(9) glacier change over time

• what does glacio-fluvial mean


  relating to or denoting erosion or deposition caused by meltwater from glaciers or ice sheets
• what is the difference between till out outwash


  till is unsorted, sharp-edges and varies in shape and size, while outwash is sorted, stratified and has no boulders
• what type of deposition causes outwash


  glacio fluvial
• what are characteristics of glacio fluvial deposits


  • reach far beyond the extent of ice
  • smaller and finer
  • found in outwash plains
  • found in eskers
  • is stratified
  • compromises sand and gravel
  • is in layers
  • deposited by meltwater
  • sub-rounded
  • reflects seasonal changes
• what are characteristics of glacial till deposits


  • deposited directly by the glacier
  • no layers
  • found in moraine
  • non-stratified
  • is angular
  • found in drumlins
  • unsorted
  • is boulder clay
  • is poorly sorted
  • found up to the limit of ice
  • coarser and larger
• what is a subglacial stream


  a stream that flows beneath a glacier, and which usually cuts into the ice above to form a tunnel
• how are meltwater streams formed


  • when glacial ice melts, water runs out as meltwater
  • warm based glaciers produce a lot of meltwater
  • surface meltwater filters through the glacier and flows through tunnels underneath the glacier before running out the snout