Glaciation

• Corrie


  A arm chair shaped hollow formed high on mountains where snow and ice have built up over many years, often in shaded north-facing hollows
• Formation of a corrie

  1. Abrasion and plucking deepen the hollow as the moving ice erodes the rock fragments, which are incorporated into the ice

  2. The hollow is deepened as the glacier grows and moves downhill
• Corrie


  • Steep back wall
  • Bowl shape
• 1. shaped valley


  A valley formed by glacial erosion, with a wide flat bottom and steep sides
• Formation of U-shaped valleys

  1. Glaciers flow downhill, following the course of old river valleys

  2. Glaciers from many corries join up to create a large valley

  3. Powerful glacial erosion, including abrasion and plucking, widens and deepens the valley

  4. If the temperature is warm enough at the end of the glacier, the enlarged glacial U-shaped valley is revealed as the glacier retreats
• 1. features of a U shaped valley

  • Wide flat bottom
  • Steep sides
• Arête


  A knife-edge ridge formed as neighbouring glaciers erode either side of a ridge, making the edge steeper
• Pyramidal peak


  A sharply pointed mountain summit formed where glaciers erode backwards, carving out rocks by plucking and weathering
• In the Lake District, there are many land use conflicts, especially between farmers and tourists
• Glacial erosion methods


  • Frost shattering
  • Plucking
  • Abrasion
• Morraine is the name given to deposits of sediment made by glaciers, including large boulders and boulder clay
• Terminal morraine


  A ridge marking the maximum advance of a glacier, where the melting ice deposited its load of sediment
• An outwash plain is formed in front of a terminal morraine, from the sediment deposited by meltwater from the glacier