Glacial Systems and Landscapes

• Ablation : The loss of mass from the glacier, e.g. meltwater, avalanches, sublimation, evaporation.
• Abrasion : Small rocks within the base of the glacier rub against the bedrock.
• Arêtes : A ridge formed between two corries.
• Accumulation : The addition of mass to the glacier, usually as snow.
• Basal Ice Melting : The weight of a temperate glacier causes meltwater, which will then erode the bedrock through fluvial erosion.
• Alpine Regions : Areas of low temperature in high altitude, mountainous regions.
• Active Layer : The top layer of soil above permafrost, which thaws annually in summer.
• Blockfields : Rock:strewn landscape caused by extensive frost action.
• Cold-Based Glacier : (Also called Polar Glaciers) The glacier’s temperature remains below zero degrees, so the base of the glacier remains frozen and moves very little.
• Compressional Flow : Ice builds up and thickens due to friction as a glacier travels upwards along a shallow gradient.
• Drumlins : When a glacier hits an obstacle that cannot be eroded, deposition from underneath the glacier builds up behind the obstacle.
• Erratics : Boulders transported and deposited by a glacier. The type of rock that forms the erratic will usually differ from the rock types in the surrounding landscape.
• Esker : A long, winding ridge of glacial deposition.
• Extensional Flow : Ice thins out, creating crevasses, due to an increase in the glacier’s velocity down a shallow gradient.
• Glacial Budget : The difference between accumulation and ablation for a glacier.
• Fluvial Erosion : Water within the glacier erodes the base of the glacier over time through: hydraulic action, attrition, corrosion.
• Glacial Period : A period of time of colder average global temperatures causing the growth of ice cover, glacial advances and sea levels to fall.
• Glacial Trough : A U:shaped valley formed from a v:shaped river valley that becomes filled and eroded over time by a glacier.
• Hanging Valleys : A valley with a wall at one end, due to the glacier that filled the valley previously being low energy.
• Holocene Epoch : Our current glacial period of limited ice cover, lasting over 10,000 years.
• Ice Wedge : Water infiltrates small cracks in the permafrost and expands on freezing repeatedly.
• Interglacial Period : A period of time of warmer average global temperatures, resulting in reduced ice cover, glacial retreat and sea levels to rise.
• Internal Deformation : Glacial movement caused by the weight of the glacier above deforming the ice.
• Milankovitch Cycles : Changes to the tilt and shape of the orbit will affect the average temperature of the Earth.
• Meltwater Channels : Streams of meltwater (melted glacier) formed by higher temperatures.
• Nivation : Erosional processes involving snow and ice.
• Moraines : Deposits of eroded material that has been transported by a glacier. Moraines may be lateral, medial, ground, recessional or terminal.
• Orbital Eccentricity : How far a planet’s orbit is from being a perfect circle.
• Patterned Ground : Patterned ground is formed through the frost heave of stones in and underneath the active layer.
• Periglacial : Landscapes found at the edge of glacier, polar and alpine regions. Permafrost occurs, with low precipitation and only highly adapted plant species survive.
• Outwash Plain : Material is washed out and deposited due to large volumes of meltwater as a glacier recedes.
• Permafrost : Permanently frozen soils throughout the year.
• Pingos : A mound produced as ground is forced upwards through frost heave.
• Plucking : Rocks on the bedrock are frozen within the glacier. As the glacier moves, the rocks are pulled from the bedrock and moved.
• Roches Moutonnées : Rock shaped by a glacier flowing over it and eroding it.
• Polar Regions : Areas of maximum ice sheets and limited vegetation, located at high latitudes on Earth.
• Solifluction : The movement of waterlogged soil, trapped between the active layer and permafrost.
• Thermokarst : Marshy, boggy wetlands caused when permafrost melts.
• Terracettes : Ridges running parallel across a hillside, believed to be created by vegetation trapping sediment falling loose down the hillside, created through frost heave.
• Till Plains : An ice sheet detaches from the main glacier and melts, releasing all loose till and sediment across the bedrock.