The deep structure of the Pernambuco Plateau, NE Brazil, and its implications for Equatorial Atlantic rifting

The Pernambuco Plateau Basin (PPB) of northeastern Brazil contains an important record of continental rifting at the boundary between the major South Atlantic basins and the Equatorial Atlantic Gateway (EAG). The geology and structure of the PPB are described using high-quality long-offset multi-channel seismic data. The deep seismic imaging reported here shows that the PPB is not thick continental crust with a thin sediment veneer, but thinned continental crust with half-graben with sediment thicknesses in excess of 3 km. Within these deep graben we find large halokinetic structures in the form of salt diapirs and pillows that root into the early synrift. Submarine volcanic edifices are also clearly imaged, the oldest of which have bases close to the synrift-to-post-rift transition. We discuss the evolution of the PPB integrating the implications of the newly observed evidence for synrift salt deposition and early post-rift submarine volcanic activity as well as a re-analysis of recent plate models. The proposed best-fit model has PPB rifting in the Aptian and early Albian, with final break-up relatively late in the Albian.