Layers of the Earth

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Layers of the Earth
Crust
Mantle
Outer Core
Inner Core
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Crust

• Avg. thickness- 35 km
• 2 kinds
• 1. Continental
• 20-90 km thick known as sial contains older
  rock, primarily granite less dense than oceanic
  crust
• 2. Oceanic
• 5-10 km thick known as sima younger rock,
  primarily basalt more dense crust

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Crust Cont.

• All life exists in the crust of the Earth.
• Approximately 90 different elements are found in
  the crust, but 5 make up 90 of the crust-
  oxygen, silicon, aluminum, iron, calcium
• Sodium, potassium, magnesium are the most
  common elements in the remaining 10

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Mantle
Earths mantle contains 80 of Earths volume
67 of Earths mass. Common elements found in the
mantle are silicon, oxygen, aluminum, iron,
magnesium. The mantle consists of solid rock,
except for the asthenosphere. Density increases
in the mantle as depth increases
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Layers of the Mantle

• The mantle is divided into 3 sections.
• Lithosphere- consists of the uppermost part of
  the mantle (rigid rock) the crust. Average
  thickness is 100 km.
• - Mohos discontinuity- boundary separating crust
  from mantle discovered in 1909 using seismic
  data found approximately 30 km from Earths
  surface

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Layers of the Mantle cont.
2. Asthenosphere- 100-250 km deep more fluid
layer, but not liquid 3. Mesosphere- lowest
layer rigid rock 660-2900 km deep -temperature
increases with depth, as does density
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Core
Diameter of the total core is 6960 km to
approximately the diameter of Mars The core is
1/6 of Earths volume 1/3 of its total mass
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Outer Core

• Approximately 2270 km thick
• Temperature approximately 4000-5000º Celsius
• Liquid very dense molten iron nickel
• Believed to create Earths magnetic field
  similar to the magnetic field around a magnet

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Inner Core

• Temperature is about 5000º Celsius
• Believed to be solid very dense iron nickel
• Remains solid due to immense pressure (may be 2
  million times stronger than normal pressure
  exerted on Earths surface) molecules can not
  spread out become liquid

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