Niobium-rich minerals from the Sheep Creek carbonatite-related deposits, Montana, USA
September 15, 2025
The Sheep Creek area in southwest Montana contains a number of small, tabular, carbonatite-related deposits that are rich in Nb- and REE-minerals. Two of the “vein-dikes” were mined at a small scale for Nb in the late 1950s. The most abundant Nb-bearing minerals are columbite-(Fe), nioboaeschynite-(Ce), baotite, and two varieties of Ti-Nb-Fe-oxide. An early oxide with Ti/Nb (atomic) near unity later broke down to a mixture of columbite + TiO2 with distinctly lower Nb content. Zircon intergrown with the Nb-REE minerals was dated by U-Pb methods to 116±2 Ma. This age is in agreement with previous dating (Th-Pb on monazite, Re-Os on molybdenite), and indicates that the Sheep Creek deposits are early Cretaceous in age.
Citation Information
| Publication Year | 2025 |
|---|---|
| Title | Niobium-rich minerals from the Sheep Creek carbonatite-related deposits, Montana, USA |
| Authors | Christopher Gammons, Heather A. Lowers, Jay M. Thompson |
| Publication Type | Conference Paper |
| Publication Subtype | Conference Paper |
| Index ID | 70277412 |
| Record Source | USGS Publications Warehouse |
| USGS Organization | Geology, Geophysics, and Geochemistry Science Center |