New crust is created at the mid-ocean ridges. The mid-ocean ridge is a series of mountain ranges that extends along the floor of the oceans and it is also a series of plate boundaries, where molten magma from the interior of the earth can escape. As the magma escapes, it cools and creates the mountains that form the mid-ocean ridge. For all the new crust that is created, some must be consumed. This happens at subduction zones, where plates are forced down into the inner recesses of the earth.