ocean crust—part of Earth’s lithosphere that underlies sea basins. Oceanic crust is primarily composed of mafic rocks (rich inward Fe in addition to magnesium) in addition to are less dense than rocks that underlie continents (continental crust is enriched inward silica in addition to aluminum). Ocean crust around the populace is significantly younger (less than 200 meg years) relative to continental crust which has typically accumulated through the natural refining processes associated amongst plate-tectonics over many hundreds of millions to several billion years.
continental crust—the relatively thick business office of the Earth’s crust that forms the large landmasses. It is to a greater extent than oft than non older in addition to to a greater extent than complex than the oceanic crust, in addition to dominantly composed of igneous in addition to metamorphic of granitic or to a greater extent than felsic composition.
Plate tectonic model
Subduction introduces oceanic crustal rocks (including sediments) dorsum into the Asthenosphere. Water in addition to gas helps low-temperature minerals to melt in addition to rising as, forming novel continental crust (less dense than oceanic crust). Floating on the Asthenosphere, the continental crustal materials accumulate, forming continents.