A Herança Estrutural e seu Controle na Extensão Crustal na Margem Proximal da Bacia de Campos

Abstract

This dissertation investigates the role of structural inheritance in shaping the crustal extension processes in the Campos Basin proximal margin during the early stages of Mesozoic rifting in Western Gondwana, with particular emphasis on the proximal margin of the Campos Basin. This research integrates the interpretation of seismic reflection data with potential-field map analyses, combining the mapping of basement morphology, fault systems, seismic-stratigraphic unconformities, and intracrustal reflectors, in conjunction with observations regarding the distribution of density and magnetic sources within the study area. The analysis includes onshore basement structures in Cabo Frio, Região dos Lagos (RJ), evaluated for comparative purposes alongside the interpreted offshore data. The results indicate that pre-existing structures of a vertically bipartite crust significantly influenced the spatial distribution of faults, the horizontal displacement of detachment faults, and the shift in the rift vergence. The integration of seismic interpretation with the Residual Bouguer Anomaly map facilitated the identification of a rounded top horst, oriented NE-SW and referred to as the Central High, along with the recognition of a V-shaped Basin. The findings underscore the crucial role of pre-existing structures within a rheologically differentiated crust in the local reorientation of the stress field and the strain localization. This process enabled the coupling of deformation and the development of detachment faults, contributing to the evolution of a Proximal Breakaway Complex. Thus, this study delineates a boundary for the Proximal Domain and enhances the understanding of the structural response of a heterogeneous crust to extensional forces during the initial stages of rifting, underscoring the significance of structural inheritance in the evolution of a Proximal Breakaway Complex and the formation of the V-shaped Basin in the Central Segment of the Campos Basin.