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TitleEpithermal gold deposits
AuthorTaylor, B E
SourceMineral deposits of Canada: a synthesis of major deposit-types, district metallogeny, the evolution of geological provinces, and exploration methods; by Goodfellow, W D (ed.); Geological Association of Canada, Mineral Deposits Division, Special Publication no. 5, 2007 p. 113-139
Year2007
Alt SeriesEarth Sciences Sector, Contribution Series 20070191
PublisherGeological Association of Canada, Mineral Deposits Division (St. John's, NL, Canada)
Documentserial
Lang.English
Mediapaper; DVD
RelatedThis publication is contained in Goodfellow, W D; (2007). Mineral deposits of Canada: a synthesis of major deposit-types, district metallogeny, the evolution of geological provinces, and exploration methods, Geological Association of Canada, Mineral Deposits Division, Special Publication no. 5
File formatpdf
ProvinceBritish Columbia; Alberta; Saskatchewan; Manitoba; Ontario; Quebec; New Brunswick; Nova Scotia; Prince Edward Island; Newfoundland and Labrador; Northwest Territories; Yukon; Nunavut
NTS1; 2; 3; 10; 11; 12; 13; 14; 15; 16; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 52; 53; 54; 55; 56; 57; 58; 59; 62; 63; 64; 65; 66; 67; 68; 69; 72; 73; 74; 75; 76; 77; 78; 79; 82; 83; 84; 85; 86; 87; 88; 89; 92; 93; 94; 95; 96; 97; 98; 99; 102; 103; 104; 105; 106; 107; 114O; 114P; 115; 116; 117; 120; 340; 560
Lat/Long WENS-141.0000 -50.0000 90.0000 41.7500
Subjectseconomic geology; metallic minerals; mineral deposits; mineral occurrences; mineral exploration; mineralization; exploration; gold; epithermal deposits; hydrothermal systems; hydrothermal alteration; alteration; hydrothermal deposits; base metals; copper; lead; zinc; geothermometry; host rocks; exploration methods
Illustrationssketch maps; plots; cross-sections; tables
ProgramConsolidating Canada's Geoscience Knowledge
ProgramTargeted Geoscience Initiative (TGI-3), 2005-2010
AbstractEpithermal Au (±Ag) deposits form in the near-surface environment, from hydrothermal systems typically within 1.5 km of the Earth's surface. They are commonly found associated with centres of magmatism and volcanism, but form also in shallow marine settings. Hot-spring deposits and both liquid- and vapour-dominated geothermal systems are commonly associated with epithermal deposits. Epithermal Au deposits are commonly consider to comprise one of three subtypes: high sulphidation, intermediate sulphidation, and low sulphidation, each denoted by characteristic alteration mineral assemblages, occurrences, textures, and, in some cases, characteristic suites of associated geochemical elements (e.g. Hg, Sb, As, and Tl). Base metal (Cu, Pb, and Zn) and sulphide minerals may also occur in addition to pyrite and native Au or electrum. In some epithermal deposits, notably those of the intermediate-sulphidation subtype, base metal sulphides may comprise a significant ore constituent.

Canadian Au production from epithermal deposits has been minor (<5%), compared to that from transitional and intrusion-related Au deposits, or to other lode Au deposits. The shallow origin of epithermal Au deposits makes them more susceptible to erosion, and, accordingly, epithermal Au deposits have represented a high-grade, readily mineable, exploration target largely in Tertiary and younger volcanic centres, including the Cordillera. However, a number of older epithermal Au deposits have also been discovered, including several Proterozoic examples in Canada. Thus, older terranes need not be excluded entirely from exploration.

Modern geothermal and volcanic systems provide natural laboratories for the study of epithermal deposits, guiding theoretical models and laboratory experiments, and expanding our understanding of potential environments and vectors to mineralized systems. Yet, a principal, unanswered question still remains: do rich Au deposits form from Au-rich sources, or from exceptionally efficient mechanisms or processes of Au precipitation?
GEOSCAN ID224176