Manifestación de la metalogénesis gondwánica en el área de Marayes Viejo, Sierras Pampeanas Occidentales, San Juan

CASTRO DE MACHUCA, BRÍGIDA; SUMAY, CELINA; CONTE-GRAND, ALICIA; MEISSL, ESTELA; PONTORIERO, SANDRA

Salta

Congreso; XIV Congreso Geológico Argentino; 1999

Universidad Nacional de Salta

This paper deals with the mineral occurrences of the Marayes Viejo district, placed in the southwestern edge of La Huerta range, Western Sierras Pampeanas, province of San Juan. The main outcrops in the area are the crystalline basement of La Huerta range (Upper Precambrian-Lower Paleozoic), an andesite porphyry: the Marayes Viejo Porphyry (PMV) (Late Permian), and continental sediments and basaltic lavas from the Marayes-El Carrizal basin (Middle Triassic). Two main fracture directions N15º and N333º, are responsible for the emplacement of narrow polymetallic quartz veins with pyrite, chalcopyrite, native copper, gold, magnetite and galena. Vein and disseminated mineralization is only recognized in the PMV and basement rocks. The economical potential of the area is restricted due to the magnitude of such occurrences. The geochronological data obtained for the PMV and intrusive rhyolites within La Huerta range, indicate a Permian to Lower Triassic age, which allows to consider the associated mineralization as belonging to the Gondwanic magmatic-metallogenic cycle.