Inherited Discontinuities and Neogene Structure: The Gulf of Suez and the Northwestern Edge of the Red Sea

The Gulf of Suez and the northern Red Sea rifts are the result of intracontinental deformation during Neogene times. The initiation and the development of the rift are controlled by (i) four main trends of faults: N140 degrees --N150 degrees; NS to N20 degrees; sub E--W; and N40 degrees --60 degrees; (ii) a zigzag faulting pattern; (iii) two main tectonic events. The first is characterized by strike-slip displacements inducing the formation of antithetic tilted blocks. The geometry of the blocks changes according to their orientation. Complex structures can result from the combination of several trends. Vertical movements are weak. The second is characterized by synthetic normal movements forming a horst and graben pattern. Vertical displacements are important and induce the generation of the axial trough and uplift of the shoulders of the rift. The zigzag pattern of the faults that govern the Rift and the initial strike-slip displacements cannot result from a simple extensional model but imply a reactivation of inherited discontinuities in the Miocene stress system induced by the northern convergent boundaries of the African and Arabic plates. The major trends of faults that control the Neogene structure have been active in this area since Palaeozoic or even Proterozoic times.