In 2021 the United States Geological Survey (USGS) sampled the lower part of the Upper Cretaceous Lewis Shale in the eastern part of the Southwestern Wyoming Province to better characterize its petroleum source rock potential for an upcoming resource assessment. Ninety-five samples from 24 wells were collected from well cuttings of the lower part of the Lewis Shale stored at the U.S. Geological Survey Core Research Center in Lakewood, Colorado. The selected wells are located near the shallow margins of the basin to obtain samples that were not subjected to the effects of deep burial and subsequent organic carbon loss due to thermal maturation as described by Daly and Edman (1987) (fig, 1). The sample intervals were selected based on high gamma ray responses that Pyles and Slatt (2007) interpreted to be organic-rich condensed sections. Special emphasis was given to the Asquith marker bed which represents the maximum transgression of the Lewis Shale (Pasternack, 2005) (fig. 2).

This data release contains geochemical and mineralogical laboratory results from core samples collected from the USGS Cow Creek 1-21 well. The well was drilled and cored in 2022 and targeted the Lewis Shale on the eastern edge of the Washakie Basin in Carbon County, Wyoming. The core data include results from total organic carbon (TOC) and total carbon (TC) analysis, programmed pyrolysis, inductively coupled plasma-optical emission spectroscopy and mass spectrometry (ICP-OES/MS), X-ray diffraction (XRD), stable isotope (C-13) analysis, and vitrinite reflectance analysis. A separate data release contains 4 geophysical wire line logs and is available at .

This data release contains data associated with the USGS SIM publication "Stratigraphic Cross Sections of the Lewis Shale in the eastern part of the Southwestern Wyoming Province, Wyoming and Colorado". North-to-southeast (A–A’), west-to-east (B–B’), and southwest-to-northeast (C–C’) cross sections were created from 105 wells throughout the eastern part of the Southwestern Wyoming Province. The cross sections highlight 15 clinothems within the Lewis Shale, Fox Hills Sandstone, and Lance Formation progradational system. Data include well information and depths to key stratigraphic surfaces for 105 wells within the three cross sections. Well information includes the cross section identification, API #, well name, latitude in decimals, longitude in decimals, projection datum, county, state, Kelly Bushing elevation in feet, section, township, and range. Wells 19*, 26*, 69* and 70* are intersection points between the three sections. The stratigraphic data are all listed in measured depth relative to the Kelly bushing elevation and include the depth to the top of the Almond Formation, depth to the top and base of the informal Asquith marker, depth to the tops of 15 flooding surfaces which define the series of clinothems within the Lewis Shale, depth the top of the Lewis Shale, and depth to the top of the Fox Hills Sandstone.

This data release contains data associated with the USGS SIM publication "Stratigraphic Cross Sections of the Lewis Shale in the eastern part of the Southwestern Wyoming Province, Wyoming and Colorado". North-to-southeast (A–A’), west-to-east (B–B’), and southwest-to-northeast (C–C’) cross sections were created from 105 wells throughout the eastern part of the Southwestern Wyoming Province. The cross sections highlight 15 clinothems within the Lewis Shale, Fox Hills Sandstone, and Lance Formation progradational system. Data include well information and depths to key stratigraphic surfaces for 105 wells within the three cross sections. Well information includes the cross section identification, API #, well name, latitude in decimals, longitude in decimals, projection datum, county, state, Kelly Bushing elevation in feet, section, township, and range. Wells 19*, 26*, 69* and 70* are intersection points between the three sections. The stratigraphic data are all listed in measured depth relative to the Kelly bushing elevation and include the depth to the top of the Almond Formation, depth to the top and base of the informal Asquith marker, depth to the tops of 15 flooding surfaces which define the series of clinothems within the Lewis Shale, depth the top of the Lewis Shale, and depth to the top of the Fox Hills Sandstone.

