Glacial Systems & Landscapes: Glacial Processes

View mindmap
  • Glacial Processes
    • Cold Based Glaciers (CBG)
      • Very cold areas - Antarctica
      • Very little melting
      • Very little movement
      • Very little erosion
    • Warm Based Glaciers (WBG)
      • Milder areas - base is above ice melting point
        • Because friction or geothermal heat
      • Meltwater = lubricant = lots of downhill movement
        • Basal sliding
          • Processes
            • Rotational flow
              • Glaciers = move in arc shape in hollow
            • Extensional flow
              • Compressio-nal flow
                • Low down = ice slow = faster ice pushes down = compression = high pressure = ice fracture in layers = slip forwards
              • Head of glacier = strong gravitational force = ice move quickly = more tension = ice fracture in layers = layers slip downwards
            • Internal deformation
              • Ice crystals shift past each other = ice bends and warps like liquid
                • Main movement for CBG
            • Basic
              • Protruding rock = more pressure = more melting
                • Ice will melt below melting point
                • Less pressure downstream obstruction= meltwater refreezes
                • Flow = fast around obstruction / slow downstream
      • Lots of erosion
    • Nivation and Frost Action Weathering
      • Frost action
        • Freeze thaw where moisture and temp fluctuates around freezing
          • Water enters cracks in cliff faces
            • Temp drops below freezing and water freezes and expands
              • Repetition weakens rocks and pieces fall off
      • Nivation
        • Temp fluctuates around freezing (lots of freezing and thawing of ice)
          • Ice freezes = expands = frost shattering  = rocks break off
            • Snow melts carrying away debris
            • Waterlogged, eroded slopes collapse
              • Snow melts carrying away debris
              • Eventually hollow = deeper and wider
                • Beginning of a corrie
    • Plucking and Abrasion
      • Plucking
        • Ice thaw and refreeze around rocks
          • Glacier moves forward plucks rock away
      • Abrasion
        • Debris carried by glacier = scrape material off valley floor and walls
    • Debris Transport
      • Subglacial = moved along the base
      • Englacial = within the body of the glacier
      • Supraglacial = on top of the glacier
    • Till = unsorted deposited sediment
      • Lodgement till = spread by moving glaciers
      • Ablation till = dropped as melts

Comments

No comments have yet been made

Similar Geography resources:

See all Geography resources »See all Glacial Systems and Landscapes resources »