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Discovery

A ridge under the northern Atlantic Ocean was first inferred by Matthew Fontaine Maury in 1853, based on soundings by the USS Dolphin. The existence of the ridge and its extension into the South Atlantic was confirmed during the expedition of HMS Challenger in 1872. A team of scientists on board, led by Charles Wyville Thomson, discovered a large rise in the middle of the Atlantic while investigating the future location for a transatlantic telegraph cable. The existence of such a ridge was confirmed by sonar in 1925 and was found to extend around Cape Agulhas into the Indian Ocean by the German Meteor expedition.

In the 1950s, mapping of the Earth's ocean floors by Marie Tharp, Bruce Heezen, Maurice Ewing, and others revealed that the Mid-Atlantic Ridge had a strange bathymetry of valleys and ridges, with its central valley being seismologically active and the epicenter of many earthquakes. Ewing, Heezen and Tharp discovered that the ridge is part of a 40,000-km (25,000 mile) long essentially continuous system of mid-ocean ridges on the floors of all the Earth's oceans. The discovery of this worldwide ridge system led to the theory of seafloor spreading and general acceptance of Alfred Wegener 's theory of continental drift and expansion in the modified form of plate tectonics. The ridge is central to the breakup of the hypothetical supercontinent of Pangaea that began some 180 million years ago.