| Basis for focus area |
Pegmatites with similar lithology and in proximity to the Platt Mine/Big Creek district pegmatites are enriched in REE-bearing minerals (Osterwald and others, 1966). Granitoids and gneisses analyzed by Souders and Frost (2006) showed enrichment in light REE. |
| Identified resources |
None. |
| Production |
None. |
| Status |
From Hausel (1986): "Uranium-bearing pegmatites associated with vermiculite and rare earths were prospected for vermiculite on the west side of the districts and south of the Mullen Creek-Nash Fork shear zone... |
| Estimated resources |
Unknown. |
| Geologic maps |
Houston and Graff (1995), scale 1:50,000; Sutherland and Hausel (2004), scale 1:100,000. |
| Geophysical data |
Inadequate aeromagnetic and aeroradiometric coverage, poor ground gravity coverage. |
| Favorable rocks and structures |
Columbite- and samarskite-bearing felsic pegmatite and numerous other regional felsic pegmatite; mineralized quartz veins; stratabound cupriferous quartzite. |
| Deposits |
King Claims (MRDS dep_id: 10018834), Union Asbestos (Platt Ranch) (MRDS dep_id: 10400295). |
| Evidence from mineral occurrences |
MRDS. |
| Geochemical evidence |
No direct geochemical evidence from pegmatites in Sierra Madre, but inferred from similar pegmatite lithologies in Medicine Bow Mountains focus area; reported occurrences of samarskite from "pre-Cambrian granite" (Osterwald and others, 1966). From Souders and Frost (2006), "All Sierra Madre granitoids and gneisses have modest LREE enrichment (Lan/Smn > 4). |
| Geophysical evidence |
No data. |
| Evidence from other sources |
No data. |
| Cover thickness and description |
Variable, mix of good exposure to abundant surficial cover and heavily forested areas. |
| Authors |
Rachel N. Toner, Patricia M. Webber, Benjamin J. Drenth, Michael L. Zientek, Robert W. Gregory, Kevin Mosser, Joshua M. Rosera. |
| New data needs |
1:24,000 scale geologic mapping supported by high-quality geophysics and lidar, especially along trace of Cheyenne Belt; new reconnaissance geochemistry. |
| Geologic mapping and modeling needs |
1:24,000 scale geologic mapping of the igneous and metamorphic stratigraphy, structural and deformation features (especially along Cheyenne Belt), and mineralization trends with precise ground control is essential. Requires outcrop-level mapping. |
| Geophysical survey and modeling needs |
Rank 1 aeromagnetics and aeroradiometrics, also a major ground gravity campaign. |
| Digital elevation data needs |
Lidar in progress with small areas complete. |
