Ocean-floor basalts – typically seamounts scraped off the subducting plate Pelagic sediments – typically immediately overlying oceanic crust of the subducting plate Trench sediments – typically turbidites that may be derived from: Oceanic, volcanic island arc Continental volcanic arc and cordilleran orogen Adjacent continental masses located along strike (such as Barbados). Material transported into the trench by gravity sliding and debris flow from the forearc ridge *:olistostrome) Piggy-back basins, which are small basins located in surface depression on the accretionary prism. Material exposed in the forearc ridge may include fragments of oceanic crust or high pressure *:metamorphic rocks thrust from deeper in the subduction zone.