ICE ON THE LAND

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  • Created by: Sam
  • Created on: 29-05-13 20:12

GLACIAL BUDGET

ZONE OF ACCUMULATION AND ZONE OF ABLATION

  • Accumulation: input of snow and ice into the glacier
  • Ablation: output of water as the ice melts
  • More accumulation than ablation in the upper part - zone of accumulation 
  • More ablation than accumulation in the lower part - zone of ablation 

GLACIAL BUDGET 

  • Difference between total accumulation and total ablation for one year
  • Amount of ice in a glacier and whether it's advancing or retreating depends on it:
    • Positive glacial budget - when accumulation exceeds ablation. Glacier gets larger and its snout advances down the valley 
    • Negative glacial budget - when ablation exceeds accumulation. Glacier gets smaller and its snout retreats up the valley 
    • When these are equal the glacier stays the same size and the position of the snout doesn't change 
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GLACIAL BUDGET (2)

CHANGE IN THE GLACIAL BUDGET

  • Glaciers advance and retreat seasonally 
    • More ablation in the summer - ice melts when it's warm, meaning a negative glacial budget and retreat
    • More accumulation in the winter - more snowfall and less melting, meaning a positive glacial budget and advance
  • Most glaciers have had a negative glacial budget since 1950 - earth's temperature has been increasing due to global warming 
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GLACIAL EROSION

GLACIERS ERODE THE LANDSCAPE AS THEY MOVE 

  • Weight of ice in a glacier makes it move downhilleroding the landscape in two ways:
    • Plucking: when meltwater at the baseback or sides of a glacier freezes onto the rock - as the glacier moves forward it pulls pieces of rock out
    • Abrasion: where bits of rock stuck in the ice grind against rock below the glacier,wearing it away 
  • At the top end ice moves in a circular motion called rotational slip - can erode hollows in the landscape and deepen them into bowl shapes
  • Rock above glaciers is also weathered by conditions around glaciers - freeze-thaw weathering

GLACIAL EROSION PRODUCES SEVEN DIFFERENT LANDFORMS 

  • Arêtesteep-sided ridge formed from two glaciers in parallel valleys - erode the sides of the valleys, sharpening the ridge between them
  • Corries: begin as hollows containing a small glacier, eroded into a steep-sided armchair shape with a lip at the bottom end by rotational slip. Can leave a tarn
  • Ribbon lakeslongthink lakes formed after glacier retreats - form in hollows where softer rock was eroded more than surroung harder rock 
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GLACIAL EROSION (2)

  • Pyramidal peak: pointed mountain peak with at least three sides, formed when three or more back-to-back glaciers erode a mountain 
  • Truncated spurs: cliff-like edges on the valley side formed when ridges of land that stick out are cut off as the glacier moves past
  • Glacial troughsteep-sided valleys with flat bottoms - start off V-shaped river valleys but change to a U-shape as the glacier erodes sides and bottom, making it deeper and wider 
  • Hanging valleys: valleys formed by tributary glaciers that flow into the main glacier. Glacial trough is eroded much more deeply by the larger glacier so these valleys are left at a higher level
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GLACIAL TRANSPORT AND DEPOSITION

GLACIERS TRANSPORT AND DEPOSIT MATERIAL 

  • Can move material over very large distances - transportation 
  • Material's frozen in the glacier, carried on its surface or pushed in front of it - bulldozing when loose material is pushed in front 
  • When the ice carrying the material melts or the ice is overloaded it's dropped - deposition 
  • Rocks of all shapes and sizes are mixed up together 

MORAINE 

  • Landforms made out of material dropped by a glacier as it melts
  • Four different types depending on position:
    • Lateral: long mound of material deposited where the side was
    • Mediallong mound of material deposited in the centre of a valley where two glaciers meet
    • Terminal: builds up at the snout when it remains stationary - deposited in semicircular mounds
    • Ground: thin layer material deposited over a large area as a glacier melts
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GLACIAL TRANSPORT AND DEPOSITION (2)

DRUMLINS 

  • Elongated hills of glacial deposits - largest over 1000m long, 500m wide and 50m high 
  • Round, blunt and steep at the upstream end and tapered, pointed and gently sloping at the downstream end
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TOURISM ON ICE - CHAMONIX

WINTER SPORTS AND SIGHTSEEING

  • Chamonix Valley is in eastern France at the foot of Mont Blanc, close to the border with Italy and Switzerland
  • One of the most popular tourist destinations in the world - 5 million visitors a year
  • Region has lots of glaciers including the Mer de Glace - longest glacier in France, 7km long, 200m deep
  • Many other tourist attractions: 6 ski areas, 350km of hiking trails, 40km of mountain bike tracks, an Alpine museum and an exhibition centre

MANAGEMENT 

  • System of avalanche barriers maintained around the resorts, e.g. at Taconnaz
  • Also avalanche awareness courses and daily bulletins to keep tourists aware of risks - less likely to be hurt or killed
  • Amount of traffic managed by providing free public transport for tourists - amount of pollution reduced by using low emission buses
  • Some hotels reducing energy use, e.g. by installing solar panels to heat water and systems to automatically turn lights off - reduced CO2 emissions 
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FRAGILE ENVIRONMENTS

  • Fragile environments are easily damaged and difficult to manage:
    • Short growing season - not much time for damaged plants to recover
    • Decay is slow because of cold - any pollution or litter remains in the environment for a long time 
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Comments

Mr A Gibson

A nice concise set of cards to print off or review on your mobile device. Nicely coloured to maximise usefulness.

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