ice sheet scouring

Question 1

ice sheets

Answer 1

• centre often cold so little erosion but edges are wamr based
  -ice hseets move slowly through basal sliding and internal deformation, moving material over large areas
  -this can lead to abrasion as debris is dragged over surfaces
  -quarrying and plucking occurs as regelation takes place

Question 2

crag and tail

Answer 2

-a very large, resistant object (crag), obstructs flow of a glacier
-ice forced over the obstruction, eroding weaker rock
- material immediately in the lee of the obstrution is protected by the crag = formation of a gently sloping tail of deposited material

Question 3

roche moutonee

Answer 3

upstream side has increase in pressure due to resistance of outcrop to moving ice caused by localised pressure
-melting causes basal slip and abrasion as glacier slides over outcrop
-downstream side has less pressure so meltwater freezes and forms bond between rock outcrop and overlying glacier
-as glacier moes forward, loose rock plucked away, leaving jagged surgace

Question 4

knock and lochan landscapes