Geography- Cold Environments

Glacial Environments:

  • Areas of land permanently covered by ice; by glaciers of ice sheets.
  • Found at high latitudes, eg Antarctic Ice Sheet and Greendland Ice Sheet above 60 latitude.
  • Found at high altitudes, eg Himalayan mountains.
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Periglacial Environments

  • Temperature is below freezing, but not covered by ice.
  • Has a layer of permafrost on or below surface.
  • Found at high latitudes eg nothern parts of Asia.
  • Found at high altitudes.
  • Found in the interior of land masses, due to continentality eg Siberia.

Tundra:

  • Fragile ecosystem found in cold environments.
  • Found where it is too cold for trees to grow, due to high altitude or latitude.
  • Arctic tundra, Antarctic tundra.
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Glacial Environments:

  • Areas of land permanently covered by ice; by glaciers of ice sheets.
  • Found at high latitudes, eg Antarctic Ice Sheet and Greendland Ice Sheet above 60 latitude.
  • Found at high altitudes, eg Himalayan mountains.
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Alpine Environments

  • Are cold areas of land at an altitude above treeline.
  • Found at high altitudes, above the treeline.
  • Found at any latitude.
  • May include periglacial and glacial conditions.
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Polar Environments

North Pole (the Arctic)

  • High latitude.
  • Arctic Circle is at 66 degrees N, 
  • Area around north pole is made of sea ice, shrinks in the summer.
  • Made up of the northern land areas of Asia, North America and Europe.

South Pole (the Antarctic)

  • High latitude.
  • Antarctic Circle is at 66 degrees S.
  • At high altitude, ice so thick it reaches over 4000 m in altitude.
  • Interior iss cold due to continentality, very far from warming effect of oceans.
  • Sea ice shrinks in summer,
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Inputs, Stores and Outputs

Inputs:

  • Snow- from precipitation or avalanches
  • Condensation of water vapour form the air
  • Sublimation of water vapour form air directly into ice
  • Rocks

Stores:

  • Ice
  • Meltwater
  • Debris

Outputs:

  • Meltwater flowing out of the glacier
  • Surface snow can melt and evaporate
  • Ice and snow can sublimate into water vapour.
  • Calving- blocks of ice fall from the snout into the sea, creating ice bergs.
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Glacial Budget

  • Accumulation= input of snow and ice into the glacial system (in cold temperatures- winter)
  • Ablation= output of water from a glacier (in warmer temperatures- summer)
  • The glacial budget is the balance between accumulation and ablation over a year.
  • Determines if the glacier advances or retreats.
  • Equilibrium point= accumulation and ablation are equal, so in one year the glacier will be in the same position.
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Formation of Glaciers

1. Snow settles, has a loose and fluffy consistency.

2. The weight of more snow makes the snow denser and more granular, called firn.

3. Air squeezed out- ice paritcles compressed together.

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Warm and Cold Based Glaciers

Warm based glaciers:

  • Base warmer than 0 degrees C, due to friction.
  • The ice at the base melts, acting as a lubricant, easy to flow downhill.
  • Lots of movement= lots of erosion.

Cold based glaciers:

  • Base below 0 degrees C, so little melting.
  • Ice frozen to base, so little movement and erosion.
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Movement of glaciers

  • Basal sliding: meltwater at base acts as a lubricant for glacier to slide over the ground. Occurs in warm based glaciers.
  • Rotational flow: glaciers move in an arc shape when in a hollow (by basal sliding)
  • Internal deformation: ice bends and warps, flowing like a liquid downhill, due to ice crystals shifting past each other. Occurs in cold based glaciers.
  • Extensional flow: strong gravitational force pulling ice down at head of glacier, so ice moves quickly, making more tension causing ice to fracture into thick layers. The layers slip downwards. Occurs in the zone of accumulation.
  • Compressional flow: the ice moves more slowly lower down the glacier, the faster ice from the head pushes down and compresses the slower ice. High pressure causes ice to fracture into layers which slip forwards. Occurs in the zone of ablation.
  • Creep: stresses build up within a glacier, allowing ice to behave with pasticity and flow, occurs where obstacles are met.
  • Surges: excessive build up of meltwater under the glacier leads to ice moving rapidly forwar.
  • Crevasses are cracks. Are caused by stress formed by extensional and compressional flow and calving. 
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Glacial Erosion

Plucking

  • Ice thaws and then refreezes around rocks.
  • As glacier moves forwards, it plucks rocks away from valley sides and floor.

Abrasion

  • Debris carried by glacier can scrape the valley walls and floor, creating striations.

