What is the Mid-Ocean Ridge?

Michael Anissimov
Michael Anissimov

The mid-ocean ridge is the world's longest mountain range, although it is submerged. It is a continuous ocean ridge that stretches through all the world's oceans, including the Pacific, Atlantic, Indian, Arctic, and Southern Ocean. It exists along the boundary of tectonic plates. In fact, the only reason that the mid-ocean ridge exists is due to weaknesses in the Earth's crust at plate interfaces which permit volcanic activity. The volcanic activity generates magma, which cools to form this continuous submarine mountain range.

The Mid-Atlantic Ridge was the first part of the Mid-Ocean Ridge to be discovered.
The Mid-Atlantic Ridge was the first part of the Mid-Ocean Ridge to be discovered.

Consisting of one continuous mountain range with four prominent branching ranges, the mid-ocean ridge has a continuous length of 40,400 mi (65,000 km). The total length of the system is 49,700 mi (80,000 km). The mid-ocean ridge has an average height of about a mile. Because it generally exists only in the darkest and deepest parts of the oceans, the mid-ocean ridge was not discovered until the 1950s. The first segment to be discovered was the Mid-Atlantic Ridge, which remains the most famous portion of the mid-ocean ridge. At first, it was thought that a long continuous submerged mountain range was only an Atlantic phenomenon, until further surveys revealed portions of the ridge worldwide. Previously, the longest known mountain range in the world was the Andes mountains in South America, with a length of 4,400 miles (7,000 km).

The mid-ocean ridge is a long mountain range that is completely submerged.
The mid-ocean ridge is a long mountain range that is completely submerged.

Now, scientists know that the mid-ocean range is continuously being formed by a phenomenon known as ocean spreading, where convective currents of magma in the mantle push volcanic material up through divergent boundaries between tectonic plates. Ocean spreading pushes the margins of oceanic tectonic plates beneath continental plates, a process known as continental subduction. The margins of these plates are subducted into the mantle, where they melt. Because of this process, the oceanic tectonic plates are all relatively young, under 100 million years in age. By radiocarbon dating different portions of exposed oceanic plate, we can determine the age of the plate and the magnitude and direction of spreading.

Michael Anissimov
Michael Anissimov

Michael is a longtime wiseGEEK contributor who specializes in topics relating to paleontology, physics, biology, astronomy, chemistry, and futurism. In addition to being an avid blogger, Michael is particularly passionate about stem cell research, regenerative medicine, and life extension therapies. He has also worked for the Methuselah Foundation, the Singularity Institute for Artificial Intelligence, and the Lifeboat Foundation.

You might also Like

Readers Also Love

Discussion Comments


I wish that I could go down there and see what it really looks like. I heard that there are even more undiscovered fish down there. --bird2323


@ Alchemy- I was reading an article in a science website that I subscribe to about a new species that biologists discovered less than a month ago. A group of marine biologists discovered a new species of snail fish in a South Pacific mid ocean ridge. The fish is all white with a long fantail and fins. It lives about 20000 feet below the surface. I can only imagine what types of life reside in these depths.


@ Glasshouse- I think that exploration of our oceans is beginning to catch up to space exploration. I recently saw a documentary on one of those nature channels that chronicled an expedition to the ocean deep. The trip took scientists along a series of volcanic mineral vents along the mid oceanic ridges where scientists discovered new species along the way.

One such discovery found a whole ecosystem based on the earth's internal energy rather than solar energy. Crabs, tubeworms, and shrimp had evolved to live around these vents in temperatures that creep up into the hundreds of degrees.


It is amazing to me that we know more about the cosmos than what lies on the sea floor. So little of the ocean floor is explored. In some ways, it is almost more of an endeavor to traverse these deep depths than it is to travel to space. I find it interesting that humans have only traveled to the deepest part of the ocean nine years before traveling to the moon, and have never repeated this manned mission since. I would think that understanding the depths of our world's oceans are just as important as understanding the depths of the galaxy.

Post your comments
Forgot password?