Earths Interior

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Earths Interior
The model scientist put forth is based on
indirect evidence which includes the study of
seismic waves into Earths interior. The diagram
to the left outlines the four major layers inside
of Earth.
Reference Tarbuck and Lutgens text Pages
173 176.
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Layers of Earths Interior
Lithosphere

• Lithosphere
• cool, rigid layer located directly above the
  asthenosphere.
• approximately 100 km thick, which includes the
  entire crust and a portion of the uppermost
  mantle.
• comprise the tectonic plates (sometimes called
  lithospheric plates).

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Layers of Earths Interior

• Crust (two types)
• Continental Crust 30 to 40 km thick
  and has low density.
• Oceanic Crust approximately 5 km thick
  and has high density.

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Layers of Earths Interior
Moho

• Mohorovicic Discontinuity (Moho)
• boundary separating the crust and the mantle.
• distinguished by an increase in rock density.
• velocity of seismic waves show an increase.

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Layers of Earths Interior
Asthenosphere

• Asthenosphere (Upper Mantle)
• located approximately 100 km to 700 km in depth.
• hot, weak zone of rock that is capable of gradual
  movement. This is the layer that the crustal
  plates rest upon.

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Layers of Earths Interior
Lower Mantle

• Lower Mantle
• this layer is approximately 2200 km thick.
• consist of high density rocks rich in compounds
  of iron, magnesium, and silicon.

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Layers of Earths Interior
Outer Core

• Outer Core
• approximately 2270 km thick.
• consist of liquid iron and nickel.
• seismic waves (S-waves) do not pass through this
  layer.

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Layers of Earths Interior
Inner Core

• Inner Core
• approximately 1216 km thick.
• consist of solid iron and nickel.

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Temperature and Density Increases with Depth

• Temperature inside Earth increases at a rate
  of approximately 35 degrees celcius per
  kilometer. This is referred to as the
  Geothermal Gradient.

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Temperature and Density Increases with Depth

• Density inside Earth increases as depth inside
  Earth increases.