|Current site name||Darwin Mines|
|Alternate or previous names||Bernon, Defiance, Essex, Independence, Intermediate, Rip Van Winkle, Thompson, Promontory, Fernando, Custer, Hayward, St. Charles, Jackass, Wonder, Standard, Christmas Gift, Lucky Jim, Belle Union, Fairbanks, Dividend, Acme, Santa Anna, Bruce, Lane, Durham, Chipmunk, Toga, Alameda, Kingman, Giroux, Ophir Mountain|
|Geographic coordinates:||-117.59979, 36.29025 (WGS84)|
|Relative position||39 miles southeast of Lone Pine, CA|
|(click for info)|
|Mount Diablo||019S||041E||24, 18,19,30||California|
|Materials||Type of material|
|USGS model code||19a|
|Deposit model name||Polymetallic replacement|
|Mark3 model number||47|
|Host or associated||Host|
|Rock type||Metamorphic Rock > Schist > Calc-Silicate Schist|
|Rock type qualifier||Calc Silicate Rock|
|Rock unit name||Keeler Canyon Formation|
|Host or associated||Associated|
|Rock type||Plutonic Rock > Granitoid > Monzonite|
|Rock type qualifier||Biotite quartz|
|Rock unit name||Darwin stock|
|Regional||Swansea-Coso Thrust System, Darwin Wash Syncline, Darwin Tear Fault|
|Local||Darwin Hills Anticline, Davis Thrust Fault, Standard Fault, Darwin Tear Fault|
|General form||Pipe; Tabular, lens|
|Development status||Past Producer|
|District name||Darwin District|
|Area name||Inyo County Planning Department|
|Ownership category||BLM Administrative Area|
|Owner||ARCO (Anaconda Mining Company) - Last known owner-operator|
Czamanske, G. K. and Hall, W. E., 1975, The Ag-Bi-Pb-Sb-S-Se-Te mineralogy of the Darwin lead-silver-zinc deposit, southern California: Economic Geology, v. 70, p. 1092-1110.
Davis, D. L., and Peterson, E. C., 1948, Anaconda's operation at Darwin mines, Inyo County, California, American Institute of Mining and metallurgical Engineers technical Publication 2407, 11 p.
Eastman, H. S., 1980, Skarn genesis and sphalerite-pyrrhotite-pyrite relationships at the Darwin mine, Inyo County, California, unpublished doctorate thesis, Stanford University,
Hall, W. E. and Mackevett, E. M., 1958, Economic geology of the Darwin quadrangle, Inyo County, California: California Division of Mines Special Report 51, 73 p.
Hall, W. E. and Mackevett, E. M., 1962, Geology and ore deposits of the Darwin quadrangle, Inyo County, California: U. S. Geological Survey Profession Paper 368, 87 p.
Hall, W. E., Rose, H. J., and Simon, F., 1971, Fractionation of minor elements between galena and sphalerite, Darwin lead-silver-zinc mine, Inyo County, California and its significance in geochemistry: Economic Geology, v. 66, p. 602-606.
Kelley, V. C., 1937, Origin of the Darwin silver-lead deposits: Economic Geology, v. 32, p. 987-1008.
Mc Allister, J. F., 1952 Rocks and structure of the Quartz Spring area, northern Panamint Range, California: California Division of Mines Special Report 25, 38 p.
Nelson, C. A., 1981, Basin and range province, in Ernst, W. G., ed., Geotectonic development of California (Rubey Volume I): Englewood Cliffs, New Jersey, Prentice-Hall, p. 202-216.
Norman, L. A., and Stewart, R. M., 1951, Mines and mineral resources of Inyo County: California Journal of Mines and geology, v. 47, n. 1, p. 17-223.
Rye, R. O., Hall, W.E., and Ohmoto, H., 1974, carbon, hydrogen, oxygen, and sulfur isotope study of the Darwin lead-silver-zinc deposit, Southern California: Economic Geology, v. 69, p. 468-481.
Stewart, R. M., 1966, Lead: in Mineral resources of California, California Division of Mines and Geology Bulletin 191, p. 216-220.
