THE EARTH´S INTERIOR

THE CRUST

BY: Valdospinos Valeria 7th B

Crust

The crust is very thin, comparing with other layers. It is made

of solid and hard rock, is the first layer. In the middle of the

crust and the mantle is the asthenosphere is also made of a hard

rock.

The crust is composed of a great variety

of igneous, metamorphic, and sedimentary rocks. The crust is

underlain by the mantle. The surface of the mantle is composed

of peridotite.

Peridotite: is a rock denser than rocks common in the overlying

crust. A boundary defined by a contrast in seismic velocity. The

crust occupies less than 1% of Earth's volume. The crust have a

continental crust and a oceanic crust.

Continental Crust

Continental

Crust is a

layer formed

by igneous, sedimentary, and metamorphic rocks. The

Continental Crust sometimes is called sial because there is

more granitic. It is  2.7 g/cm 3 of density, but it less than

the Mantle and the Oceanic Crust. Continental crust makes

up about 70% of the volume of Earth's crust.

Oceanic Crust

The Oceanic crust  is the part of Earth's lithosphere,

the oceanic crust make up the seafloor. The Oceanic

Crust sometimes

is called sima because of

the basaltic rock, which is rich in iron and magnesium.

Oceanic crust is 2.9 g/cm3 of density. Oceanic crust is

6

km thick. There happens a lot of violent things like

earthquakes, volcanic eruptions, or tsunamis.