Rifting and salt deposition on continental margins: Differences and similarities between the red sea and the south atlantic sedimentary basins

Abstract

The results of regional deep seismic acquisition in the South Atlantic continental margins provide new constraints on the birth and development of sedimentary basins formed during the Gondwana breakup. The interpretation of these seismic profiles integrated with gravity and magnetic potential field data suggest alternative models for the birth of oceanic basins that evolve from an earlier phase of intracontinental rift, salt deposition and continental breakup by mantle exhumation or by development of oceanic spreading centres preceded by igneous intrusions and extrusions in the transition from continental to oceanic crust. The analysis of regional deep-penetrating seismic profiles in the South Atlantic and Red Sea, integrated with potential field methods and plate reconstructions, provides a template for the interpretation of the tectono-sedimentary features that are characterized from the proximal rifts onshore and in the platform. Basinward, more elusive features are characterized toward the transitional and oceanic crust in divergent margins. This work discusses alternative interpretations for syn-rift successions and salt distribution in regional seismic profiles from the Red Sea, which have been integrated with results of wells that penetrated the stratigraphic section below the evaporites in a few exploratory wells along the Arabian and African conjugate margins. These interpretations can be compared with similar tectono-stratigraphic settings in the South Atlantic, which are constrained by several exploratory wells that penetrated the syn-rift sequence in both shallow and deep waters. The temporal development of syn-rift structures, magmatism, salt deposition, oceanic propagators and development of the divergent margins suggest that the Red Sea constitutes a better analogue for the development of the South Atlantic divergent continental margins than the Iberian margin.