Modelo Gravimétrico 2D Y Su Comparación Con Espesores Corticales Sísmicos En Una Sección A Los 30 ° De Latitud Sur
Mario E. Gimenez, Myriam P. Martinez and Francisco Ruiz
Event name: 11th International Congress of the Brazilian Geophysical Society
Session: Gravity & Magnetics
Publication date: 24 August 2009
Info: Extended abstract, PDF ( 205.63Kb )
We made a gravimetric model, on a section which crossed through the Andean Cordillera, Pampean Ranges and Precordillera in an west to east direction, at -30° latitude south and 71° at 65° longitude west. The response of gravimetric model of the crust, fixed to the curve of the Bouguer anomaly upward continuation at 40km in height, which would correspond to the moho ondulations. This result was compared with the crustal thickness obtained by means of: (1) the Moho depths given by the apparent phase velocities Pn (Fromm et al., 2004)and (2) receiver function of wave S (Heit et al., 2008). In This study evaluated the gravimetric effect of the three cortical models compared with the regional Bouguer anomaly. The conclusions reveal that the major discrepancy between the models is produced in the Cuyania terrane, principally in the Precordillera zone. This includes the "PACH" and "HEDI" seismological stations and on minor measurement to the "RINC" station, located in the Famatina terrane. In accordance with the existing geological information, the Precordillera is a thin-skin structure, whith a décollement horizon at 18km of depth.
From the isostatic viewpoint, based on the Airy concept, the region is an unbalanced, manifesting a scarcity of root. This evidence would be the contrast-position to the seismological models which indicate that below the Precordillera, the Moho excedes depths of 70 km, that being the deepest of the Andean Cordillera.