Question- 6 marks
Describe the conditions and processes which have lead to slumping
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QuestionSelect one feature of erosion and one feature of of deposition, and explain the processes involved in the formation of each feature. (6 marks)
Answer: A corrie is a feature of glacial erosion. It it formed when snow gathers in a hollow on the north side of a mountain. As more snow builds up it is compacted into ice also known as neve. This ice starts to erode the bottom of the hollow by abrasion and rotational slip causing the hollow to deepen and the bottom to be smoothed The back wall is steeped by plucking and freeze thaw weathering.
Erosional Features
eg Hanging Valley
Corrie
Roche Moutonee
Answer: Corries are formed when snow collects on a mountainside hollow (usually north facing) during glaciation. This snow compacts into ice forming a glacier. As the weight of the glacier pulls it down the mountain out of the hollow erosion occurs as plucking, which is the process where ice freezes onto rocks and then as the ice moves it pulls the rocks away with it, steepens the back wall and abrasion, which is where rocks which are stuck in the bottom of the glacier scrape away at the surrounding rock, deepening the floor.This causes the hollow to become deep and have a very steep back wall. In addition, frost shattering also occurs at the steep back side of the corrie. The crrie moves down the mountain in a circular motion known as rotational movement. Where erosion is least, at the front of the hollow, a rock lip forms. This continues until the glacier melts leaving a deep, steep sided, horseshoe shaped hollow called a corrie. The glacier meltwater may form a pool in the corrie, this is called a tarn.
Answer:A hanging valley is created when the a v-shaped valley is deepened and widened by the glacier and therefore forms a U-shaped valley. Howevery the tributery valey with the smaller glacier is not affected as much and therefire after the glacier of the main valley has moved down or melted, the tributary valley remains hanging over the U-shaped valley, and when the small glacier melts, a water fall is formed.
Depositional Features
eg Drumlins
Terminal Moraine
Esker
Answer:
With reference to conditions and processes, describe in detail one of the following mass movements:- Slumping
Rockfall
Mudflow (4 marks)
Answer:Rockfall happens on cliffs with a steep or vertical cliff face. Water can seep into cracks in the cliff face causing frost shattering. The water squeezes into the small crack and in cold temperatures will freeze. As the ice expands the cracks in the cliff grow bigger and bigger. Also the process of exofolation also adds to this effect. This happens when there is a range of temperatures during the day, eg when the temperarure rapidly rises and falls. This will cause the rocks to contract and release rapidly which will weaken the rocks. As the cracks get bigger due to these processes, parts of the cliff face will break off and fall as rocks. The rocks that fall from the cliff will build up at the bottom, this is known as scree.
Question : Select one feature of erosion and one feature of deposition, and explain the processes involved in the formation of each feature. (6 marks)
Answer : Drumlins- these are streamlined oval shaped hills made from unsorted till or boulder clay. They are formed when the forward movement of ice moulds the moraine dumped by the glacier into their oval shape. The steep side of the oval is on the upstream side called the ‘stoss’ side with a gentler downstream side called the ‘lee’ side. They are often formed in groups called 'swarms'.
Corrie- Snow gathers in mountain hollows, especially north facing hollows, where there is more shade. This snow builds up and compacts to ice called neve. The action of gravity means the ice moves down the hill, and therefore sticks to back walls and plucks rock from the surface. Rocks on the back walls are loosened by freeze-thaw action. Ice moving with loose rock and deepens the hollow by abrasion. Ice in a corrie has a rotational movement which means that the front of the corrie is less eroded, and a rock forms.
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