NCD:______________
Topic Two Notes
Earth’s Frozen Water
Glacier
 a large, moving mass of compressed ice and snow
Ice Cap
 a large dome-shaped glacier that flows outward from its
center
 cover large areas of land
 e.g. polar ice caps
Ice Field
 upland area that feeds two or more glaciers
 e.g. The Columbia Ice Fields feed six major glaciers
How Do Glaciers Form?
 begin as new snow
 increased pressure from accumulated snow that piles up
 melting occurs lower in glacier
 gradually becomes ice
 there must be 30 meters of snow to form a glacier
Types of Glaciers
There are four main types of glaciers:
1. Valley glacier (or mountain glacier)
 forms within a mountain range
 e.g. Rocky Mountains
2. Piedmont glacier
 formed by the spreading or joining of valley
where they emerge from their valleys
glaciers
3. Ice cap glacier
 dome-shaped (polar ice caps)
4. Continental glacier
 covers all of or most of an entire continent
 e.g. Greenland (1.8 million square km)
 e.g. Antarctica (13 million km2)
Glacial Features
 Icefall – where a glacier flows off a steep cliff
The Khumba Icefall – Mt. Everest
 Crevasse – a crack that forms in the ice
How Glaciers Shape the Land
 Glaciers can advance or retreat, however, they are ALWAYS
moving downhill
 Glaciers push aside and pick up loose materials such as
rock, sand, gravel, and boulders.
How Glaciers Move
Glaciers are “rivers of ice”. How fast or slow they move
depends on the following:
 Volume of ice
 Slope of the land
 Slope of the upper surface of ice
 Amount of water in the ice
 Amount of debris
 Temperature of the ice
 Friction between ice and ground
Glacial Erosion:
 Striations – parallel scars or scratches left by rock fragments
in the ice.
 Cirques – a bowl-shaped basin
 Arête – a ridge formed by two or more glaciers
 Horn – three or more cirques that form a sharp peak
 Valleys eroded by glaciers are U-shaped; valleys eroded by
streams and rivers are V-shaped (glaciers change)
 Meltwater – melting of snow and ice carves channels in
glaciers
 Millwell – rounded hole in the ice carved by a stream of
water
Glacial Deposition:
 Till – a mixture of different sized sediments left by a melting
glacier
 Moraine – a large ridge of rock and soil left behind
 Outwash – material that is left by meltwater from a glacier
 Esker – a winding ridge of sand and gravel
 Erratic – huge rocks left by glaciers
 E.g. Big Rock in Okotoks
The Importance of Glaciers
 Climate
 Water resource
 Habitat for animals
 Scientific study
 Shapes the land