Ice Movement; Short and Snappy

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  • Created by: jack1506
  • Created on: 28-03-14 10:40

Internal Deformation

  • Internal Deformation can occur in both Warm and also Cold Based Glaciers.
  • Involves Ice Crystals Slipping and Sliding over each other.
  • The crystals can also become deformed and fractured due to the force of gravity downhill.
  • It usually occurs at the same time as Basal Sliding.
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Basal Sliding

  • Involves movement of a large block of ice
  • In series of short jerks
  • Meltwater forms on the upslope side of obstacles on the valley floor, which increases resistance
  • This increases Presssure, causing localised melting of the ice
  • Called Pressure melting
  • Meltwater allows the ice to flow up
  • On the other side of the obstacle it will often then refreeze the meltwater.
  • Due to there being less pressure.
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Extensional Flow

  • Occurs when there is a sudden steep gradient in front of the ice
  • The ice flows down the gradient faster and becomes thinner
  • Overstretching in the ice results in the formation of glaciers
  • When the ice reaches the end of the steep gradient, compressional flow begins
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Compressional Flow

  • A reduction in gradient slows the ice's flow
  • The Ice then piles up at the bottom of the gradient, becoming thicker
  • This is called Compressional Flow
  • Crevasses opened up by extensional flow will now be closed
  • In the centre of the gradient, rotational movement takes place
  • This is the movement that forms Corries

 

 

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