Lithogeochemistry of selected surface and drill core samples from the Chrome and Iron Mountain areas of the Stillwater Complex, Montana

Sulfide- and chromite-bearing samples of the Basal and Ultramafic series of the Stillwater Complex are known to contain elevated concentrations of chromium, nickel, copper, cobalt, gold, and platinum-group elements (PGE). Drill core and surface samples were collected from the Chrome and Iron Mountain areas for whole rock geochemical analysis, with specific interest in PGE, cobalt, and gold concentrations. Core samples are from exploration drilling programs by AMAX in the 1960s and 1970s and Beartooth Platinum in 2004-2007. Reported whole rock data were measured using the following methods: major elements by wavelength dispersive X-ray fluorescence (WDXRF), 60 trace elements by inductively coupled plasma—optical emission spectrometry (ICP-OES), total sulfur and carbon by combustion and infrared detection, ferrous oxide by titration, essential and non-essential water by gravimetric analysis, and gold, platinum, and palladium by lead-fusion fire-assay. Chromitite samples, with greater than 20 wt% Cr2O3, were also analyzed for the full suite of PGE by nickel sulfide fire assay and instrumental neutron activation. Data are reported in a comma-separated values (CSV) file (Chrome_Iron_Stillwater_Geochemistry) that lists the samples that were analyzed, drill hole identification number and depth (if applicable), latitude/longitude location information, and brief sample descriptions. All column headings and abbreviations are explained in the accompanying data dictionary (Chrome_Iron_Geochem_DataDictionary).