Sierra Nevada Foothills

Region West, Southwest
Mineral systems
Deposit types
Other minerals

Information leading to the delineation of this focus area

Basis for focus area MRDS producers or past producers.
Identified resources Historical production of gold and silver.
Production Unknown.
Status Past mining.
Estimated resources Unknown (significant remaining gold resource suspected throughout the Motherlode).
Geologic maps Jennings and others (2010), scale 1:750,000; Saucedo and Wagner (1992), scale 1:250,000; Wagner and others (1981), scale 1:250,000; Wagner and others (1991), scale 1:250,000; Wagner and Bortugno (1982), scale 1:250,000.
Geophysical data Inadequate Rank 3, 4, and 5 aeromagnetic and Rank 5 aeroradiometric coverage.
Favorable rocks and structures Variable: diorite, granite, greenstone, schist, slate. Royal Mountain King Mine: low-sulfide Au-quartz vein; mineralization restricted to quartz veins and wallrocks along low-angle imbricate thrusts.
Deposits Northern area: Royal Mountain King mine (MRDS dep_id: 10310580), Surcease mine (MRDS dep_id: 10035946), Alabama-California mine (MRDS dep_id: 10310695), Bonanza King (MRDS dep_id: 10034260), Canada Hill (MRDS dep_id: 10007536); Southern area: Alice mine (MRDS dep_id: 10076677), Antimony Consolidated mine (MRDS dep: 10076678), Mammoth Eureka mine (MRDS dep_id: 10110700, Tom Moore (MRDS dep_id: 10110701), Wiggins mine (MRDS dep_id: 10236180).
Evidence from mineral occurrences MRDS.
Geochemical evidence Unknown.
Geophysical evidence Unknown.
Evidence from other sources Unknown.
Comments There is general agreement on an orogenic-origin of Sn in the Mother Lode (central and western Sierra). More unclear is the origin of Sn in southern Sierra (South of Lake Isabella, San Emigdio area). Further investigation could characterize the deposits, and age-dating could determine their relationship (if any) to Sn in the Mother Lode.
Cover thickness and description Mother Lode and southern Sierra veins exposed at surface.
Authors David A. Ponce, Ben Parrish, Erica Key.
New data needs Updated geologic mapping, lidar, geochemistry, aeromagnetic and aeroradiometric surveys.
Geologic mapping and modeling needs Updated geologic mapping.
Geophysical survey and modeling needs High-resolution, Rank 1 aeromagnetic and aeroradiometric surveys.
Digital elevation data needs Lidar variable over scattered focus area; some complete, some in progress, some inadequate.