8.4 Earth

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8.4 Earths Layers
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Layers by Composition

• Earths interior consists of three major zones
  defined by its chemical composition.
• Crust
• Mantle
• Core

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Crust

• Thin, rocky outer layer of Earth, is divided into
  oceanic continental crust.
• Oceanic crust is made up of igneous rocks basalt
  and gabbro.
• Continental crust is made up of many rock types.

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Mantle

• Over 82 of Earths volume is contained in the
  mantle
• Mantle a solid, rocky shell that extends to a
  depth of 2890 km.
• The boundary between the crust mantle shows a
  change in chemical composition.

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Core

• Sphere composed of an iron-nickel alloy.
• Extreme pressure is found here.

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Layers by Physical Properties

• Earths interior gradually increases in
  temperature, pressure, and density with depth.
• Earth is divided into layers based on their
  physical properties
• Lithosphere
• Asthenosphere
• Outer Core
• Inner Core

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Lithosphere Asthenosphere

• Lithosphere Earths outermost layer that
  consists of the crust and uppermost mantle. It
  forms a relatively cool, rigid shell
• Asthenosphere located below the lithosphere.
  Relatively soft, and weaker layer. Warmer than
  the lithosphere

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Lower Mantle

• Located near the base of the mantle
• More rigid layer
• Rocks are still very hot and capable of gradual
  flow

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Inner Outer Core

• Composed mainly of iron-nickel alloy
• Divided into 2 main regions that both have
  different physical properties
• Outer Core- liquid layer flow of metallic iron
  in this zone is what creates the Earths magnetic
  field
• Inner Core- High temperatures material is
  compressed into a solid state by the high pressure

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