Glaciers

glaciers

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Fluvioglacial = processes and landforms associated with the action of glacial melt water

Glacier = tongue shaped mass of ice moving slowly down a glacier

Ice Sheet = body of ice covering an area of at least 50,000 km2

Ice Cap = body of ice covering an area below 50,000kmw2

Periglacial = process and landforms associated with the fringe of an area near to an ice sheet or glaciers

Tundra = climatic an vegetation type

Temperate Glaciers = melt in summer, releasing huge amounts of melt water acting as a lubricant, reducing friction

Polar Glaciers = occur in areas where the temperature is permanently blows 0 degrees, slow movement as they are frozen to their beds

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Compressing Flow = occurs when there is a reduction in the gradient of the valley floor

Extending Flow = occurs when the valley gradient becomes steeper

Basal Flow = as glacier moves over ice their is friction

Surges = occur when there is a build up of meltwater under the glacier

Internal Flow = occurs when ice crystals orientate themselves in the direction of the glaciers movement

Creep = occurs when stress builds up with a glaicer allowing ice to behave as a flow

Rotational Flow = occurs within a glacier where ice moving downhill can pivot at a point productin rotational movement

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Ablation = melting

Zone of accumulation = inputs exceed outputs, mass is gained

Zone of ablation = outputs exceed inputs, mass is lossed

Equilibrium = separates net loss from net gain

Net Balance = difference between the total accumulation and total ablation in one year

Glacial Advance = supply exceeds losses and the snout moves down the valley

Glacial Retreat = glacier shrinks in size and snout moves up the glacier

Abrasion = occurs when the material that the glacier is carrying rubs away on the valley floor or sides

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Plucking = glacial freezes onto and into rock outcrops as the ice moves forwards it pulls away massed of rock, leaving a jagged landscape

Freezethaw action/ frost shattering = occurs in areas where the temperature rises in that day but decreases as night. Water with enters the cracks freezes and expands by 9%

Nivation = process that operates underneath a patch of snow

Corrie = arm chair shaped hollow with a steep back wall and often contains a small lake

Arete = when 2 corries like back to back or side to side, enlargement occurs leaving a narrow steep ridge

Pyramidal Peak = when 3 or more corries develop, sharp appearence due to frost shattering

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Glacial Trough = U shaped valley, straighten, widen and deepen

Trough end = glacial valley end abruptly at their heads with a steep wall

Ribbon Lakes = rock basins filled with these

Fjord = form when sea levels rise

Hanging Valleys = at the side of the main valley

Truncated Spurs = areas of land projecting from the river valley sides are removed by the glacier

Rouch Mountatins = small areas of rock on the valley floor are not completely removed

Supra Glacial = transported on the surface of the glacier

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Englacial = buried within the glacier

Subglaical = found at the base

Till/boulder clay = material that is depostitied directly by the ice

Ablation Till = produced at the snout when the ice melts, producing terminal, push and recessional moraines

Drumlin = rounded hill

Stoss = steeping end of drumlin

Lee = sloping end of drumlin

Swarms = grounds of drumlins

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Moraines = lines of series of mounds of material, running across the glacial valley

Terminal Moraine = found that the end/snout of the glacier

Recessional Moraine = series of moraines that form along the valley, marking points where retreat halted

Stratified = layered

Eskers = deposits made by subglacial streams, have long ridges and are sinuous

Kames = mounds of fluvioglacial material

Outwash Plains = found at the front of the snout

Permafrost = permanetly frozen ice

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Continuous Permafrost = found in coldest regions, no melting occurs

Discontinuous Permafrost = occurs in slightly warmer regions, there are gaps in the permafrost

Sporadic Permafrost = found when the annual temperature is around freezing point

Solifucation = when the active layer thaws in summer, excessive lubrication reduces the friction between soil particles

Frost Heave = as active layer starts to refreeze, ice crystals begin to develop

Groundwater freezing = where the permafrost is thin, water is able to seep through the upper layers of the ground and then freeze

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Inputs: snowfall, avalanches, accumulation
Stores: glacier ice, melt water
Throughputs: ice movement, flooding
Outputs: melting, evaporation, and ablation

Altitude: height of thing above reference level
latitude: angular difference between north and south equator measured in degrees

Glacial budget = balance between glacial accumulation and glacial ablation

accumulation zone has a positive net balance as accumulation exceeds ablation and the ablation zone has a negative net balance as melting exceeds accumulation

Crushing is the weight of the overlying rock that caused the weak rock to break up

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Erosion factors include
- debris which is the quantiy of rock debris below the glacier
- velocity, the higher velocity will create stress along the bed
- cold based and frozen to their beds
- warm based allow basal sliding and abrasion to occur
- ice thickness, the thicker the ice the more effective that abrasion is

The main processes of fluvioglacial erosion are attrition, abrasion, corrosion, hydraulic action, caviation

The main processes of fluvioglacial depotition are: meltwater discharge decreases causing the loss of energy, the meltwater is deposited. Heavy particles will be dropped first, deposits are also found in layers

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