Glacial Processes and Ice Movement

  • Created by: roror
  • Created on: 18-05-18 10:16
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  • Glacial Processes and Ice Movement
    • Erosion
      • Plucking
        • Glacier freezes onto rocky outcrops, and pulls away rock as glacier moves away
        • Mostly occurs at glacier base, where pressure causes melting-which will refreeze and attach to rock
        • Leaves a jagged surface
      • Abrasion
        • Material that's transported, it rubs against the valley floor and sides
        • Coarse materials cause striations, fine sediments polish
      • Nivation
        • Series of processes (freeze thaw,chemical weathering) that operate under a layer of snow
        • Nivation hollows occur when there's the accumulation of more debris by repeating seasons of freeze and thaw with moresnow
          • Form beginning of a corrie
    • Transportation
      • Sub-glacial
        • Base of glacier
      • En-glacial
        • Within glacier
      • Supra-glacial
        • Ontop of glacier
    • Depostion
      • Till- unsorted, released by meting ice
      • Angular depsoits
    • Ice Movement
      • Accumulation makes them move due to gravity
        • Moves like plastic under pressure
          • Will shatter if put under immediate tension
      • Lower zone has meltwater due to pressure
        • Moves like plastic under pressure
          • Will shatter if put under immediate tension
      • Internal Deformation
        • Stress builds up, often when an obstacle is met
        • Ice crystals orientate themselves in direction of ice movement and slide past each other
        • Mostly cold based
      • Rotational Flow
        • In corrie, when ice moving downhill pivots around a point
      • Compressional Flow
        • When there's a reduction in gradient of valley floor
        • Decceleration and thickerice
        • Lots of erosion
      • Basal Sliding
        • Meltwater acts as a lubricant, speeding iceflow
      • Extensional Flow
        • Valley is steep,ice accelerates and ice is thinner
          • Lots of crevasses
      • Surges
        • Rapid,sudden movements due to excessive build-up of meltwater

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