Glaciation Pack C

Question 1

Where is ice now and why?

Answer 1

Ice sheets - Greenland (11% of ice) and Antarctica (85% of ice)
Remaining 4% of ice - Iceland, North Canada, Alaska, Himalayas, Rockies, Cascades, Andes and Alps

Question 2

Where was ice 20,000 years ago?

Answer 2

Ice sheets - Greenland, Laurentide, Patagonian, Eurasian, Antarctica
Ice caps - South Island, Himalayas

Question 3

What are the three states of equilibria

Answer 3

Steady-state:
- Changes in accumulation and ablation but they don’t vary much so the glacier’s overall size stays the same
E.g. seasons

Metastable:
- Changes from one state of equilibrium to a new state of equilibrium due to an event causing a change in conditions
E.g. subglacial volcanic activity

Dynamic:
- State of equilibrium changes over a longer timescale
E.g. climate change

Question 4

What is the thermal regime?

Answer 4

The internal distribution of temperature of the glacier

Question 5

What are warm based glaciers like and why?

Answer 5

• Water is present throughout the ice mass
• Acts as a lubricant at the base of the glacier (sole)
• Water allows for much higher rates of movement and thus more erosion
• Relatively high rates of accumulation each summer and ablation each winter due to the mild climate
• Found in mountainous (high altitude) regions at lower latitudes
  E.g. Swiss Alps, Athabasca

Question 6

What are cold based glaciers like and why?

Answer 6

• Occur in the high latitudes where temperature is far below 0
• Ice of glacier remains at below melting point through the year
• Therefore ice is stuck to bedrock all year
• Little ice movement and erosion
• Slow rates of accumulation and ablation due to the extremely cold climate
  E.g. In Greenland and Antarctica