In 2024, the United States Geological Survey (USGS) compiled rock properties data from the USGS Core Research Center's (CRC) database for the Southwestern Wyoming Province and adjoining areas to better characterize the potential hydrocarbon sources and reservoirs in the area. Data from 53 wells were collected from data analysis results located in the CRC database. These data are derived from a combination of USGS and non-USGS laboratory analyses, with samples provided over several decades by researchers who accessed the CRC collection. The compiled data are from pre-Cretaceous Formations in the Southwestern Wyoming Province area. For each well, accompanying metadata details the sample sources, analytical methods, and quality considerations to aid in scientific analysis and public use.

In 2019 the U.S. Geological Survey (USGS) quantitively assessed the potential for undiscovered, technically recoverable continuous (unconventional) oil and gas resources in the Niobrara interval of the Cody Shale in the Bighorn Basin Province (Finn and others, 2019). Leading up to the assessment, in 2017, the USGS collected samples from the Niobrara and underlying Sage Breaks intervals (Finn, 2019) to better characterize the source rock potential of the Niobrara interval. Eighty-two samples from 31 wells were collected from the well cuttings collection stored at the USGS Core Research Center in Lakewood, Colorado. The selected wells are located near the outcrop belt along the shallow margins of the basin to obtain samples that were not subjected to the effects of deep burial and subsequent organic carbon loss due to thermal maturation as described by Daly and Edman (1987) (fig. 1). Sixty samples are from the Niobrara interval, and 22 from the Sage Breaks interval (fig. 2).

In 2019 the U.S. Geological Survey (USGS) quantitively assessed the potential for undiscovered, technically recoverable continuous (unconventional) oil and gas resources in the Niobrara interval of the Cody Shale in the Bighorn Basin Province (Finn and others, 2019). Leading up to the assessment, in 2017, the USGS collected samples from the Niobrara and underlying Sage Breaks intervals (Finn, 2019) to better characterize the source rock potential of the Niobrara interval. Eighty-two samples from 31 wells were collected from the well cuttings collection stored at the USGS Core Research Center in Lakewood, Colorado. The selected wells are located near the outcrop belt along the shallow margins of the basin to obtain samples that were not subjected to the effects of deep burial and subsequent organic carbon loss due to thermal maturation as described by Daly and Edman (1987) (fig. 1). Sixty samples are from the Niobrara interval, and 22 from the Sage Breaks interval (fig. 2).

This data release contains the whole-rock major and trace element analyses of 51 samples of intrusive igneous rocks from the Wet Mountains area of Custer and Fremont counties of south-central Colorado, collected by U.S. Geological Survey (USGS) geologists. The samples were collected from breccias, veins and thin dikes, and a variety of carbonatite, felsic, mafic, and ultramafic intrusions across the area. The first 41 samples listed in this data release were collected in July 2007, originally as part of a reconnaissance study of the thorium deposits of the area (Van Gosen and others, 2009). The samples are grab samples from outcrops, shallow open-pit excavations, and mineral prospect trenches. The last 10 samples listed in this data release were originally collected and geochemically analyzed in 1976 as part of a USGS study of carbonatites in this area (Armbrustmacher, 1976, 1979; Armbrustmacher and Brownfield, 1978). These 10 carbonatite samples were reanalyzed by modern analytical methods in 2007, and the new data are included in this data release. The Wet Mountains area hosts a variety of alkaline intrusions (Armbrustmacher, 1984), which includes three Cambrian-age alkaline complexes (Olson and others, 1977) that intruded the surrounding Precambrian terrane. These are (1) the McClure Mountain Complex (Shawe and Parker, 1967; Armbrustmacher, 1984), (2) the Gem Park Complex (Parker and Sharp, 1970), and (3) the complex at Democrat Creek (Armbrustmacher, 1984). In the Wet Mountains area, elevated concentrations of thorium and rare earth elements (REEs) occur in veins, syenite dikes, fracture zones, breccias, and carbonatite dikes (Armbrustmacher, 1988). These thorium-REE deposits are distal to the alkaline complexes but are thought to be genetically associated. Characteristics of the thorium and REE deposits in the area, as well as typical concentrations and resource estimates, are detailed in the publications listed in the supplementary file “Wet Mountains area publications.pdf”. Armbrustmacher (1988) determined that vein and fracture zone deposits contain most of the thorium and REE resources in the area. These are linear features, typically 1–2 meters thick, but a few are as much as 15 meters thick. Some individual thorium veins can be traced in outcrop for 1,500 m and some radioactive fracture zones for as much as 13 kilometers. Most of these vein- and fracture-zone deposits occur within a 57 square kilometers tract of Precambrian gneiss and migmatite (Scott and others, 1976) located south and southeast of the quartz syenite complex at Democrat Creek; in this area Christman and others (1953, 1959) mapped nearly 400 veins. Most of the samples in this data release are examples of unaltered alkaline igneous rocks of the intrusive complexes rather than the mineral deposits. These samples were selected in the field to study possible relationships between the magmatic complexes and the thorium-REE deposits. All samples included in this data release were analyzed by laboratories contracted by the USGS. Major and trace element concentrations were determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES) and inductively coupled plasma-mass spectrometry (ICP-MS). An acceptable criteria for the data has been identified based on (1) if recovery of each element is within a designated percentage at five times the lower limit of determination, and (2) the calculated relative standard deviation of duplicate samples is no greater than that percentage. The reported laboratory percentages for the acceptance criteria are +/- 15 percent for ICP-AES and ICP-MS. Ten carbonatite samples were additionally analyzed by wavelength dispersive X-ray fluorescence (WDXRF) to determine the concentrations of major elements as oxides. The reported laboratory percentages for the acceptance criteria are +/- 5 percent for WDXRF. Data are reported in a comma-separated values (CSV) file that lists the samples that were analyzed,

