An accumulation of different sedimentary and metamorphic rocks combined with scraps of ocean crust is called

Accretionary wedge. The accretionary wedge is formed from several sediments: marine sediments, but also erosional materials from volcanoes. ocean floor basalts, volcanic island masses, pelagic sediments, trench sediments and other materials transported by gravity. All these sediments are in the non-subducting tectonic plate of the Earth.

Answer;

Accretionary wedge

Explanation;An accumulation of different sedimentary and metamorphic rocks combined with scraps of ocean crust is called accretionary wedge.Accretionary wedge results from the sediments that are accreted onto the subducting tectonic plate at a convergent plate boundary.At the abduction zone, the lower plate scrapes along the bottom of the overriding plate as it enters the earth, an action which erodes material that consists of rock and sediment that then accumulate onto the overriding plate in an accretionary wedge.