModelElementValuePoints Point feature class: Stratigraphic data were compiled from 441 well log records throughout the GBCAAS study area. Oil and gas well data from WY, CO, NM, AZ, and UT were downloaded from state oil and gas commission web sites. Water well data were compiled from NV and UT state water databases and from a USGS report (DAS129). The measured depths to subsurface geologic unit contacts were compiled and selected contacts in each well were assigned as contacts between hydrogeologic units for input to the 3DHFM. XY coordinates were assigned in a GIS from the location of borehole collar, HGU top elevations were calculated using reported downhole depth intercepts and the elevation at the well collar. Borehole XYZ data for each HGU were stored in files for use in interpolating top of each HGU. DAS127, Nevada oil and gas exploration wells DAS128, Utah oil and gas exploration wells DAS129, MX missile program in Nevada DAS130, Southern Nevada Water Authority exploration and production wells DAS131, Water wells in Utah 2007 Sampling grids from the DVRFS framework model to populate HGU top elevations in cells in the HFM_ModelGrid Polygon feature class: The existing 3D-hydrogeologic framework for the Death Valley regional flow system (DVRFS) model (DAS137) was sampled for incorporation into the GBCAAS 3DHFM. The DVRFS hydrogeologic model consists of 27 separate HGUs. Individual HGUs in the DVRFS model were assigned to the nine HGUs used in the GBCAAS 3DHFM. Using a GIS, gridded data from relevant HGU surfaces of the Death Valley framework were sampled at cell centroids of the GBCAAS 3DHFM and assigned as HGU top elevation (DAS138) or thickness (DAS139) for each of the nine HGUs used in the GBCAAS 3DHFM. DAS137, DVRFS Model report Chapter E DAS138, DVRFS tops digital release DAS139, DVRFS thickness digital release 2007 Creating interpolated surfaces from model input data contained within ModelElementValuePoints Point feature class: Point data from all input sources were combined and interpolated using standard grid interpolation methods from the well, cross section, model data and geologic map input data points within the ModelElementValuePoints Point feature class. Resulting grids, representing elevation and extent of an HGU, were saved as temporary files that were subsequently sampled to cells in the HFM_ModelGrid Polygon feature class. Input data points within the ModelElementValuePoints Point feature class were interpolated into grids representing the HGU surfaces using 3D modeling software. Further modification and interpretation of the gridded HGU surfaces was completed using a geographic information system (GIS). Input data points were pre-processed with a declustering routine prior to surface gridding, such that multiple closely-spaced data points were assigned an averaged location and altitude value that was used as input to the surface-modeling routine. Input data were gridded using an inverse distance algorithm, where the value assigned to a grid node was computed as a distance-weighted average of the nearest 12 directionally distributed neighbors. The value of each of the data points was exponentially weighted according to the inverse of its distance from the grid node; weighting was adjusted to balance the effects of strong, local control with a broader regional average. Interpolated surfaces represent the top altitude of each of the pre-Cenozoic HGUs—NCCU, the lower carbonate aquifer unit (LCAU), the upper siliciclastic confining unit (USCU), the upper carbonate aquifer unit (UCAU), the thrusted noncarbonate confining unit (TNCCU), and the thrusted lower carbonate aquifer unit (TLCAU). The depth-to-basement surface is used as the base of the basin-fill HGUs and represents the composite top of the pre-Cenozoic HGUs. DAS140, GBCAAS Conceptual Model Report Appendix 1 DAS141, GBCAAS tops digital release DAS142, GBCAAS Conceptual Model Report 2007 Assigning elevation to surface-mapped HGUs to populate HGU top elevations in cells of the HFM_ModelGrid Polygon feature class: Using a GIS, queried the spatial location of cells in the HFM_ModelGrid Polygon feature class, selecting cells that lay within the surface-mapped polygon of each HGU in the MapUnitPolys Polygon feature class. Assigned land-surface elevation to cells corresponding to surface-mapped exposures of each HGU. The elevation of any younger HGUs that had been removed by erosion were also assigned the same elevation and assigned zero thickness. DAS106, Geologic map databases for the western states DAS143 2007 Assigning subsurface elevation to cells in the HFM_ModelGrid Polygon feature class by sampling gridded surfaces: Where HGUs were present in the subsurface, interpolated surfaces created from the input data were sampled at each model cell and the top of HGU elevation assigned from the surface; HGU thickness was calculated as the distance between subjacent and superjacent surfaces and stored within the attribute table. Because of the requirement for grids to be continuous, where stratigraphically lower units are exposed at land surface, one or more shallower units are required to have the same land-surface elevation but to have zero thickness. Caldera boundaries contained within the GeologicLines Line feature class were used to control the extent of pre-Cenozoic HGUs within the mapped calderas. Calderas were assumed to have similar hydrogeologic properties as the noncarbonate confining unit (NCCU); therefore, the area contained within a caldera boundary is designated as NCCU and extends vertically to the base of the volcanic unit (VU). 