A ridge in the sea floor - for example, the Mid Atlantic Ridge, in the middle of the Atlantic Ocean - which is the site of formation for new tectonic plate material. When two plates move apart, a ridge often forms along the boundary where they are separating, filling in with magma and so forming new ground. Many of these ridges lie deep under the oceans.
A continuous ridge, or broad, fractured topographic swell, that extends through the central part of the Arctic, Atlantic, Indian, and South Pacific oceans. It is several hundred kilometers wide, and its elevation above the ocean floor is 600 m or more. The ridge marks a divergent plate boundary where new oceanic lithosphere is being formed.