Describe the processes which occur at a divergent plate boundary.

At a divergent (constructive) plate boundary, the Earth's plates move apart from one another. Magma originating from the mantle rises to the surface, forming new crust; this process generates convection currents which cause the crust to be pushed apart. An example of this type of plate boundary is the Mid-Atlantic Ridge, where magma rises to form new oceanic crust on either side of a Mid Ocean Ridge.