Tuesday, February 2, 2010

What's the difference between mid-ocean ridges and rift valleys?

Please help....i'm so confused.





Also, what forms where two plates under an ocean spread part? I thinking it's rift valleys, but then again......What's the difference between mid-ocean ridges and rift valleys?
Ok, both mid-ocean ridges and rift valleys are formed at Divergent plate boundaries. Mid-ocean ridges occur when two oceanic plates are pulling apart from one another, for example the Mid-Atlantic Ridge. Rift valleys occur when continental plates are pulling apart from one another, for example the East African Rift Valley.





When oceanic plates spread apart, you get mid-ocean ridges!





Hope this helps!What's the difference between mid-ocean ridges and rift valleys?
ridges: divergent boundaries, go up like a mountain


Valleys:Convergent boundaries, go down like valley


both underwater


Answer 2 ur Q: mid ocean ridges
Mid ocean ridges are formed by divergent plates. Rift valleys are formed by convergent plates. when two ocean plates spread apart, a mid-ocean ridge is formed.
When crustal spreading occurs, the fracture that results is called a rift. The primary cause of rifting is the upwelling of the underlying mantle. In the ocean, the rifting process is associated with a rising of the crust along the rift line because of this upwelling mantle, so an oceanic rift appears as a ridge-like structure. They are called mid-ocean rifts and mid ocean ridges (the more common term) because the crust is moving away in both directions, so the feature commonly occurs at the middle of the ocean basin.





Sometimes, the tension in the crust spreads from the ocean into areas covered by continental crust. Because the continental crust is so much thicker, the ridge aspect of the process is less apparent. Instead, the rifting aspect is the dominant feature. In both cases, the primary process is the thinning of the crust as each side moves away from the other. Eventually, rift valleys (e.g., the east african rift) develop into rift basins (e.g., the red sea), and then into ocean basins (e.g., the atlantic ocean).





In summary, a mid-ocean ridge is a rift zone formed in oceanic crust. A rift valley is a similar feature that occurs in continental crust.





So when geologists talk about the breaking up of supercontinents like pangaea and laurasia, they immediately think in terms of a process that starts as a rift valley, develops into a rift basin, and then expands into an ocean.





I hope this helps clarify things a bit.
ok, mid-ocean ridges are the areas in the middle of the ocean (such as at the Mid-Atlantic Ridge) where the ocean floor opens and spreads. Here, magma (or lava once it reaches the surface) creates new rock and land. This is what pushes the plates further apart. It is where NEW LAND IS CREATED. Rift valleys from what I am aware of, is also where land is spreading, but it does not create NEW land the same way the mid-ocean ridge does. This creates great valleys whereas the mid-ocean ridges create volcanic areas. Therefore, the mid-ocean ridge is what form when two plates under an ocean spread apart.

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