Preliminary results of the petrology and geochemistry of Las Tunas mafic-ultramafic belt in Frontal Cordillera, Mendoza, Central Andes, Argentina

GARGIULO, M. FLORENCIA; BJERG, ERNESTO A.

Granada

Seminario; 4th EURISPET on High-pressure Metamorphism and Subduction Zones; 2009

6th Research Framework Program of the European Union and The Marie Curie Actions. Universidad de Padua (Italia) y Universidad de Granada (España)

The ultramafic bodies are mainly restricted to shear zones developed in the metamorphic basement; while the mafic rocks crop out concordant with the schistosity or gneissic foliation from the metasedimentary units. The ultramafic rocks are strongly serpentinized dunites, Di-dunites, Di-Spl-dunites, Spl-dunites, Fo-pyroxenites and clinopyroxenites with chondritic or primitive mantle geochemical signature. Those with chondritic signature show unusual enrichment in the LREE, which has been related with the development of amphibole reaction zones due to silicatic metasomatism, probably related with the Late Paelozoic intrusion in the area. The mafic bodies have subalkaline basaltic composition with E to N-MORB geochemical signature and they seem to be genetically related with eachother through a partial melting process. Las Tunas mafic-ultramafic belt was affected by regional metamorphism in greenschist to amphibolite facies conditions which is consistent with the metamorphism affected the metasedimentary basement.