Nature of orogenic gold-related hydrothermal alteration at Incahuasi, Puna Catamarqueña, Argentina

DIANA IRENE MUTTI; CAROLINA MENDEZ; JUAN MANUEL GARCÍA

Nancy

Congreso; 13th SGA Biennial Meeting "Mineral Resources in a Sustainable World"; 2015

The Ordovician quartz-gold orogenic veins at Incahuasi are hosted in very low metamorphic grade leptosedimentites of Falda Ciénaga Formation. At mining district scale, the leptometamorphic sequence shows N-S braquisyncline structure and belts of chloritic and phyllic hydrothermal alterations with strong structural control. At individual veins scale a fine pervasive to moderate phyllic alteration halo of its wall ? rock accompany the mineralization. Integrated petrological and geochemical examination of veins, metasedimentary wall-rocks and its precursor protholith, reveal that hydrothermal alteration involved mainly Si, K, Al, Fe, Mg, S, As and Au transference from the precursor country rock to the mineralization sites. The use of chlorite as geothermometer allowed to determine the initial temperature of the mineralization deposition, which is 335 ± 20 º C, in accordance with the previous study of fluid inclusions.