Transcript EARTH`S CRUST

EARTH’S CRUST
Centre of the Earth
• Approximately 6400 km
below the surface
Inner Core
• A mass of iron with a temperature of
3870* C
• At such temperatures iron would
normally melt BUT immense pressure
keeps it in a solid state
Approximately 2400 km in diameter
Outer Core
•
•
•
•
Mass of molten iron
Approximately 2200 km thick
Surrounds the solid inner core
Electrical currents generated from this
area produce the Earth’s magnetic field
Mantle
• Approximately 2850 km thick
• It reaches about half the distance to the
centre of the earth.
• Parts of this layer become hot enough to
liquefy and become slow moving rock
called magma
Crust
• Layer of rock varying from 10 km
thick under the ocean floors to
100 km thick under the mountains
Lithosphere
• The rigid outer 100 km of the Earth
• This includes the crust and the top of the
upper mantle
QUESTION
• How do we know that it is hot beneath the
Earth’s crust?
• Volcanoes erupt
• In some places on the Earth’s surface:
mud appears to boil
• Geysers erupt
• Hot springs