Investigação do estiramento crustal e a relação com os eventos magmáticos da fase rifte da Bacia de Campos na área do Alto de Cabo Frio

Abstract

The Cabo Frio High is a crystalline basement high, located south of the Campos Basin, recognized by many authors as a (structural) boundary separating the Campos and Santos Basins. The present study sought to investigate the morphology of the Cabo Frio High basement, with emphasis on the occurrences of magmatism and its relation with crustal thinning; seeking to better understand its tectonic development in its most distal portion. From the integration of geophysical data, seismic sections analysis, magnetic data and gravimetric modeling, it was evidenced the relation of the occurrence of magmatism and possible structures (faults or fractures) generated during the distension processes in the Rift phase of Campos Basin. We identified the presence of a volcanic high, almost outcropping on the seafloor, laterally separating salt domes in the Cabo Frio High area. We observed the presence of magmatic conduits that possibly served as feeders for the igneous material that covers the top of the basement in the Cabo Frio Outer High area. This volcanic top is associated with a positive magnetic anomaly in the Reduced to the Pole (RTP) profile, supporting its igneous nature, associated with a region where the crust presents extensional structures, indicates a possible tectonic origin for the observed magmatism. A differentiation could be observed between the volume of salt deposited between the proximal and distal regions and the crustal thinning, which constitutes one in the basin and thickening in the upper region, which constitutes an uplift of the embasement from the beginning of the basin formation to the beginning of the Albian.