These data are microanalyses of 22 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 uranium mineralized core drilled at the Coles Hill uranium deposit, Pittsylvania County, Virginia, and one sample of the host rock collected from a surface outcrop about 5 miles from the deposit. The Coles Hill deposit is hosted in the Taconian (approx. 480-450 Ma) Martinsville igneous complex, and a genetic model for the deposit was published in 2022 (Hall et al., 2022).
The thin sections are identified by the drill hole id (Table 1) followed by the depth at which the sample was collected. For instance, thin section 41-125-424 was collected from Coles Hill drill hole number 41-125, at 424 feet below the collar of the drill hole (as measured along the trace of the hole). The spectra for EDS measurements are provided in separate documents in .docx (word) files, with one document for each area within the thin section (e.g., 41-125-424_area1_EDS) that was examined. Element spectra were collected in multiple spots within each area, with element ID provided by the EDS vendor algorithm. The separation between areas is marked by successively labeled files (e.g. area 1, area 2, and so on). For most sample areas in the thin sections, higher-resolution images are also provided as part of this data release. The images are titled with the drill hole/thin section number (e.g., 41-125_424) followed by the sampled area (e.g., 41-125-424_area1) then the image type (e.g., SEI, BSE, or MAP). 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. Where captured, an image “MAP” is also provided showing the location of the area that was analyzed on a composite backscattered electron detector image of the thin section. In limited circumstances more detailed higher-resolution images were captured for areas of particular interest and these are listed as “detail” images (e.g. 41-125-424_area2detail_VCD). In other limited circumstances, zoomed-out images and element spectra were captured to record the mineralogical context of the area details; and these are designated “overview” images. The thin sections and rock samples are stored in an area known as the hot rocks room, Building 810, Denver Federal Center, Lakewood, Colorado, USA.