Ajo District, Pima Co., Arizona, USA

Ref.: Lakes, A. (1900) Copper deposits of the Ajo basin and Gila basin, Arizona: Mines and Minerals: 21: 12-15.

Joralemon, I.B. (1914), The Ajo copper district, Arizona, Engineering and Mining Journal: 98: 663.

Joralemon, I.B. (1915).

Bramwell, A.W. (1918) In Ajo and Scheelite districts: Arizona Mining Journal, December 1918: 2(7): 20.

Bramwell, A.W. (1919) News of Ajo and Gunsight districts: Arizona Mining Journal, April 1919: 2(11): 24-25.

Bryan, K. (1925), the Papago country, Arizona, USGS Water Supply Paper 499.

Stewart, L.A. (1933) Study of the Ajo copper ore minerals: Tucson, University of Arizona, M.S. thesis, 24 p.

Schwartz, G.M. (1934), Paragenesis of the oxidized ores of copper, Economic Geologist: 29: 55-75.

Gilluly, James (1935) The copper deposits of Arizona; Ajo district, in Copper resources of the world, v. 1: International Geological Congress, 16th, Washington, D.C., 1933, p. 228-233.

Gilluly, James (1936) Pediments of the Ajo region, Arizona [abs.]: Washington Academy of Sciences, Journal, v. 26, p. 388-389.

Gilluly, J. (1937), Geology and ore deposits of the Ajo quadrangle, Arizona, Arizona Bureau of Mines Bull. 141.

Gilluly, James (1938) Ajo district, in Some Arizona ore deposits: Arizona Bureau of Mines Bulletin no. 145: 86-90.

Gilluly, J. (1942a), Mineralization of the Ajo copper district, Arizona, American Mineralogist: 27: 222-223.

Gilluly, J. (1942b), The mineralization of the Ajo copper district, Arizona, Economic Geology: 37: 297-309.

Gilluly, J. (1946), The Ajo Mining District, Arizona, USGS PP 209.

Butler, B.S. (1947) Review of 'The Ajo mining district, Arizona' by James Gilluly (U.S. Geological Survey Professional Paper 209): Economic Geology: 42(6): 583-587.

Galbraith, F.W. (1947), Minerals of Arizona, Arizona Bureau of Mines Bull. 153: 24.

Schwartz, G.M. (1947), Hydrothermal alteration in the 'porphyry copper' deposits, Economic Geology 42: 319-352.

Dehlinger, M.E. (1949) Report on Ajo quadrangle: Compass [Sigma Gamma Epsilon]: 26: 182-188.

Romslo, T.M., and Robinson, C.S. (1952) Copper Giant deposits, Pima County, Arizona: U.S. Bureau of Mines Report of Investigations R.I. 4850, 9 p.

Schwartz, G.M. (1958), Alteration of biotite under mesothermal conditions, Economic Geology: 53: 164-177.

Galbraith, F.W. & Brennan (1959), Minerals of Arizona: 64, 92.

Hutton, C.O. & A.C. Vlisidis (1960), Papagoite, a new copper-bearing mineral from Ajo, Arizona, American Mineralogist: 45: 599-611.

Sun, M.S. (1961), Differential thermal analysis of shattuckite, American Mineralogist: 46: 67-77.

Bell, P.M., and Roy, R.F. (1965) Heat flow at Ajo, Arizona: Carnegie Institution of Washington Year Book 64, 1964-1965, p. 150-153.

Bell, P.M., and Roy, R.F. (1967) Heat flow and gravity measurements at Ajo, Arizona: Carnegie Institution of Washington Year Book 65, 1965-1966, p. 414-415.

Keith, Stanton B. (1974), AZ Bur. of Geol. & Min. Technology, Geol. Survey Br. Bull. 189, Index of Mining Properties in Pima County, AZ: 82 (Table 4).

Cox, D.P., Czamanske, G.K., and Bain, J.H.C. (1981) Mineral-rich fluid inclusions in the root zone of a porphyry copper system, Ajo, Arizona [abs.]: Geological Society of America Abstracts with Programs: 13(7): 433.

May, D.J., Peterson, D.W., Tosdal, R.M., LeVeque, R.A., and Miller, R.J. (1981) Miocene volcanic rocks of the Ajo Range, south-central Arizona [abs.], in Howard, K.A., Carr, M.D., and Miller, D.M., eds., Tectonic framework of the Mohave and Sonoran Deserts, California and Arizona: U.S. Geological Survey Open-File Report 81-0503, p. 65-66.

UyTana, V.F. (1983) Physiochemical characteristics during potassic alteration of the porphyry copper deposit at Ajo, Arizona: Tucson, University of Arizona, M.S. thesis, 96 p.

Cox, D.P., and Ohta, E. (1984) Maps showing rock types, hydrothermal alteration and distribution of fluid inclusions in the Cornelia pluton, Ajo mining district, Pima County, Arizona: U.S. Geological Survey Open-File Report 84-0388, 9 p., 1 sheet, scale 1:62,500.

Gray, Floyd, and Miller, R.J. (1984) New K-Ar ages of volcanic rocks near Ajo, Pima and Maricopa Counties, southwestern Arizona: Isochron/West, no. 41, p. 3-6.

Peterson, J.A., Cox, D.P., and Gray, F. (1985) Mineral resource assessment of the Ajo and Lukeville 1o by 2o quadrangles, Arizona: U.S. Geological Survey Open-File Report 85-0527, 79 p., 3 sheets, scale 1:250,000.

