Influência da herança estrutural do embasamento na evolução da Bacia Rio do Peixe através de abordagens geofísicas e geológicas

Abstract

In this research, the role of crystalline basement structural inheritance was investigated based on the brittle reactivation of shear zones within a sedimentary basin, aiming to describe the formation and evolution of the Rio do Peixe Basin (RPB) in Northeast Brazil. The RPB was formed at the intersection of three Precambrian geological domains, highly deformed by shear zones and intruded by Neoproterozoic granitic rocks. An integrated dataset including aeromagnetic, gravity, 2D/3D seismic, and field data was analyzed to assess how Precambrian shear zones may have influenced its internal geometry. The results indicate that magnetic lineaments correlated with Precambrian shear zones persist uninterrupted in the sedimentary cover region, revealing the structural framework of the RPB. This magnetic pattern demonstrates that structures from the underlying basement significantly influenced the geometry of the basin sedimentary fill. Gravity modeling and seismic section interpretation allow the observation that inherited basement structures, particularly the shear zones delineating crustal subdomains, controlled the location and internal architecture of the rifts, as well as acted as weakness crustal zones susceptible to brittle reactivations, comprising the main normal faults of the rift phase. Furthermore, the study revealed the migration of depocenters towards the northeast, in the Brejo das Freiras sub-basin, associated with the development of the Portalegre Fault segment with NE-SW orientation, attributed to the basin-opening process. Thus, the combination of geological and geophysical data provides a current and detailed image of the half-grabens and depocenters, strongly controlled by the inherited faults of the Precambrian basement structural framework. This multidisciplinary analysis opens new research perspectives to enhance our understanding of the tectonic evolution of intraplate basins in northeastern Brazil, as well as the marginal basins located on the Brazilian Equatorial Margin. Finally, the present study of tectonic processes that influenced the RPB geological evolution can assist in comprehending the evolution of other intraplate and marginal basins in northeastern Brazil, which were also influenced by the fragmentation of tectonic plates.