Abstract

Mi Vida is a porphyry copper-type deposit located in northwestern Argentina in the province of Catamarca. It was investigated by Cities Service Minerals during a two-year exploration program which included geological, geochemical, and hydrothermal alteration studies, as well as 7,927 meters of diamond drilling.A Precambrian or lower Paleozoic complex composed of schists, migmatites, and granites was intruded by a syenodiorite stock with differentiated marginal facies and associated bodies of andesite porphyry and andesite flow breccias. Related to this intrusive event is a biotitic and biotitic-sericitic alteration phase accompanied by pyrite-chalcopyrite-bornite-molybdenite-magnetite mineralization. A volcanic event followed, during which rhyolites were emplaced. After this a huge breccia pipe body was formed. A sericitic-siliceous alteration, with the unusual alteration minerals alunite and zunyite, is related to this last event. Also related to the breccia is a mineralizing pulse with a very unusual assemblage: pyrite-covellite-bornite-enargite-molybdenite-sphalerite-galena-marcasite-rhodochrosite-native sulfur.It is concluded that Mi Vida is, perhaps, an example of a deposit midway between the porphyry copper deposits and the volcanic-exhalative copper-lead-zinc deposits found in several parts of the world.

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