Dacita El Arriero exponente del magmatismo y metalogénesis gondwánica en la sierra de La Huerta, provincia de San Juan: alteración hidrotermal y mineralización

CASTRO DE MACHUCA, BRÍGIDA; MEISSL, ESTELA

Río Cuarto (Córdoba)

Congreso; 7º Congreso de Mineralogía y Metalogenia; 2004

AMA - Universidad Nacional de Río Cuarto y Universidad de Buenos Aires

The porphyritic dacite of El Arriero (DEA), placed in the eastern flank of La Huerta Range, Western Pampean Ranges, province of San Juan, is characterized by intense propylitic alteration and silicification that also affect the metamorphic host rocks. Evidences of minor phyllic and potassic (biotite facies) alteration are also recognized. Metallic mineralization in the DEA as well as in a surrounding breccia appears disseminated, in quartz±calcite veinlets and/or in drusy aggregates. The main hypogene ore minerals are pyrite, magnetite and chalcopyrite, plus minor pyrrhotite, ilmenite and native gold. Radiometric K/Ar and 40Ar/39Ar dating, permit assigning the DEA to the Gondwanic magmatic-metallogenic cycle. The economical perspectives of the area are restricted due to the magnitude of such occurrence.