Earth crust:

• The outer layer of the earth.

• thinnest layer

• Made up of both continental (land)and oceanic crust(under the ocean).

• least dense

• Composed of mostly granite and basalt

  Earth Mantle:

• Largest layer of the Earth

• Composed of silicate rocks rich in magnesium and iron

• Intense heat causes the rocks to rise and then cool and sink.

• The process is called convection, which causes the crust to move.

• Average temperature 3000

• Made up of mostly magma

• Contains convection currents that move the tectonic plates

Earth outer core:

• Liquid layer 2,300 km thick, second larges

• Composed of liquid iron and nickel

• Lies between inner core and mantle

• Because the magma moves around the inner core, Earth’s magnetic field is created.

Average temperature 4000o -5000o

Earth Innercore:

• A solid ball of metal

• Made of solid nickel and iron

• Densest layer of the Earth

• Average temperature 5000-6000

• Spins at a speed faster than the Earth rotates

• So hot it melts everything in the outer core

• a soild

Seismic:

• Seismic waves are used to determine which layers of the Earth are solid or liquid.

• Some seismic waves cannot pass through certain layers giving us a clue to the layer’s composition.

  Oceanic Crust:

• A thin layer of crust that overlies the ocean basins

• More dense than continental crust

• Mostly basalt rock

• Thinner than continental crust.

• Younger (newer) than continental crust

  Continental Crust

  Continental Crust:

• Layer of rock which forms the continents

• Less dense than oceanic crust

• Mostly granite

• Thicker than oceanic crust

• Older than oceanic crust