Deep seismic refraction method for crustal structure determination of Borborema Province Southern and Transverse Zone, Northeastern Brazil

Abstract

The Borborema Province is a complex mosaic of crustal blocks apparently amalgamated in consequence of geological processes that have been realized in several stages for a long time, but their final configuration is due to the Brasiliano Orogeny, occurred in late Neoproterozoic to early Phanerozoic. Remarkable granitic plutonism in the area, associated to an essentially transcurrent deformation responsible for the formation of the major lineaments of continental scale, were generated by this event. Although studied in great detail, these structures are motive for controversy, existing hypothesis that treat these lineaments as important crustal sutures and those that describe theses structures as shear zones of less importance. Due to the excellent exposition conditions, the Borborema Province presents a geological and structural framework reasonably well known, due to geological surveys during the last decades, to recently gravimetric and air geophysical surveys and to considerable advance allowed by geochemical and isotopic studies that offer a solid base to approach relevant geotectonic questions. For this reason, the project “Geophysics and Tectonics Studies in Borborema Province, Northeastern Brazil” was proposed and approved in 2005 inside the program Institutes of the Millennium of MCT/CNPq. Among the proposed studies in this project are the deep seismic refraction experiments, with seismic linear arrays that will, if possible, reach the lithosphere bottom. This research project for a Ph D degree will be developed using data of the deep seismic refraction lines to be deployed in the Rio Grande do Norte Domain, and Transversal Zone regions of the Borborema Province.