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Glaciated Landscapes
~Processes
© Boardworks Ltd 2005
© Boardworks Ltd 20052 of 17
How much of the British Isles was covered by ice?What is the glacier system?Which processes operate in the glacier system?
Lea
rnin
g o
bje
ctiv
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© Boardworks Ltd 20053 of 17
Ice Age in Britain
Use an atlas to help you name the source regions of the valley glaciers.
How much of the British Isles was covered in ice?
0 200km
During this time temperatures fluctuated and ice advanced and retreated four times. The northern and eastern parts of the British Isles were covered in ice.
The Ice Age in Britain began about 1,000,000 years ago and lasted until about 20,000 years ago.
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How much of the British Isles was covered by ice?What is the glacier system?Which processes operate in the glacier system?
Lea
rnin
g o
bje
ctiv
es
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What is the glacier system?
The glacier system consists of inputs, transfers (flows), stores and outputs in the same way as a river.
Inputs come from avalanches along the sides of the glacier but mainly from precipitation as snow.
Over time snow accumulates and is compressed into ice. The water held in storage is the glacier.
Under the force of gravity, the glacier flows downhill.
Meltwater is the main output from the glacier, along with some evaporation.
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Label the glacier system
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Acccumulation and ablationThe balance between inputs and outputs varies.
In the winter, inputs usually exceed outputs near to the head of a glacier (accumulation).
In the summer and at lower altitudes, outputs will exceed inputs (ablation).
The balance between the annual rate of accumulation and ablation determines whether the glacier will advance or retreat.
Today, most of the world’s remaining glaciers are retreating.
Meltwater pouring from a glacier’s snout, SW Iceland
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Accumulation and ablation
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Meltwater at the snout of a glacier
Why do you think the ice is blue?
What are the two outputs that you can see in this picture?
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Zone of accumulation
B
A Is the zone of accumulation at A or B?
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How much of the British Isles was covered by ice?What is the glacier system?Which processes operate in the glacier system?
Lea
rnin
g o
bje
ctiv
es
© Boardworks Ltd 200512 of 17
Frost shattering
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How do glaciers erode?
PluckingThe water at the bottom of the glacier freezes onto rock on the valley base. As the glacier moves, the rock is pulled away from the valley base. Plucking mainly occurs when the rock is well-jointed.
AbrasionThe moraine frozen into the glacier scours the valley sides and base. This is a sandpapering effect, similar to corrasion by a river but on a far larger scale.
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Processes in the glacier system
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Examination question
Study the systems diagram:
For a glacier, list: two inputs, one store and two outputs.
Describe two processes by which glaciers can erode the landscape.
inputs
stores
transfers
outputs
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Test your knowledge of glaciation
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Key ideas
A glacier is a system with inputs, flows, stores and outputs.
The balance between accumulation and ablation determines whether a glacier will advance or retreat.
Glacial processes include frost shattering, plucking and abrasion.
Frost shattering is a type of weathering.
Plucking and abrasion are processes of erosion.
