glacial processes. snow metamorphosis snow firm glacial ice ~80 years in alpine glacier denser
TRANSCRIPT
Glacial Processes
Snow metamorphosis
Snow Firm Glacial Ice
~80 years in alpine glacier
Denser
Glaciers grow and their snout moves when accumulation is greater than ablation – animated GIF that should play for your computer (but don’t worry if it does not)
Snowline – elevation above which snow persists year round
Snowline
Types of Glaciers: Ice Cap
Greenland from space
Small Ice Caps occur outside Greenland and Antarctica
Types of Glaciers: Piedmont
Piedmont Glacier
Types of Glaciers: Alpine
Larsen Ice Shelf Collapse
calving (icebergs)Loss of glacial ice
Ablation by melting
How do glaciers move?One way: the flow internally (internal deformation)
mm per day
Another way is Regelation Slip (freeze-stick, melt flow) at the base of the glacier
centimeters
per day
3rd: bed deformation (water & sediment act like ball bearings reducing friction) at the base of the glacier – resulting sudden surge
Meters
per day
Movement can crack glaciers creating crevasses
Crevasses can form by compression or extension
The top crevasse separating snow from moving ice is the bergshrund
Glaciers and Our Diet
Position of snout (belly) reflects balance of accumulation and ablation
Is this accumulation or ablation zone?
AccumulationZone
Ablation Zone
