Flashcards in Lithosphere Deck (15)
Explain the process of abrasion
Pieces of rock are held in the ice and scrape and grind along the bottom and sides of glacial valleys (like sandpaper).
Explain the process of plucking
Ice freezes onto rocks fractures and becomes attached to it. As the ice/glacier moves, it tears/plucks away the rocks.
Explain frost frost shattering/freeze thawing
Water enters small cracks in the rock (by precipitation), the water will then begin to freeze and expand. Overtime the rock will shatter due to the expanding ice, the collection of bits of rock is called scree.
What side of a mountain will snow fall on?
The north side of the mountain.
How is a corrie formed?
Once the glacier begins to form, gravity begins to pull the glacier downhill, the debris at the bottom begin the grind away the rock at the bottom to form a hollow. Due to less erosion at the front of the glacier a corrie lip is formed.
How is a u-shaped valley formed?
It begins when a glacier begins to move down from a mountain down through a v-shaped valley and begins to erode away the interlocking spurs and continue to go through the valley eroding away the sides giving the u shape. There is usually a misfit stream left behind as a remnant of a river that used to run through the valley.
How is a ribbon loch formed?
A ribbon loch is formed when the u shaped valley is blocked off at one end (usually by a terminal moraine) the u-shaped valley can end up getting flooded and the result can be a lake/loch.
How is a hanging valley formed?
A smaller glacier will move down towards the u shaped valley eroding away a smaller section, the smaller glacier then joins with the larger glacier and once the ice melts you are left with a hanging valley.
How is an arête formed?
-Two glaciers erode back to back into a mountain by plucking as they move downhill.
-This forms two corries.
-Plucking makes the ridge narrower and this is called an arête.
- Freeze-thaw weathering makes the arête sharper.
How is a moraine formed?
- The glacier pushes debris forward forming a moraine
- The glacier starts to melt and retreat leaving the moraine
- This process can happen again forming a second moraine, the first being called a terminal moraine and the second a terminal moraine.
What is a terminal moraine?
It is the moraine found at the furthest point reached by the glacier.
Give an example of a corrie
Corries Cas in the cairngorms, Red Tarn, Coirie an Lochan
Give an example of a pyramidal peak
Bynack more in the cairngorms
Give an example of an arête
Can mor dear arête ( Ben Nevis)