Chapter 7 - 'Introduction' Flashcards
Define what a glacier is.
Body of ice formed by land, in motion and confined by terrain.
(Commonly valleys)
Describe what happens in the zone of accumulation.
Accumulating snow undergoes firnification, the ice flows downhill under its own weight and gravity.
Describe what happens in the zone of ablation.
The ice enters a point called the terminus, this is where ice starts melting. The ice changes the colour of the ice from bright white to grey. Melt water flows from this point.
Define what an ice sheet is.
Body of ice burying large tracts of land, not confined by valleys.
Describe where ice sheets most commonly form.
High latitudes that are characteristically very cold and subject to long winters and short summers.
State:
How long have ice sheets been present.
When they peaked.
At least 40 million years in Antarctica.
21000-18000 years ago.
State:
Location of the freshwater ice comes from and what percentage this make up.
The percent of land currently covered by glaciers and ice sheets.
The percent of freshwater this represents.
Antarctica and Greenland.
99%
10%
75%
Describe the process of firnification.
As snow builds up, the snow becomes compact under the weight and is converted to ice.
List the four main categories of land covered by ice in the cryosphere.
Land covered by glaciers.
Land covered by ice sheets.
Ice in the sea.
Land covered by ice seasonally.
