EARLY CRETACEOUS EXTENSION IN NORTHEAST BRAZIL RELATED TO THE SOUTH-ATLANTIC OPENING

Detailed study of microfaults and associated striated fault planes affecting the Early Cretaceous infilling of Rio do Peixe basins (northeast Brazil) allows us to determine a regional stress field with a NNW-SSE oriented extensional component. In the basement, reactivated E-W and NE-SW ductile shear zones of Pan-African age both controlled the architecture and elongation of the basins. These en-echelon half-grabens illustrate the first stages of intracontinental rifting of a pre-fractured crust. During the Early Cretaceous, the northeast Brazilian province was subjected to NW-SE extension related to the eastward opening of the South Atlantic ocean.