Red Sea rifting in central Egypt: constraints from the offshore Quseir province

Abstract

Southern and Central Red Sea oceanic crust formation is generally accepted to have started ∼5 Ma. However, the nature of the crust in the Northern Red Sea (NRS) is still debated. This paper describes the rift architecture, dynamics and evolution of the NRS and identifies domains that relate to first-order geodynamic processes. The proximal margin domain is located onshore and is characterized by latest Oligocene-Miocene half-graben basins. New seismic interpretations show that the offshore region is a necking domain dominated by low angle, high offset extensional faults, which led to the exhumation of lower crustal gabbros at Brothers Islands. 2D forward models suggest that necking passes into a distal margin domain, where the continental crust thins to < 10 km at 120 km from the coast. Sensitivity testing of interpretations for the distal domain indicates a probable scenario where exhumed lower continental crust or serpentinized mantle is present. A comprehensive rift model for the NRS in the Quseir sector accounts for circa 25 Ma magmatic underplating accompanied by half-graben development, followed by Early Miocene crustal thinning accommodated by an east-dipping detachment fault, and a Late Miocene phase with a flip of the detachment geometry, that led to the present-day configuration.