Mine detail: West Fork East Adit

Previously called 'J-M Reef'

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Location

Lat / long:

45.39881, -109.96885

Resource(M)

Primary:	Platinum, Palladium, Rhodium
Secondary:	Gold
Tertiary:	Copper, Nickel
Ore:	Chalcopyrite, Pentlandite, Pyrite, Pyrrhotite
Gangue:	Apatite, Chlorite, Hornblende, Magnetite, Olivine, Phlogopite, Plagioclase, Pyroxene, Serpentine, Talc, Tremolite
Orebody form:	STRATIFORM, DISSEMINATED
Discovery year:	1967

Production

Operation type:	Unknown
Production size:	None
Development status:	Occurrence

Geology

Host type:	Norite,Troctolite,Anorthosite,Harzburgite
Structure:	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)
Tectonic:	Tectonic 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

References

MRDS	MP00102
DEP	10048513
Reference	{Analytical Data:: CONN, 1979}{Deposit:: SEGERSTROM, 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.}{Deposit:: 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.}{Deposit:: 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.}{Deposit:: CONN, H.K., 1979, THE JOHNS-MANVILLE PLATINUM-PALLADIUM PROSPECT, STILLWATER COMPLEX, MONTANA, U.S.A.: CANADIAN MINERALOGIST, V. 17, P. 463-468.}
Reporter	Peterson, Jocelyn A.