Music Valley

Region West, Southwest
Mineral systems
Deposit types
Critical minerals
Other minerals

Information leading to the delineation of this focus area

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.