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In what ways and for what reasons do the landforms of upland glaciated regions differ from those of lowland glaciated regions?

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Introduction

Geography Essay 2000. In what ways and for what reasons do the landforms of upland glaciated regions differ from those of lowland glaciated regions? (15 marks) Glaciers' are extremely vigorous, moving masses of ice on land. They are examples of open systems. Their main output is snow either from direct snowfall or from avalanches. It accumulates in the upper part of a glacier, which looks white. The snow is stored in the system as glacier ice and is carried down slope by the glacier's movement. The main output is water. Although some water evaporates directly from the surface into the atmosphere, mass water loss results from melting as lower altitudes, or latitudes with higher temperatures are reached. Therefore, there are various landforms, which develop as a glacier follows its course. The upland glaciated regions differ from the lowland glaciated regions due to a number of factors. Valley glaciers are powerful agents of erosion. They have contributed greatly to the spectacular scenery found in many mountainous areas, being directly responsible for deepening pre-existing river valleys. By doing this, they have exaggerated, in quite a dramatic manner, the vertical differences between frost-shattered peaks above and flat valley floors below. ...read more.

Middle

A corrie is a deep, armchair-shaped hollow high up on the mountainside. Initially a nivation hollow forms due to solifluction, which is the moving of soil down slope in periglacial areas caused by summer melting of the surface layer and freeze-thaw action beneath the snow patch, which cause the underlying rocks to disintegrate. The absence of complete summer melting in the high altitudes allows the compaction process and the snow is steadily transformed first to fern and then to ice. When the ice mass reaches a certain thickness it starts to move by internal deformation and by sliding over its bed. At this point it becomes a small glacier. With movement, erosion increases significantly and the small glacier excavates a basin at the side of the mountain peak. A rock lip develops where the rate of erosion falls and the lip may have a thin veneer of moraine, which makes it the highest place in a glaciated landscape where deposition occurs. A cirque glacier steadily erodes backwards into the slope behind it, a head-ward process known as sapping. If two cirques are sapping head-wards towards each other, a knife edged ridge called an ar�te is usually formed. ...read more.

Conclusion

They are usually marked by waterfalls. The ice may also carve deep rock basins frequently filled with ribbon lakes. In this region, ice erosion takes place wherever the ice is in contact with rock, whereas earlier direct erosion by the river took place only in the small part of the valley where the stream was flowing. The irregular long profile of glaciated valleys demands separate explanation. Extended flow increases ice thickness as it fills the hollow. This increases the weight for abrasion, and leads to more pressure melting at the base of the glacier which encourages plucking. Another reason for localised valley deepening is additions of ice. A steep drop in level often occurs towards the head of a valley after cirque glaciers increase the size of the glacier in the main valley, thereby giving a sudden boost to its ability to erode. This is the trough end. Tributary glaciers joining the main glacier lower down the glacier have a similar effect. Therefore, landforms of valley glaciers in the central region of a glaciers course are different from those in the higher region because they are formed due to diverse factors. The landforms of the lowland glaciated region are often formed by deposition. They are considered to be smaller and less impressive although they can be quite extensive. ...read more.

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