The deep structure of the Pernambuco Plateau, Northeast 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 is 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 grabens in which sediment thicknesses reaches in excess of 3 km. Within these deep grabens we find large halokinetic structures in the form of salt diapirs and pillows that root into the early syn-rift. Sub-marine volcanic edifices are also clearly imaged, the oldest of which have bases close to the syn-to-post rift transition. We discuss the PPB evolution integrating the implications of the newly observed evidence for syn-rift salt deposition and early post-rift sub-marine volcanic activity as well as a reanalysis 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.