12Plate restoration of South America and Africa to their pre-breakup position faces the 13 problem of gaps and overlaps between the continents, an issue commonly solved with 14 implementing intra-plate deformation zones within South America. One of these zones is often 15 positioned at the latitude of SE/S Brazil. However, geological evidence for the existence of a 16 distinct zone in this region is lacking, which is why it remains controversial and is not included in 17 all modeling studies. In order to solve this problem we present a study of multiple geological 18 aspects of both parts of the margin, SE/S Brazil and its conjugate part NW Namibia at the time of 19 continental breakup. Our study highlights pronounced differences between these regions with 20 respect to Paraná-Etendeka lava distribution, magmatic dyke emplacement, basement 21 reactivation, and fault patterns. In Namibia, faults and dykes reactivated the rift-parallel 22Neoproterozoic basement structure, whereas such reactivation was scarce in SE/S Brazil. Instead, 23 most dykes, accompanied by small-scale grabens, are oriented margin-perpendicular along the 24 margin from northern Uruguay to São Paulo. We propose that these differences are rooted in 25 large-scale plate movement and suggest a clockwise rotation of southern South America away 26 from a stable northern South America and Africa, in a similar way as proposed by others for a 27Patagonian continental section just prior to South Atlantic rifting. This rotation would produce 28 margin-parallel extension in SE/S Brazil forming margin-perpendicular pathways for lava 29 extrusion and leading to the asymmetric distribution of the Paraná-Etendeka lavas. NW Namibia 30 instead remained relatively stable and was only influenced by extension due to rifting, hot spot 31 activity, and mantle upwelling. Our study argues for significant margin-parallel extension in SE/S 32 Brazil, however not confined to a single distinct deformation zone, but distributed across ~1000 33 km along the margin. 34 35