Glaciers
Glaciers are made up of fallen snow that,
over many years, compresses into large,
thickened ice masses. Glaciers form when
snow remains in one location long enough
to transform into ice. What makes glaciers
unique is their ability to move. Due to
sheer mass, glaciers flow like very slow
rivers. Some glaciers are as small as
football fields, while others grow to be
over a hundred kilometers long.
Quick Facts
Presently, 10% of land area is covered with glaciers.
Glaciers store about 75% of the world's freshwater.
Glacierized areas cover over 15,000,000 square
kilometers.
Antarctic ice is over 4,200 meters thick in some areas.
During the last Ice Age, glaciers covered 32% of the
total land area.
If all land ice melted, sea level would rise
approximately 70 meters worldwide.
Alpine Glaciers Alpine glaciers form in high mountain valleys above the
snowline.
Continental Glaciers
Continental glaciers are large ice sheets covering major portions of entire continental land areas
Today they are found covering large portions of Greenland and Antarctica.
The erosional and depositional effects are found throughout most areas in the Northern Hemisphere.
Glaciers Erode In Three Ways
1) Glacial ice pushes loose material along the sides and in front of it in a kind of bulldozing action. This material is often incorporated into the glacier as the ice flows over it.
Glaciers Erode In Three Ways
2) The material embedded in the ice gouges out new material from a new surface.
Rock surfaces that have been glaciated can either have smooth surfaces called glacial polish or scratches and gouges called glacial striations.
Glaciers Erode In Three Ways
3) Ice freezes to underlying rock surfaces and as the ice flows forward, it pulls or plucks out fragments.
Arête: a steep-sided, sharp-edged bedrock
ridge formed by two glaciers eroding away
on opposite sides of the ridge.
Cirque: a semicircular or amphitheater-shaped bedrock
feature created as glaciers scour back into the mountain.
This is where the snow and ice forming the glacier first
accumulates; it is the "headwaters" of a glacier.
Moraines
• Lateral – lower energy at sides of glaciers causes deposit of glacial debris.
• Medial – lateral moraine of two adjacent glaciers join.
• Terminal – lower energy at snout of glaciers causes deposit of glacial debris
Lateral Moraine
Medial Moraine
Terminal Moraine
Fiord
A drowned U – shaped valley filled with sea water.
Western Brook Pond
