Describe one feature of a divergent plate boundary. (6 marks)

A divergent plate boundary occurs when two plates move away from each other. Rift valleys can form at slow-spreading boundaries as the mid-ocean ridge which builds up on the boundary through solidified magma has enough time to cool and build to a steep and high mountain chain. Tensional stress as the plates pull apart causes cracks parallel to the fault, created by emerging magma, to spread apart and split the mid ocean ridge into two halves- one each side of the boundary. as the plates continue to spread they form a low lying valley between the two sides of the mountain chain. Rifting can also occur at non-oceanic boundaries. When two plates which are not submerged diverge they can also create a rift e.g. East African Rift valley. If a non-oceanic rift valley is flooded- such as the red sea, it is known as a graben.