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Glaciated Landscapes - Coggle Diagram

- - - - Positive figure indicates a net gain of ice, increasing the volume of ice and allowing the glacier to grow or advance.
      - Negative figure indicates a loss of ice through the year and the glacier will contract and retreat up-valley.
    - - Pressure melting: only occurs in warm-based glacier. Ice melts when temperature exceeds 0 degrees Celsius at the surface, but at the base, ice can melt at low temperatures, e/g/ -2 degrees Celsius. This is because pressure from the overlying ice enables this and friction with the valley beds and sides. Pressure melting only occurs in warm based glaciers.
      - Warm based glacier surface temperature exceeds 0 degrees C in summer.
      - Wider variation in surface temp in warm based glacier (-20 degrees compared to -10 in cold based).
    - - Base of glacier in cold based glaciers is -10, but just below 0 in warm blood.
  - - - Inputs: precipitation, avalanches, debris from mass movements, weathered and eroded material, potential energy from it's high location, thermal energy from the heat of the sun, kinetic energy from wind and moving glaciers.
      - Outputs: meltwater, debris (an accumulation of unsorted and unconsolidated soil and rocks formed by glacial erosion), glacial drift (material transported and deposited by a glacier or glacial meltwater), energy is lost through reflection from snow and ice (known as high albedo), water vapour through evaporation or sublimation.
      - Energy
        
        Potential: the capacity to do work that a body possesses by virtue of its position and that is potentially transformable to another form of energy. It is stored energy.
        
        Kinetic: the capacity to do work as a result of motion. All moving things have types of energy - the heavier a thing is the faster it moves the more of this energy it has.
        
        Thermal: The capacity to do work as a result of heat. It is the energy that comes from the movement of atoms and molecules in a substance.
  - - - The pleistocene ice age - lasted from around 2 million years ago to 11700 years ago. The end of the Pleistocene corresponds with the end of the last glacial.
      - The Holoscene ice age - The past 10,000 years is considered to be Holoscene and makes the current interglacial.
  - - - snow falls in flake and can trap lots of air.
      - snow becomes compacted by the weight of later snow falls.
      - The increase in pressure on the buried snow also results in pressure melting. A tiny amount of meltwater forms between the snow crystals.
      - Snow that survives the summer is called firn.
      - More meltwater continues to fill the air passages and refreezes into bigger ice crystals. it can take thousands of years but eventually a solid mass of ice will form.
        
        In Antarctica, there is no summer melting, and so it takes longer for ice crystals to grow in size and for air to be expelled from the dense mass of ice. It takes 1000 years.
        
        In the alps, summer meltwater percolates into the firn and refreeze at night or during the winter to fill the space between the firn crystals. Therefore compaction and ice crystallisation occurs at a quicker rate so less time is needed for the firm to transform into ice. It takes 20-40 years.