Layers of the Earth

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Layers of the Earth
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Layers of the Earth

• Crust
• Mantle
• Core

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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).

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CRUST
The outermost layer of Earth Composed of eight
major elements

• Oxygen
• Silicon
• Aluminum
• Iron
• Calcium
• Sodium
• Potassium
• Magnesium

• Composed of 2 major rock types
• Basalt (Ocean Crust)
• Granite (Continent Crust)

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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.

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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)

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MANTLE
1800 miles thick Composed of very HOT, dense
rock

• - Temperatures range from 1600F to 4000F!!
• - Convection currents in the lower/middle
  mantle move the plates.
• Plates float on the mantle.

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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.

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CORE
Located at the center of the Earth Divided into
two parts

• INNER CORE
• OUTER CORE

inner
outer
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OUTER CORE

• 1400 miles thick
• SO HOT that everything is in the
• liquid state!
• - Temperature ranges from 4000F
• to 9000F
• Above the inner core
• Liquid
• Made mostly of iron
• and nickel

inner
outer
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INNER CORE

• 800 miles thick
• Temperature and pressure
• are VERY strong!
• Temperatures may reach
• over 10,000F (hotter than
• the sun!)
• Solid and dense
• Made mostly of iron

inner
outer
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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!!!!!!