The deep oceans are far from flat. They feature ridges, trenches, seamounts, and valleys, creating a diverse and dramatic ...

They are higher and usually steeper than a hill and are generally over 600 metres high. They are often ... line of mountains under the ocean called the Mid-ocean Ridge - the longest mountain ...

high-resolution imaging of the mantle beneath the Mid-Atlantic Ridge. In the standard view of plate tectonics, ocean expansion is driven mainly by the pull of gravity, as denser plates sink back ...