Mid Ocean Ridge
Great Mountain Chain

The mid ocean ridge is a mountain range on the floor of the world's oceans. Rift valleys in the center of the mountain range runs down its spine. It sometimes reaches 3,128 (1000 m) above the seafloor.

Length of global mid-ocean ridge system
The entire global mid-ocean ridge system in the oceans is 49,700 miles (80,000 km) long. It has a continuous mountain system that is 40,400 miles (65,000 km) long making it the longest mountain range on Earth.

Mid Ocean Ridge NOAA

Section of the mid-ocean ridge system
on the ocean floor

Rift valleys
The youngest rocks on the ocean floor are located in the rift valleys where magma pushes up the crust as it move from the upper mantle to vents on the ocean floor. The molten lava cools and forms parallel lines of basalt rocks on each side of the rift valley during an eruption.

Ocean floor movement
Each subsequent lava eruption causes the older rocks to move away from the spreading center. All across the ocean the seafloor moves from spreading ridges to subduction zones where the oceanic crust is recycled.

Worldwide mid-ocean ridges, NOAA

Worldwide mid-ocean ridges, NOAA

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Surveying the ocean floors
Research ships began surveying the ocean floors in the 1950s using sonar as they traversed the oceans worldwide. A Columbia University ship, Vema, recorded information on the Atlantic Ocean seafloor. Prior surveys had shown a rise on the ocean floor but it was thought to be a small area.

Atlantic Ocean mountain range
The full extent of the mountain range in the Atlantic Ocean was discovered by researchers when the data from the ship was analyzed. The submarine mountain range was named the Mid Atlantic Ridge.

Global mid-ocean system
New surveys by other ships discovered that the Mid Atlantic Ridge was in fact just one segment of the global mid ocean ridge system that is found in all the oceans on Earth.

More Plate Tectonic Links

Earthquake Epicenter The epicenter of an earthquake is a point on the Earth's surface, not where the earthquake originates.

Caribbean Plate This plate is small but very complex. It has a subduction zone, transform fault, and triple junction.

What is an Earthquake Find out what causes the Earth to shake, rattle and roll during an earthquake. 

Convergent Boundary There are two types of boundaries where plates converge. They produce great mountain ranges and large earthquakes.

Transform Boundary  These boundaries are found all around our ocean floors where oceanic plates are separating.

Mid Ocean Ridge The global mid-ocean-ridge system is the longest chain of mountains on Earth and was not discovered until the 20th Century.

Plate Tectonics Find out lots of fascinating facts and interesting trivia on plate tectonics.

Kids Fun Science The links on our home page include information about volcanoes, science activities, plate tectonics, the rock cycle and much more.

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