[QUOTE][b]--In the Atlantic, If my mind serves me right, there is only one subduction zone and that is above cuba, which is one of the deepest in the world, the pacific plate (the ring of fire) is quite known for its subduction zones encompassing its perimeter. Magma upwelling is what forced the continents to split to form the mid-atlantic ridge and the atlantic ocean.[/QUOTE]
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You seem quite confident of that, but are you sure that the magma upwelling in the mid-ocean ridges is not an effect of the plates drifting apart, rather than the cause?
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