2007 Creating 3DHFM volume from data in the HFM_ModelGrid Polygon feature class: A closed-volume 3D HFM was created by stacking the individual HGU gridded surfaces using 3-D geological modeling software. The stacking order is defined by the geologic age of the unit, from oldest (Precambrian) to most recent (Quaternary). An exception to the stacking rule applies to the thrusted surfaces, TNCCU and TLCAU, which are stacked relative to time of movement (Mesozoic) rather than age of deposition. HGU thickness is represented by the difference between altitudes of successive HGU surfaces such that the bottom of an HGU is always equal to the top of the HGU directly below it in the stacking order. Where the thickness is zero at a location, the respective HGU does not exist at that location. 2007 Error checking cell values in the HFM_ModelGrid Polygon feature class: HGU elevation and thickness values in the cells of the HFM_ModelGrid Polygon feature class were inspected for spurious local highs and lows in elevation and thickness. A GIS was used to error-check the framework cells for cases where: 1) the elevation of a geologic unit is less than (lower than) that of an underlying geologic unit, 2) the elevation of a geologic unit is equal to that of an underlying geologic unit, but thickness of the unit is reported as nonzero, 3) removed all cases of unit elevation being <Null>, making sure each point had a defined value for HGU top elevation and thickness. Revisions were made to the geospatial database as needed. Grid cell values were locally hand edited to make adjacent cells elevation and thickness more consistent with each other. 2008 Targeted revisions to HGU elevation and thickness values in the cells of the HFM_ModelGrid Polygon feature class: Targeted revisions to the elevation and thickness of HGU's in specific areas of the framework model were made based on framework-driven issues identified during initial numerical hydrologic simulations. This was an iterative process that involved (1) identifying a needed change to the 3DHFM based on an issue identified during numerical simulation, (2) editing HGU elevation and thickness values in the cells of the HFM_ModelGrid Polygon feature class to affect a change in the 3DHFM geometry, and (3) re-running a numerical simulation to evaluate the effect. 2009 Created nonspatial tables Using formats specified by the USGS National Cooperative Geologic Mapping Program’s digital geologic map data schema (GeMS; DAS03), the following nonspatial tables were constructed: DataSources_GBCAAS; a tabulation of data citations that apply to all spatial features. Linked through the unique key DataSourceIDs (of the format DAS*) to every feature in the dataset. DescriptionOfModelElements_GBCAAS defines the geologic entities that are present throughout the database. The table describes for each modeled HGU the component geologic units, lithologic characteristics, and stacking order within the 3DHFM. ElementTypeDict Standardized, non-spatial table that defines the geologic and geometric nature of what is being measured, such as top of unit, base of unit, elevation, depth. GeoMaterialDict Non-spatial table that provides values of GeoMaterial, placed in a hierarchy, and their definitions. For further information, see Appendix A in GeMS documentation, available at http://ngmdb.usgs.gov/Info/standards/GeMS. This table was not modified by the authors. Glossary_GBCAAS Nonspatial table that provides definitions for some of the terminology used in the database . DAS03, Geologic Mapping Schema (GeMS) 2025 Metadata and Entity and Attribute Data Dictionary were created. The collection of written steps, usage guidelines, abstract, summary of results, purpose, spatial and technical limitations, and definitions of spatial and nonspatial data were summarized and formatted using both legacy metadata information and new interpretive metadata content. An Entity and Attribute data dictionary was created to provide a user with a broader understanding of all elements and terminology used to create the metadata, spatial data formats, and nonspatial data formats. This provides users with ample opportunity to understand and direct their questions to answers within the documentation, including processing steps, term recognition, citation clarification, citation usage, and logic for data structure. 2025 Review Digital data were reviewed for scientific content, geologic names standard and GIS and metadata validity. Data were revised based on reviews of all items. 2025 Finalize data Final revised GIS datasets, nonspatial tables, and metadata were created for release. 2025 Vector Unknown 1 Albers Conical Equal Area 29.5 45.5 -96.0 23.0 0.0 0.0 coordinate pair 0.6096 0.6096 meters North_American_Datum_1983 GRS 1980 6378137.0 298.257222101 Refer to DataDictionary_GBCAAS.csv for a complete description of data, tables, min-max values, and units. DataDictionary_GBCAAS.xlsx and DataDictionary_GBCAAS.csv U.S. Geological Survey - ScienceBase mailing address

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Denver CO 80225 1-888-275-8747 sciencebase@usgs.gov Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. Digital Data https://doi.org/10.5066/P13BAFSV None 20260122 Donald Sweetkind USGS - ROCKY MOUNTAIN REGION Research Geologist mailing and physical

Denver Federal Center,DFC Bldg 25

Lakewood CO 80225 303-236-1828 dsweetkind@usgs.gov FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998