A new scheme for the opening of the South Atlantic Ocean and the dissection of an Aptian salt basin

Abstract

SUMMARY We present a revised model for the opening of the South Atlantic Ocean founded on a remapping of the continent–ocean boundaries and Aptian salt basins, the chronology of magmatic activity in and around the ocean basin and on the timing and character of associated intraplate deformation in Africa and South America. The new plate tectonic model is internally consistent and consistent with globally balanced plate motion solutions. The model includes realistic scenarios for intraplate deformation, pre-drift extension and seafloor spreading. Within the model, Aptian salt basins preserved in the South American (Brazilian) and African (Angola, Congo, Gabon) continental shelves are reunited in their original positions as parts of a single syn-rift basin in near subtropical latitudes (10 ◦ S–27 ◦ S). The basin was dissected at around 112 Ma (Aptian–Albian boundary) when the model suggests that seafloor spreading commenced north of the Walvis Ridge–Rio Grande Rise.