Geoquímica y metalogénesis de las pegmatitas y granitos asociados del sector sur del distrito Comechingones, Córdoba

Abstract

Geochemical and metallogenetical study of the pegmatites and associated granites from southern Comechingones pegmatitic field, Córdoba. The Comechingones pegmatitic field (CPF) is located in theeastern flank of the Sierra de Comechingones, Córdoba province. It is composed of granite pegmatites belonging to the Rare-Element class, beryl type, beryl-columbite-phosphate subtype; some of them are transitional into the Muscovite class. Beryllium, Nb, Ta and U deposits, as well as high-quality industrial mineral deposits, are frequently associated with these pegmatites. In the southern part of the CPF two different pegmatite types have been described.Type I pegmatites constitute large zoned bodies with up to 1000 m long and 50 m thick, and may constitute rare element deposits, whereas type II pegmatites occur as small, unzoned quartz-rich dykes, without metalliferous mineralizations, spatial and genetically associated with aplitic leucogranites. Preliminary geochemical data from bothpegmatites types and granites are presented and discussed in this contribution. Geochemical evidences, supported by field and petrographic observations, suggest that the two types of pegmatites identified in the study area represent two different, probably diachronic, magmatic stages. Type I pegmatites display a geochemical gradation in a S-N direction, from barren pegmatites in the south to fractionated pegmatites in the northern part of the study area, andare the lithological product of the first magmatic stage. The second stage lead to the crystallization of aplitic granites and barren type II pegmatites, geochemically less fractionated than type II pegmatites.

Keywords

• Geochemistry
• Metallogenesis
• LCT pegmatites
• Granites
• Comechingones pegmatitic field
• Sierras Pampeanas de Córdoba.