Distinguish between the processes of erosion and weathering in an area undergoing glaciation.

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Distinguish between the processes of erosion and weathering in an area undergoing glaciation.

Erosion is defined as the removal and transport of earth materials by natural agents and can be split into two main categories. Abrasion (or corrasion) is the glacier's use of angular debris, held by the ice, to scrape away at the underlying rock. Evidence of this in an area undergoing glaciation are scratches on rock known as striations. Plucking involves the glacier freezing on to blocks of rock and pulling them away. Meltwater will assist in this plucking process: pressure builds up behind a protrusion of rock and so causes melting. The meltwater penetrates any cracks and freezes around the rock (regelation) which is then pulled out by the glacier. Weathering is similar to erosion in that it includes the breakup of rocks, just not the transportation of the materials formed as does erosion. The specific definition of weathering is the breakup of rock due to exposure to the atmosphere. The weathering of a rock by freeze-thaw action (or frost shattering) may break up rock in periglacial conditions before glaciers advance. At the early stage of corrie formation freeze-thaw action and possibly chemical weathering will weather rock beneath the accumulating patch of snow (the process of nivation). During glaciation, meltwater will give rise to freeze-thaw action at the base of the glacier.

 

Examine the impact of glacially eroded landforms on human activity

"The impact of glaciation on human activity has been considerable both in lowland and highland areas." (David Jones and Lawrence Kimpton 2000). This question focuses on how human activity has been affected by glacial erosion. The most recent glacial period began approximately 30,000 years ago and ended 10,000 years ago. At its peak 29% of the Earth’s surface was covered by ice in comparison to 10% covered today. Sea level fell by at least 100 m and the beach was as much as 150 km further east along the Atlantic coast, thus forming land bridges between North America and Asia, which allowed for the migration of animals and humans to previously glaciated areas. Glacial eroded landforms include the features horns (pyramid shaped peaks), arêtes (knife shaped ridges), cirques (a bowl shaped depression found in mountains), erratics (boulders), valleys, tunnels and lakes. These landforms have affected human activity in various ways, including tourism, communications, farming and settlement and industry.

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     Many upland areas that experienced the effects of prolonged glacial erosion during the Pleistocene have become important centres of tourism. Highland areas both those glaciated in the past and those with glaciers remaining today, are major areas of tourism because of the spectacular scenery and their suitability for winter sports. The Cirque-arete-trough landscape attracts hill walkers, scramblers, climbers, mountaineers, photographers, botanists, skiiers, snowboarders, hang gliders, painting, canoeing, sailing etc. In Britain, the Highlands of Scotland have become an important centre for summer holidays and winter skiing, whilst the National Parks of Snowdonia, the Lake District and Peak District ...

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