In contrast to the Proterozoic, Archean rocks are often heavily metamorphized deep-water sediments, such as graywackes, mudstones, volcanic sediments and banded iron formations. Greenstone belts are typical Archean formations, consisting of alternating high- and low-grade metamorphic rocks. The high-grade rocks were derived from volcanic island arcs, while the low-grade metamorphic rocks represent deep-sea sediments eroded from the neighboring island frogs and deposited in a forearc basin. In short, greenstone belts represent sutured protocontinents.
In contrast to the Proterozoic , Archean rocks are often heavily metamorphized deep - water sediments , such as graywackes , mudstones , volcanic sediments and banded iron formations . Greenstone belts are typical Archean formations , consisting of alternating high- and low - grade metamorphic rocks . The high - grade rocks were derived from volcanic island arcs , while the low - grade metamorphic rocks represent deep - sea sediments eroded from the neighboring island frogs and deposited in a forearc basin . In short , greenstone belts represent sutured protocontinents .
From where did high grade Archean rocks originate?
From where did high grade Archean rocks originate ?
volcanic island arcs
volcanic island arcs