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Ice Revision
The Global Distribution of Cold Environments
Glacial
1) Glacial envs found high altitude + high latitude
2) Land permanently covered by ice, either by glacier or ice sheets
3) Glaciers masses of ice flow downhill. 2 types- valley + corrie
4) Only form where very cold so found at:
5) High latitudes e.g. Antarctic sheet (south) and Greenland ice sheet (north) both
entirely above 600 latitude
6) High altitudes e.g.…read more

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Polar/ Cold Glaciers
1) Ice remains frozen at base so little water or movement so little erosion.
2) Little snowfall due to high pressure and limited melting therefore low ice budget
Glacial Movement
1) Rate of movement depends on temperature of ice. Some ice warmer than others
and depends on PMP (temp on which ice is on verge of melting)
2) PMP normally 00C in surface, below lower due to increased pressure.…read more

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Influences of Rate of Movement
1. Snow + ice don't move downslope until thickness exceeds 60m
2. Steep gradients flow faster
3. Faster over impermeable surfaces due to water available for slippage
4. Precipitation and ablation play role in amount of meltwater available
5. Greatest velocity at firm line as velocity related to thickness
6. The centre of glacier moves faster due to no friction with sides
Glacial Processes
1.…read more

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Depositional Landforms
Moraine
1. Lateral moraine- sides of the glacier
2. Medial moraine- in the centre of the valley where two glaciers converged
3. Terminal moraine- builds up at the end of the glacier and is deposited as till
4. Recessional moraine- marks the end of a glacier and different stages of time
5. Push moraine- when a glacier re-advances, it pushes the terminal moraine further
forward
Drumlins
1. Half-egg shaped hills of till, up to 1500m long and 100m high.…read more

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Meltwater streams are often braided- they split into lots of mini streams that cross
over each other. This is as the meltwater is flowing more slowly so it can't carry its
load so it's deposited and the stream has to flow around it
4. Fluvioglacial deposits are sorted and glacial deposits are unsorted
Fluvioglacial Landforms
1. Kames- mounds of gravel and sand. When isolated they can be formed by glacial
debris being stuck in crevasse as being transported in a stream through ice.…read more

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Outwash material may be deposited on top of the till
following retreat of ice.
5. Ice Marginal Lake- Flow of stream from tributary valley blocked by glacier which is
present in main valley
6. Proglacial Lake- Lies in front of a glacier and filled with meltwater, but trapped
between glacier and higher relief (e.g. terminal moraine)
7. Moraine Damned Ribbon Lake- Water retained by ridge of terminal moraine across
valley floor
8.…read more

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Frost contraction in following
years can re-open cracks in same place, splitting ice wedge. More water seeps in
and freezes, widening the wedge.
3. Patterned ground- in areas where temp varies between 0 & -40C, frost heaving
and thawing that follows sorts material. Called patterned ground. When stones
reach surface, roll down to edges of mounds that have formed, so form circles
around (polygons when mounds close). If mounds on slope, stones roll downhill
and form lines.…read more

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Larger material travels quickly downslope due to frost heaving
bringing the stones upto the surface and rolling them down until
hit something which stops them e.g. vegetation or shallow slope.
Creates stone wall, acts as a dam to soil
3. Fnier material accumulate behind stone wall to create terrace
4. Example: Cairngorms, Scotland
2. Turf-banked
1. Forms under continuous vegetation where frost heaving less
effective at raising stones to surface so turf-banked lobes form
instead
2.…read more

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VG rely on caribou for food + hides for clothes and tents. Bones + antlers: soup /
tools. Evidence of traditional hunting e.g. caribou fences (wood) trap herd after
pass through gap in forest or ford across stream), as funneled into U-shape, easy
prey.
10. Now, still hunt during migrations. But not nomadic but settle on Old Crow by
Porcupine River. Now use snowmobiles and rifles.
11.…read more

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