Главная » Earth Materials читать онлайн | страница 46

Читать книгу Earth Materials онлайн

46 страница из 155

volcanic‐magmatic arcsvolcanic arcs

batholith beltsplutonic magmatic arcs

new continental crust


ssss1 Subduction zone depicting details of sediment distribution, sedimentary basins and volcanism in trench‐arc system forearc and backarc regions.

Areas of significant relief, such as trench‐arc systems are ideal sites for the production and accumulation of detrital (epiclastic) sedimentary rocks (ssss1). Huge volumes of detrital sedimentary rocks produced by the erosion of volcanic and magmatic arcs are deposited in forearc and backarc basins (ssss1). They also occur with deformed abyssal sediments in the forearc subduction complex. As these sedimentary rocks are buried and deformed, they are commonly metamorphosed (ssss1 and ssss1).

Continental collisions

As ocean basins shrink by subduction, portions of the ridge system may be subducted. Once the ridge is subducted, growth of the ocean basin by sea‐floor spreading ceases, the ocean basin continues to shrink, and the continents, microcontinents or arcs on either side are brought closer together as subduction proceeds. Eventually they converge to produce a continental collision.

Правообладателям