Journey to the Center of Earth

Layers of the Earth

• Crust

• Lithosphere

• Asthenosphere

• Mantle

• Outer Core

• Inner Core

Crust

• Ranges from 5 – 100 km thick

• Continental crust: dense silicate materials – solid and rocky outer layer **Silicon, Oxygen & Aluminum**

• Oceanic crust: thin and denser minerals

The Mantle

• It is 2,900 km thick

• It made of Silicon, Oxygen, and Magnesium (more dense)

• Temperature ranges from 870°C to 2,200°C

The Outer Core

• It is 2,250 km thick

• Made of MOLTENMOLTEN iron and nickel LIQUID

• Temperature ranges 2,200°C to 5,000°C

The Inner Core• It is 1,200 km thick

• Made of SOLIDSOLID Iron and Nickel

• Temperature ranges from 5,000°C or higher

• The reason it is solid is due to the high pressure exerted on it from the outside layers.

THE CRUSTAL SURFACE.

• CONTINENTAL CRUST – i

is between 20 and 60 km thick. It is composed of granitic rocks, which are less dense than basaltic rocks of the oceanic crust. So, most of continental crust is above sea level.

• OCEANIC CRUST -

is only about 10 km thick. It is composed of basaltic rocks, which are more dense than granitic rocks of the continental crust. So, oceanic crust is below sea level.

Earth’s interior layers.

• The major layers of the Earth consist of the crust, lithosphere, asthenosphere, mantle, outer core and inner core.

Composition of the Earth.

ironoxygen

silicon magnesium

the other

0%

10%

20%

30%

40%

THE THEORY OF PLATE TECTONICS• The framework explains how

and why the surface of the earth constantly changes is called theory of plate tectonic.

• The theory states that the earth’s outer shell, the lithosphere is divided into eight large plates.

• Because each plate moves as a single unit, the interiors of the plates are generally stable. All major activity such as earthquake or volcano occur along the plate boundaries.

Convection CurrentsConvection Currents

• Middle Mantle (Asthenosphere) is composed of hot, dense rock that thickly flows.

• This movement is the reason Earth’s crustal plates move in the Lithosphere.

• Convection Currents are caused by hot material, deep in the mantle, rising then cooling and sinking again