Glaciated landscapes as systems

Glaciated landscapes as systems

1. Inputs

   • Precipitation
   • Avalanche
   • Meltwater
   • Kinetic, thermal & potential energy
   • Material from deposition, weathering & mass movement
     • Rocks/sediment
     • Debris

2. Throughputs

   • Meltwater
   • Stores
     • Sediment held in glacier
   • Flows
     • Basal sliding of ice

3. Outputs

   • Meltwater
   • Iceburgs
   • Debris
   • Water vapour - sublimation & evaporation

4. Processes

   • Plucking
     • Erosion (> abrasion)
     • Rock particles in glacier plucked into ice flow
       • Rock ↑ pressure → melting ice (enters weakness - joints, bedding planes)
     • Roche moutonnée: jagged lee side
   • Abrasion
     • Erosion - rock in glacier scrapes along bedrock covered in ice
     • Roche moutonnée: Smooth stoss side
   • Ablation
   • Accumulation
   • Transportation

5. Glacier mass balance

   • Accumulation
     • Addition of mass (↑ latitude & altitude - temp prevents melting)
     • Snowfall (& avalanche)
     • Accumulation zone: upper zone
   • Ablation
     • Loss of mass - melting and sublimation
     • Ablation zone: lower zone
   • Mass balance
     • Accumulation -- ablation: over 1 year
     • +ve: advance
     • Retreat

6. Formation

   • 1. Fresh snow: ↓ density 0.05g/cm^3
     • 2. Firn: Snow surviving 1 summer - density 0.4g/cm^3)
       • 3. Glacier ice: further compaction of snowfall - density 0.83-0.91g/cm^3
         • (True glacier ice - 100m & below (blue as no air)