Abstract

CACACE, Francisco E; FERNANDEZ IHIGO, Carolina; FERRACUTTI, Gabriela R  and  BJERG, Ernesto E. Petrografía y geoquímica del cuerpo ígneo el renegado, sierra grande de San Luis. Rev. Asoc. Geol. Argent. [online]. 2016, vol.73, n.2, pp.242-255. ISSN 0004-4822.

The igneous body El Renegado is located in the southern portion of the La Jovita-Las Águilas mafic-ultramafic belt outcropping on the Eastern slope of the Sierra Grande of San Luis. This NNE belt extends for about 100 km and its width varies between 3 and 5 km. Although it is located close to several well studied mafic-ultramafic bodies, as is the case of Las Aguilas, Las Higueras, Virorco, Escuela Las Pircas and El Fierro, it has not been the subject of previous studies. The neighboring bodies are known to carry an associated mineralization of Fe-Ni-Cu-Co sulfides and platinum group minerals. Magmatic modal layering has been recognized in several outcrops of El Renegado mafic rocks. Geochemical data (major and trace elements and REE) indicate this body is the result of a fractional crystallization process, which increased from east to west. Virorco, Las Aguilas and Las Higueras mafic-ultramafic rocks are also the result of a fractional crystallization process and the comparison of their geochemistry with that of El Renegado shows that it is part of the same magmatic sequence and would represent the most evolved member of the group.

Keywords : Mafic-ultramafic rocks; Magmatic layering; Fractional crystallization; Sierras Pampeanas.

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