An Integrated Domain-Based Evolution Model for Red Sea: New Sea-Floor Spreading Evidence

Khamis Sherif Farhoud, Ahmed N. El-Barkooky

The evolution and lateral extent of oceanic accretion within the central and northern Red Sea remain subjects of long-standing tectonic debate. Although young oceanic crust beneath the southern axial trough is widely accepted, uncertainty persists regarding whether complete separation between the Arabian and Nubian plates has occurred across the basin or whether oceanic crust remains confined to the narrow Median Ridge Valley. This study investigates the crustal architecture of the Red Sea through integrated magnetic, gravity, bathymetric, seismic, and stratigraphic analyses, evaluated with quantitative tests of symmetry, kinematics, and alignment. Organized magnetic anomaly patterns identified in the Central Red Sea indicate a prolonged phase of seafloor spreading: spreading-parallel profile widths of 242 and 212 km, with three modern full rates, bracket accretion between ~10-12 Ma (chron-anchored minimum) and 20.4-24.1 Myr (constant-rate bound), supporting a prolonged pre-evaporite accretion phase. To evaluate this framework independently of magnetic observations alone, regional two-dimensional gravity forward models, lithospheric density, and deep multichannel seismic reflection and refraction data were incorporated, and new mirror-symmetric forward magnetic models (R² = 0.86-0.88). The results reveal a basement framework strongly segmented by fault systems associated with the offshore continuation of Precambrian suture zones and the Dead Sea-Aqaba transform system, which control the lateral offset and fragmentation of oceanic domains: the onshore Nakasib and Sol Hamed suture traces project to within 10-13 km of independently mapped offshore magnetic boundaries, and adjacent magnetic stripe groups are offset 49.6 ± 4.8 km across the Atlantis II Transform Fault. Integrated geophysical and stratigraphic evidence suggests the presence of a laterally continuous mafic crustal domain extending up to approximately 125 km from the Median Ridge Valley. These findings imply that the oceanic-continental boundary in the central basin lies close to the present-day coastlines and provide a revised framework for the spatial and temporal evolution of Red Sea rifting.