The Paleocene Fort Union Formation hosts a compositionally diverse array of Eocene plugs, dikes, and sills arrayed around the Eocene Big Timber stock in the Crazy Mountains of south-central Montana. The geochemistry and petrography of the sills have no

The spatial databases represent the original content of 43 published geologic maps, provide normalized map unit descriptions, and provide additional information and interpretation not in the original reports.

Geologic map unit and lithologic descriptions used in Open File Report 2005-1235, with extensive bibliographic references to geologic literature that could not be included in the spatial database.

Polygons that describe areas of rock outcrop in the area of the Stillwater Complex, Montana from published reports and field mapping sheets. Includes both legacy data and outcrops from recent field mapping. This dataset contains overlapping polygons, as some areas had mapping from different sources that overlapped the same locations. Data are provided in shapefile format.

Data from a helicopter-borne electromagnetic and magnetic survey flown over this area area in 2000. Nominal elevation of the sensor was 60 meters. Survey coverage comprises 1,914 line kilometers. Data are provided in CSV format.

Photographs and micrographs of rock taken from cores in this area. Data are provided in JPEG and CR2 formats.

Micrographs (photographs taken using a microscope) of xenoliths (pre-existing rock material included in younger rocks) in this area, to understand the formation of mineral deposits there. Data are provided in JPEG and CR2 formats.

U-Pb isotopic data collected on zircon in xenoliths from the Sliderock Mountain and Susie Peak plutons using the sensitive high-resolution ion microprobe-reverse geometry (SHRIMP-RG) at Stanford University. Data are provided in CSV format, locations are provided in shapefile format.

Scanned drill core logs and explanatory material provided in PDF format. Hand-written notes provided in CSV format. Locations provided in shapefile format.

Whole rock geochemical analysis of sulfide- and chromite-bearing samples in this area, with specific interest in PGE, cobalt, and gold concentrations. Data are provided in CSV format.

Bright phase and energy-dispersive spectroscopic analyses were performed to evaluate platinum-group element and mineral distribution in a variety of rock types from the lower stratigraphy of the Stillwater Complex in Montana. Data are provided in CSV format, supporting analytical data are provided as PDF reports and TIFF images.

Geologic structure strike and dip information from this area from pre-existing digital strike and dip information and from digitizing strike and dip locations from georeferenced map images. Data are provided in shapefile format.

Gravity measurements were collected during 2013, 2014, 2020 at 168 sites on and around the Stillwater layered mafic complex. Data are provided in CSV and shapefile formats.

Whole-rock major, minor, and trace element geochemistry of rock samples collected from diamond drill holes that intersect the textural discontinuity at the top of the Reef Package from the underground working of the Stillwater Mine. Data are provide in CSV format.

<p>The Stillwater Complex is a Neoarchean, ultramafic to mafic layered intrusion exposed in the Beartooth Mountains in south-central Montana. This igneous intrusion contains magmatic mineralization that is variably enriched in strategic and critical commo