crust (redirected from crustal)

crust

Outermost solid part of the Earth, essentially composed of a range of igneous and metamorphic rock types. In continental regions, the crust is made up chiefly of granitic rock, whereas the composition of the ocean floor corresponds mainly to that of basalt and gabbro. On average, the crust extends 22 mi (35 km) downward from the surface to the underlying mantle, from which it is separated by the Mohorovicic discontinuity (the Moho). The crust and top layer of the mantle together form the lithosphere.

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crust

1. Geology the solid outer shell of the earth, with an average thickness of 30--35 km in continental regions and 5 km beneath the oceans, forming the upper part of the lithosphere and lying immediately above the mantle, from which it is separated by the Mohorovicić discontinuity

2. the dry covering of a skin sore or lesion; scab

3. Oenology a layer of acid potassium tartrate deposited by some wine, esp port, on the inside of the bottle

4. Biology the hard outer layer of such organisms as lichens and crustaceans