In the picture above, two oceanic plates a moving apart from each other. When they both move apart, a space is left open for magma to rise into the ocean, where it cools and forms new land. Whenever an oceanic boundary is occurring, new ocean floor is created, and a mid ocean ridge is created. Also, there can be a continental divergent boundary, where two continental plate are moving apart from each other. When this happens, a rift valley is created.