GEOLOGY OF LAS CHACRAS-PIEDRAS COLORADAS BATHOLITH, SAN LUIS PROVINCE.

Abstract

Las Chacras-Piedras Coloradas Batholith crops out in the Pampean Ranges ofSan Luis Province and is made up offour nearly circularplutons interfering each to other and distributed along a NW-SE fracture; its K-Ar age is Carbonic. Rocks are granites s.l. which grade from highly porphyritic, biotite and/or amphibole-bearing to fine, equigranular biotite muscovite-bearing facies; their petrographic features might have originated by a volatile migration-related evolution mechanism, the fluids might also be responsible for the retrograde metamorphism of the contact schists. The internal geometry of plutons, as well as the country rocks deformation, account for a diapiric ascent and late ballooning emplacement during late to post-tectonic deformational stages. Las Chacras-Piedras Coloradas batholith, which c1early differentiates from other previous granitic events cropping out in the same geologic environment, c10sed the paleozoic magmatic activity in San Luis Ranges. It is here considered that Renca batholith and the circular pluton which crops out near Quines belong to the Las Chacras-Piedras Coloradas granitic event.