Geography

Physical - Glaciers, Costal, and the Earth

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Glacial Erosion

Abrasion - 

Rocks embedded in the bottom of the glacier wear away the rock underneath which the glacier passes (sandpaper effect.) Some sharper rocks make deeper marks called striations

 

Plucking - 

Tearing away blocks of rock from the bedrock (bottom of the valley) as the glacier moves. These have been frozen by water going in the cracks and freezing – called plucking.

 

Factors which affect erosion: denser glaciers, more debris, the ice touching the sides and floor of the valley, rocks which are weaker.

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Glacial Weathering

 Slow disintegration of rock in situ or near the earth’s surface, weakens the rock so erosion is more aggressive, it is created by climate changes and is not the same as erosion.

Freeze-thaw weathering (frost-shattering) -

Water flowing in to the cracks in the rock, freezing over night, which expands and breaks up the rock into scree.

Scree is broken up fragments of rock

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Upland Glacial Erosion features

  1. Corries

Caused by free-thaw which weakens the rock, this means erosion can take place (abrasion then plucking)

Rotational slip movement - > pressure from the ice at the bottom of the headwall than near the front, slips forward.

The headwall is at the back of the corrie and is jagged and irregular, the basin is hollow and smooth (filled with water) the lip is smooth and the scree is at the bottom of the headwall (red tarn corrie)

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Upland Glacial Erosion features

  1. Arêtes

A long knife edged ridge with steep drops either side, which separates 2 corries


    3. Pyramidal Peaks

A high central peak of rock with arêtes radiating off in different directions, it is usually rocky and angular

 

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Lowland Glacial Erosional Features

When the glacier is large enough to move over the corrie lip, they move down the valley and merge with several other corrie glaciers, forming a valley glacier.

A valley glacier fill an entire valley making it very erosive, they pluck and use abrasion to erode the sides and floor of the valley.

The V shaped profile of the winding river valley changes to a long straight U-shaped profile.

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CASE STUDY

Grosser Aletsch Glacier

  • Europe's longest glacier (23km long today)
  • Originates from the Southern side of Jungfrau and Monch
  • Maximum dept 900m

Since 1860 it has been on a continuous retreat with 2006 being the worst year. Has been retreating up to 50m a year.

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Glacial Deposition Features

Moraine Ridges - any debris which is carried along by the ice.

All material transported by glaciers are called moraines. Most are carried in the base but some are carried on the surface and these show up as a dark line on top of the glacier.

Piles of material along the sides are called LATERAL MORAINES

Two separate Lateral Moraines form together to get one MEDIAL MORAINE.

The material for these moraines is broken off from the rocky peaks above by freeze-thaw.

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Erratics

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Erratics

This is the name given to a boulder dropped by ice in an area where it does not belong, and you can tell this by the different types of rock.

The big grit boulder has been dumped on top of the local white lime stone rock.

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Jungrfrau Glacial Region of Switzerland

People visit there because:

  • winter snow, all-year glaciers
  • best high mountain scenery
  • easy access
  • highest railway station in Europe
  • facilities and accommodation

Environmental problems are occurring in the area due to more visitors in this glacial landscape, these problems are - alpine habitats for wild flowers and wildlife are being lost, trees are being damaged.

Local authorities have managed the tourism to make it more sustainable in the long term, they have done this by restricting car access, all transport services run on clean electricity from hydroelectric landscapes.

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Jungrfrau Glacial Region of Switzerland

The development of tourism has been socially beneficial to this area as it offers jobs and attracts people from other countries.

Visitors are extremely economically important to this glacial area as there are agricultural activities which no longer happen, this is the only source of income for these mountains.

Long term effects of global warming are meaning that no snow is falling so snow machines have  to be used which are expensive and noisy.

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Glacial Deposition Features

Moraine Ridges - any debris which is carried along by the ice.

All material transported by glaciers are called moraines. Most are carried in the base but some are carried on the surface and these show up as a dark line on top of the glacier.

Piles of material along the sides are called LATERAL MORAINES

Two separate Lateral Moraines form together to get one MEDIAL MORAINE.

The material for these moraines is broken off from the rocky peaks above by freeze-thaw.

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