Morpho-structural controls and influence of Brazilian-Pan African structures in the Marginal Ridge and Romanche Fracture Zone: Brazilian Equatorial Margin
Transform Margin, Romanche Fracture Zone, Transbrasiliano, Ceará Basin
The evolution of the South Atlantic Ocean, induced by the split of South American and African continents, are explained by typical divergent margins evolution models. However, the Equatorial Atlantic experienced a more complex evolution, within transform context, where the Ocean Fracture Zones has an important role. This work presents geological structures on the Brazilian Equatorial Margin, as the Ceará Terrace and the Canopus Bank, which the genesis are unknown. The results shows the importance of these structures as well as the Brasilian-Pan African structures in the evolution of the equatorial margin. By the analyses of 2D seismic data and exploration wells in deep waters on Ceará Basin, it was possible to recognize an uplift in the rift sequence of the Ceará Terrace. These structures are suggest to be a Marginal Ridge, predicted on the transform margins evolution models. The data shows that the Cerará Terrace are controlled by the Romanche Fracture Zone as well as the continental lineaments, displaying folds and normal faults, which indicate tectonic inversion. The preliminary analysis of the results suggest tectonic reactivation in the area and morpho-tectonic control of the submerse canyons. Such reactivations are related to the Brasilian-Pan African structures, in special, the Transbrasiliano Lineament, and a possible relation with Romanche Fracture Zone.