Glaciers Flashcards
Glaciers: Can be
Valley glaciers or ice sheets / ice caps.
A glacier is like a
River of ice, gradually moving downhill.
Glaciers: Must be on
Land throughout the year.
Glaciers: Occur in
Polar regions and mountain areas, produced by snowfall and low temperatures.
Ice sheets: In
Polar regions, the ice is continent-sized ice sheets.
Ice sheets: 95% of the plants ice is
On Greenland and Antartica.
Ice caps:
Smaller ice sheets in mountain regions.
Glacier movement: Downhill flow by
Force of gravity.
Glacier movement: Greater thickness of ice &
Steeper gradient = faster flow.
Glacier movement: Ice crystals can melt then
Recrystallise further downslope, resulting in the glacier moving downhill.
Glacier movement: Repeated melting and
Freezing at base helps the glacier to slide downhill.
Glacier movement: Flow is achieved by
Movement within individual ice crystals.
Glacier movement: Increasing snow adds
Pressure to a glacier, resulting in deformation/creep along internal planes within ice crystals.
Glacier movement: Over time, crystals tend to
Orientate themselves in a downslope direction, favouring further flow.
Valley glaciers: Form in
Mountain regions.
Valley glaciers: Are ribbons of
Ice, confined by the surrounding topography, which controls the shape and direction of movement.
Valley glaciers: Approx
1km - 2km long with areas of less than several km.
Valley glaciers: Large glaciers may
Move the the valley floors to form ice fields.
Accumulation:
The addition of mass to a glacier.
Ablation:
The loss of mass from a glacier.
Main output:
Meltwater, from the melting of ice.
Main input:
Snow, which becomes glacier ice.
Mass balance: A measure of
Change in the total mass of a glacier during a year.
Mass balance: Positive -
Results in the front end advancing.
