Caracterización química de granates en la Sierra de El Gigante, San Luis, Argentina.

JUAN A. MURRA; JUAN A. MURRA; CARLOS IVÁN LEMBO WUEST; CARLOS IVÁN LEMBO WUEST; SEBASTIÁN O. VERDECCHIA; SEBASTIÁN O. VERDECCHIA

Córdoba

Congreso; Congreso de Mineralogía, Petrología Ígnea y Metamórfica, y Metalogenia (XIII MinMet ? IV PIMMA); 2019

Asociación geológica argentina y Asociación mineralógica argentina

Chemical characterization of garnets in the sierra de El Gigante, San Luis, Argentina. The sierra de El Gigante is part of the Sierras Pampeanas Occidentales of Argentina, which has been linked to the mesoproterozoic terrain of MARA. This mountain range is composed mainly of marbles, graphitic schists, quartz-micaceous schists, quartzites and amphibolites. Based on the lithological and geochronological record, these metamorphic units have been correlated with the Secuencia Metasedimentaria Difunta Correa exposed in the sierra de Pie de Palo, which would have been deposited during the Neoproterozoic and later affected by the Famatinian Orogeny. The units of the sierra El Gigante are characterized by containing garnet in most lithological varieties, such as metapelites, metapsamites and metabasic rocks. Chemically, they are mostly almandinic (40 a 60%), with nuclei rich in Mn, while the edges are enriched in Ca. These garnets are usually poikilitic with inclusions of epidote, albite and rutile-ilmenite, suggesting low to medium temperature at high pressure conditions during its formation.