Cold 1- Glaciers Flashcards
Cold environments
Icy landscapes found in high latitudes or high altitudes, with severely cold temperatures, snow & ice and little vegetation
Glacial/polar areas
Areas covered by ice sheets and glaciers, mainly in polar regions (very dry, -50°c)
Can be maritime (Arctic) or land-based (Antarctic) areas
Periglacial areas
Found in dry high latitude areas on the edge of glaciers (permafrost)
Tundra is a periglacial area with vegetation
Alpine areas
Found in high altitude mountainous areas with snow but slightly warmer temperatures
Glaciers as systems
Inputs- snow (& avalanches)
Processes- ablation, sublimation, calving (ice bergs break off snout)
Outputs- ice, meltwater and sediment
Types of glaciers
Polar (cold-based) glaciers- occur near the poles, very little movement
Alpine (warm-based) glaciers- water lubricates the glacier so more movement occurs
Types of ice movement
Internal flow (internal deformation) Basal flow (slippage)- regelation slip & creep
Internal deformation
Movement of ice within a glacier, crystals orientate themselves in the direction of the glacier’s movement and can slide past each other
Regelation slip
Ice mass slides over small obstacles due to the pressure on the upglacial side causing melting
Creep
Stress builds up within a glacier, causing the glacier to become more plastic and flow (large obstacles)
Factors affecting ice flow
Gravity/gradient, friction, mass of ice, meltwater, temperatures, geology
Types of flow
Extensional flow- slope steepens, ice accelerates and stretches Compressional flow- slope reduces, glacier slows down and thickens Rotational flow (in a corrie)
Glacial surges
Huge glaciers are capable of sudden and rapid downhill movement (high temperatures produce lots of meltwater)
Piedmont glacier
The glacier flows from a valley onto a floodplain
