CIG   05423
CENTRO DE INVESTIGACIONES GEOLOGICAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
The Rb-Sr low grade metamorphism age of the Paleozoic Río Seco de los Castaños Formation, San Rafael Block, Mendoza Province, Argentina
Autor/es:
CINGOLANI, CARLOS A.; VARELA, RICARDO
Lugar:
Bariloche
Reunión:
Simposio; VI South American Symposium on Isotope Geology; 2008
Institución organizadora:
INGEIS
Resumen:
THE Rb-Sr LOW-GRADE METAMORPHISM AGE OF THE PALEOZOIC RIO SECO DE LOS CASTAÑOS FORMATION, SAN RAFAEL BLOCK, MENDOZA, ARGENTINA Cingolani, C.A. and Varela, R. * +Centro de Investigaciones Geológicas (CONICET-UNLP), calle 1 n. 644, 1900-La Plata, Argentina (carloscingolani@yahoo.com; varela@cig.museo.unlp.edu.ar) Keywords: San Rafael Block, Mendoza, low-grade metamorphism age, Rb-Sr whole rock method ABSTRACT      The Río Seco de los Castaños (RSC) Formation is one of the ‘pre-Carboniferous’ units outcropped in the San Rafael Block. The obtained sedimentological and petrographical data constrains the paleoenvironment as a distal to proximal silty-siliciclastic marine platform-deltaic system with a short transport from his source. In this work eight fine grained samples were selected for analysis by Rb-Sr systematic in order to know the age of the post deposition event. The Rb-Sr age of 336±23 Ma suggests an isotopic homogenization during Early Carboniferous low-grade metamorphic event. The high value of the initial isotopic ratio 87Sr/86Sr (0. 7243) suggests a provenance for the sedimentary detritus from an evolved continental crust source. This isotopic data of the RSC low-grade metamorphism during the Early Carboniferous linked with the ‘Chanic’ gondwanic tectonic phase that affected the Precordillera-Cuyania terrane during the Chilenia terrane collision. This Rb-Sr data also help to constraint the depositional age and the discussion about the source areas of the RSC basin.