ABSTRACT
The Red Sea formed due to the separation of the Arabian Plate from the African Plate during the Late Oligocene-Early Miocene. This chapter is an attempt to evaluate the crustal structural types and their relations to the major tectonic plate boundaries between Arabia and Africa at the northern Red Sea rift region. The boundary analysis method employed low-pass filtered and horizontal gradient (HG) gravity anomalies. The linear characteristics of the magnetic data were illustrated using tilt derivatives technique. Based on our results, six domains (crustal blocks) have been identified; these blocks are separated from each other depending on the geotherm, crustal type and thickness, and sediment thickness.
3D gravity inversion results and low-pass filtered Bouguer anomaly maps indicate that positive regional anomalies over both the southeastern Mediterranean basin and the Red Sea rift and subdomains are due to the high density of the oceanic crust. Negative Bouguer anomalies over the northern Arabia subzone, particularly in the areas covered by Cenozoic volcanism (Harrats), may result from the low densities of the surface volcanics and/or a very thick upper continental crust. However, the negative anomaly of the Gulf of Aqaba-Dead Sea transform zone is attributed to crustal thickening below this region.
