Analysis of the crustal structure of São Francisco Craton and their marginal strip based on GDS and gravity data

Abstract

Geomagnetic Depth Sounding (GDS) is a natural source electromagnetic method used to investigate great depths of the Earth's interior to obtain the electrical conductivity distribution. GDS data from nineteen stations distributed in the São Francisco Craton (SFC) and its marginal strips have been processed and analyzed. The processing of the GDS data employed consolidated techniques such as contour maps of the Fourier transform, horizontal polarization ellipse, data stacks in time-domain and frequency-domain, as well as the implementation of electromagnetic modeling based on line source of current. To assist the interpretation of the GDS, Bouguer and geological maps of the tectonic compartments of the SFC have been employed. In addition to those mentioned, inverse gravimetric modeling has been implemented for the Moho depth based on the Parker-Oldenburg methodology. The joint analysis of GDS and gravimetric data and the geological model allowed to design conductive blocks in the crust along with the investigated profile ensured by the development of an innovative approach to electromagnetic modeling GDS.