Structural and stratigraphic aspects of the Recife-Natal coastal zone, based on well data

Abstract

New data concerning the basement configuration are presented in the coastal zone of the Paraíba Basin, between the cities of Recife and João Pessoa extending to the region of Natal. The basement contour map was obtained through the interpolation of well data, including lithological profiles of strati-graphic and ground water wells. The gathered data were treated by specific software to generate a surface model. The basement of the region behaves as a low angle ramp, covered by a thinner sedimentary sequence (max 400 m) than that of the neighbor coastal basins.  Two depocenters (grabens) have been identified: Itamaracá, in the coast of the state of Pernambuco; and João Pessoa-Cabedelo, in the coast of the state of Paraíba. The studied zone was divided in two sectors: one, between the shear zones of Pernambuco (ZCPE) and Patos (ZCPA) (Paraíba Basin), where the coastal basin is wider and steeper and the other ranging from the Patos shear zone to the vicinities of Natal (Natal Platform). An additional seismic data set has been used to show a general view of the basement behavior in the platform, thus it has been possible to confirm the structural ramp features extended from the coastal zone to the platform and the separation of the ramp in two sectors: the coastal zone and platform. The Paraíba Basin platform is, also, wider and steeper than the Natal Platform. Data integration obtained from both zones - the coastal and the platform - revealed that the basement of those basins represents a low gradient structural ramp with a slope in the shelf break. It has been observed that the platform corresponds to the distally steepened ramp model