1.andesite:an intermediate type of volcanic rock between basalt and rhyolite.2.back-arc basic:a seafloor spreading system of volcanoes caused extension behind an island arc that is above a subduction zone.3.barrier island:a low,elongated coastal island that parallels the shoreline and protects the beach from storms.4.basalt:a dark,volcanic rock rich in iron and magnesium and usually quite fluid in the molten state.5.carbonate:a mineral containing calcium carbonate such as limestone and d
