Cold Environments (AQA)

cold environments summary (optional physical topic)

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  • Created by: Jess
  • Created on: 09-05-11 11:12

Global Distribution


- the areas covered by ice sheets and glaciers


- exist in dry, high-latitude areas

- not permanently covered by snow and ice, vegetation is sparse

- has permafrost (permanently frozen ground)


- may contain small ice caps, mountain glaciers and tundra environments

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Ice formation

- snow initially falls as flakes, which has a feathery structure that traps air

- snow accumulates and compression compacts the lower layers of snow

- this compact form is called firn or neve

- meltwater seeps into the gaps and then freezes, further compacting the mass

- as more snow falls, air is progressively squeezed out of the lower snow

- after a period of time, solid ice develops

- this changes from a white colour (indicating air) to blue (indicating lack of air)

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Types of glacier


- melt in summer, releasing huge amounts of meltwater

- this type of glacier is more likely to erode, transport, and deposit


- occur in areas where the temperature is permanently below 0

- movement is slower than temperate glaciers

- much less erosion, transportation and deposition occurs

- it has a rigid, brittle zone (upper part of the glacier)

- also has a mouldable, plastic zone (lower part)

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Types of ice movement

COMPRESSING FLOW - occurs where there is a reduction in gradient leading to ice deceleration and thickening of the ice mass

EXTENDING FLOW - occurs when the valley becomes steeper, the ice accelerates and becomes thinner

BASAL FLOW - (sliding/slippage) meltwater acts as a lubricant

SURGES - meltwater leads to the ice moving rapidly forward, up to 250-300m

INTERNAL FLOW - crystals orientate themselves and slide past each other

CREEP - stress build up allowing the ice to behave with plasticity and flow

ROTATIONAL FLOW - occurs within the corrie, here ice can pivot about a point

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Glacial Erosion

ABRASION - when material carried by the glacier rubs away at the valley floor and sides, the coarser material may leave scratches on the rock known as striations

PLUCKING - involves the glacier freezing onto and into rock outcrops, and as the glacier moves forward it pulls away masses of rock, leaves a jagged landscape

FREEZE-THAW - water enters cracks in the rocks and freezes overnight, ice takes up more space than water so it then exerts pressure on the crack, and the crack widens

NIVATION - a series of processes that operate underneath a patch of snow, leading to the disintegration of the rock surface

CORRIES - the original process is believed to be nivation, which acts upon a shallow, periglacial hollow and enlarges it into a corrie

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