Crust (geology)
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In geology, a crust is the outer layer of a planet, part of its lithosphere. Planetary crusts are generally composed of a less dense material than that of its deeper layers.
On partially-molten planets, such as Earth, the lithosphere is floating on fluid interior layers. Because of the partially-fluid upper mantle, or asthenosphere, underneath, floating lithospheres are often broken into tectonic plates that move. On Earth there are two types of crust: continental crust (sial) and the more dense oceanic crust (sima).
See also
de:Erdkruste
et:Maakoor
es:Corteza terrestre
fr:Croûte terrestre
ms:Kerak bumi
ja:地殻
pl:Skorupa ziemska
pt:Crosta
simple:Crust