This data release contains the whole-rock major and trace element analyses of 51 samples of intrusive igneous rocks from the Wet Mountains area of Custer and Fremont counties of south-central Colorado, collected by U.S. Geological Survey (USGS) geologists. The samples were collected from breccias, veins and thin dikes, and a variety of carbonatite, felsic, mafic, and ultramafic intrusions across the area. The first 41 samples listed in this data release were collected in July 2007, originally as part of a reconnaissance study of the thorium deposits of the area (Van Gosen and others, 2009). The samples are grab samples from outcrops, shallow open-pit excavations, and mineral prospect trenches. The last 10 samples listed in this data release were originally collected and geochemically analyzed in 1976 as part of a USGS study of carbonatites in this area (Armbrustmacher, 1976, 1979; Armbrustmacher and Brownfield, 1978). These 10 carbonatite samples were reanalyzed by modern analytical methods in 2007, and the new data are included in this data release. The Wet Mountains area hosts a variety of alkaline intrusions (Armbrustmacher, 1984), which includes three Cambrian-age alkaline complexes (Olson and others, 1977) that intruded the surrounding Precambrian terrane. These are (1) the McClure Mountain Complex (Shawe and Parker, 1967; Armbrustmacher, 1984), (2) the Gem Park Complex (Parker and Sharp, 1970), and (3) the complex at Democrat Creek (Armbrustmacher, 1984). In the Wet Mountains area, elevated concentrations of thorium and rare earth elements (REEs) occur in veins, syenite dikes, fracture zones, breccias, and carbonatite dikes (Armbrustmacher, 1988). These thorium-REE deposits are distal to the alkaline complexes but are thought to be genetically associated. Characteristics of the thorium and REE deposits in the area, as well as typical concentrations and resource estimates, are detailed in the publications listed in the supplementary file “Wet Mountains area publications.pdf”. Armbrustmacher (1988) determined that vein and fracture zone deposits contain most of the thorium and REE resources in the area. These are linear features, typically 1–2 meters thick, but a few are as much as 15 meters thick. Some individual thorium veins can be traced in outcrop for 1,500 m and some radioactive fracture zones for as much as 13 kilometers. Most of these vein- and fracture-zone deposits occur within a 57 square kilometers tract of Precambrian gneiss and migmatite (Scott and others, 1976) located south and southeast of the quartz syenite complex at Democrat Creek; in this area Christman and others (1953, 1959) mapped nearly 400 veins. Most of the samples in this data release are examples of unaltered alkaline igneous rocks of the intrusive complexes rather than the mineral deposits. These samples were selected in the field to study possible relationships between the magmatic complexes and the thorium-REE deposits. All samples included in this data release were analyzed by laboratories contracted by the USGS. Major and trace element concentrations were determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES) and inductively coupled plasma-mass spectrometry (ICP-MS). An acceptable criteria for the data has been identified based on (1) if recovery of each element is within a designated percentage at five times the lower limit of determination, and (2) the calculated relative standard deviation of duplicate samples is no greater than that percentage. The reported laboratory percentages for the acceptance criteria are +/- 15 percent for ICP-AES and ICP-MS. Ten carbonatite samples were additionally analyzed by wavelength dispersive X-ray fluorescence (WDXRF) to determine the concentrations of major elements as oxides. The reported laboratory percentages for the acceptance criteria are +/- 5 percent for WDXRF. Data are reported in a comma-separated values (CSV) file that lists the samples that were analyzed,

