glacial movement

Question 1

extesional flow

Answer 1

at the head of the glacier, the valley is steep so there is a strong gravitational force pulling the ice downwards

when the ice moves quickly there is more tension

this causes the ice to fracture into thick layers, which can slip downwards

Question 2

compressional flow

Answer 2

lower down in the glacier, ice is moving more slowly because the valley is less steep

the faster ice from the head of the glacier pushes down on the slower ice and compresses it

the high pressure causes the ice to fracture into layers and the layers slip forward

Question 3

faster moving ice is found…

Answer 3

• on steeper slops
• at the base of the glacier
• be a part of a larger glacier
• be temperate (warm bases)
• moving over impermiable bedrock
• be found in narrow valleys

Question 4

positive feedback loop

Answer 4

if the glacier has a large volume of meltwater, it will move relatively quickly due to basal slip.
this will generate greater levels of heat due to friction and the heat will further increase the meltwater, therefore the speed the glacier moves

Question 5

negative feedback loop

Answer 5

a fast moving glacier will become thinner as the amount of meltwater increases

this thinning eill eventually slow the glacier down, as less pressure will be exterted on the base og the glacier which means less meltwater would be produced

Question 6

slope

Answer 6

• if a glacier is on a steep slope, its weight will have more of an impact on its movement. this is because the force exerted downslope is stronger than the friction holding it in place
• this means that glaciers on steep valley slopes will move much faster than those on flat valley floors

Question 7

temperature

Answer 7

the degree to which a glacier moves depends on its melting point
- the surface of the glacier will have a melting point at 0ºC.
- at greater depths within the glacier the melting point will be lower
- this is due to the increased pressure from the ice above
-the ise within the glacer will flow at a faster rate than at the surface

Question 8

how do

temperatures in polar regions

affect the movement of glaciers

Answer 8

in polar regions where temperatures are very lowm they are more likely to be cold based and more likely to freeze to the bedrock and move more slowly due to the absense of meltwater

Question 9

size

Answer 9

the larger the glacier, the greater the pressire on the base of the glacier and the easier the ice will melt.
this creates a faster moving glacier

Question 10

altitude

high altitude glaciers

Answer 10

glaciers at higher altitudes are more likely to experience greater levels of precipitation which lead to hugher rates of accumulation and have a positive mass balance.

this means that the glacier will be able to advance and move mofre quickly. however at high altitudes the glacier is likely to freeze to the bed and slow down the glacier

Question 11

altitude

lower altitfute

Answer 11

temperatetues are warmer at lower altitudes. this means glaciers are likely to undergo melthing at the base of the glacier which can increase basal slip and cause the rate of the glacier movement to increase

Question 12

altitude

temperate glaciers

Answer 12

temperate glaciers are likely to be found at lower altitudes or sea level.

the sounts ofsome of the glaciers can move faster at up to 10 a day. this may be due to a glacial surge

Question 13

glacial surge

Answer 13

where the snout moces very quickly due to instability within the end of the glacier

Question 14

lithology

permeable

Answer 14

a permeable bed rock will soak up some of the meltwater at the base of the glacier, reducing the glaciers ability to moce

Question 15

lithology

impermiable

Answer 15

glaciers on top of impermeable rock will move faster because of increased meltwater which reduces friction

Question 16

lithology

soft rock

Answer 16

softer rocks like clay or chalk allow glaciers to move faster because the glacier is less likely to be stopped bu obstructions

Question 17

topography

Answer 17

• narrowing of valleys can cause a glacier to thicken and move faster
• the widening of valleys cause glaciers to spread more and thinm making them move slowly