glaciation keywords

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.

Accumulation - The addition of mass to the glacier, usually as snow.

Active Layer - The top layer of soil above permafrost, which thaws annually in summer.

Alpine Regions - Areas of low temperature in high altitude, mountainous regions.

Arêtes - A ridge formed between two corries.

Basal Ice Melting - The weight of a temperate glacier causes meltwater, which will then erode the

bedrock through fluvial erosion.

Basal Sliding - Glaciers sliding over bedrock, due to meltwater between the two surfaces.

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.

Corries - A round hollow in the side of a hill, widened from an initial smaller hollow by a glacier

within the hollow.

Crushing - The weight of the glacier causes fracturing in the bedrock.

Drumlins - When a glacier hits an obstacle that cannot be eroded, deposition from underneath the

glacier builds up behind the obstacle.

Environmental Fragility - An environment is vulnerable or at risk, with low resilience or ability to

adapt to changes.

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.

Fluvial Erosion - Water within the glacier erodes the base of the glacier over time through:

hydraulic action, attrition, corrosion.

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Frost Heave - The freezing and expansion of water beneath the ground, resulting in floor uplift.

Glacial Budget - The difference between accumulation and ablation for a glacier.

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.

Kames - Piles of material, sorted due to the differing weight of sediment, left on the valley floor after

a glacier melts.

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.

Moraines - Deposits of eroded material that has been transported by a glacier. Moraines may be

lateral, medial, ground, recessional or terminal.

Nivation - Erosional processes involving snow and ice.

Orbital Eccentricity - How far a planet’s orbit is from being a perfect circle.

Outwash Plain - Material is washed out and deposited due to large volumes of meltwater as a

glacier recedes.

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.

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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.

Polar Regions - Areas of maximum ice sheets and limited vegetation, located at high latitudes on

Earth.

Roches Moutonnées - Rock shaped by a glacier flowing over it and eroding it.

Solifluction - The movement of waterlogged soil, trapped between the active layer and permafrost.

Solifluction Lobes - As the active layer thaws, soil falls down the hillside in tongue-shaped lobes.

Terracettes - Ridges running parallel across a hillside, believed to be created by vegetation

trapping sediment falling loose down the hillside, created through frost heave.

Thermokarst - Marshy, boggy wetlands caused when permafrost melts.

Till Plains - An ice sheet detaches from the main glacier and melts, releasing all loose till and

sediment across the bedrock.

Warm-Based Glacier - (Also called Temperate Glaciers) Faster travelling glaciers due to basal

meltwater trapped underneath the glacier, acting as lubrication to allow the glacier to move.