The Upper Colorado River Basin has a drainage area of about 113,500 square miles in western Colorado, eastern Utah, southwestern Wyoming, northeastern Arizona, and northwestern New Mexico. In the 1980’s and 1990’s, the Upper Colorado River Basin was a study area under of the U.S. Geological Survey's Regional Aquifer-System Analysis (RASA) program (Sun and Johnston, 1994; Sun and Weeks, 1991). The objectives of the RASA program for the Upper Colorado River Basin were to provide regional assessments of major aquifer systems by providing quantitative assessments of the occurrence, movement, and availability of water stored in rock formations that underlie the basin/watershed. These assessments included: (1) the classification of stratigraphic sequences into those intervals that constitute aquifers and those that constitute confining beds; and (2) the generation of maps that portrayed the areal extent of aquifers, aquifer thickness, and overburden thickness. These studies generated a large body of subsurface geologic information as part of the regional aquifer analyses, some of which are captured in this digital data release. Aquifer systems in consolidated rocks in the Upper Colorado River Basin have been grouped into three major subdivisions of sedimentary rocks; in descending order: (1) Tertiary-rock aquifers, (2) Mesozoic-rock aquifers, and (3) Paleozoic-rock aquifers (Taylor and others, 1983; 1986). Within each aquifer group, rocks are further divided into aquifers and confining units on the basis of lithology, depositional environment, and hydrologic characteristics (Glover and others, 1998; Freethy and Cordy, 1991; Geldon, 2003). In a report describing consolidated-rock aquifers of Paleozoic age, 7 hydrostratigraphic units were defined, four aquifers and three confining units (Geldon, 2003). The hydrostratigraphic units of Paleozoic age are locally exposed around the margins of uplifts and in deeply-incised canyon; they occur widely in the subsurface of the Upper Colorado River Basin study area, except in parts of the Uinta, Wind River, and Uncompahgre uplifts where they have been removed by erosion. These hydrostratigraphic units are part of the stratigraphic sequence of Paleozoic rocks that has a total thickness of more than 5,000 ft. This digital dataset contains spatial datasets corresponding to the contoured subsurface maps of Paleozoic rock units produced by the U.S. Geological Survey's Regional Aquifer-System Analysis (RASA) of the Upper Colorado River Basin (Geldon, 2003). The data define the thickness, extent, nomenclature, and facies characteristics of principal hydrostratigraphic units of Paleozoic age in the basin. The digital data describe the following hydrostratigraphic units: the Flathead aquifer, the Gros Ventre confining unit, the Bighorn aquifer, the Elbert-Parting confining unit, the Madison aquifer (consisting of two zones, the Redwall-Leadville zone, and the Darwin-Humbug zone), the Four Corners confining unit (consisting of the Belden-Molas subunit and the Paradox-Eagle Valley subunit), and the Canyonlands aquifer (consisting of three zones, the Cutler-Maroon zone, the Weber-de Chelly zone, and the Park City-State Bridge zone). Contoured thickness and lithology data for each unit are contained in line features classes within a geodatabase; unit extents, facies extents, and formation nomenclatural extents are represented as polygon feature classes. Both types of data are also saved as individual shapefiles. Nonspatial tables define the data sources used, terminology, and the stacking hierarchy and component geologic formations of each the of hydrostratigraphic units