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Gold Reef prospect, U.S. Army Yuma Proving Grounds, Silver District, Trigo Mts, La Paz Co., Arizona, USA

Latitude: 33°4'53"N
Longitude: 114°30'41"W
‡Ref.: Wilson, E.D. (1941), Tungsten Deposits of Arizona. Arizona Bureau of Mines Bull. 148: 21.

Dale, V.B. (1959), Tungsten deposits of Yuma, Maricopa, Pinal and Graham Counties, Arizona, U.S. Bureau of Mines Report of Investigation 5516: 29-30.

Galbraith, F.W. & D.J. Brennan (1959), Minerals of Arizona: 81.

Lemmon, D.M., and Tweto, O.L. (1962) Tungsten in the U.S., USGS map, MR-25.

Parker, F.Z. (1966) The Geology and Mineral Deposits of the Silver District Trigo Mountains, Yuma County, Arizona. Masters Thesis, San Diego State College.

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: 176 (Table 4).

Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd. ed.: 363.

Lemmon, D.M., unpublished data.

MRDS database Dep. ID file #10027191,MRDS ID #M002421; and, Dep. ID #10210205, MAS ID #0040120226.

A former surface W-Fe mine located in the NW¼ sec. 30, T4S, R22W (sec. 15 per MRDS), about 3½ miles by trail N of Knowles Camp, on a military reservation. Owned by H. Knowles & R. Young. NOTE: Alternate coordinates provided: 33.055N, 114.5733W.

Mineralization is a quartz vein deposit hosted in brownish quartz-sericite schist intruded by rhyolite and aplitic dikes. The schist strikes N.35ºE. & dips 30ºNW. The principal vein is spotty scheelite with iron oxides, quartz, and calcite in a narrow vein (0.61 meters wide) in a fault fissure zone that strikes N.55ºW. and dips 80ºS. and is traceable on surface intermittently for about 500 feet (152.4 meters). The vein is hosted in Mesozoic metamorphic quartz-sericite schist intruded by Tertiary rhyolite to aplitic dikes. Wall rocks exhibit alteration to sericite. The vein consists of irregular masses of sheared grayish-white quartz from less than 1 inch to 2 feet wide.

Workings include shallow prospect pits. There was a possible small production in 1953.

Mineral List

Calcite
Hematite
Limonite
Muscovite
var: Sericite

Scheelite


5 entries listed. 3 valid minerals.

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