How did the Red Sea form between Africa and the Arabian Peninsula?

The Red Sea formed through a complex process of tectonic rifting that began approximately 33 million years ago during the Oligocene Epoch. This development was driven by upwelling from Earth’s mantle, which caused the crust to dome, rise, and eventually thin and extend, creating extensive fault systems.1

The process occurred in distinct phases:
* Initial Rifting: As Arabia began to split away from Africa, rising magma produced significant flood basalts along the region's margins.1
* Divergence: A fault-bounded depression, or rift valley, developed between northeastern Africa and western Arabia. This valley was periodically flooded by the Mediterranean Sea and later influenced by the Indian Ocean as land barriers subsided.2
* Oceanic Crust Formation: By about 6 to 5 million years ago, rifting had progressed sufficiently to allow for the formation of oceanic crust, marking the birth of a proto-ocean.1

This tectonic movement continues today, with Africa and Arabia moving apart at a rate of approximately 0.59 to 0.62 inches per year, accompanied by ongoing seismic activity and volcanism.3