Glaction

• Glacial ice deposits


  1. Boulder clay in irregular heaps

  2. Ice retreats

  3. Ice advances again

  4. Ice shapes and smooths the boulder clay into rounded oval-shaped hills
• Drumlin


  • Steep slope is the direction from which the ice advanced
  • Gentle slope is the direction in which the ice was travelling
• Snow collects in a mountain hollow high

  up in the mountain. With repeated

  snowfalls, the snow compacts to form ice.

  A glacier is born. Through plucking and

  abrasion, the hollow grows deeper.

  Freeze-thaw action is also at work here.

  When the glacier is big enough, it begins to

  flow over the edge of the cirque. It then

  begins its journey down the valley. When

  the glacier melts, a lake called a tarn may

  be trapped in the cirque hollow.