Characterization of the Sierras de Córdoba eastern boundary from

LUZ A. OROZCO, EDUARDO A. ROSSELLO, CRISTINA POMPOSIELLO, ALICIA FAVETTO, & CRISTÓBAL P.

Niza,m Francia

Simposio; 7th International Symposium on Andean Geodynamics (ISAG 2008, Nice); 2008

The Sierras de Cordoba constitutes a part of the faulted, rotated, tilted and peneplained blocks of the Sierras Pampeanas located between 29°S and 33° 30´S and between 64°W and 66°W, and represents the easternmost expresion of the Andean deformation on its foreland. The Andean deformation inverted by compresion the preexisting tectonic discontinuities particularly the listric growth extentional faulting bounding the Cretaceous rifts towards the west (Cobbold et al., 1996). The Sierras de Córdoba is the easternmost orographic feature of the Sierras Pampeanas. It is constituted by several NS trending belts extending being the most important ones the Sierra Norte, the Sierra Chica and the Sierra Grande. The studied area includes part of the Sierra Chica and the westernmost portion of the Llanura Chacopampeana (Figure 1a). In the Sierra Chica, the exposed basement is composed by a metamorphic-migmatitic complex, where the prevailing rocks are tonalitic – biotitic gneisses, locally alternating with micaceous schists and migmatites. The pleneplained top of the range plunges towards the east underneath the adjacent plain (Llanura Chacopampeana), which was reached at the Santiago Temple well (Figure 1b). Here an olivinic metagabbro was found at a depth of 997 meters deep, with a reported K/Ar data of 787+/-150 Ma (Russo et al., 1987). The Chacopampean plain (covering more than 1,000,000 km2 of central Argentina) lacking any surficial feature representing the tectonic activity in such huge extension, has on the other side a rich story of underground tectonic events. These events, even when they took place at different geological times and are partially recognized by only a few oil wells and seismic records in diverse places having similar geometries, corresponding to other major geological structures of the Argentine geology (Chebli et al., 1999). In this paper we present morphostructural results obtained from both gravimetric and magnetotelluric surveys associated to digital elevation model (DEM) allowing to establish relationships between the Sierras de Córdoba and its eastern sedimentary cover.et al., 1996). The Sierras de Córdoba is the easternmost orographic feature of the Sierras Pampeanas. It is constituted by several NS trending belts extending being the most important ones the Sierra Norte, the Sierra Chica and the Sierra Grande. The studied area includes part of the Sierra Chica and the westernmost portion of the Llanura Chacopampeana (Figure 1a). In the Sierra Chica, the exposed basement is composed by a metamorphic-migmatitic complex, where the prevailing rocks are tonalitic – biotitic gneisses, locally alternating with micaceous schists and migmatites. The pleneplained top of the range plunges towards the east underneath the adjacent plain (Llanura Chacopampeana), which was reached at the Santiago Temple well (Figure 1b). Here an olivinic metagabbro was found at a depth of 997 meters deep, with a reported K/Ar data of 787+/-150 Ma (Russo et al., 1987). The Chacopampean plain (covering more than 1,000,000 km2 of central Argentina) lacking any surficial feature representing the tectonic activity in such huge extension, has on the other side a rich story of underground tectonic events. These events, even when they took place at different geological times and are partially recognized by only a few oil wells and seismic records in diverse places having similar geometries, corresponding to other major geological structures of the Argentine geology (Chebli et al., 1999). In this paper we present morphostructural results obtained from both gravimetric and magnetotelluric surveys associated to digital elevation model (DEM) allowing to establish relationships between the Sierras de Córdoba and its eastern sedimentary cover.et al., 1987). The Chacopampean plain (covering more than 1,000,000 km2 of central Argentina) lacking any surficial feature representing the tectonic activity in such huge extension, has on the other side a rich story of underground tectonic events. These events, even when they took place at different geological times and are partially recognized by only a few oil wells and seismic records in diverse places having similar geometries, corresponding to other major geological structures of the Argentine geology (Chebli et al., 1999). In this paper we present morphostructural results obtained from both gravimetric and magnetotelluric surveys associated to digital elevation model (DEM) allowing to establish relationships between the Sierras de Córdoba and its eastern sedimentary cover.2 of central Argentina) lacking any surficial feature representing the tectonic activity in such huge extension, has on the other side a rich story of underground tectonic events. These events, even when they took place at different geological times and are partially recognized by only a few oil wells and seismic records in diverse places having similar geometries, corresponding to other major geological structures of the Argentine geology (Chebli et al., 1999). In this paper we present morphostructural results obtained from both gravimetric and magnetotelluric surveys associated to digital elevation model (DEM) allowing to establish relationships between the Sierras de Córdoba and its eastern sedimentary cover.et al., 1999). In this paper we present morphostructural results obtained from both gravimetric and magnetotelluric surveys associated to digital elevation model (DEM) allowing to establish relationships between the Sierras de Córdoba and its eastern sedimentary cover.