Relatively short segments of transform boundaries along oceanic ridges are not identified. Click on map to view larger version. A gap is created when oceanic lithosphere separates along the oceanic ridge. The gap is filled by magma that rises from the asthenosphere. The magma cools and solidifies to create new oceanic lithosphere.
Plates interact along plate boundaries.
Example, the mid-Atlantic ridge separates North American and Eurasian plates in the north Atlantic Ocean. Example, the Juan de Fuca plate descends below the Pacific northwest. Transform plate boundary - where plates slide past each other, neither is consumed or created. Example, San Andreas Fault, California separates North American and Pacific plates. The evolution of a divergent plate boundary has three recognizable stages.