Question

Describe how the following features found in upland glaciated landscape are formed

1. U-shaped valley
2. Pyramidal peak

Answer 1

U-shaped valley

• A pre-existing V –shaped valley is filled with ice/glacier
• The gracier erodes the V-shaped valley by abrasion and plucking process vertically and laterally
• The valley is deepened and widened by vertical erosion and lateral erosion
• The end spurs are truncated/trimmed/cut
• The ice melts away leaving a U-shaped valley
   

Pyramidal peak 

• Initially ice collects in several hollows on the maintain side
• The ice exerts pressure on the hollows/cracks
• The plucking action of the ice enlarges the hollow so that more ice collects in them
• Freeze and thaw action of the ice leads to the expansion of cracks/hollows making them large basins which are called cirques
• Nivation into back walls of the hollows make them recede into the mountain side/the cirques recede towards each other.
• Steep sided, knife edged ridges/arêtes converge at the top of the mountain forming a jogged peak called a peak/horn(surrounded by corries/cirques)