Question: Why are mid-ocean ridges important to the theory of plate tectonics? Need Assignment Help? The shape of mid-ocean ridges aligns very closely with the shape of the continental margins, showing they were once connected. Their flat-topped structure indicates they were once in shallower water and moving plates transported them to deeper water. The pattern of earthquakes found there show that plates are subducting. Rock samples there showed that new seafloor crust was formed at them, then moved away from them on the moving plates.