The Crust

1
The Crust

• SOLID layer of rock that forms Earths outer
  skin, including the solid earth and oceans.

2

• CONTINENTAL CRUST
• 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 - composed of basaltic rocks,
  which are more dense than granitic rocks of the
  continental crust. So, oceanic crust is below sea
  level.

3
The Crust (CONTINUED)

• Composition mostly oxygen, silicon,
• aluminum (Granite and
  Basalt)
• Temperature Varies from air
  temperature to 870 Co (1600 F)
• Thickness 35 - 70 km (3 miles 25 miles)

4
Lithosphere

• Upper part of the mantle and the crust.
• Floats on top of the soft rock below it.
• Litho means stone in Greek.
• The crust and upper part of
• the mantle are very similar,
• so they are combined in this
• layer.

5
The Mantle

• SOLID layer of hot rock between the crust and
  core.

6
Mantle (continued)

• Composition Solid rock, mostly iron and
• magnesium
• Temperature
• (16,000 - 4000 F)
• Thickness 2900 km (1800 mi)
• (contains most of earths mass)

Convection currents - hot material in the mantle
rises, cools and then sinks.
7
Asthenosphere

• Upper part of the Mantle.
• Molten (melted) rock layer.
• About 175 km thick.

8
The Core

• Center of the Earth
• under extreme pressure

9
The Outer Core

• Composition LIQUID iron and nickel
• Relative Temperature 3,700oC 4,300oC
• (4000o 9,000o F)
• Thickness 2,200km (1400 miles)

10
The Inner Core

• Composition SOLID iron and nickel
• Temperature 7,200oC (13,000o F)
• Thickness 5,200km 6,428km

The inner core is very hot, pressure from the
weight of the rest of the Earth doesnt allow
the material to melt. Irons normal temperature
of melting is 15350C, but in the earth inner core
it could stand 40000C with no melting. Pressure
equals 45,000,000 pounds per square inch.