Which mechanism causes the formation of a volcanic arc during oceanic plate subduction?

💡 Explanation

When an oceanic plate subducts, dehydration melting of the mantle wedge occurs because water is released from the subducting plate, lowering the melting point of the above mantle, which generates magma that rises which leads to volcanic arc formation above the subduction zone. Therefore, dehydration melting results, rather than plume upwelling, crustal unloading, or isostatic shifts that are triggered independently.

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