Theory

• What is a glacier

  Land based mass of ice that moves under its own weight
• What is a glaciated landscape

  landscape that has been shaped by glaciers
• What are characteristics of valley glaciers

  10-30km long

  confined by valley sides
• What are characteristics of an ice sheet

  Extend for more than 50,000km

  move outwards not downwards
• How much of earths surface is covered by glaciers

  10%
• What was the last ice age

  Pleistocene ice age - 11,700 years ago
• What is the zone of accumulation 


  Area of glacier that experiences inputs such as snow
• What is the zone of ablation

  Area that experiences outputs like melting or evaporation
• What is the equilibrium line

  Line in the middle of accumulation and ablation
• What is a glacier mass balance

  Difference between amount of snow accumulated and amount of ablation over a one year period.
• If inputs are more than outputs what happens to the glacier

  It advances
• If outputs are more than the inputs what happens

  Retreats
• How is glacial ice formed

  New snow compresses previous snow and forces air out. Ice begins to form through diagenesis.
• What are warm based glaciers

  High altitude locations with steep relief. More meltwater
• What are cold based glaciers

  High latitude with little melt water and lower temperatures.
• What is the pressure melting point

  Temperature at which ice is at the verge of melting. Doesn’t have to be below 0
• What are the three kinds of basal sliding

  Slippage

  regelation

  substrate deformation
• What is slippage

  When meltwater reduces friction and the glacier begins to slide over bedrock
• What is regelation (creep)

  When the base of a glacier meets an outcrop the pressure will increase causing meltwater, causes ice to deform and spread over rock.
• What is substrate deformation

  When meltwater mixes with bedrock and creates a lubricated surface
• What is internal deformation

  Intergranular slip

  laminar flow
• What is intergranular slip

  When ice crystals become flattened and slide over each other in a movement
• What is extending flow

  When ice moves over a steep flow it can’t deform quickly enough so cracks and crevasses form
• What is compressing flow

  Ice thickens
• What is freeze thaw weathering 


  When the water gets into cracks and freezes and expands the crack
• What is plucking 


  Rocks or stones get frozen to the bottom of the glacier and get plucked from the ground
• What is abrasion

  Rocks and stones at the bottom of the glacier run against the bedrock and wears it away
• Is the glacial system open or closed

  Open - starting mass can change over the year
• What factors affect glaciated systems

  Climate, geology, relief and latitude
• What are geomorphic processes

  Natural mechanisms like erosion and weathering that influence a landscape
• Three types of weathering

  Physical

  chemical

  biological
• What is freezethaw

  When water enters joints or cracks and freezes so expands the crack
• What is first shattering

  When frozen water in cracks expands and the rock shatters
• What is pressure release

  Weight of overlying glacier decreases the underlying rock fractures
• What is tree roots

  When tree roots cause rocks to break
• What is carbonation

  When rainwater combines with carbon dioxide
• What is mass movement

  downslope transportation of material under gravity.
• What is a slide

  When an entire mass of material moves downward along a straight line slip plane.
• What is a slump 


  When material moves down a curved slip plane.
• What are rockfalls

  When rock comes detached and falls to foot of slope