A Gravimetric Study of Heterogeneities in Intermediate Crust beneath the General Levalle Basin- Córdoba Province? Argentina

MARTINEZ, P., DÁVILA, F.M., GIMENEZ, M.E., ASTINI, R.A., ALVAREZ PONTORIERO, O., LINCE KLINGER, F., RUÍZ, F., SÁNCHEZ, M.

Congreso; 12th International Congress of the Brazilian Geophysical Society; 2012

We present the results of a gravimetric study carried out in the region of the General Levalle sedimentary basin, Cordoba province, Argentina. We obtained the geometry of the basement roof for the region where the basin is located and the surface of the crust-mantle interface. The latter resulted in a surface of mild slope that deepens to the west. The fact that the interface crust-mantle is rather plane indicate that the sedimentary column has no antiroot that isostatically balances it. Also, the gravimetric effect of the sediments was evaluated and subtracted from the Bouguer anomalies. In the basin area, a positive gravimetric effect was identified, which may be linked to inhomogeneities located in the intermediate crust. On the basis of the gravimetric results, their comparison with stratigraphic analysis and of basin studies of the region, we propose possible alternatives that consider the presence of thick masses in the intermediate crust: 1)Emplacement of alkaline magmas during the Cretaceous extension, 2) An anomaly in the geometry of the crust, whether by the effect of a thinned crust associated to Cretaceous rifting or to Cenozoic extension or 3) Due to the flexion of the upper crustal layer during the Andean compression.