| Basis for focus area |
Focus area based on inclusion of numerous MRDS past producers and producers. |
| Identified resources |
Historical production of beryllium (beryl), feldspar, and mica. |
| Production |
Unknown. |
| Status |
Past mining. |
| Estimated resources |
Unknown. |
| Geologic maps |
Bryant and others (1981), scale 1:250,000; Taylor (1975), scale 1:24,000; Sheridan and Marsh (1976), scale 1:24,000; Sheridan and others (1972), scale 1:24,000. |
| Geophysical data |
Inadequate Rank 5 aeromagnetic and Rank 3 aeroradiometric coverage. Rank 5 aeromagnetic coverage. |
| Favorable rocks and structures |
Pegmatite; Idaho Springs Formation (microcline-quartz-plagioclase-biotite gneiss). |
| Deposits |
Centennial Cone Prospect (MRDS dep_id: 10013731), Cressman Gulch, Grover, K.L. Green Ranch Pegmatite, Little Abner Pegmatite, Mt. Judge, Shaffer Hill. |
| Evidence from mineral occurrences |
MRDS. |
| Geochemical evidence |
Pegmatitic beryl and monazite (Hanley and others, 1950). |
| Geophysical evidence |
Unknown. |
| Evidence from other sources |
Unknown. |
| Comments |
Monazite-bearing pegmatite dikes that are mostly of interest for mineral collectors. Fluorite, Nb, Sc, and Ta inferred from the mineral system/deposit type table (Hofstra and Kreiner, 2020). |
| Cover thickness and description |
No cover. |
| Authors |
David A. Ponce, Nora K. Foley, Michael K. O'Keeffe, Joshua M. Rosera. |
| New data needs |
Rank 1 aeromagnetic and aeroradiometric surveys. |
| Geologic mapping and modeling needs |
The entire area has been mapped at 1:24,000 scale (Black Hawk, Ralston Buttes, Golden, Squaw Pass, Evergreen, and Morrison quadrangles). |
| Geophysical survey and modeling needs |
High resolution, Rank 1 aeromagnetic and aeroradiometric surveys. |
| Digital elevation data needs |
Lidar in progress. |
