Glaciers

• A glacier is a large ice mass which flows across land and through valleys under the force of gravity
• How are glaciers formed?

  1. Snowflakes collect or accumulate in the mountainside.
  2. Snow continues to fall.
  3. With more snowfalls, the weight compresses the snow together
  4. The compressed snow becomes a mass of solid ice
  5. If the ice does not melt the snow continues to fall the ice mass will become bigger and heavier
  6. The force if gravity causes this large ice mass to move downhill very slowly
• Accumulation


  Inputs to the Glacier, such as snowfall and avalanches
• Ablation


  Outputs from the Glacier, such as melting
• Glacial Budget


  The balance between the inputs and the outputs of the Glacier
• Glacials


  • Colder times with extensive glaciation (ice ages)
• Weathering


  The break up of rocks in their original place, close to the earth's surface
• Erosion


  The wearing away of landscape by rock or ice
• Interglacials: Warmer times in between glacial periods
• Plucking


  Occurs when rock and stones become frozen to the base and sides of the glacier

  Glacier moves, plucking the rock and stones from the ground/rock face

  Leaves a jagged landscape
• Abrasion


  Occurs when rocks and stones become embedded in the base and sides of the glacier

  Causes the wearing away of the landscap

  Leaves behind smooth, polished surfaces
• Freeze-thaw weathering


  In warmer temperatures, snow melts and water fills cracks in the rockWhen temperature drops to freezing, the water in the cracks freezes and expands
• Bulldozing


  Material is pushed downhill by the sheer force of the glacier.