Description
Johns-Manville
Commodities
PrimaryRhodium, Palladium, Platinum
SecondaryGold
TertiaryNickel, Copper
Commodity typeM
Deposit
Model4: Merensky Reef PGE
Deposit sizeN
Orebody formSTRATIFORM, DISSEMINATED
Ore controlMagma Mixing
Materials
Ore mineralsChalcopyrite, Pentlandite, Pyrite, Pyrrhotite
GangueApatite, Chlorite, Hornblende, Magnetite, Olivine, Phlogopite, Plagioclase, Pyroxene, Serpentine, Talc, Tremolite
Geology
Host rockNorite,Troctolite,Anorthosite,Harzburgite
StructureThe 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)
Tectonic settingTectonic Setting At Time Of Emplacement Of The Stillwater Complex Is Unknown. The Complex Was Emplaced Shortly After A Major Regional, Subduction-Related Magmatic Event That Culminated In Emplacement Of The 2.73-2.79 Ga Granitoid Suite In The Batholith Exposed In The Beartooth Uplift (Wooden And Others, 1991). However, There Is No Evidence That The Magmatism That Formed The Stillwater Complex Is Related To Convergent Margin Tectonics And Magmatism
Economic & production
Development statusOccurrence
Discovery year1967
Identification
Deposit ID10048513
MRDS IDMP00102
Alternate namesJ-M Reef
RegionNA
Data scoreB
Coordinates45.39881, -109.96885
References
CONN, 1979SEGERSTROM, KENNETH, AND CARLSON, R.R., 1982, GEOLOGIC MAP OF THE BANDED UPPER ZONE OF THE STILLWATER COMPLEX AND ADJACENT ROCKS, STILLWATER, SWEET GRASS, AND PARK COUNTIES, MONTANA: U.S. GEOLOGICAL SURVEY MISCELLANEOUS GEOLOGIC INVESTIGATIONS MAP I-1383, SCALE 1:24,000.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.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.CONN, H.K., 1979, THE JOHNS-MANVILLE PLATINUM-PALLADIUM PROSPECT, STILLWATER COMPLEX, MONTANA, U.S.A.: CANADIAN MINERALOGIST, V. 17, P. 463-468.