Direct and inverse 2-D gravimetric modeling of the crustal structure at the base adjacent to the Sergipe Sub-basin.

Abstract

We characterize the subsurface structure of the basement adjacent to the Sergipe Sub-basin using gravimetric data to provide information on the distribution of density contrast, geometry and depths of the main sources, from acquisition, processing, and direct and inverse two-dimensional modeling. Such information generated an optimization of the understanding in relation to the basement framework and its relationship with the sedimentary part of the Sergipe sub-basin. The study was based on geological information, density of rocks  collected in the locality, gravimetric data, and interpretation of magnetic maps. The two-dimensional gravimetric inversion allowed us to reach an optimal result for the density contrast value of the main sources, which was 0.15-0.20 g/cm³. Anomalous sources have been mapped reaching depths of 5 to 7 km. In the sedimentary region of the sub-basin, its sediment-basement interface reaches a limit of 4 to 5 km in depth. The integration of these data allowed for a more realistic subsurface density model, as well as an interpretive geological model, and predicts that the dome regions of this basement are accommodated in the upper part of the crust.