Answers for - Glacial systems
What is a glacier? Alpine vs. continental glaciers?
Why study glaciers?
- presently covers 10% of land surface (Antarctica,
Greenland, Iceland, Svalbard, Alaska, Himalayas, Alps, Southern
- 2% of earth's water budget, 75% of freshwater
- excellent climatic indicator.
- during recent Ice Age much more extensive
and so there are many 'relict' landscapes, shaped by glaciers.
- in paleontology and anthropology history
of glaciation and changing environments controlled migration
- they are just fascinating and beautiful.
How are the rocks
incorporated into the glacier?
- rockfalls onto the ice from surrounding rock
- plucking of ricks from underneath the ice.
- abrasion of rock by sliding ice.
What are some of
the potential causes of Ice Ages?
- extraterrestrial causes: many unknowns and
- Milankovich cycles:
- sun-earth distance cycles over 105,000 years.
- 22-24.5 degrees over 41,000 years.
- direction of tilt (precession of equinoxes)
26,000 year cycle.
- all should influence how much solar energy
the earth is getting and thus influence our climate.
- terrestrial causes:
- on long term: position of continents.
- pulses of volcanic activity.
- positive feedback cycle: albedo of snow is
70%, while that of normal ground is 20%.
- are we in or out of an Ice Age?
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