 The metamorphosed igneous rocks were derived from volcanic island arcs, while the metamorphosed sediments represent deep-sea sediments eroded from the neighboring island arcs and deposited in a forearc basin.Greenstone belts, being both types of metamorphosed rock, represent sutures between the protocontinents.The Earth's continents started to form in the Archean, although details about their formation are still being debated, due to lack of extensive geological evidence.