glacial processes. snow metamorphosis snow firm glacial ice ~80 years in alpine glacier denser

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