Glaciated landscapes as systems

• Glaciated landscapes are open systems; this means that energy and mass can cross into the surrounding environment.
• Inputs

  Kinetic energy from wind.

  Thermal energy from solar radiation and geothermal heat.

  Potential energy from material on slopes.

  Mass from direct snowfall.

  Mass from blown snow.

  Mass from avalanches and rockfall.
• Outputs

  Meltwater.

  Water Vapour.

  Icebergs and ice blocks.

  Glacial and fluvio-glacial sediments.
• Plucking


  As the glacier moves, the bottom ice pull away pieces of rock from the surface of the slopes.
• Abrasion


  When rocks become embedded in the glacier and rub against the bedrock whilst the glacier moves.
• Ablation


  The removal of surface snow or ice by sublimation, melting or evaporation.
• Accumulation


  The addition of snow and ice in a glacier.
• Throughputs


  Consists of stores, including ice, water and debris accumulations.

  Transfers, including movement of ice, water and debris downslope under gravity.
• Dynamic equilibrium


  Lack of change in a system as inputs and outputs remain in balance.
• Glacial mass balance.


  The difference between the inputs and outputs over a year.
• Zone of accumulation


  Upper part of a glacier where input > output
• Zone of ablation


  Lower part of a glacier where output >input
• the equilibrium line is the boundary between the zone of accumulation and the zone of ablation.
• Seasonal variations

  Accumulation will exceed ablation in winter.

  Ablation will exceed accumulation in summer.
• Climate change will cause changes over a longer timescale.
• Climate’s influence on glaciated landscapes

  Aeolian processes of erosion, deposition and transportation.

  Precipitation inputs snow, sleet and rain.

  Temperature fluctuation affects inputs and outputs; areas of high altitude susceptible to summer snowmelt; areas of high latitude may never reach temperatures above 0 degrees.
• Geology’s influence on glaciated landscapes

  Lithology is the chemical and physical composition of rocks, which effects the impact of weathering and erosion e.g. clay‘s weak lithology makes erosion effective.

  Structure the existence of joints, bedding planes, faults, angle of dip and permeability.
• High latitudes (e.g. Arctic and Antarctic) have cold dry climates, landscapes develop under stable ice sheets.
• Landscapes with low latitudes but high altitudes develop under dynamic valley glaciers (e.g. Rocky Mountains).
• Relief and Aspect’s influence on glaciated landscapes

  Steep relief gives more energy to a glacier because of gravity.

  Aspects facing away from the sun will have temperatures remaining below zero for longer, causing less melting (Positive glacial mass balance).

  Aspects facing the sun will have more melting (potentially negative glacial mass balance).
• Valley glaciers


  Contained within valleys.

  May be outlets from ice sheets or fed from corries.

  Follow the course of the existing valley.
• Ice Sheets


  Large accumulations of ice extending more than 50000 km squared.