Gravimetric interpretation and crustal structure in the General Lavalle basin, Córdoba Province, Argentina

Abstract

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 and the surface of the crust-mantle interface for the region where the basin is located. The latter resulted in a surface with a gentle slope deepening to the west. The fact that the crust-mantle interface is rather plane indicates that the sedimentary column has not an anti-root to isostatically compensate it. Also, the gravimetric effect of the sediments was evaluated and substracted 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, and their comparison with stratigraphic analysis and 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 crust geometry, whether by the effect of a thinned crust associated to Cretaceous rifting or to Cenozoic extension, or 3) due to the flexion of the crust upper during the Andean compression.