Geological Survey Professional Paper 197—D The Basin and Range Province in Utah, Nevada, and California

The Great Basin region contains a large number of mineral deposits, concerning which there is a literature much too extensive to be adequately mentioned here, especially as the Cordilleran ore deposits have so recently been reviewed elsewhere (1). Summaries, with complete bibliographies, are already available for Utah (32, 24) and Nevada (139, 65, 178) and to a lesser extent for southeastern California (107).

By far the most productive deposits are those of the nonferrous metals, which in the last 75 years have yielded gold, silver, copper, head, and zinc valued in all at more. than $3,500,000,000. There are several hundred mining districts containing ores of these metals scattered over the whole province, but by far the greater part of the vast output has come from a small number of districts. The Bingham or West Mountain district, in Utah, with a total production of more than $1,000,000,000, is the largest of these (23, 24). It contains, in addition to its famous disseminated or "porphyry" copper deposits, large bodies of silver-lead-zinc ore that have replaced limestone beds. Another large, low-grade copper deposit occurs in the Robinson or Ely district, in east-central Nevada (219, 194), which has produced about $325,000,000, chiefly in copper.

All the large lead-zinc or silver-lead-zinc deposits are replacement bodies in limestone and, like the large copper deposits, appear to be genetically related to small intrusive masses that approach quartz monzonite in composition. The best-known districts that have produced these ores and the respective values of their production are the Tintic district, Utah, more than $350,000,000 (1542, 24); Eureka, Nev. (87, 43), about $150,000,000; Pioche, Nev. (254), and the San Francisco district, Utah (31), each about $40,000,000; Cottonwood, Utah (36), about $35,000,000; Goodsprings, Nev. (1504), about $25,000,000; and Cerro Gordo, Calif. (130), about $15,000,000.

The gold and silver produced in the province has been derived in large part from epithermal "bonanza" deposits in Tertiary volcanic rocks, which are generally considered to be younger than the granular igneous rocks associated with the base-metal deposits. The Comstock district at Virginia City, Nev. (12, 120), with a production of about $400,000,000; Tonopah, Nev. (188), with $150,000,000; and Goldfield, Nev. (196), with nearly $90,000,000, are the three most famous of these bonanza camps.

Of the minor nonferrous metals, arsenic occurs in considerable amounts at Manhattan, Nev. (63), and at Gold Hill, Utah (187), and there are several small quicksilver deposits. Small quantities of antimony have been mined in the Panamint Range, Calif.

Many iron-ore deposits are known in the province (107), but, with the exception of those at Iron Springs, Utah (138), they have not been productive as sources of metallic iron. Most of them are composed of magnetite and hematite and are localized at contacts of limestone and igneous rock, but brown iron ore has been mined for smelter flux at Tintic, Utah, and Battle Mountain and Pioche, Nev. The numerous tungsten deposits (102), on the other hand, have been sporadically active, and those at Atolia, Calif. (116) and Mill City, Nev. (123), especially have yielded considerable amounts of ore. Among the other ferro-alloy metals (107), only manganese is present in quantities that appear to warrant hope of much future production. It has been mined mainly at Pioche.

The most serious deficiencies in the mineral resources of the province lie in the mineral fuels. Oil shales (259) and impure coals have been found in some of the Tertiary sedimentary rocks, but so far they have been unable to compete economically with the petroleum of southern California or the coal of eastern Utah.

Other nonmetallic products, however, are present in large quantities (107). They include especially such salines as kernite and other borate deposits, gypsum, and the various salts, including those of potassium, which occur in both the Tertiary sedimentary beds and in the many existent playas of the province. The Tertiary beds also contain accumulations of clay, diatomite, and volcanic ash, and the older rocks have provided large quantities of limestone and dolomite, cement rock, and silica. Especially noteworthy are the deposits of dumortierite that are mined at Rochester, Nev. (131), for use in the manufacture of spark plugs.