Meltwater erosion

  • Meltwater streams are powerful enough to erode valley sides and floor by fluvial processes eg, attrition, abrasion, hydraulic action.

Weathering- frost shattering

  • Breaks rocks from back and side walls of valley. 
  • Meltwater from snow freezes in the cracks, as it freezes it expands exerting pressure on the rocks which break off.
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Transportation & Deposition

Transportation

  • Glaciers carry debris gathered by plucking or other erosion, from sand to boulders.
  • Supraglacial= carried on top of glacier surface.
  • Englacial= carried within glacier.
  • Subglacial= carried along base of glacier.

Deposition

  • Till= unsorted mixture of material deposited by glacier.
  • Drop any size anywhere.
  • Lodgement till is spread onto valley floor by moving glaciers.
  • Ablation till is dropped as glacier melts by the snout.
  • Till points in direction of moving glacier.
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Glacial Landforms

  • Corrie: a hollow where snow accumulates, b sliding, abrasion,plucking deepen into a bowl shaped-hollow, with steep back wall. Rotational flow.Tarns, lakes in corrie as glacier retreats, filled with meltwater.
  • Arete: steep-sided ridge formed when 2 glaciers in parallel valleys erode valley sides.
  • Pyramidal peak: pointed mountain peak with at least 3 sides, formed by 3 corries back to back.
  • Glacial troughs: steep-sided valley with flat bottoms, formed by erosion of V-shaped valley by glacier.
  • Hanging valley: freeze thaw weathering on the sides weakens the rock as does plucking as the ice freezes to the sides and tears pieces away as it moves – these provide the tools for abrasion. Formed by tributary glaciers, interlocking spurs of the former river valley are bulldozed out of the way to create the steep sides of the glacial trough – which are truncated spurs. Marked by a waterfall.
  • Truncated spurs: ridges of land that stick out are chopped off by moving glacier.
  • Valley steps: steps in glacial trough, formed as glacier erodes floor more deeply due to less resistant rock.
  • Ribbon lakes: long thin lakes formed when glacier retreats in dips formed by erosion of less resistant rock.
  • Fjords: long deep inlets formed when a valley eroded by a glacier is flooded.
  • Roche moutonnee: resistant rock on valley floor. Upstream side is smooth due to abrasion, downstream side is steep and rough due to plucking.
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Moraines, Drumlins & Erratics

Morraines-freeze thaw weathering weakens the rock on the valley sides and providing a source of loose material

  • Lateral: deposited at sides of glacier.
  • Medial: deposited in centre where 2 glaciers join.
  • Terminal: deposited at end of glacier.

Drumlins

  • Half-egg shapped hills of till.
  • Upstream sideis wide and tall, downstream side is narrow and low. Form in groups. 
  • Drumlins result from deposition and are formed beneath glaciers.The glacier is overloaded by moraine, decrease in energy, struggles to cope with transporting to lower parts of its course. Moraine is deposited. Shape due to the direction of movement of the ice with the blunt end.  Obstacles in the path of the glacier may be responsible – encouraging the deposited material to be moulded into the characteristic elongated shape.

Erratics

  • Rocks picked up and carried by a glacier and deposited in different area of geology,
  • Erratics in Eastern England that are from Norway.
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Fluvioglacial Processes & Landforms

  • Meltwater streams cause erosion as a river does- causes more erosion than rivers due to pressure of ice causing the streams to flow quickly. They form deeps troughs called meltwater channels.
  • Braided streams are streams split into lots of smaller streams that cross over each other, as they flow more slowly so sediment is deposited on the ground.
  • Outwash plains are layers of gravel, sand and clay formed in fornt of the former snout. Sediment is sorted into layers- gravel first as it is heaviest.
  • Kettle holes form when blocks of ice are buried by deposits, so when the ice melts the leave holes in the outwash plain.
  • Eskers  are long, winding ridges of sand and gravel, in same direction as glacier. Deposited by meltwater streams in tunnels under the glacer, when glacier melts and stream dries up the sediment remains.
  • Kames are mounds of sand and gravel on valley floor, formed when meltwater streams on top of glacier collect in depression and deposit debris. When ice melts, debris dumped on floor.
  • Kame terraces are piles of deposits against valley wall by meltwater streams. 
  • Proglacial lakes form in front of glaciers, when meltwater streams flow into the lake they deposit their sediment on the ice- called deltas. As ice melts, deltas are dumped on valley floor forming kame deltas.
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Periglacial Processes & Landforms

