Nye Basin Lip

Stillwater County, Montana, United States

PlatinumPalladiumRhodiumChromium

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Commodities

PrimaryPlatinum, Palladium, Rhodium, Chromium

Commodity typeM

Deposit

Model2: Bushveld Cr

Deposit sizeN

Orebody formMASSIVE BAND AND DISSEMINATED

Ore controlCrystal Settling In Large Magma Chamber

Materials

Ore mineralsChromite

GangueOlivine

Geology

Host rockPeridotite

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), Local Faults Of Small Offset

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

Identification

Deposit ID10042335

MRDS IDM060086

Alternate namesLower Basin

RegionNA

Data scoreB

Coordinates45.38075, -109.85829

References

WIMMLER, N.L., 1948, INVESTIGATION OF CHROMITE DEPOSITS OF THE STILLWATER COMPLEX, STILLWATER AND SWEETGRASS COUNTIES, MONT.: U.S. BUREAU OF MINES REPORT OF INVESTIGATIONS 4368, P. 26-29.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, P. 918.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, P. 7-8.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.