Microanalysis of samples collected from sandstone-hosted uranium and vanadium deposits in the Colorado Plateau: Utah, New Mexico and Colorado, USA

These data are microanalyses of 91 polished thin sections that were examined using a scanning electron microscope (SEM) equipped with an energy dispersive spectrometer (EDS) to identify minerals and observe their relationships at high magnification. Samples are from the Triassic Chinle and Jurassic Morrison Formations and adjacent units, which are the main hosts for sandstone-hosted uranium-vanadium deposits in the Colorado Plateau region. The samples were collected in 2019, 2020, and 2021 from mine dumps and surface mineralized rock at deposits throughout the Colorado Plateau in Utah and Colorado. Samples from New Mexico were from archival drill core and outcropping mineralized rock collected by Alexandra Pearce as part of her dissertation research at the New Mexico Institute of Mining and Technology, Socorro, New Mexico (Pearce, 2020) and were provided to USGS by Dr. Pearce for this study. The spectra for each EDS measurement are provided in separate documents in Portable Data Format (pdf), with one document for each thin section (e.g., BC-20-01B) that was examined. Element spectra were collected at multiple sites within each thin section, and at multiple spots at each site. Sites are arranged in numeric order in the PDF file for each thin section. The separation between sites is marked by a new image of the site showing the numbered spots for each site. For each sample site in the thin sections, three images (BSE, SEI, and MAP) are provided as part of this data release. The images are titled (e.g., BC-20-01B_BSE _001, BC-20-01B_SEI_001 and BC-20-01B_MAP_001), with the sample name (e.g., BC-20-01B) followed by the image type (e.g., SEI or BSE), then site number (e.g., 001). The naming convention for image types is "SEI” for images taken using a secondary electron detector and “BSE” for images taken using the backscattered electron detector. An image “MAP” is also provided for each analyzed site showing the location of this site on a composite BSE image of the thin section. These thin sections and rock samples are stored in the hot rocks room, Building 810, Denver Federal Center, Lakewood, Colorado, USA. Raw EDS data are saved in the Vendor’s proprietary data formats. Visual displays of the EDS spectrum can be saved by the Laboratory Analyst or User in any image format or in a MS Word document. Report options exist that will output elemental compositions based on the Vendor’s standardless analysis routines. These data are for informational purposes and are not to be used in publication. Quantitative elemental composition by EDS in the DML is not routine and outside the scope of this SOP