The Influence of the Late Cretaceous – Early Tertiary Fold Structures on the Geometry and Evolution of Extensional Fault

The detailed mapping and structural analysis of the Southern Galala and Wadi Araba on the Western margin of the Gulf of Suez reveals that the pre-rift structures are represented by three belts of asymmetrical plunged folds of ENE and NE orientations. These folds coeval sometimes with ENE reverse fault, ENE, WNW and E-W dextral strike slip fault with subordinate NW and N-S normal faults. These structures are superimposed by the Oligo-Miocene rifting. This rift is characterized by two fault systems; the rift boundary fault system and the rift interior fault system. The fault systems are represented by several segments of NNW-SSE to N-S oriented extensional faults. These segments are linked via relay ramps or NE oriented faults. The rift related faults arrest and die out in splays or horstailing into numerous segments including the NW-SE to N-S oriented faults at the ENE oriented pre-existing fold belts. The pre-rift fold belts act as stress barriers which inhibit the NW propagation of the extensional faults. Moreover, these fold belts control the location and style of linkage.