Abstract

GARGIULO, María Florencia  and  BJERG, Ernesto A. Talc mineralization related to the ultramafic bodies of the Río de Las Tunas belt, Frontal Cordillera of Mendoza province. Ser. correl. geol. [online]. 2012, vol.28, n.1, pp.117-130. ISSN 1666-9479.

This contribution shows the main characteristics of the talc mineralization related to the Río de Las Tunas ultramafic bodies in the Salamanca Mining District, Frontal Cordillera of Mendoza province. According to the parageneses defined on the studied samples, three generations of talc were established: 1º) crystallized in metaperidotites and related to the prograde stage of the regional metamorphism; 2º) crystallized in reaction zones (mostly in the talc zone) developed at the boundary between metaperidotites and their country-rocks. These reaction zones evidence a metasomatic process due to geochemical gradient between the ultramafic body and their country-rocks. This process was developed during the retrogression of the regional metamorphic cycle. 3º) Talc present in shear-zones that cut across the ultramafic bodies. The extreme serpentinization of the ultramafic bodies is concentrated in shear-zones where the serpentine is subsequently replaced by talc ± carbonates related with a hydrothermal stage. Aqueous fluids relatively enriched in CO₂ flowed through these shear-zones causing the cease of serpentine formation favoring the talc and/or carbonates. Mined talc deposits are those in shear zones and reaction zones. They are mostly industrial-, asbestine- or talcschist-type. The talc related to the hydrothermal stage can locally reach first and extra qualities.

Keywords : Talc; Ultramaphic bodies; Río de Las Tunas belt; Frontal Cordillera; Mendoza.

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