Neoproterozoic lithospheric structures at the Borborema Province: Integration of magnetotelluric resistivity sections and their relations to neighboring lithospheric blocks of the Parnaíba Basin and São Francisco Craton

Borborema Province is an orogenic belt of Neoproterozoic age part of the Brasiliano/Pan African Orogeny (600 Ma) in the northeast corner of the Brazilian shield. With an area of approximately 380,000 square kilometers, it is composed of fold and thrust belts, progressively stretched on continental scale transcurrent faults, and coeval plutonism. Its north and east flanks are limited by the Atlantic Ocean from a Mesozoic rift, and include passive margins basins and oceanic crust. Southwards, it is adjacent to the São Francisco Craton, while the west limit is overlain by the Paleozoic Parnaíba intracratonic basin. Besides the extensive metasedimentary and magmatic Neoproterozoic crust, it also involves Archean and Paleoproterozoic units. However, those units are obliterated by Brasiliano/Pan African Orogeny that segregates and disperses over the tectonic belts, hampering the interpretation of the architecture of the collisions of paleoplates during the Neoproterozoic. Magnetotelluric geophysical survey acquisitions have been conducted over the last decade by initiative of several Brazilian researchers and have been integrated to other geophysical methods in geotectonics in order to study the deepest parts of the lithosphere. We conducted the integration of twenty resistivity magnetotelluric sections and their interpretations, downplaying the electric response of the upper lithosphere (<100 km deep), aiming to emphasize and map differences in the lithospheric mantle. The resulting map shows high to moderate resistivity cores in the upper mantle, which are interpreted as continental lithospheric relicts, among high conductivity belts, associated to the Brasiliano paleosutures. These results are corroborated by gravimetric and magnetometric data. We propose that the southern limit of the Borborema Province with the São Francisco Craton is located under the Pernambuco lineament region, and that the western boundary with the Parnaíba lithospheric block is located under the Orós-Jaguaribe – Ceará Central Domain.