Glacial Erosion Landforms - Corrie Flashcards
What is the starting point of a glacier?
Usually corries.
Other worlds for corries.
Cwms.
Cirques.
Describe the formation of a corrie.
Snowflakes collect in a hollow.
As more snow falls, the snow is compressed and the air is squeezed out to become firn or neve.
With the pressure of more layers of snow , the firn other thousands of years become glacier ice.
What makes the hollow bigger?
Erosion and weathering by abrasion.
Plucking.
Freeze-thaw weathering.
Even though the ice trapped in a hollow and unable to move down hill, what happens?
Gravity will still encourage it to move.
What does rotational slip cause?
The ice to pull away from the back wall creating a crevasse or bergschrund.
What does plucked debris from the back wall cause?
Further erosion through abrasion which deepens the corrie.
Where is some debris deposited?
At the edge of the corrie, building up the lip.
These processes create what?
A characteristic rounded, armchair shaped hollow with a steep back wall.
What happens when the ice in the corrie melts?
A circular lake is often formed at the bottom of the hollow, known as a tarn.
Give an example of a tarn>
Red Tarn on the eastern flank of Helvellyn.
