At a divergent boundary, a rift is formed. Sometimes, the gap may widen further or it may stop. If the rift widens, then it becomes a rift valley. When the divergent boundary occurs in the deep ocean, a mid-ocean ridge is formed. Divergent boundaries occur when two tectonic plates pull away from each other. An example of a divergent boundary on land is the rift valley of East Africa and an example of a mid -ocean ridge is the Mid - Atlantic Ridge found at the bottom of the Atlantic.