Granitos fértiles y granitos estériles: aspectos comparativos de algunos cuerpos de Sierras Pampeanas

LAZARTE JOSÉ; AVILA JULIO; FOGLIATA, ANA; GIANFRANCISCO MIGUEL

Acta Geológica Lilloana

Fundación Miguel Lillo

Lugar: San Miguel de Tucumán; Año: 2008 vol. 20 p. 47 - 48

0567-7513

Abstract.— “Fertile and barren granites: comparative aspects of some bodies in Sierras Pampeanas”. Geologic characteristics and the metallic mineralization associated of granitoids Sierra Pampeanas are reviewed. There are three types: a) old biotite granitoids, with and without deformation, (Chango Real and Belén), b) two micas (Río Rodeo Granite) and two micas with cordierite (Mazán Granite) and c) muscovite (La Quebrada Granite) and biotite granites (Quimivil, Papachacra and El Salto granites). All of them are of evolved type. Geochemical characters of this bodies are analyzed, in a comparative way. Barren granites are characterized by lower silica content, higher TiO2, CaO and MgO contents and high K/Rb and Ba/Rb, low Rb/Sr relations and little negative Eu anomaly. Plutons related with mineralization are rich in Rb contents and have greater negative Eu anomaly than barren granites. It is also observed that evolution degree and fertility are always related. It is concluded that, features like high contents of Y, Th and U are related to deep source of magma, characteristic of a post orogenic granite stage.