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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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. Although a smooth valley cross-profile is created, the dominant feature of the long profile of a glaciated valley is its irregularity. When the glacier was present, it ruthlessly exploited weaknesses within rocks, such as joints, and variations in resistance between one band of rock and another as it moved down the valley. Also, ablation which is loss of ice due to evaporation and melting, increases down glacier from the fern line, where it is nil, to the glacier snout, at the bottom end, where it is at a maximum. The ablation and the glaciers’ forward motion are critical. If ablation is greater then the snout will retreat. If accumulation is greater then the snout advances. If accumulation is equal to ablation then the snout remains stationary. This is a determining factor of where and what landforms are produced along the path of a glacier. The landforms of glacial erosion can be divided into three simple categories, higher altitude, middle altitude and lowland.

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One of the most evident higher altitude landforms of a glaciated region is a cirque or corrie. These are formed where ice first accumulates. 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 ...

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