Glacial landscapes

Features of a glacial landscape

You will see in the diagram below some features of a glacial landscape.

Glacial landscape

Match the following features to the numbers on the diagram: arête, hanging valley, corrie, U-shaped valley, alluvial fan, pyramidal peak, corrie loch (or tarn), misfit stream, ribbon lake, truncated spur, screes.

Answer

  1. is a pyramidal peak because it has steep, triangular faces divided by sharp ridges or arêtes.
  2. is an arête, because it is a sharp ridge between corries.
  3. is a corrie, because it is an armchair shaped hollow with steep back and sides.
  4. is a corrie loch, or tarn, has a body of water which has gathered in the hollow in the corrie floor.
  5. is an Alluvial Fan, because it is a fan shaped pile of rock remains (alluvium) washed down by the stream and piled up where the steep valley side meets the valley floor.
  6. is a ribbon lake, because it is a long narrow lake in a part of the valley cut deeper by the glacier.
  7. is a truncated spur, because the ridge has been cut off sharply by the ice that flowed down the main valley.
  8. is a misfit stream, is so-called because it is far too small to have cut the valley.
  9. is a hanging valley, because the valley floor is much higher than the floor of the main valley.
  10. is a U-shaped valley, because it has steep sides and a nearly flat floor. The other side of the valley is missing in this cut-away diagram.

Questions

Question

Describe the formation of a corrie. You may use diagrams to illustrate your answer.

Formation of a CorrieStage oneFormation of a CorrieStage twoFormation of a CorrieStage three
  • Snow collects in hollows.
  • Snow compacts to ice.
  • Ice moves under gravity, lubricated by melt water.
  • Ice rotates to lip.
  • Abrasion deepens corrie.
  • Plucking steepens back and sides.
  • Corrie loch may fill hollow.

Question

Describe the formation of a pyramidal peak. You may use diagrams to illustrate your answer.

Formation of a Pyramidal Peak Formation of a pyramidal peak
  • Three or more corries are eroded backwards into the same mountain.
  • The ice steepens the back walls through plucking.
  • Abrasion deepens the hollows.
  • Freeze-thaw weathering creates a jagged peak.
  • Where corrie sidewalls meet they form arêtes (knife-edge ridges).
  • With a pyramidal peak in the middle.
Question

Describe the formation of a U-shaped valley. You may use diagrams to illustrate your answer.

Formation of a V Shaped ValleyStage oneFormation of a V Shaped ValleyStage twoFormation of a V Shaped ValleyStage three
  • A glacier flows in an earlier 'V'-shaped river valley.
  • The glacier plucks rocks from the sides of the valley making it steeper.
  • It also abrades the floor of the valley making it wider and deeper.
  • When the ice melts the valley has changed from a ‘V’ shape to U-shape.
  • It has very steep sides and a fairly flat floor
  • Any later rivers are called 'misfit streams' because they are far too small to have cut the valley.