GLACIATION

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  • Created by: Chloe
  • Created on: 28-01-17 12:22

OUTWASH FORMATION

  • Outwash plains form due to deposited material by meltwater streams.
  • They are also known as sandur.
  • It is a flat expanse of land in a proglacial area.
  • As meltwater streams lose their energy in lowland areas, they deposit their load.
  • The largest material is deposited closest to the ice front.
  • The finest material is deposited furthest away. 
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VARIATIONS IN OUTWASH PLAINS

  • The volume of sediment deposited can vary temporarily.
  • If the air temperature is cooler, there will be less ablation, therefore a reduced volume of meltwater. This means the stream has less energy due to the decreased volume, therefore it can't carry a great volume of sediment or larger material. 
  • This means that only finer/smaller sediment can be carried.
  • You can see the variation if you look at the layers of rock.
  • Conversely, when the temperature is warmer, there is more meltwater. This is due to an increase in ablation and decrease in accumulation.
  • Since there is more meltwater, the stream has a greater amount of energy, therefore it can carry a greater load. It can also carry larger pieces of sediment.
  • This means that there is a greater variety of sizes of sediment being deposited.
  • You can clearly see a difference in the composition of the layers.
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HOW DOES CLIMATE CHANGE EFFECT GEOMORPHIC PROCESSE

  • Freeze-thaw weathering is a geomorphic process.
  • Colder temperatures lead to more freeze-thaw cycles.
  • This means more rocks are being broken up.
  • Frost heave is also affected by climate change.
  • A decrease in temperature results in more stones rising towards the surface. 
  • This is because more water us freezing in the active layer, pushing more stones up.
  • Ground ice development is another geomorphic process affected by climate change.
  • When there is more ablation in the summer, it percolates into the sub-surface where it accumulates.
  • During the winter it freezes and expands.
  • This forces the surface upwards since it can't extend into the permafrost below.

THESE INFLUENCE PERIGLACIAL LANDFORMS, E.G. PINGOS, AND PATTERNED GROUND.

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