Montana · Stillwater, Sweet Grass County
Producer

Stillwater Complex

Stillwater, Sweet Grass County, Montana, United States
PalladiumCopperChromiumPlatinumNickelSilverRhodiumCobaltOsmiumGoldAluminumIridium
⌖ Show on mapUSGS source ↗
Commodities
PrimaryPalladium, Copper, Chromium, Platinum, Nickel
TertiarySilver, Rhodium, Cobalt, Osmium, Gold, Aluminum, Iridium
Deposit
Deposit typeMAGMATIC SEGREGATIONS AND SULFIDE CRYSTALLIZATION (MERENSKY REEF PGE, STILLWATER NI-CU, BUSHVELD CR)
Model1: Stillwater Ni-Cu2: Bushveld Cr4: Merensky Reef PGE
Deposit sizeL
Ore controlMAGMATIC SEGREGATION BY CRYSTAL SETTLING FOR CHROMITE DEPOSITS, MAGMATIC SEGREGATION BY LIQUID IMMISCIBILITY FOR CU-NI DEPOSITS, MAGMATIC SULFIDE CRYSTALLIZATION FOR JM REEF DEPOSITS
Geology
StructureCUMULATE LAYERING, NUMEROUS FAULTS OFFSETTING MINERALIZED LAYERS, THE STILLWATER COMPLEX IS EXPOSED ALONG THE NORTHERN MARGIN OF THE BEARTOOTH UPLIFT, ONE OF SEVERAL LARAMIDE BASEMENT-CORED RANGES THAT MAKE UP THE ROCKY MOUNTAIN FORELAND OF SOUTH-CENTRAL MONTANA (FOOSE AND OTHERS, 1961: KULIK AND SCHMIDT, 1988)
Economic & production
Development statusProducer
Discovery year1883
Identification
Deposit ID60000949
MRDS IDM045489
RegionNA
Data scoreB
Coordinates45.41662, -110.00079
References
PAGE, N.J, AND NOKLEBERG, W.J., 1974, GEOLOGIC MAP OF THE STILLWATER COMPLEX, MONTANA: US.S GEOLOGICAL SURVEY MISCELLANEOUS GEOLOGIC INVESTIGATIONS MAP 1-797, SCALE 1:12,000.PAGE, N.J, AND DORHENWEND, J.C., 1973, MINERAL RESOURCE POTENTIAL OF THE STILLWATER COMPLEX AND ADJACENT ROCKS IN THE NORTHERN PART OF THE MOUNT WOOD AND MOUNT DOUGLAS QUADRANGLES, SOUTHWESTERN MONTANA: U.S. GEOLOGICAL SURVEY CIRCULAR 684, 9 P.CABRI, L.J., AND LAFLAMME, J.H.G., 1974, RHODIUM, PLATINUM, AND GOLD ALLOYS FROM THE STILLWATER COMPLEX, MONTANA: CANADIAN MINERALOGIST, V.12, P. 399-403.CABRI, L.J., LAFLAMME, J.H.G., STEWART, J.M., AND CHEN, T.T., 1975, NEW DATA ON SOME ARSENIDES AND ANTIMONIDES: CANADIAN MINERALOGIST, V. 13, P. 321-335.PAGE, N.J, RILEY, L.B., AND HAFFTY, JOSEPH, 1969, PLATINUM, PALLADIUM, AND RHODIUM ANALYSES OF ULTRAMAFIC AND MAFIC ROCKS FROM THE STILLWATER COMPLEX, MONTANA: U.S. GEOLOGICAL SURVEY CIRCULAR 624, 12 P.PAGE, N.J, RILEY, L.B., AND HAFFTY, JOSEPH, 1972, VERTICAL AND LATERAL VARIATION OF PLATINUM, PALLADIUM, AND RHODIUM IN THE STILLWATER COMPLEX, MONTANA: ECONOMIC GEOLOGY, V. 67, NO. 7, P. 915-923.PAGE, N.J, ROWE, J.J., AND HAFFTY, JOSEPH, 1976, PLATINUM METALS IN THE STILLWATER COMPLEX, MONTANA: ECONOMIC GEOLOGY, V. 71, NO. 7, P. 1352-1363.ENGINEERING AND MINING JOURNAL, 1975, JOHNS-MANSVILLE FINDS GOOD PLATINUM-PALLADIUM VALUES IN MONTANA'S STILLWATER: ENGINEERING AND MINING JOURNAL, V. 176, NO. 2, P. 36.CZAMANSKE, G.K., AND ZIENTEK, M.L., EDS., 1985, THE STILLWATER COMPLEX, MONTANA: GEOLOGY AND GUIDE: MONTANA BUREAU OF MINES AND GEOLOGY SPECIAL PUBLICATION 92, 396 P.PREMO, W.R., HELZ, R.T., ZIENTEK, M.L., AND LANGSTON, R.B., 1990, U-PB AND SM-ND AGES FOR THE STILLWATER COMPLEX AND ITS ASSOCIATED SILLS AND DIKES, BEARTOOTH MOUNTAINS, MONTANA: IDENTIFICATION OF A PARENT MAGMA?: GEOLOGY, V. 18, P. 1065-1068.ZIENTEK, M.L., 1993, MINERAL RESOURCE APPRAISAL FOR LOCATABLE MINERALS: THE STILLWATER COMPLEX, IN HAMMARSTROM, J.M., ZIENTEK, M.L., AND ELLIOTT, J.E., EDS., MINERAL RESOURCE ASSESSMENT OF THE ABSAROKA-BEARTOOTH STUDY AREA, CUSTER AND GALLATIN NATIONAL FORESTS, MONTANA: U.S. GEOLOGICAL SURVEY OPEN-FILE REPORT 93-207, P. F1-F83.