Joint modeling gravity, geoidal and geothermal of the Lithosphere in Sergipano Belt and tectonic implications, NE Brazil

Abstract. In this research paper were applied methods which integrate geophysical and petrological data to the crustal and lithospheric structure in the Sergipano Belt, in the Southern Borborema Province, NE Brazil. These methods allowed us to unveil the main crustal features and their tectonic relationships with the crust-mantle interface (Moho), as well as the lithosphere-asthenosphere boundary (LAB) of this region. The crust structure was constrained by available geological, gravimetric and seismological data, and chemical composition for mantle bodies. Gravity, geoid and heat flow data integrated with existent geological and geophysical data provides to understand the evolution of the Southern Borborema Province. The modeling method was based on local isostasy in which the first phase of the work consisted on the filtering of geoid anomaly and topography data using low-pass in the harmonic and frequency domains, respectively, to estimate the thickness of the crust and the lithosphere, and the second phase is characterized by geothermal modeling. The crustal structure was constrained by geological information, thermo-physical parameters, and gravity and magnetic data inversion results, while the lithospheric mantle was constrained by chemical composition of xenoliths. The results show that maximum depths of Moho and thermal lithosphere (LAB) along the modeled profile are 34–42 km and 194–202 km observed, and temperatures are recorded with an average of 600 °C in the Moho temperature at Sergipano belt. The results presented suggest a thinning lithospheric mantle below the Sergipano belt, with values varying between 168 to 180 km, excepting in Girau do Ponciano whose is 194 km and a moderate lithospheric thickening below the Rio Coruripe, and thicker lithosphere at Pernambuco-Alagoas terrains reached 202 km.