Olson, Terri Michalchuk, Brad Hackley, Paul Valentine, Brett Parker, Jason San Martin, Ricardo 20221012 Tabular Reston, VA U.S. Geological Survey https://doi.org/10.5066/P9SQGBKQ Imaging of Niobrara Formation and Mowry Shale samples from a range of thermal maturities provided observations and data on pore systems, organic matter (OM) types and associations with mineralogy and fabric, wettability, and microporosity associated with both diagenetic and detrital clays. Imaging techniques included scanning electron microscopy, organic petrography and correlative scanning electron microscopy, and mapping of mineralogy through energy dispersive spectroscopy. Data were collected in order to study variation in pore type, size, and connectivity and relationships with mineralogy and fabric. 2022 publication date Complete None planned -109.64355468672 -101.77734374953 46.799759935293 43.196848320197 USGS Thesaurus organic petrography scanning electron microscopy porosity USGS Metadata Identifier USGS:62de8ee7d34e295035a9c3ff Geographic Names Information System (GNIS): https://www.usgs.gov/us-board-on-geographic-names/domestic-names?p=gnispq Montana Wyoming Geolex, https://ngmdb.usgs.gov/Geolex/search Mowry Shale Powder River Basin Niobrara Formation USGS Thesaurus: Time Periods Cretaceous Period Eocene Epoch none none Paul C. Hackley Northeast Region: GEOLOGY, ENERGY&MINERALS SC Research Geologist mailing and physical

Mail Stop 954, 12201 Sunrise Valley Dr

Reston VA 20192 US 703-648-6458 phackley@usgs.gov No formal attribute accuracy tests were conducted No formal logical accuracy tests were conducted 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 carefully for additional details. No formal positional accuracy tests were conducted No formal positional accuracy tests were conducted Conventional and/or sidewall cores were taken from both Niobrara Formation and Mowry Shale intervals in six wells in the Powder River Basin (PRB). These wells spanned a range of thermal maturity (Table 1) and approximately 100 miles parallel to the basin axis. Specific well locations are proprietary. More extensive imaging (Scanning electron microscope (SEM) mosaics, mineralogy mapping, organic petrography and correlative microscopy) was performed on a high-graded set of six samples, three from the Niobrara and three from the Mowry. Thin sections were made from most samples. 2022 The same six samples (three Niobrara Formation and three Mowry Shale) that were imaged in high-resolution SEM mosaics were used for organic petrography and correlative microscopy. Core samples were prepared at the U.S. Geological Survey (USGS) by crushing a representative split to approximately 1 to 3 mm size chips, which were mounted into 1-inch pellets in a heat-setting plastic binder [PMMA; TransOpticTM poly(methyl methacrylate); Buehler, Inc.]. Pellet mounting conditions were 180°C and 4000 psi for 10 min. Petrographic pellets were ground and polished to a 0.05 µm finish according to ASTM D2797 (ASTM, 2015a). ASTM, 2015a, D2797 Standard practice for preparing coal samples for microscopical analysis by reflected light, Petroleum products, lubricants, and fossil fuels; Gaseous fuels; coal and coke, sec. 5, v. 05.06. ASTM International, West Conshohocken, PA. 2022 Reflectance analyses were performed under oil immersion following ASTM D7708 (ASTM, 2015b) using a 50× (0.85 NA) objective with incident white light. Reflectance analyses used a Leica DM4000 microscope with LED illumination and monochrome camera detection controlled by the DISKUS FOSSIL program from Hilgers Technisches Buero. A Klein and Becker yttrium-aluminum-garnet standard (Ro = 0.908%) was used for reflectance calibration. Mean reflectance of vitrinite (VRo), solid bitumen (BRo) and phosphatic bone material is reported to two decimal places by convention with standard deviation and number of measurements. Mean reflectance values comprised of less than 20 measurements are considered semi-quantitative and are for use as a qualitative thermal maturity indicator only (ASTM, 2015b). ASTM, 2015b, D7708 Standard test method for microscopical determination of the reflectance of vitrinite dispersed in sedimentary rocks, Petroleum products, lubricants, and fossil fuels; Gaseous fuels; coal and coke, sec. 5, v. 05.06. ASTM International, West Conshohocken, PA. 2022 Geographic Names Information System (GNIS) placenames Point Table 1.csv Vitrinite, bitumen, and bone fragment reflectance data Producer defined Sample ID Identifier of sample assigned in the field Producer defined Sample identifier Formation Formation from which sample was collected Producer defined Formation identifier, indicating Niobrara Formation or Mowry Shale, rock type, and age USGS ID Identifier assigned by USGS laboratory, indicating date and order of sample processing Producer defined Sample identifier VRo Vitrinite reflectance in percent Producer defined 0.68 0.85 Percent nd - no vitrinite reflectance data available for sample no. Number of vitrinite reflectance measurements taken on sample Producer defined 12 26 Number of measurements Cells containing "-" indicate no measurement was taken on sample s.d. Standard deviation of vitrinite reflectance measurements Producer defined 0.06 0.11 Unitless Cells containing "-" indicate no measurement was taken on sample BRo Bitumen reflectance in percent Producer defined 0.52 1.15 Percent nd - no bitumen reflectance data available for sample no. Number of bitumen reflectance measurements taken on sample Producer defined 12 30 Number of measurements Cells containing "-" indicate no measurement was taken on sample s.d. Standard deviation of bitumen reflectance measurements Producer defined 0.05 0.10 Unitless Cells containing "-" indicate no measurement was taken on sample Bone Reflectance of phosphatic bone fragments in percent Producer defined 0.23 0.23 Percent nd - no bone reflectance data available for sample no. Number of measurements taken on bone fragments Producer defined 23 23 Number of measurements Cells containing "-" indicate no measurement was taken on sample s.d. Standard deviation of reflectance measurements taken on bone fragments Producer defined 0.04 0.04 Unitless Cells containing "-" indicate no measurement was taken on sample GS ScienceBase U.S. Geological Survey mailing and physical

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Denver CO 80225 United States 1-888-275-8747 sciencebase@usgs.gov * Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. * 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 for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. The file contains data available in comma separated value (.csv) file format. The user must have software capable of opening and viewing a .csv file. 20221012 Mary R. Croke Northeast Region: GEOLOGY, ENERGY&MINERALS SC Physical Science Technician mailing and physical

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Reston VA 20192 US 703-648-6454 mcroke@usgs.gov Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998