Masonic District

Mono County, California, United States

GoldSilverCopperLeadMercuryArsenicAntimonyBismuth

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Commodities

PrimaryGold, Silver

TertiaryCopper, Lead, Mercury, Arsenic, Antimony, Bismuth

Commodity typeM

Deposit

Deposit typeHydrothermal stringer zones, breccia filling, or "ledges"

Model154: Epithermal quartz-alunite Au

Orebody formLenticular masses, zones or "ledges" ("ledges" follows the usage of Ransome, 1909, for ore bodies at Goldfield, Nevada)

Ore controlThe principal ore controls include temperature, pressure, faulting, and lithology (Red Wash Volcanics and granodiorite). Where the volcanics and granodiorite are in depositional contact, the volcanics are more intensely altered and mineralized. At the Serita Mine, the ore occurs in steeply dipping or vertical zones that extend upward from the basement contact. The mineralized "ledges" are fault-controlled and occur along faults and in association with subsidiary faults oriented 90? or 45? to the strike of the ledges. At the Chemung Mine, highest ore grades occur at intersections of cross faults and the main veins ("ledges"). At the Perini and "Goldfound" (Gold Fund) mines, stoping is most prevalent on cross faults in the "ledges".\n\nThe hard silicified "ledges" formed in association with faulting. Subsequent faulting shattered the ledges, providing permeable passageways for subsequent gold-bearing hydrothermal fluids. Gouge zones are present along the margins of the ledges. At the Serita Mine, silicification is areal in extent as compared to silicified linear "ledges" in other parts of the district. All of the productive mines in the district have been in silicified zones or ledges, but not all such zones or ledges have been productive.\n\nThe northeast trending fault zone north of Masonic Mountain is a likely candidate for the deeper portion of the hydrothermal system associated with gold mineralization in the Masonic District. \n

Materials

Ore mineralsGold, Telluride, Galena, Argentite, Bornite, Chalcopyrite, Famatinite, Enargite, Malachite, Chrysocolla, Stibnite, Cinnabar, Barite

GangueChalcedony, Quartz, Opal, Hematite, Limonite, Gypsum, Barite, Jarosite, Chlorite, Epidote, Albite, Montmorillonite, Illite, Sericite, Adularia, Calcite, Sulfur

Geology

Host rockAndesite,Basalt,Granite · "Red Wash Volcanics", "Masonic Mountain Granodiorite"

Associated rockMetamorphic Rock,Volcanic Rock (Aphanitic)

Tectonic settingBack-arc extensional cratonic basin

AlterationSilicic; quartz, opal, chalcedony\nAdvanced Argillic; kaolinite, alunite \nPropylitic; \n\nSilicification is of several varieties, including, in probable temporal order, from early to late: 1) gray opal flooding; 2) dense, fine, quartz-alunite with sporadic crystalline alunite in pheonocryst sites; 3) a fine chalcedony-opal flooding; and 4) black chalcedony-opal-microcrystalline pyrite veins; fine chalcedony-opal flooding into the hanging wall on the southeast of the Chemung structure.\n\nThe alteration sequence as reported by (Johnson, 1951) (from oldest to youngest):\n1. Sericitic alteration, which is most abundant in the granodiorite;\n2. Quartz-alunite-kaolinite alteration with diaspore in the outer portion of this zone;\n3. Increase in silica by deposition of silica or leaching of other constituents, or both.\n

Economic & production

Development statusPast Producer

Discovery year1902

Identification

Deposit ID10310709

Alternate namesSuccess, Chemung, Gold Fund, Home View, Lakeview (Lake View), Maybell, Melor, Perini (Perrini), Pittsburg Liberty, Red Rock, Rough-and-Ready, Serita (Sarita), Valley View, New York, Jump-Up-Joe, Lost Horse

RegionNA

Data scoreA

Coordinates38.3575, -119.12444

References

Berger, B. R., 1987, Descriptive model of epithermal quartz-alunite Au, in Mineral Deposit Models: U.S. Geological Survey Bulletin 1693, p. 158-159.Boalich, E. S., 1923, Mono County, Masonic District: California State Mining Bureau Report 18, p. 415-416.Chender, M., and Fordham, W., 1983, Sarita (Project): The Minesearch Annual, California, Oregon, and Washington, Metals Economic Group, v. VIII, p. 289-291.Chesterman, C. W., Chapman, R. H., and Gray, C. H., Jr., 1986, Geology and ore deposits of the Bodie mining district: California Division of Mines and Geology Bulletin 206, 35 pages, 5 plates, 11 figures, 7 tables, 17 photographs.Clark, W. B., 1970, Gold districts of California: California Division of Mines and Geology Bulletin 193, p. 150.Clark, W. B., 1998, Bodie District, in Gold Districts of California, Sesquicentennial Edition, California Gold Discovery to Statehood: California Division of Mines and Geology Bulletin 193, p. 147-148.Eakle, A. S., and McLaughlin, R. P., 1919, Mono County, Masonic District: California State Mining Bureau Report 15, p. 160-165.Heald, P., Foley, N. K., and Hayba, D. O., 1987, Comparative anatomy of volcanic-hosted epithermal deposits: acid-sulfate and adularia-sericite types: Economic Geology, v. 82, no. 1, p. 1-25.Johnson, R. F., 1951, Geology of the Masonic mining district, Mono County, California: M.A. thesis, Univ. of Calif. Berkeley, 51 p.King, T.V.V., Berger, B.R., Ridley, Ian, and Clark, R.N., 1996, in Green, R.O., Editor, Defining the interdependence of volcanism, tectonism, and fluid availability in the formation of epithermal mineralization at Aurora-Bodie CA/NV using AVIRIS Data: Summaries of the Sixth Annual JPL Airborne Earth Science Workshop, March 4-8, 1996, Vol. 1, AVIRIS Workshop, JPL Publication 96-4, Vol. 1, p. 149-154 (also: ftp://popo.jpl.nasa.gov/pub/docs/workshops/96_docs/21.PDF)Legend Metallurgical Laboratory, Reno, NV, 1988, Letter report in California Geological Survey Minefile Folder No. 322-6121.Mono County Historical Society 2004 Newsletter, Masonic Mining District: http://www.cagenweb.com/com/mono/historicalsociety/2004newsletter.txt, 4 p.North American Gold Mining Industry News, 1985, Mariah picks up option on Masonic gold property: North Am. Gold Mining Industry News, November 22, 1985, v. 3, issue 27, 2 p.Sampson, R. J., and Tucker, W. B., 1940, Mineral resources of Mono County: California Journal of Mines and Geology, Report of State Mineralogist, v. 36, no. 2, p. 115-156.Strachan, June 1987, Chemung Hill: unpublished consulting report, a portion of which (pp. 287-291) is in the California Geological Survey Minefile Folder No. 322-6121.Tingley, J. V., and LaPointe, D. D., 2000, Masonic District, in The Nevada Mineral Industry 1999: Nevada Bureau of Mines and Geology Special Publication MI-1999, p. 22.Whitney and Whitney web site: http://www.whitneywhitney.com/projects.shtml.Yahoo Mining/Metals News, 12/15/1999; Elko Daily Free Press, 12/24/1999, referenced in: Masonic District in The Nevada mineral industry 1999, Nevada Bureau of Mines and Geology Special Publication MI-1999, p. 22.