Earth structure

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  • Created by: selemo
  • Created on: 14-10-16 14:51
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  • Structure of the Earth
    • Inner core
      • Depth of 5,150-6,370 kliometers.
      • Made of  solid iron and nickel.
      • suspended in molten outer core.
      • Solidified as result of pressure-freezing.
    • Outer core
      • Depth of 2,900-5,150 Kilometers.
      • Hot, electrically conducting liquid (mainly Iron and Nickel.)
        • Secondary type seismic waves can't pass through the outer core as it is a liquid.
      • Conducting layer combines with Earth's rotation to create dynamo effect.
        • Maintains a system of electrical currents.
        • Creates Earth's  magnetic field.
        • Responsible for subtle jerking of Earth's rotation.
      • Not as dense as pure molten Iron, indicates presence of lighter elements.
        • 10% of the layer is composed of Sulfur and Oxygen.
    • Lower Mantle
      • Depth of 650-2,900 Kilometers.
      • Composed mostly of silicone, magnesium and oxygen.
        • Also contains Iron, Calcium and Aluminium.
        • Scientists assume Earth has similar proportion and abundance of cosmic elements as found in the Sun.
    • Upper Mantle
      • Depth of 10-400 Kilometers.
      • Solid fragments of mantle found in eroded mountain belts and volcanic eruptions.
      • Olivine and Pyroxene have been found.
        • Olivine (Mg,Fe)2SiO4
        • Pyroxene (Mg,Fe)SiO3
        • These and other minerals are crystalline at high temperatures.
      • Part of upper mantle called Astheno-sphere is partially molten.
    • Oceanic Crust
      • Depth of  0-10 Kilometers.
      • Ocean Ridge System, a 40,000 kilometer network of volcanoes.
        • Generates new crust at the rate of 17 Km cubed per year.
        • Covers ocean floor with igneous rock called basalt.
        • Hawaii and Iceland are examples of accumulation of basalt islands.
    • Continental Crust
      • Depth of  0-75 Kilometers.
      • Composed, essentially of crystalline rocks.
        • Low density, buoyant  minerals.
        • Dominated mostly by  Quartz and feldspars (metal-poor silicates.)
      • Crust is the surface of the Earth.
      • Cold rocks deform more slowly, refer to the rigid outer shell as the Lithosphere.


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