  • Permafrost- permanetly frozen ground. Continuous- all ground frozen -5 for 2 years, Discontinuous- some ground frozen -2 for 2 years.
  • Ice wedges- frost contraction occurs (low temps contract the ground and crack), temp increases, meltwater goes into cracks.Water freezes in the cracks making ice wedges. Get bigger as process is repeated.
  • Nivation- snow falls in hollow, freeze-thaq breaks off rocks, meltwater washes it away, corrie gets deeper and wider.
  • Soliflucation- water logged active layer of soil flows easily over frozen impermeable layer. Lobes form where one section of soil is moving faster than soil around it.
  • Pingos- hill with core of ice. Open system pingos- discontinuous permafrost, groundwater pushed up through gaps, water collects + freezes creating core of ices pushes ground up. Closed system pingos- continuous permafrost where there is a lake insulating ground, lake dries, permafrost advances around area of unfrozen ground. Water collets and freezes creating a core of ice pushes up ground. If ice thaws, pingo collapses, leaving pond surrounded by ramparts.
  • Patterned ground- frost heave; stones pushed to surface, roll down the edges of the mounds and create circles. Frost contraction causes ground to crack into polygon shape filled with stones.
  • Frost heave- water freezes in ground, bumps on surfaces, ice can be lens shaped. Ice lifts up the surface layer of soil. Ice lenses form under stones- as ice lens expands push stones up to surface, ice lenses under the stones stop the stones slipping back down. Eventually stones rise above ground surface.
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Issues in Cold Environments

-Contain resources that attract developments eg:

  • Whales, seals, fish. In northern Russia whales are hunted for their skin, meat and blubber.
  • Minerals, eg. discovery of gold in Canada and Alaska led to development.
  • Oil, eg Alaska has a lot of oil and oil companies try to exploit the resource.

-Have attractive scenery, so attracts tourism. Number of tourists visiting Antarctica has increased by 39,300 in 16 years.

-Potential for hydroelectric power production.

Fragile ecosystems:

  • Struggle to revover from damage.
  • Harsh climate means short growing season, plants and animals are adapted to cold conditions so find it hard to survive if environment changes, and pollution broken down slowly.
  • Tundra found in some cold environments is fragile.
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Issues in Cold Environments

Fishing

  • Disrupt food chains.
  • Overfishing can deplete a species population, eg Patahonian Toothfish in Antarctica.

Oil extraction

  • Oil spills can occur during transportation of oil or pipeline leaks, endangering species.

Hydroelectric power production

  • Block migratory path of fish
  • Heat up water

Tourism

  • Cruise ships increase pollution and tourists disrupt wildlife and habitats.
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Case Study- Antarctica

  • Largest wilderness area on Earth, contains 90% of all ice on Earth.

Fragile ecosystem

  • Very little water for plants to grow, and very cold- average temperature is -49 degrees C.
  • Very little sunshine in winter, so plants can't survive.
  • Takes a long time for the land to recover from damage.
  • Sea ecosystem is fragile, food chain easily affected.

Resources

  • Rich in natural resources like fish, coal, oil and has attractive scenery.
  • Attractive to scientific researchers.

Antarctic Treaty

  • Set up in 1961, 12 countries agreed to laws to protect it.
  • Includes protocals and conventions that control and prohibit activities.
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Case Study- Antarctica

Oil Extraction & Mining

  • Are banned due to possible environmental impact.
  • Madrid Protocol 1998 bans all mining and oil extraction for 50 years.

Whaling

  • Allowed, but decrease in whale population. Were 250,000 blue whales but now less than 1,000
  • 1994 declared a whale sanctuary and commercial hunting prohibited.

Tourism

  • 2007-2008 46,000 tourists visited, 5,000 scientific researchers in summer.
  • Antarctic Treaty prohibits discharging of oil or plastic from cruise ships.
  • Was expected to have 80,000 tourists per year from 2010.
  • 2003-2004 2622 tonnes of Patagonian toothfish caught illegally.
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Permafrost melting

Causes:

  • Buildings release heat
  • Vegetation removed- less insulation.
  • Vehicles tracks.

Environmental impacts

  • Permafrost shrinks, carbon rich peat releases co2 and methane.
  • Removal of vegetation- slow rate of plant growth.

Solutions:

  • Smaller buildings elevated.
  • Large structures built on aggregate pads- insulator.
  • Utildors built- insulated box carries water, sewage and heating mains. 

Permafrost is permanently forzen ground with top layer that can melt in summer called active layer. Continuous ( all ground frozen) or discontinuous (part of ground frozen)

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