Peterson, J.A. and Tosdal, R.M. (1986) Mineral Occurrence Map and Tabulation of Geologic, Commodity, and Production Data, Ajo and Lukeville Quadrangles, southwestern Arizona. USGS Miscellaneous Field Studies Map MF-1834-A (scale 1: 250,000).

Peterson, J.A., Cox, D.P., and Gray, F. (1987) Mineral resource assessment of the Ajo and Lukeville 1o by 2o quadrangles, Arizona: U.S. Geological Survey Miscellaneous Field Studies Map MF-1834-B, 3 sheets, scale 1:250,000.

Theobald, P.K., and Barton, H.N. (1987) Maps showing anomalous copper concentrations in stream sediments and heavy-mineral concentrates from the Ajo and Lukeville 1o x 2o quadrangles, Arizona: U.S. Geological Survey Miscellaneous Field Studies Map MF-1834-C, 1 sheet, scale 1:500,000.

Barton, H.N., and Theobald, P.K. (1988) Regional geochemical studies of the Ajo and Lukeville 1o x 2o quadrangles, Arizona, [abs.], in Schindler, K.S., ed., USGS research on mineral resources -- 1989; Fifth annual V.E. McKelvey forum on mineral and energy resources: U.S. Geological Survey Circular 1035, p. 2-4.

Cox, D.P. (1988) Geochemistry of Laramide and Middle Tertiary plutons in the Ajo mining district, Pima County, Arizona: U.S. Geological Survey Open-File Report 88-0672, 13 p.

Gray, Floyd, comp. (1988) Abstracts of the symposium of the geology and mineral deposits of the Ajo and Lukeville 1o x 2o quadrangles, Arizona: U.S. Geological Survey Open-File Report 88-0217, 31 p.

Gray, Floyd, Miller, R.J., Grubensky, M.J., Tosdal, R.M., Haxel, G.B., Peterson, D.W., May, D.J., and Silver, L.T. (1988) Geologic map of the Ajo and Lukeville 1o by 2o quadrangles, southwest Arizona: U.S. Geological Survey Open-File Report 87-0347, 23 p., 1 sheet, scale 1;250,000.

Theobald, P.K., and Barton, H.N. (1988) Maps showing anomalous concentrations of lead, molybdenum, bismuth, and tungsten in stream sediment and heavy-mineral tungsten in stream sediment and heavy-mineral concentrate from parts of the Ajo and Lukeville 1o x 2o quadrangles, Arizona: U.S. Geological Survey Miscellaneous Field Studies Map MF-1834-D, 1 sheet, scale 1:500,000.

Theobald, P.K., and Barton, H.N. (1988) Maps showing anomalous concentrations of zinc, silver, antimony, manganese, barium, and strontium in stream sediment and heavy-mineral concentrate from parts of the Ajo and Lukeville 1o x 2o quadrangles, Arizona: U.S. Geological Survey Miscellaneous Field Studies Map MF-1834-E, 1 sheet, scale 1:500,000.

Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd. ed.: 107, 109, 110, 117, 126, 128, 152, 193, 214, 215, 235, 258, 262, 283, 286, 302, 314, 359, 390, 397, 399, 431.

Force, E.R. (1997) A new mid-Tertiary unit in the Ajo district, southern Arizona, and implications for extensional history, in Richard, S.M., comp., Field guide, Quitovac, Sonora and Ajo, Arizona, Guidebook for the Arizona Geological Society Spring Field Trip, May 22-23, 1997: Arizona Geological Society Field Trip Guidebook, 13 p.

Richard, S.M., comp. (1997) Field guide, Quitovac, Sonora and Ajo, Arizona, Guidebook for the Arizona Geological Society Spring Field Trip, May 22-23, 1997: Arizona Geological Society Field Trip Guidebook, [87] p.

Wilkinson, W.H., Jr., More, S.W., Rivera, J.S., and Mortensen, J.K. (1998) Geological and structural evolution of the Ajo copper deposit, Pima Co. AZ [abs.], in 1999 SME Annual Meeting and Exhibit, March 1-3, Denver, Colorado, Technical Program: Society for Mining, Metallurgy, and Exploration, Inc., Supplement to Mining Engineering, p. 31.
Arizona Bureau of Mines file data.

A Cu-Ag-Au, silica, feldspar, mica (Mo-Zn) mining area located in T.12-13S., R.6-7W., in the Little Ajo Mountains and Chico Shuni Hills.

Mineralization is varied: (1) Cu-Ag & Au mineralization on fracture planes and disseminated in brecciated Laramide intrusive and adjacent Cretaceous volcanics. Some local, high-grade, narrow, irregular vein-like deposits in volcanics and spotty occurrences near fault zones in volcanics and intrusive. Erratic secondary copper mineralization in fanglomerate; (2) Pegmatite veins and masses in Mesozoic granitic intrusive; and, (3) Spotty, irregular gold placers.

Workings include predominantly open pit mining operations. Small, irregular production of high-grade, oxidized copper ore occurred from about 1854 to 1917 and almost continuously thereafter from the open pit operations. Total production through 1972 would amount to some 350,000,000 tons of ore containing about 2,800,000 tons of Cu, 19,000,000 oz. of silver, and 1,550,000 oz. of gold. Considerable silica flux and some feldspar and scrap mica were also produced.