Reinterpretation of the suture zone between the Itabuna-Salvador-Curaçá and Jequié blocks, of the São Francisco Craton, Bahia, Brazil, using structural and geophysical data

Abstract

The study area is located in the central portion of the São Francisco Craton (SFC), between two of the main blocks that compose this feature: the Jequié and the Itabuna-Salvador-Curaçá blocks. The main objective of this study was to reevaluate the transition zone between both blocks, employing airborne geophysical, geologic and structural data. The geophysical data are represented by gamma-ray spectrometry and magnetic surveys, which showed the structure of the lithotypes mapped and helped in the identification of their limits. The analysis of these images established five radiometric domains and six magnetic zones. The geophysical data interpreted along with mapping survey, with macroscopic description and structural data, allowed better identification of the suture zone between the referred blocks. The structural analysis identified four deformation phases, characteristic of a transpressional zone, uplifting the ISCB onto JB. The present study proposes the modification of the limits between these blocks to a more southern location and updates the regional geotectonic understanding of the central region of the state of Bahia.