A divergent boundary happens when two plates move away from each other. As the plates separate along the boundary, the block between the faults cracks and drops down into the soft, plastic inside called the asthenosphere. Also, the mid Atlantic ridge is in the Atlantic Ocean and an example of a divergent boundary. The plate separation is a slow process. For example, divergence threw the Mid Atlantic ridge causes the Atlantic Ocean to widen at only about 2 centimeters per year.
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