Geography Ice Flashcards
What are the glacial processes ?
Plucking,freeze-thaw weathering and abrasion
What is freeze-thaw weathering?
A type of weathering where water repeatedly freezes and puts pressure on the rocks to break them down.
What is abrasion?
The wearing away of the rocks at the base and sides of the glacier.
What is plucking?
The tearing away of blocks of rock which have become frozen onto the base and sides of a glacier.
How does abrasion cause striations?
The rocks in the ice scrape long grooves in the ground called striations
Why are striations important?
They show you the direction the ice moved
How are glaciers formed?
- Glaciers form in very cold places.
- Lots of snow falls but not all of it melts.
- This means that overtime lots of layers of snow lie on top of each other.
- As the snow layers build up, the lower layers compact into ice forming a glacier.
- The glacier gradually moves down a slope.
When was the last ice age?
Began 1,000,000 years ago
Ended roughly 10,000 years ago
How much of the globe was covered in ice?
30%
What is a glacial period?
When the ice advances
What is an interglacial period?
A warm period between a glacial period
Facts about the Mer De Glace
. In the Northern slopes of Mont Blanc in France
. It’s 7km long, 1260m wide and 200m thick
. Moves at the speed of 70 meters per year
. About 200 years old
What is a corrie?
A steep sided bowl shaped hollow at the head of a glaciated valley.
How is a corrie formed?
- A corrie is formed when snow collects in a hollow on the side of a mountain. Overtime more snow collects which compresses the lower layers into ice.
- The hollow is then depended and widened by the Corrie glacier through the processes of plucking and abrasion.
3.this over deepening leads to the bowl shape characteristic of a Corrie.
How is a U-shaped valley formed?
As a glacier flows down an old v shaped valley it erodes the bottom and sides of the valley by abrasion and plucking which forms a U-shaped valley.
