Where plates separate

Part of Hall of Planet Earth.

Plate Separating Model AMNH/R.Mickens

Plates move apart from each other along divergent boundaries. In the ocean basins these boundaries are the mid-ocean ridges, where new oceanic crust forms. Where continents are pulled apart, large gaps, or rift systems, develop. The Great Rift Valley of East Africa is one such rift. In time, it may become like the Red Sea, a more developed rift along which the Arabian and African plates are separating. The Red Sea is a new ocean basin that may eventually grow to the size of the Atlantic Ocean.

East African Rift Zones Plate Map_ILL
Red Sea Plate Map_ILL
Mid-Atlantic Ridge Plate Map_ILL
Making oceanic crust_ILL
The plates that make up the brittle outer 100 kilometers of the Earth spread apart at divergent boundaries. Most of these boundaries are found in the middle of ocean basins.