| Lat / long: | 45.42742, -110.10358 |
| Primary: | Chromium |
| Secondary: | Platinum |
| Ore: | Chromite |
| Gangue: | Olivine |
| Orebody form: | LENSES |
| Discovery year: | 1940 |
| Operation type: | Unknown |
| Production size: | None |
| Development status: | Occurrence |
| Host type: | Peridotite |
| 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), Cross-Faulting Offsets Chromitite Layers |
| 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 |
| MRDS | M060091 |
| DEP | 10042339 |
| Reference | {Deposit:: 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. 39-40.}{Deposit:: HOWLAND, A.L., 1955, CHROMITE DEPOSITS IN THE CENTRAL PART OF THE STILLWATER COMPLEX, SWEET GRASS COUNTY, MONTANA: U.S. GEOLOGICAL SURVEY BULLETIN 1015-D, P. 112-113.}{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:: 1955 GEOLMAP HOWLAND, BULL 1015-D, P. 112}{Deposit:: TRENCHING AND ANALYSES BY THE USBM DURING WWII} |
| Reporter | Dohrenwend, John C., Doyle, Brien (Wells, John), Peterson, Jocelyn A. |