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Sulfosalt melts / John Mavrogenes in Economic geology, Vol. 105 N° 2 (Mars/Avril 2010) 

Public ISBD [article]  in Economic geology > Vol. 105 N° 2 (Mars/Avril 2010) . - pp. 257-262 Titre : Sulfosalt melts : evidence of high-temperature vapor transport of metals in the formation of high-sulfidation lode gold deposits Type de document : texte imprimé Auteurs : John Mavrogenes, Auteur ; Richard W. Henley, Auteur ; Agnes G. Reyes, Auteur Année de publication : 2011 Article en page(s) : pp. 257-262 Note générale : Economic geology Langues : Anglais (eng) Mots-clés : Sulfosalt  Metals  Vapor  transport  Sulfidation  Gold  deposits Index. décimale : 553 Géologie économique. Minérographie. Minéraux. Formation et gisements de minerais Résumé : In enargite-gold (high-sulfidation) vein deposits, magmatic fluid is considered responsible for the transport of metals and sulfur into the depositional regime. New data from Field-Emission SEM analyses of sulfosalt mineral assemblages (primarily enargite and tennantite) from El Indio, Chile, and Summitville, Colorado, provide direct evidence of high-temperature deposition, including the following: (1) the preservation of delicate euhedral quartz assemblages in sulfosalts, (2) a range of discrete Sb-rich sulfosalt, quartz, feldspar, and flourapatite vug-filling minerals, and (3) symplectic sulfosalt-chalcopyrite textures that are arguably quenched melts. Together, these features indicate formation from the vapor phase at high temperatures. Furthermore, euhedral quartz crystals from El Indio contain high-temperature, vapor-rich fluid inclusions. Combined, these observations are interpreted as suggestive of deposition in response to vapor-phase decompression within fracture arrays that may be considered the analogues of the feeder fractures beneath large low-grade silver-gold deposits such as Yanacocha, Peru. DEWEY : 553 ISSN : 0361-0128 En ligne : http://econgeol.geoscienceworld.org/content/105/2/257.abstract [article] Sulfosalt melts : evidence of high-temperature vapor transport of metals in the formation of high-sulfidation lode gold deposits [texte imprimé] / John Mavrogenes, Auteur ; Richard W. Henley, Auteur ; Agnes G. Reyes, Auteur . - 2011 . - pp. 257-262. Economic geology Langues : Anglais (eng) in Economic geology > Vol. 105 N° 2 (Mars/Avril 2010) . - pp. 257-262 Mots-clés : Sulfosalt  Metals  Vapor  transport  Sulfidation  Gold  deposits Index. décimale : 553 Géologie économique. Minérographie. Minéraux. Formation et gisements de minerais Résumé : In enargite-gold (high-sulfidation) vein deposits, magmatic fluid is considered responsible for the transport of metals and sulfur into the depositional regime. New data from Field-Emission SEM analyses of sulfosalt mineral assemblages (primarily enargite and tennantite) from El Indio, Chile, and Summitville, Colorado, provide direct evidence of high-temperature deposition, including the following: (1) the preservation of delicate euhedral quartz assemblages in sulfosalts, (2) a range of discrete Sb-rich sulfosalt, quartz, feldspar, and flourapatite vug-filling minerals, and (3) symplectic sulfosalt-chalcopyrite textures that are arguably quenched melts. Together, these features indicate formation from the vapor phase at high temperatures. Furthermore, euhedral quartz crystals from El Indio contain high-temperature, vapor-rich fluid inclusions. Combined, these observations are interpreted as suggestive of deposition in response to vapor-phase decompression within fracture arrays that may be considered the analogues of the feeder fractures beneath large low-grade silver-gold deposits such as Yanacocha, Peru. DEWEY : 553 ISSN : 0361-0128 En ligne : http://econgeol.geoscienceworld.org/content/105/2/257.abstract