Geophysical Evidence for Magmatism Southwest of the Brothers Islands, Northern Red Sea (Offshore Quseir, Egypt)

Abstract

The Red Sea formed due to the separation of Arabia from Nubia during the Late Oligocene-Early Miocene, involving a counter-clockwise rotation of the Arabian plate. Although the southern and central sectors of the Red Sea reached the oceanic stage and display a prominent NW-SE oriented axial ridge, the nature of the crust in its northward termination is still controversial (e.g., Augustin et al., 2021). Onshore observations in the present-day margins of the northern Red Sea (NRS) indicate a "classic" rifted margin dynamic dominated by normal fault and half-graben geometries and provide constraints on the timing and evolution of rifting (Figure 1a; Bosworth & Burke, 2005;Cochran, 1983Cochran, , 2005. Omar and Steckler (1995) concluded that the early stage of rifting was accompanied by two uplift and erosion phases of the shoulders. The first stage started ∼34 Ma in the Early Oligocene, while the second uplift and erosion phase occurred during the latest Oligocene to Early Miocene. However, geological and thermochronometric evidence from the Quseir area on the Red Sea coast indicates that only the second uplift and erosion phase at 23 Ma exists (