Afar Triple Junction - Plate Tectonics

Plate Tectonics

The Aden Ridge, Red Sea Rift, and the East African Rift all meet at the Afar Triple Junction. Here, the Arabian plate and Nubian and Somali proto-plates are being pulled apart, which forms three divergent plate boundaries. Divergent plate boundaries are fundamental features of plate tectonics and are associated with rifts and mid-ocean ridges. Plate separation causes deeper mantle asthenosphere to rise into the widening region (shown in figure). The Aden Ridge and the Red Sea Rift began to widen before the East African Rift with the separation of the African and Arabian plates about 25 million years ago. Prior to the opening of these rifts, Africa and Arabia were connected. The East African Rift is the third limb, or branch, in the triple junction occurring when the African Plate began to split into the Somali Plate to the southeast and the Nubian Plate to the northwest. The East African Rift began extending about 15 million years after both the Aden and Red Sea rifts.