How are subduction boundaries related to mid-ocean ridges?

Answer 1

The ocean ridges push the old crust into a convergent boundary where it goes into a mantle convection current. The crust then melts in the convection current and is pushed out of the ocean ridge to restart the process again.

Answer 2

Convection ocean ridges are places where two plates are spreading apart, and magma from the mantle rises up, creating new ocean crust. A good example of this is the Mid-Atlantis ridge, where the Eurasian plate and the North American plates are pulling away from each other, creating volcanoes and earthquakes.

Subduction zones occur most often between continental plates and ocean plates. The denser, heavier ocean plate, when pushed up against the lighter continental plate, is forced back down into the Earth, where it is destroyed. This happens often in contact between ocean plates and continent plates. The Himilayas are actually a result of this type of subduction: as the Indian-Australian plate is forced under the Eurasian plate, the Eurasian plate is actually pushed up. Mt. Everest is rising, very slightly, every year as the Eurasian plate continues to be forced up.

Answer 3

Mid ocean ridges are the zone where oceanic crust is formed and subduction zones are the zones where it sinks down into the mantle, so one looks basically at the birthplace and graveyard of the oceanic crust in these zones.

Both zones are associated with forces acting upon the oceanic crust.

The mid ocean ridges are a zone of high topography (they are effectively a mountain chain) and this this topography and the continuous generation of new (still hot) crust in this area creates a pushing effect (known as the ridge push).

In the subduction zone, old and cool oceanic crust is subducted into the mantle. Cold oceanic crust has a density which exceeds that of the upper mantle so that the oceanic crust actively sinks into the mantle (this is known as slab pull).

In that way the ridge push helps subducting the crust via pushing it or alternatively the subduction pull helps creating new oceanic crust.

Answer 4

Volcanoes can be created at subduction zones from the downward movement of water filled oceanic crust into the mantle and the melting of the crust above it.

Answer 5

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