Southern California magnesite

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

Information leading to the delineation of this focus area

Basis for focus area Buffer of 2 km around MRDS magnesite producers, past producers, and prospects in San Bernardino and Riverside Counties.
Identified resources Identified resources of magnesium (magnesite). Historical production of magnesium (magnesite).
Production Unknown.
Status Past mining. Current exploration for magnesite by MGX Minerals (as of 2018).
Estimated resources Drilling and trenching by the USGS and others found high quality magnesite at depths of 100 ft, it is possible that there are an additional 5 to 10 million short tons of magnesite at White Moon.
Geologic maps Stone and Howard (1979), scale 1:250,000; Rogers (1965), scale 1:250,000; Jennings (1961), scale 1:250,000; Bishop (1963), scale 1:250,000.
Geophysical data Inadequate aeromagnetic and aeroradiometric coverage.
Favorable rocks and structures Dolomite and other sedimentary rocks.
Deposits Needles magnesite deposit (White Moon claims) (MRDS dep_id: 10164450).
Evidence from mineral occurrences MRDS.
Geochemical evidence Unknown.
Geophysical evidence Unknown.
Evidence from other sources Bradley (1925).
Comments Sedimentary magnesite, deposited as beds in inland lakes of Tertiary age, occurs near Needles and Kramer, San Bernardino County, and near Bissell, Kern County (Vitaliano, 1950, p. 365). From Roker (2018): "White Moon could replace up to 64% of the imported magnesite because White Moon may be capable of producing 250,000 short t of magnesite annually for 30 years. Magnesite produced from White Moon will have substantial economic advantages over imports from China because of substantially lower transportation costs and no tariffs, which are currently imposed on magnesite imports from China.
Cover thickness and description Exposed and shallow subsurface.
Authors Jane M. Hammarstrom, Erica Key, David Reioux.
New data needs Deposit type in question-is this alteration of dolomite or lacustrine evaporite? Focus will be on characterizing the deposits that are known, larger-scale geologic mapping will be biggest help towards this goal.
Geologic mapping and modeling needs Since deposit types are still in questions (alteration vs. evaporite origins), compile 1:24,000 scale mapping around known magnesite past producers from MRDS to aid in deposit characterization.
Geophysical survey and modeling needs High-resolution, Rank 1 aeromagnetic and aeroradiometric surveys.
Digital elevation data needs Needs lidar coverage.