Enquiry question two Flashcards
Describe the glacial system
What is the zone of equilibrium and what factors affect it?
The area on the glacier where there is a balance between accumulation and ablation
Depends on:
- the rates of accumulation or ablation
- the time of year/season
- glacial retreat occurs when ablation > accumulation
- glacier increases if accumulation > ablation
What processes contribute to accumulation and ablation?
accumulation
snowfall
avalanches
wind blown snow
hoar frost
ablation
windblown snow off glacier
avalanching off glacier
sublimation - ice -> water vapor without being water first
calving - breaking off of ice chunks from the glacial snout
How are moraines formed?
As the glacier advances it pushes debris in front of it
When it retreats it leaves it as a mound
As it advances again, it forms a new mound
These are moraines
How does impact on the environment depend on the speed of the glacier
Faster = more likely to impact and transform the landscape
Slower = less likely to impact it
How do glaciers erode the ground?
As glaciers move, they pick up debris
Which helps erode the base and the sides
Like sandpaper
Describe the terms on this graph and why it changes
Positive regime: occurs when accumulation > ablation
the result of seasonal changes, inputs outweighing outputs and long term change as a result of cooling climatic factors
Negative regime: occurs when ablation > accumulation
CASE STUDY The Athabasca Glacier - Canadian Rockies
Warm based
Located between the Banff and Jasper NPs
Remnants of much larger Cordilleran ice sheet - covered much of N America
Retreats between 1-3m a year - begun to speed up
Since 1750 (end of little ice age) it has retreated by 2km
Retreat can be tracked by the push moraines, (found in front as material that is bulldozed in the winter and left behind in summer)
Now believed to retreat up to 5m pa
