lithosphere Flashcards
Explain the formation of a corrie (8 marks)
Glaciers form in north facing hollows where more snow falls in winter than melts in summer
This snow compresses into neve and eventually into ice
The glacier begins to move downhill due to the weight of the ice is being pulled down by gravity
Abrasion - rocks that are frozen into the base and sides of the glacier scrape against the bedrock like sandpaper when the glacier moves
- this deepens the hollow which created a bowl shaped feature
Plucking - pulls the rocks that are frozen in the glacier from the ground,
- this makes the back wall steeper
Freeze thaw weathering - water that is trapped freezes and expands and contracts which weakens the rock until fragments break off
When the ice melts an armchair shaped hollow is left in the mountainside which is called a corrie
Explain the formation of an arete (8 marks)
Glaciers form in north facing hollows where more snow falls in winter than melts in summer
This snow compresses into neve and eventually into ice
The glacier begins to move downhill due to the weight of the ice is being pulled down by gravity
Abrasion - rocks that are frozen into the base and sides of the glacier scrape against the bedrock like sandpaper when the glacier moves
- this deepens the hollow which created a bowl shaped feature
Plucking - pulls the rocks that are frozen in the glacier from the ground,
- this makes the back wall steeper
Freeze thaw weathering - water that is trapped freezes and expands and contracts which weakens the rock until fragments break off
When the ice melts an armchair shaped hollow is left in the mountainside which is called a corrie
Aretes are sharp, knife-edge ridges that form when 2 corries form next to each other either back-to-back or side to side, and as the corries erode the ridge between them becomes narrower
An example of an arete is striding edge
Explain the formation of a pyramidal peak (8 marks)
north facing hollows - more snow falls in winter than melts in summer
This snow compresses into neve and eventually into ice
The glacier begins to move downhill due to the weight of the ice is being pulled down by gravity
Abrasion - rocks that are frozen into the base and sides of the glacier scrape against the bedrock like sandpaper when the glacier moves
- this deepens the hollow which created a bowl shaped feature
Plucking - pulls the rocks that are frozen in the glacier from the ground,
- this makes the back wall steeper
Freeze thaw weathering - water that is trapped freezes and expands and contracts which weakens the rock until fragments break off
A pyramidal peak is formed when three or more corries and aretes meet
An example of a pyramidal peak is mount Everest
Explain the formation of a U shaped valley (8 marks)
north facing hollows - more snow falls in winter than melts in summer
This snow compresses into neve and eventually into ice
The glacier begins to move downhill due to the weight of the ice is being pulled down by gravity
Abrasion - rocks that are frozen into the base and sides of the glacier scrape against the bedrock like sandpaper when the glacier moves
- this deepens the valley floor and flattens it
Plucking - pulls the rocks that are frozen in the glacier from the ground,
- this makes the valley sides steeper
Freeze thaw weathering - water that is trapped freezes and expands and contracts which weakens the rock until fragments break off
Interlocking spurs will be cut off, leaving truncated spurs and steep valley sides
After glaciation, a u shaped valley is left with steep sides and a wide flat base, a misfit stream may be present
