Glaciated Uplands Flashcards
What is abrasion?
A type of glacial erosion that occurs when rock fragments frozen into the bottom of a glacier scrape and erode the valley floor.
How is a corrie formed?
When snow over time gathers in North facing hollows to make ice which by the force of gravity, the ice moves downhill. The ice them freezes onto rock on the back of the hollow. As it moves, it plucks rock from the landscape. Rocks on the back wall are removed by freeze-thaw weathering. Rocks frozen in the base of the ice act like sandpaper and deepen the hollow by abrasion. The rotational movement of the ice helps to create a deep hollow and a rock lip is formed by over-deepening. The glacier melts and retreats, often leaving a corrie loch in the base of a corrie.
How is an arête formed?
The ice in the corrie erodes the hollows using plucking and abrasion. As each glacier erodes both corries on either side of the ridge, the edge becomes steeper and the ridge becomes narrower. The ridge is jagged as it has been exposed to freeze-thaw weathering.
How is a pyramidal peak formed?
A pyramidal peak is formed where three or more corries meet back to back. During the ice age snow collected in hollows around the mountain. The snow turned to ice, forming glaciers, which moves downhill due to gravity. Glaciers erode backwards towards each other removing rocks using the process of plucking and abrasion. This creates corries on all sides of the mountain. Freeze-thaw weathering erodes the top of the mountain and creates a pointed peak.
How is a U-shaped valley formed?
Snow and ice compress to form a glacier in a V-shaped river valley. The glacier uses the process of plucking to steepen the sides of the valley. Ice abrasion widens and deepens the valley creating a flat valley floor. The valley is also weathered above and below the glaciers by freeze-thaw weathering. The V-shaped valley is turned into a U-shaped valley by ice erosion.
Name land uses for glaciated upland landscapes.
Industry, farming, water storage and supply, forestry, renewable energy, recreation and tourism.
What is freeze-thaw weathering?
When water enters cracks in upland rocks and freezes at night. Continuous freezing and thawing puts pressure on the rocks until small pieces of rock break off (also called frost shattering).
What is erosion?
The wearing away of a landscape.
What is plucking?
When ice freezes onto rocks at the side of the landscape and when it moves downhill (under the force of gravity), rocks are ripped out. This provides material for abrasion.
