Flexi Says: An ocean-ocean convergent boundary occurs location where two oceanic plates come together and the denser plate sinks, or subducts, beneath the less dense plate, forming a deep ocean trench. Chains of volcanoes, called island arcs, form over subduction zone melting occurs where the subducting plate reenters the mantle. The magma rises and erupts over a long period of time, forming the volcanic islands.
