Geology and gold deposits of the Oatman district, northwestern Arizona

Geology and gold deposits of the Marysville mining district, Montana

Gold deposits of the Boulder County gold district, Colorado

The Goldfield gold district, Esmeralda and Nye Counties, Nevada

The Tonopah precious-metal district, Esmeralda and Nye Counties, Nevada

The Republic gold district, Ferry County, Washington

The Comstock Lode precious-metal district, Washoe and Storey Counties, Nevada

The gold deposit at La Josefina, in the Deseado Massif of Argentina, is a low-sulfidation epithermal deposit with some features of the intermediate sulfidation style; the Au occurs in quartz veins and hydrothermal breccias hosted by acid pyroclastic rocks produced by Jurassic bimodal volcanism. Exploration for this deposit type uses geochemical data for vectoring to mineralized rocks. Although a general suite of elements with anomalous concentrations around low-sulfidation deposits is known, that suite varies amongst individual deposits, which should be studied individually.

Epithermal gold deposits in Chile are Cretaceous to Cenozoic in age. The ores and the volcanic rocks with which they are associated were generated at a noncollisional, ocean-continent convergent plate margin. They are related to long, slightly sinuous north-northeasttrending magmatic belts roughly parallel to the Pacific coast. Most of the deposits are associated with eroded volcanic centers and subvolcanic porphyries. North-south variations in the nature, extent, and timing of magmatism control the succession of mineralization events. In the Late Cretaceous, vein districts (e.g., E1 Bronce) and hydrothermal alteration zones were formed in central Chile.

The El Dorado Au-Cu deposit is located in an extensive intra-caldera zone of hydrothermal alteration affecting Upper Cretaceous andesites of the Los Elquinos Formation at La Serena (
29470 S Lat., 70430 W Long., Chile). Quartz-sulfide veins of economic potential are hosted by N25W and N20E fault structures associated with quartz-illite alteration (þsupergene kaolinite).

Металлы платиновой группы это важнейшее стратегическое сырье, в связи, с чем потребность в их обнаружении представляет очень важную задачу для геологии. С каждым годом увеличивается потребность в золоте и металлах платиновой группы. К числу перспективных на благороднометалльное оруденение относится Центральный регион России. Необходимо развитие социально-экономического положения этого региона за счет увеличения минерально-сырьевой базы.

Many of the methods now used for gold extraction are based on techniques that have been known or established for centuries. Gravity concentration, amalgamation, cyanide leaching, chlorination, zinc precipitation, and carbon/charcoal adsorption are all processes that have been used for at least a hundred years, and combinations of these remain as the basis for most gold recovery flowsheets.

GAROFALO, P. S. & RIDLEY, J. R. Gold-transporting hydrothermal fluids in the Earth’s crust: an introduction
POKROVSKI, G. S., AKINFIEV, N. N., BORISOVA, A. Y., ZOTOV, A. V. & KOUZMANOV, K. Gold speciation and transport in geological fluids: insights from experiments and physical-chemical modelling
GAROFALO, P. S., FRICKER, M. B., GU¨ NTHER, D., BERSANI, D. & LOTTICI, P. P. Physical-chemical properties and metal budget of Au-transporting hydrothermal fluids in orogenic deposits

Within the last decade, the high and continuing demand for gold has prompted a global gold rush on a scale never before seen, not even in the heady days of Ballarat, California and the Yukon. Gold is being sought on every continent and, with very few exceptions, in every country around the world. Such interest and fierce competition has demanded considerable innovation and improvement in exploration techniques paralleled by a rapid expansion of the geological database and consequent genetic modelling for the many different types of gold deposits now recognized.

The Republic of South Africa is a metal producer of the first rank. Gold is the most important of the metals and up to the end of 1971, U.S.$ 32 billion had been realized from its sale. This figure was equivalent to 80% of the total value of all metals sold. The gold province is located on the Kaapvaal craton which is composed of Precambrian sedimentary-volcanic and granite-greenstone assemblages ranging in age from 1,750 to 3,500 million years. This craton forms the southern part of the Southern African Shield. No significant gold mineralization has yet been found beyond the boundaries of this shield. On the Kaapvaal craton, five Proterozoic sedimentary-volcanic basins lie on an Archean basement.  <...>