glacial erosions

Question 1

glacier formation

starting statement for each answer

Answer 1

snow gathers in north facing hollows away from the sun where it accumulates. After many years, snow compresses to form glacial ice and gravity causes the glacier to move downhill.

Question 2

formation of a corrie

Answer 2

glacial formation, plucking desc, freeze thaw desc, abrasion desc

• Bergschrund crevasse opens up at the back of the hollow.
• this allows meltwater and rock fragments to get to the base of the glacier increasing erosive power
• the weight of the glacier pushes down causing rotational sliding, which deepens the hollow
• example if Brown Cove

Question 3

formation of a pyramidal peak

Answer 3

glacial formation, plucking desc, abrasion desc

• forms when 3 or more corries erode back to back
• freeze-thaw weathering (desc) transforms the peak from a rounded summit to the sharp pointed peak
• example is Matterhorn in Switzerland

Question 4

formation of arete

Answer 4

glacial formation, plucking desc, freeze thaw desc, abrasion desc

• arete is formed when two corries erode back towards each other
• freeze thaw weathering can make the ridges more pronounced and can cause scree slopes to develop
• example is Striding Edge

Question 5

formation of u-shaped valley

Answer 5

glacial formation, plucking desc, freeze thaw desc, abrasion desc

• former interlocking spurs may be cut off by the glacier as it flows downhill leaving truncated spurs and steep valley sides
• example is Glencoe

Question 6

formation of ribbon lake*

Answer 6

glacial formation, plucking desc, freeze thaw desc, abrasion desc

• former interlocking spurs may be cut off by glacier resulting in truncated spurs
• ribbon lakes can form where softer bedrock is eroded more deeply than the surrounding area
• an example is Loch Muick

Question 7

formation of a hanging valley

Answer 7

glacial formation, plucking desc, freeze thaw desc, abrasion desc

• former interlocking spurs may be cut off by the glacier as it flows downhill leaving truncated spurs and steep valley sides
• Smaller tributary glaciers erode their valleys much less due to less moraine and mass
• After glaciation, the tributary glacier is left hanging above the main valley.
• when the river returns, waterfalls can form in hanging valleys