Mid-Atlantic Ridge

  • This submerged mountain range, which extends from the Arctic Ocean to beyond the southern tip of Africa, is but one segment of the global mid-ocean ridge system that encircles the Earth.
  • The rate of spreading along the Mid-Atlantic Ridge averages about 2.5 centimetres per year (cm/yr), or 25 km in a million years.
  • rate may seem slow by human standards, but because this process has been going on for millions of years, it has resulted in plate movement of thousands of kilometres.
  • Seafloor spreading over the past 100 to 200 million years has caused the Atlantic Ocean to grow from a tiny inlet of water between the continents of Europe, Africa, and the Americas into the vast ocean that exists today.
  • In 1947, a team of scientists led by Maurice Ewing confirmed the existence of a rise in the central Atlantic Ocean and found that the floor of the seabed beneath the layer of sediments consisted of basalt, not the granite which is the main constituent of continents.
  • They also found that the oceanic crust was much thinner than continental crust. The new data that had been collected on the ocean basins also showed characteristics regarding the bathymetry.
  • One of the major outcomes of these datasets was that all along the globe, a system of mid-oceanic ridges was detected. An important conclusion was that along this system, new ocean floor was being created.