Types Of Glacier And Movement

Question 1

Formation of glacier ice

Answer 1

Snow falls as flakes

Temps are low enough for snow to remain frozen throughout the year, new snow leads to building layers and the lower layers compact to firn

Mass of ice will form a glacier which can take 30-1000 years

Glacier ice depth of 100m and is a bluish colour

Question 2

Valley glaciers

Answer 2

Contained within valleys

Outlets from ice sheets or can be fed by corries

They follow the course of existing valleys as they move downhill

Question 3

Ice sheets

Answer 3

Large accumulations of ice extending more than 50,00km2

Antartica and Greenland

Question 4

Warm-based glaciers

Answer 4

Occur in temperate areas - western Norway and southern Iceland

Small and have summer melt

Meltwater lubricated the glacier

More movement and more erosion, transportation and deposition

Ice is above the pressure melting point due to warmer atmospheric temps

Weight of ice and the effect of geothermal heat at the bed.

Move around 20-200m per year.

Question 5

Cold-based glaciers

Answer 5

Occur in polar regions eg, Artic and Antartica

Large with vast ice caps and sheets covering vast km

Low precipitation low snow

Low levels of accumulation and no melting so the ice stays very cold

Below pressure melting point temperature

Little meltwater = slow movement

Often frozen to the bed of the glacier = less erosion, transport and deposition

Only move a few metres per year

Question 6

Basal sliding

Answer 6

Movement by gravity

Gradient - steeper = more movement

Thickness of ice = affect the basal sliding temp and pressure melting point

Glacial budget = positive = advance

Breaks up crevasses when solid ice is moving = upper zone

Ice under steady pressure which ‘deforms’ and moves in a fluid way = lower zone

Warm base glaciers ( slippage - circular motion causing ice to move away from the back wall of a hollow ,creep - downward movement of loose rock and soil down a gentle slope and bed deformation - movement of soft sediment or weak rock beneath a glacier ( more effective beneath temperate glaciers as the underlying rock and sediment are saturated with water)

Question 7

Internal deformation

Answer 7

Cold- base glaciers

Inter granular flow -individual ice crystals move relative to each other

Laminar flow - individual ice crystals move along layers within glaciers