The L ay

ersof theE arth

Shyrlene L. Brier

The Earth is divided into four layers :

oCrustoMantleoOuter CoreoInner Core

CRUSToIt is the thin and the outer most layer of the Earth. oIt is hard.oComposed of different minerals.

CRUSToIt makes up only one percent of the Earth’s mass.oThere are two kinds of crust :

• Continental crustIt is thicker than the

CRUST

oceanic crust. It can range from

25 km thick at the edges to 70 km thick near the center.

CRUST

•Oceanic crustIt is only about 7 km thick and considerably more dense.

LITHOSPHEREo. The crust and the uppermost part of the mantle.oA solid region that is broken into plates which is about 65 to 100 km thick.

MANTLEoIt is the layer below the crust.o. It makes up almost two thirds of the earth's mass and is about 2900 km thick.

MANTLE

oIt is hotter and denser because of the temperature and pressure inside the Earth.

MANTLEoThe mantle is divided into region; the upper and lower sections.oThe upper part of the mantle is cooler and more rigid than the deep mantle;

MANTLEin many ways, it behaves like the overlying crust.

Together they form a rigid layer of rock called the lithosphere

ASTHENOSPHEREoIt is directly below the upper section.oHeat and pressure cause a small amount of melting to occur in the asthenosphere.

ASTHENOSPHEREoThis zone is composed of hot, semi-solid material, which can soften and flow after being subjected to high temperature and pressure over geologic time.

CORE

oThe center of the earth.oIt makes up nearly one third the mass of the earth.

COREoThe core is also divided into two regions, the inner core and the outer core.oScientists believe that the outer core is a liquid and the inner core is a solid.

COREoThe outer core is made of iron and is very dense.oThe inner core is made of solid iron and nickel. It is kept in the solid state because of the extreme pressure from the other layers.

The End :D