As Geography - Exploitation and development of cold environments

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Cold environments
Landforms
Erosional landforms
Corries:
Arm chair shaped hollow with a steep back wall and a lake known as a tarn found at the
bottom.
Snow accumulates and lasts a whole summer season
The snow becomes more compact and forms neve/firn
Freeze thaw weathering takes place at the back wall and loosens material which finds its way
into the glacier
Plucking takes places at the backs, sides and beneath the glacier causing more material
within the corrie glacier
Rotation flow causes the arm chair shape and the glacier to advance ­ ice in the corrie pivots
about a point of rotation due to overlying pressure, increasing pressure causes over
deepening of the corrie floor
Corries form best on north east facing slopes in the northern hemisphere
Two corries back to back forms an arête, and 3 or 4 forms a pyramidal peak
Glacial trough:
Ice from a corrie occupies a former v shaped river valley
The ice removes the interlocking spurs to create truncated spurs
Tributary glaciers may join this glacier and form hanging valleys
The ice then also deepens and widens the valley by abrasion, plucking and bulldozing
This creates a U shaped valley
Depositional landforms
Moraines:
Moraine is material that is carried and deposited by a glacier
May include lateral, terminal, recessional, medial and ground moraine.
Freeze thaw weathering weakens the valley rock on the valley sides providing a source of
loose material
Rock falls from the valley side may form lateral moraines due to plucking and abrasion of
valley sides
Ground moraine forms when material enters glaciers in crevasses at the top of the glacier
and finds a route to the base of the glacier. The material is then transported by the glacier
beneath it.
Material is unsorted.
Drumlins:
Drumlins are oval egg shaped hills, which reach up to 50-60m in height, 25-600m in width
and 800-1500m in length

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When many a found in one place they are referred to as `swarms'
Drumlins have a blunt end `stoss' and tapered end `lee'
Drumlins form sub glacier at the lower sections of the glacier
When the glacier passes over an obstacle the ice becomes overloaded with lodgement till
and its capacity to carry material is reduced
Moraine is dropped, the blunt end faces the advancing ice and as it moves over the obstacle
the tapered end is created downstream
Fluvioglacial landforms
Meltwater channels:
Also known…read more

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Periglacial Landforms
Permafrost:
Permafrost is permenantly frozen ground, it is the layers below the surfaceee that remains frzen
for at least two years
Temperatures must therefore be extremely cold for its formation
There is some melting up to 3m below the surface, this is the active layer
There are three different types of permafrost ­ continuous, discontinuous and spoaradic
There further away from the pole the less permafrost there is as the temperature increases
Nivation hollows:
Nivation hollows are bowl shaped hollows
Nivation occurs mainly…read more

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Ice lens forms beneath the dome and increases in size due to the upward movement of
additional water under pressure
Ice lens causes the doming at the surface and cracks to appear within the formation
Solifluction lobes:
Solifluction occurs in warmer seasons where summer thaw of the active layer releases great
amounts of melt water
It cannot percolate so saturates the soil
This reduces internal friction between particles and so the saturated soil begins to flow
downhill on even the smallest of slopes as there…read more

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Basal sliding
Overlying pressure sub glacier causes ice to melt when it reaches its pressure melting
point and so produces melt water
Melt water lubricates the base of the glacier and the bedrock
Subsequent movement causes friction enhancing melting further
This causes the glacier to move more rapidly as it is no longer frozen to its base
Obstacles are overcome as the added pressure allows ice to move them with the aid
of melt water, this is known as regelationship
Larger items are over come…read more

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