Reconstruction Of Past Glaciers

Question 1

Types of linearity

Answer 1

Linear
Damped
Non-linear
Threshold

Question 2

When was the Holocene?

Answer 2

12,000 years ago. Last interglacial. Experienced 10 degrees of cooling.

Question 3

Potential causes of cooling?

Answer 3

Milankovitch
Formation of mountains causing feedback
Changing ocean circulation.

Question 4

What is eccentricity?

Answer 4

100,000 year cycle. 
How eliptical earths orbit is. 
Maximum difference 30% more radiation. 
Matches with glacial/interglacial cycles 
- 10,000 interglacial. 90,000 glacial.

Question 5

What is obliquity?

Answer 5

41,000 year cycle.
Tilt of the earth. 
Maximum tilt 24 degrees. 
Minimum 21 degrees. 
Influences seasons

Question 6

What is Precession?

Answer 6

19/27,000 year cycle.

Earths wobble.

Question 7

Geomorphological fingerprints show:

Landforms that can be used to reconstruct past glaciers are:

Answer 7

Ice extent
Ice flow
Thermal regime

Moraines - indicate ice volume and past extent.

Thermal regime showed through landscape unmodified landscape = cold based ice as slow moving.
Highly eroded landscape = warm based.

Question 8

Case Study of unmodified landscape.

Answer 8

Gamburtsev mountains - East Antarctica.
2,500 meters of ice rumoured birth place of Antarctic ice sheet yet very young mountain range.
Cold based, slow moving ice preserved the landscape.

Question 9

Small scale case Study for mapping past extent of glaciers.

Answer 9

Kea Point, New Zealand.

Mapping of past moraines shows extent of Mueller glacier. Contextualises retreat rates.

Question 10

Case Study for reconstructing past glaciers.

Answer 10

Brit Ice Project (Clark 2004).
Reconstructed ice streams and ice sheet extent across UK.
Used ice cores to get precipitation data to see how the ice sheet responded to changes.

Question 11

Thermal regime indicates how ice masses behave.

Answer 11

Cold based vs warm based

Cold based preserve landscapes. 
Case Study:
Gamburtsev mountains - East Antarctica. 
2,500 meters of ice rumoured birth place of Antarctic ice sheet yet very young mountain range. 
Cairngorms, Scotland. (Glasser, 2007). 
- unmodified.

Question 12

2 Types of dating

Answer 12

Absolute - gives age in calendar years.

Relative - oldest at the bottom.

Question 13

Dating techniques

Answer 13

Cosmogenic nuclides - cosmic rays absorbed in rocks when exposed to sunlight. More cosmic rays = longer exposure to sunlight.
Radiocarbon dating - reconstructs ice sheets in Antarctica. C14.