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Layers of the Earth
Crust
Mantle
Core
Why do we have these layers?
As the Earth cooled the heavier, denser
materials sank to the center and the
lighter materials rose to the top. Because
of this, the crust is made of the lightest
materials (rock- basalts and granites)
and the core consists of heavy metals
(nickel and iron).
CRUST
The outermost layer of Earth
Composed of eight major elements:
Oxygen
Calcium
Silicon
Sodium
Aluminum
Potassium
Iron
Magnesium
Composed of 2 major rock types:
-Basalt (Ocean Crust)
-Granite (Continent
Crust)
CRUST
3 – 5 miles thick in the oceans (Oceanic Crust)
5 – 25 miles thick in the continents (Continental
Crust)
-The crust of the Earth is
broken into many pieces
called plates.
-The crust and the upper
layer of the mantle
together make up a zone of
rigid, brittle rock called the
Lithosphere.
MANTLE
The largest layer of Earth, directly
above the outer core
Composed of:
- Silicon - Iron
- Oxygen - Magnesium
Divided into:
- Upper mantle
(Part of the Lithosphere)
- Lower /Middle mantle
(asthenosphere)
MANTLE
1800 miles thick
Composed of very HOT, dense rock
- Temperatures range
from 1600°F to
4000°F!!
- Convection currents in
the lower/middle mantle
move the plates.
* Plates float on the
Convection Currents
A cycle that is believed to move the
plates
Caused by magma heating, rising, then
cooling and sinking, and then heating,
rising, cooling and sinking, and
repeating the cycle over and over.
CORE
Located at the center of the Earth
Divided into two parts:
INNER CORE
OUTER CORE
OUTER CORE
- 1400 miles thick
- SO HOT that everything is in the
liquid state!
- Temperature ranges from 4000°F
to 9000°F
- Above the inner core
- Liquid
- Made mostly of iron
and nickel
INNER CORE
- 800 miles thick
- Temperature and pressure
are VERY strong!
- Temperatures may reach
over 10,000°F (hotter than
the sun!)
- Solid and dense
- Made mostly of iron
What is the pressure like?
The pressure is so great that
you would be squeezed into a
ball smaller than a marble if you
were able to go to the center of
the Earth!!!!!!