Movement in warm based glaciers

Question 1

Basal flow/slippage

Answer 1

• Ice melts at the base of the glacier due to pressure and friction = even though temp isn’t above freezing
• Meltwater acts as a lubricant

Question 2

Regulation slip

Answer 2

• Localised pressure melting due to small obstacles on the bedrock floor

Question 3

Creep

Answer 3

• Ice behaves plastically = stress concentrations around larger obstacles on bedrock

Question 4

Surges

Answer 4

• Excessive build-up of meltwater (inputs) under the glacier leads to the ice moving rapidly forward
• 250-300 m in one day
• Hazard to inhabitants living below snout

Question 5

Rotational flow

Answer 5

• Occurs within a corrie
• Temps fluctuate around 0 degrees = freeze-thaw
• Ice moving downhill can pivot about a point
  = rotational movement
• Occurs where tributary glaciers join or glacial valleys steepen or narrow
  = Increased depth of ice + downward pressure

eg/ Cirques