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Understanding Mid-Ocean Ridges

written by: R. Elizabeth C. Kitchen•edited by: Laurie Patsalides•updated: 7/8/2011

This article focuses on mid-ocean ridges. It will discuss what they are and what they do.

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    A mid-ocean ridge is simply a mountain underwater in the ocean. They are also sometimes referred to as mid-oceanic ridges. They typically contain a rift, which is a valley, running along their spine. These rifts are created by plate tectonics, which is the large scale motions of the lithosphere on Earth. A mid-ocean ridge is created by ocean floor spreading. This process is responsible for seafloor spreading. When a seafloor is uplifted due to convection currents which cause the mantle to rise as lava emerges. Once the lava cools, new crust is created resulting in mountains under the ocean.

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    The world's mid-ocean ridges form a single global system and are all connected. This makes them the world's largest mountain range. Its total length is 49,700 miles.

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    Mid-Ocean Ridges New crystallized magma is constantly forming new crust for the mid-ocean ridge. At ocean ridges the crust is constantly renewing itself. Mid-ocean ridges that spread more slowly tend to have wider, larger rift valleys. An example is the Mid-Atlantic Ridge. This ridges terrain is very rugged and the rift valleys can reach widths of ten to twenty kilometers with a ridge crest relief of nearly three-thousand feet.

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    Mid-ocean ridges are formed by two processes. These processes include ridge-push and slab-pull. The weight of a ridge will push away the remaining tectonic plate from the ridge, particularly towards what is known as a subduction zone. This is the ridge-pull process. The slab-pull process begins at the subduction zone. When a tectonic plate's weight is pulled below the above plate dragging the remaining plate behind it is the slab-pull process.

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    Mid-ocean ridges were officially discovered in the 1950's. They were not discovered earlier because they are located deep within the ocean. When mid-ocean ridges were first discovered, scientists thought they were only in the Atlantic Ocean.

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    Today's Mid-Ocean Ridges

    • Chile Rise
    • Southwest Indian Ridge
    • Southeast Indian Ridge
    • Cocos Ridge
    • Central Indian Ridge
    • East Pacific Rise
    • Reykjanes Ridge
    • Chukchi Cap
    • Pacific-Antarctic Ridge
    • Alpha Ridge
    • Mid-Atlantic Ridge
    • Explorer Ridge
    • Juan de Fuca Ridge
    • Gorda Ridge
    • Mid-Arctic Ridge (also known as the Gakkel Ridge)
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    Pacific Marine Environmental Laboratory. (2011). Mid-Ocean Ridges. Retrieved on April 20, 2011 from the Pacific Marine Environmental Laboratory:

    Science Daily. (2010). Mid-Ocean Ridge. Retrieved on April 20, 2011 from Science Daily:

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    Photo Credits

    Mid-Ocean Ridge Render: Wikimedia Commons - NASA