The Mid-Atlantic Ridge is a major plate boundary that that runs from North to South and spans the entire
Atlantic Ocean. Discovered in the 1950s (though speculated about previously), the ridge is a
divergent boundary where new
crust is created while pushing Africa and Europe further away from North and South America. Submerged volcanic mountain ranges develop along the ridge and occasionally break the ocean surface to form islands such as
Iceland,
Saint Helena, and the
Azores.
Spreading rates of the plates are estimated to be about 1 to 10 cm (0.5 to 4 inches) per year. See also
plate tectonics.
In its entire length, the basin of the sea (the Atlantic) is a long trough, separating the Old World from the New, and extending probably from pole to pole. This ocean-furrow was scored into the solid crust of our planet by the Almighty hand, that there the waters which "he calls seas" might gather together, so as to "let the dry land appear," and fit the Earth for the habitation of man....
Could the waters of the Atlantic be drawn off, so as to expose to view this great sea-gash, which separates continents and extends from Arctic to Antarctic, it would present a scene the most rugged, grand, and imposing. The very ribs of the solid Earth, with the foundations of the sea, would be brought to light, and we should have presented to us at one view, in the empty cradle of the ocean, "a thousand fearful wrecks" with that dreadful array of dead men's skulls, great anchors, heaps of pearl and inestimable which, in the poet's eye, lie scattered in the bottom of the sea, making it hideous with sights of ugly death.
Matthew Fontaine Maury from The Physical Geography of the Sea,1855.