Tectono-Stratigraphic Evolution of South Atlantic Extensional Rifted Margins: Constraints from Sandbox Analogue Modeling*

A series of 3D sandbox analogue models with the support of 2D structural restoration on selected regional transects were used to analyze the pre-salt tectono-stratigraphic evolution of the Central segment of the South Atlantic Ocean (Figure 1). Seafloor spreading in the study area took place at the Aptian-Albian boundary, and the conjugate West Africa and Brazil rifted continental margin segment is classified as a “magma-poor” margin segment characterized by the presence of an intermediate/transitional crust between the continental and the oceanic crust. This contribution presents the results of a set of sandbox modeling experiments aimed to elucidate the structural elements and features reflecting the syn-rift basin evolution and the processes that governed the pre-breakup lithospheric extension at a rifted margin. The extensional sandbox analogue models were performed at full lithospheric-scale: a 4-layers setup (upper and lower crust/mantle) with alternating layers of sand and silicone putty, representing different rheological layering (strength-depth functions). Lateral anisotropy in the viscosity of the lower crust or upper mantle has been introduced in some 3D models to represent cold and/or warm lithosphere condition, as largely accepted to occur in both African (the High Velocity Layer of Contrucci et al., 2004, and Pan African Fold Belt