| Basis for focus area |
Music Valley is about 19.3 km (12 mi) southeast of Twentynine Palms, California. Mineralization consists of 7 "prospects" and/or "deposits" exposed along a north- northwest-trending belt hosted by the 1.7 Ga Pinto Gneiss (Evans, 1964). |
| Identified resources |
Identified resources of REE. |
| Production |
Music Valley: Although no production, about 500 metric tons (550 tons) of ore from two prospects was stockpiled near Twentynine Palms, California (Evans, 1964). |
| Status |
Past mining; no current mining. |
| Estimated resources |
Music Valley: 5000 metric tons, grade 5.36% TREO (Long and others, 2010). |
| Geologic maps |
Jennings and others (2010), scale 1:750,000; Howard (2002), scale 1:100,000; Howard and others (2013), scale 1:62,500; Powell and others (2015), scale 1:12,000. |
| Geophysical data |
Aeromagnetic surveys are predominantly of Rank 3 and aeroradiometric surveys of Rank 5 (inadequate). Detailed land gravity and magnetotelluric surveys are in progress. |
| Favorable rocks and structures |
Mineralization is hosted by the Paleoproterozoic Pinto Gneiss, “but nearly always confined to biotite-rich lenses, pods, and folia” (Evans, 1964). Mineralization is also associated with and occurs along the eastern margin of a Mesoproterozoic gabbro-diorite body (Evans, 1964; McKinney and others, 2015). |
| Deposits |
Music Valley deposit (MRDS dep_id: 10212860; USMIN Site_ID: CA00053) (includes Ajax, Uranus 2, 4, 6, Baby Blue, Hansen, and U-Thor prospects). |
| Evidence from mineral occurrences |
MRDS; USMIN. |
| Geochemical evidence |
The Music Valley deposit has some geochemical and geochronological data. Xenotime and monazite are the dominant minerals present, but include allanite and uranothorite. Some biotite zones contain 10-15% and up to 35% xenotime. See Evans (1964) and McKinney and others (2015). |
| Geophysical evidence |
The Music Valley deposit is associated with radiometric anomalies, and occurs along the edge of a gravity and magnetic anomaly associated with a gabbro-diorite intrusion. |
| Evidence from other sources |
The Pinto Gneiss may be related to an igneous protolith enriched with REE that were remobilized and concentrated along the contact with a Mesoproterozoic gabbro-diorite intrusion (McKinney and others, 2015). |
| Comments |
All but two of the prospects are within Joshua Tree National Park. About 450 metric tons (500 tons) of radioactive Pinto Gneiss from the Uranus 4 prospect was stockpiled at Silver Bell processing plant about 2.5 mi north of Twentynine Palms, California. About 45 metric tons (50 tons) of mineralized gneiss from the U-Thor prospect was stockpiled at a mill 3.5 mi southeast of Twentynine Palms (Evans, 1964). |
| Cover thickness and description |
Exposed at the surface. |
| Authors |
David A. Ponce. |
| New data needs |
Detailed geologic mapping. |
| Geologic mapping and modeling needs |
Require 1:12,000 scale or better mapping of deposits; 1:24,000 scale mapping of the Pinto Gneiss; detailed mapping of Mesoproterozoic diorite at Music Valley; detailed mapping of alteration zones; and 3D geologic modeling. |
| Geophysical survey and modeling needs |
Require high-resolution aeromagnetic, and radiometric surveys; 2D and 3D geophysical modeling. |
| Digital elevation data needs |
Require lidar survey of entire Mojave Desert and subsequent analysis. |