Miscellaneous information on the Darwin District is contained in File Number 322-7210 (CDMG Mineral Resources Files, Sacramento) and in files of the Anaconda Geological Documents Collection at the University of Wyoming.
|Subject category||Comment text|
|Deposit||Approximately 94% of California's lead production and 28% of California's zinc production has come from polymetallic lead-silver-zinc deposits in the western Basin and Range province which includes the Death Valley region and most of Inyo County. The majority of deposits in California lie in a northwest-southeast trending mineralized belt extending from the Inyo Mountains southeast through the Argus Range to the Nopah Range. The bulk of production comes from three leading mining districts within this trend; the Darwin District, the Cerro Gordo District in the southern Inyo Mountains, and the Tecopa District at the south end of the Nopah Range east of Death Valley. The Darwin District ranks first in mineral production, followed by the Cerro Gordo and Tecopa districts. Silicified limestone, in the form of calc-hornfels and tactite is the host rock for the lead-silver-zinc deposits. At Darwin, Paleozoic beds of the Permo-Pennsylvanian Keeler Canyon Formation were folded, overturned, faulted, and locally metamorphosed during emplacement of the nearby Coso Range batholith and satellite Darwin stock. The main structural feature of the Darwin District is a north trending overturned syncline intruded by the quartz monzonite Darwin stock near its axis and complexly faulted. Intrusion of the stock into the overturned syncline resulted in a contact metamorphic aureole consisting of calc-silicate minerals peripheral to the intrusive which was later faulted and fractured prior to mineralization. The Davis Thrust Fault strikes northerly along the west side of the Darwin Hills and confined mineralization to the rocks in the footwall between the fault plane and the Darwin stock to the east.. Later introduction of ore solutions created structurally controlled ore bodies which include bedded replacement deposits, irregular replacement bodies, and fissure deposits along faults and fractures within the altered carbonate country rocks. Proximity to faults and intrusive contacts was largely responsible for ore body localization with most ore bodies near N 50? -70? E striking feeder faults. The primary hypogene sulfide ores are argentiferous galena, sphalerite, and chalcopyrite. Gangue minerals include calcite, fluorite, pyrite, and pyrrhotite. A zone of rich oxidized ore extends form the surface to almost 1,000 feet with cerrusite and hemimorphite being the main ore minerals.|
|Environment||The Darwin District is an area of low arid hills (Darwin Hills) within the Darwin Plateau in west central Inyo County. It is located midway between the highest point (Mt. Whitney @ 14,496 feet) and the lowest point (Badwater in Death Valley @ -282 feet) in the contiguous United States, approximately 40 miles west and east respectively. The district is centered around the Darwin Hills, which displays a peak elevation of 6,010 feet at Ophir Mountain, It is surrounded by the Inyo Mountains (max. elev. 9,183') to the north, the northwest flank of the Argus Range to the east (max. elev. 8,839') and the northeast flank of the Coso Mountains (max. elev. 8,160'). The China Lake Naval Weapons Center borders the district to the south. The area is sparsely populated. The town of Darwin, which once supported the thriving district, has a current population of about 40 and consists of a scattering of mostly unoccupied dilapidated wooden buildings and cabins. The old mill buildings and the extensive company housing complex of the Anaconda Darwin mining camp were removed in the 1990s. Most of the historic mine workings are on public lands administered by the BLM or on patented claims. After cessation of mining in the late 1970s as many as 72 patented claims and 230 unpatented claims were on file with the BLM. The next largest town, Lone Pine (pop. 1,660) is 39 miles northwest. Vegetation consists of sparse creosote bush, cacti, and Joshua trees. In the neighboring Argus and Coso Ranges pinon pine and juniper are also common. The climate is arid high desert. Total annual precipitation is 6.67 inches at Haiwee Station (14 miles west). Average summer high temperature is 95.3? in July and average low temperature 28.8? degrees in January. Daily temperature fluctuations can be extreme Drainage is into the Panamint Valley. The Darwin Hills are drained by Lucky Jim Wash and Darwin Wash on the west and east respectively. South of the Darwin Hills, Lucky Jim Wash joins Darwin Wash which flows northward through Darwin Canyon into the Panamint Valley.|
|Reporter||15-OCT-2002||Downey, Cameron I. (Higgins, Chris, T.)||California Geological Survey CGS (Formerly CDMG)|
|Editor||01-SEP-2007||Schruben, Paul G.||U.S. Geological Survey||Converted from S&A FileMaker format to Oracle. Edit checks on rocks, units, and ages with Geolex search, and other fields.|