Mineralization is varied: (1) Gold-bearing Quaternary gravels, up to 15 feet thick, in gulches, benches, and terraces over Tertiary sediments on a North-sloping pediment faulted against Mesozoic schist and gneiss of the mountain mass; (2) Zone of variable marble interbedded with schist and quartzite, about 150 feet wide, in metamorphosed Mesozoic sedimentary beds, crossing the North end of the Gila Mountains; and (3) Spotty and weak oxidized copper and gold ores in irregular, lensing quartz veins cutting metamorphosed Mesozoic sediments.
Workings are mostly dry placer operations worked mainly from 1858 to about 1865, and sporadically, on smaller scale, mainly from 1931-1943 and 1946-1950. Estimated and recorded production would be close to 26,000 oz. Au and about 1,200 oz. Ag. Also shallow prospects.
ReferencesWilson, E.D. (1933) Geology and Mineral Deposits of Southern Yuma County, Arizona. Arizona Bureau of Mines Bulletin 134: 181-189, 200-201, 202-207, 208-210.
Wilson, E.D. (1961) Gold Placers and Placering in Arizona. Arizona Bureau of Mines Bull. 168 (revised 1978): 18-21.
Johnson, M.G. (1972), Placer gold deposits of Arizona, USGS Bull. 1355, 103p.: 67-69.
Keith, Stanton B. (1978) State of Arizona Bureau of Geology and Mineral Technology, Geological Survey Branch Bull. 192, Index of Mining Properties in Yuma County, Arizona: 145 (Table 4).
Arizona Bureau of Mines file data.
Mineral ListMineral list contains entries from the region specified including sub-localities
12 entries listed. 7 valid minerals.
Localities in this Region
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Locality Updated: Mértola, Mértola, Beja District, PortugalFrom Rui Nunes, 11th Mar 2014 10:57:01