2.5 continued

Question 1

Regelation creep

Answer 1

Occurs as basal ice deforms under pressure when encountering obstruction such as rock steps

Question 2

Basal sliding

Answer 2

Involves the movement of large blocks of ice - usually in series of short jerks

Question 3

Basal sliding explained

Answer 3

• Meltwater forms on the upslope side of obstacles on the valley floor.
• Causes an additional resistance causing an increase in pressure which leads to localised melting of ice (pressure melting)

Question 4

Meltwater in P/M

Answer 4

-Meltwater enables the ice to flow up and over the obstacle, although it often refreezes on the downslope, when the pressure is reduced

Question 5

Head of the glacier

Answer 5

• Valley is steep
• Strong gravitational force pulling the ice downwards
• The faster ice from the head of the glacier pushes down on the slower ice and compresses

Question 6

Pressure

Answer 6

Higher pressure causes the ice to fracture into layers, and the slip forward (compressional flow)

Question 7

Subglacial bed deformation

Answer 7

• This occurs when a glacier moves relatively weak or unconsolidated rock
• Locally 90% of the forward motion of glacier ice

Question 8

Internal deformation

Answer 8

• Ice bends and warps to flow downhill like a liquid

- Ice crystals slipping and sliding over each other

Question 9

Lithology

Answer 9

-Different rock types and their characteristics

Question 10

Lithology explained

Answer 10

-Temperate zones=movement is faster over impermeable surfaces than permeable, because basal meltwater is retained