Structural Control of the São Francisco River Delta from the Aeromagnetic Data, Brazil

Abstract

The São Francisco River delta is a Quaternary sandy plain built on a structural low of the Sergipe-Alagoas Basin, known as the São Francisco Low. The inner limit of the São Francisco River delta is defined by rectilinear cliffs between the delta plain and the Barreiras Formation, which coincide with important faults delimiting the São Francisco Low. Moreover, on the continental shelf, the deltaic clinoform developed over a topographic low limited by rectilinear scarps that present compatible orientation with the Sergipe-Alagoas structural framework. Thus, based on a theoretical background that indicates the existence of structural control over the formation of delta systems in general, and previous knowledge of this area, it is possible that the Sergipe-Alagoas Basin structure has influenced the delta. This relationship can be inferred using adequate methodology. Magnetometric data was integrated in the present study with the geological information on the area. The main objective was to evaluate the existing structural controls over the formation of the São Francisco delta and neighboring areas. The first stage of the present study consisted of a thorough bibliographic review and the search for pre-existing geophysical data in the region.