Which mechanism causes the formation of an island arc system near oceanic trenches?

💡 Explanation

When an oceanic plate subducts, dehydration melting occurs because the sinking plate releases water into the mantle wedge, lowering its melting point and generating magma which rises and forms volcanoes that create curved island arcs. Therefore, subduction zone volcanism forms the arcs, rather than upwelling, spreading or plume erosion which have divergent mechanisms.

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