Caracterización petrográfica y geoquímica de los granitos del borde oriental de la sierra de la Huerta, provincia de San Juan, Argentina

PONTORIERO, SANDRA; CASTRO DE MACHUCA, BRÍGIDA; CONTE-GRAND, ALICIA

Montevideo

Congreso; XI Congreso Latinoamericano de Geología y III Congreso Uruguayo de Geología; 2001

DINAMIGE y Sociedad Uruguaya de Geología

Along the eastern edge of La Huerta range, as part of a famatinian aged magmatic arc, few small, lenticular to tabular-shaped well foliated leucomonzogranites are found. They are grouped and informally termed Granito Arenoso (GA). The GA bodies are intruded parallel to the foliation of the enclosing rocks, mainly metatonalites and quartz metadiorites of the same magmatic complex. Contacts are intrusive and sharp, xenoliths are rare. The foliation has been induced by regional stress during emplacement (syntectonic granites). According to their geochemistry, they are classified as high-silica granites (75.30 to 77.70 percent SiO2), slightly peraluminous, with a clear calc-alkalic affinity. The emplacement of the GA bodies took place during a low to medium-temperature metamorphic event. The chemical features suggest that they were formed in a complex tectonic regime, related to a continental- margin magmatic arc.