Seismic profiles from Limpopo Magma-rich transform margin

The continental rifted margins of Mozambique provide an excellent example of continental passive margins with a significant structural variability associated to magmatism and inheritance. Despite accumulated knowledge in this area, the tectonic structure and nature of the crust from Mozambique margins, especially the Limpopo transform margin are still poorly known. Here, we use high-resolution seismic reflection dataset and wells from industry topropose a structural interpretation of this area and a new conceptual model of oblique/hyper oblique margin. Our results indicate first that the Limpopo transform margin limits a continental crust westward, with deep Karoo grabens, from an oceanic crust domain eastward. Such fault controlled volcano-sedimentary basins result from two main tectonic events: a first E-W extension trend during the Permo-Trias (T1) followed by an NNW-SSE trending during the Jurassic (T2), oblique to the margin direction as attested by the presence of flower structures. The onset of oceanic spreading occurred then after ca. M25 (i.e. 156 Ma), triggering the uplift and erosion of the proximal parts of the margin as well as the formation of several other magmatic infilling (T3). This margin may be thus considered as magma-rich transform margin. Our new conceptual model from the onset of the rifted margin to the seafloor spreading shows a complex evolution where transtensional deformation contributes significantly to the distribution of magma generated. Such extensional pattern which is made of syn-transfer and - transform faults forming pull-apart structures becomes more important with time.