tectonic plates make up the earth's crust.
tectonic plates make up the earth's crust.
plates that make up the earth's crust?
tectonic plates
list of tectonic plates









































this is a list of tectonic plates on the earth's surface. tectonic plates are pieces of earth's crust and uppermost mantle, together referred to as the lithosphere. the plates are around thick and consist of two principal types of material: oceanic crust (also called "sima" from silicon and magnesium) and continental crust ("sial" from silicon and aluminium). the composition of the two types of crust differs markedly, with mafic basaltic rocks dominating oceanic crust, while continental crust consists principally of lower-density felsic granitic rocks.









































section::::current plates.
list of tectonic plates
peridotite is the dominant rock of the earth's mantle above a depth of about 400 km; below that depth, olivine is converted to the higher-pressure mineral wadsleyite. oceanic plates consist of up to about 100 km of peridotite covered by a thin crust; the crust, commonly about 6 km thick, consists of basalt, gabbro, and minor sediments. the peridotite below the ocean crust, "abyssal peridotite," is found on the walls of rifts in the deep sea floor. oceanic plates are usually subducted back into the mantle in subduction zones. however, pieces can be emplaced into or overthrust on continental crust by a process called obduction, rather than carried down into the mantle; the emplacement may occur during orogenies, as during collisions of one continent with another or with an island arc. the pieces of oceanic plates emplaced within continental crust are referred to as ophiolites; typical ophiolites consist mostly of peridotite plus associated rocks such as gabbro, pillow basalt, diabase sill-and-dike complexes, and red chert. other masses of peridotite have been emplaced into mountain belts as solid masses but do not appear to be related to ophiolites, and they have been called "orogenic peridotite massifs" and "alpine peridotites." peridotites also occur as fragments (xenoliths) carried up by magmas from the mantle. among the rocks that commonly include peridotite xenoliths are basalt and kimberlite. certain volcanic rocks, sometimes called komatiites, are so rich in olivine and pyroxene that they also can be termed peridotite. small pieces of peridotite have even been found in lunar breccias.
peridotite