Which mechanism causes island arc formation during subduction of an oceanic plate beneath another oceanic plate?

💡 Explanation

When an oceanic plate subducts, dehydration reactions occur as water is released from minerals in the downgoing slab, lowering the mantle's melting point, inducing partial melt. Therefore partial melting generates buoyant magma that rises to form island arcs, rather than rebound, expansion or extension, which require different tectonic settings.

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