Large tectonic and lithospheric structures of the Red Sea region

Abstract

Using new tectonic data regarding the timing and mechanical development of large fracture structures and a review of deep seismic data especially in relation to crustal thickness, a geodynamic evolutionary model for the Nubo-Arabian region is described. Combination of the data sets results in a 3-D picture of the crustal structure of the region and definition of problems regarding the geodynamic evolution of the Red Sea structure. Evidence from northwest Saudi Arabia, bordering the northern end of the Red Sea, suggests that rifting began around 32–30 Ma. During the Miocene, rifting intensified probably including significant lithospheric thinning. This first stage of development ended in the Middle Miocene, about 14 Ma, when the complete rift structure was about as wide as the present day Gulf of Suez. Between the Middle Miocene and the Upper Miocene/Pliocene boundary, about 10 ± 2 Ma, the Aqaba-Levant structure became active and thus the Gulf of Suez became essentially stagnant. Since this time about 70% of the total opening of the Red Sea has occurred, again probably including significant lithospheric thinning. This opening has been taken up totally by the movement along the Aqaba-Levant fault. Finally, about 5 Ma seafloor spreading began in the central axial trough of the Red Sea south of 21°N. A better knowledge of the thickness and nature of the present day Red Sea crust is still required so that the amount of opening of the Red Sea can be more accurately estimated.