Petrology, U/Pb dating and (C-O) stable isotope constraints on the source and evolution of the adakite-related Mezcala Fe-Au skarn district, Guerrero, Mexico - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Mineralium Deposita Année : 2004

Petrology, U/Pb dating and (C-O) stable isotope constraints on the source and evolution of the adakite-related Mezcala Fe-Au skarn district, Guerrero, Mexico

Résumé

The Mezcala gold district, Guerrero, Mexico, is a Cretaceous to early Paleocene oxidized Fe-Au skarn deposit, genetically associated with an adakitic magmatic event of 63±2 Ma, dated by ion-probe U/Pb on zircons. The inner and outer alteration patterns and the mineralogical sequence (high garnet/pyroxene ratio, high ferric/ferrous ratio >1, predominance of Fe-poor garnet and pyroxene, low total sulfides) found in Mezcala are compatible with the description of an oxidized gold skarn type. Carbon and oxygen isotope analyses of the inner calcite zone (–9.98 to –11.64 and +13.21 to +14.59, respectively) unequivocally support a magmatic signature of the hydrothermal fluid. Carbon and oxygen isotopes from the outer calcite zone (–8.81 to +3.45 and +12.95 to +22.77, respectively) suggest a complex mechanism of degassing and subsequent cooling/dilution of the resulting magmatic brine with the meteoric water. Gold appears to be closely associated with the adakite stock, whereas its transport is related with the outflow of highly oxidized magmatic brines from the intrusion. The gold precipitation is triggered by cooling/dilution of the degassed magmatic brine by the meteoric fluids

Dates et versions

hal-00123657 , version 1 (10-01-2007)

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Gilles Levresse, E. Gonzalez-Partida, A. Carrillo-Chávez, Jordi Tritlla, Antoni Camprubi, et al.. Petrology, U/Pb dating and (C-O) stable isotope constraints on the source and evolution of the adakite-related Mezcala Fe-Au skarn district, Guerrero, Mexico. Mineralium Deposita, 2004, 39, pp.301-312. ⟨10.1007/s00126-003-0403-y⟩. ⟨hal-00123657⟩
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