Minerals that melt at lower temperatures and are lighter than the surrounding material tend to rise, melting their way up through the overriding plate to erupt as volcanoes on the ocean floor.
熔点较低,及轻于周围物质的矿物质往往会往上升,融化并穿破其上方的板块,爆发成为海底的火山喷发。
The coupling relation between the directions of the overriding plate extension and oceanic plate motion supports the slab rollback model for the back-arc extension.