Los mármoles cálcicos de El Escorial (complejo metamórfico Cushamen, macizo norpatagónico)caracterización isotópica de 87Sr/86Sr y edad de sedimentación
- Murra, Juan A. 1
- Baldo, Edgardo G. 1
- Verdecchia, Sebastián O. 1
- Ramacciotti, Carlos D. 1
- Galindo, †Carmen 2
- 1 Centro de Investigaciones en Ciencias de la Tierra (CICTERRA), Universidad Nacional de Córdoba (CONICET-UNC), Avda. Vélez Sársfield 1611 (5000), Córdoba, Argentina.
- 2 Departamento de Petrología y Geoquímica, Univerdidad Complutense de Madrid, Instituto de Geociencias (UCM, CSIC), 28040 Madrid, España.
ISSN: 0718-7106, 0718-7092
Year of publication: 2022
Volume: 49
Issue: 1
Pages: 77-93
Type: Article
More publications in: Andean geology: Formerly Revista geológica de Chile
Abstract
The El Escorial marbles (Cushamen Metamorphic Complex) along with amphibolites form metamorphic septa within the permian granitoids of the Mamil Choique Formation (261-286 Ma). The metamorphism, determined in granulite facies migmatic gneisses septa cropping out 120 km southwest of El Escorial, occurs at 311±27 Ma (CHIME method in monazite). The marbles are calcitic (calcite >95%, R.I.: 0.5 to 2.5%) and show 87Sr/86Sr ratios between 0.70768 and 0.70825 (n=10). The data provided in this work, added to previous contributions, allow to constraints the sedimentation age of the silicic-carbonate successions of the Cushamen Metamorphic Complex between ca. 385 and 335 Ma. This suggests the existence of a mixed carbonate-siliciclastic platform at least in the southernmost portion of southwestern Gondwana between Middle Devonian and early Carboniferous (Middle Mississippian).