Cold Environments - Physical Geography

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Katabatic Winds
Cold mountain winds - the dense air flows down from the mountains to the lowlands chilling the ground as it passes over.
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Glacial Environments:
Contain snow and ice all year round.
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Periglacial Environments:
Significant cover of snow and ice but not all year round. Found in areas of high altitude or high latitude.
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Insolation:
Incoming solar radiation - heat received from the sun.
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Orographic Rainfall:
Rain that is produced as air is forced to rise over high ground such as mountain barrier, it subsequently cools, condensation occurs, and precipitation is produced.
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Plucking:
Plucking is the ripping out of material from the bedrock. Plucking involves downward pressure caused by the weight of the ice and then downhill drag as the ice moves, slow enough for meltwater to freeze onto obstacles.
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Abrasion:
Erosion of the bedrock by material carried by the glacier. The coarse material will scrape the rock leaving striations and shatter marks, while the finer material will smooth and polish the rock.
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Striations:
Scratch marks on a rock caused by abrasion.
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Chatter marks:
Discontinuous scratch marks on a rock caused by abrasion.
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Roche Montonnee:
Rock that has been plucked and made smooth by glaciers. Upstream side is smooth due to abrasion, while the downstream slope is steeper and rougher due to plucking.
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Freeze-thaw weathering:
Freeze-thaw will cause the expansion and contraction of joints - dilation - which weakens them causing them to fracture. As water freezes it expands by 10%, exerting pressures of up to 2100kg/cm2.
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Chemical weathering by meltwater:
Carbon Dioxide is more soluble at lower temperatures, hence meltwater streams have the capacity to hold much more CO2.
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Factors affecting the amount of glacial erosion:
1) Local geology: Areas with well-fractured, jointed bedrocks are easily plucked. 2) Velocity of the glacier: This is dependent on gradient, fast flowing ice leads to increased erosion. 3) Amount and character of the load carried by the glacier.
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Divergent flow:
Ice flow which is around an object rather than over it.
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Congelifraction:
The splitting up of rocks by freeze thaw action.
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Frost heave:
The process where water freezes in the soil and pushes the surface upwards.
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Carbonation:
A form of weathering in which calcium carbonate reacts with an acid water to form calcium bicarbonate which is soluble and removed in solution.
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Hydrolysis:
A chemical weathering process where water reacts with minerals such as feldspars to produce clay minerals.
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Cambering:
The process where segments of rock become dislodged from the main body of rock and begin to move downhill.
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Till:
Sediment deposited by a glacier - unsorted, angular material, varying in size, deposited directly by the ice.
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Regelation:
Ice melts in high pressure regions and freezes in low pressure regions.
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Formation of Cirques:
Accumulation of snow, Rotational flow of ice under gravity = downslope movement, basal ice abrades the bedrock, headwall retreats due to frost weathering, Berrgschrund formed by rotational downslope movement, rock particles enter and further abrade.
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Neve:
A transitional stage between snow and ice. It has survived at least one summer's melting, and has been compressed by the following winter.
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Extrusion flow:
The movement of ice as a result of becoming too deep or heavy and therefore unstable. It 'collapses' and begins to flow outwards as a result of its own weight and pressure.
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Bergschrund:
A large crack or crevasse.
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Glacial Troughs:
Freeze-thaw weathering weakens the floor and sides allowing rapid erosion, Ice channels through the valley combining plucking and abrasion.
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Pressure release:
Weathering when a rock expands outwards after pressure is removed and as a result fractures or cracks appear in the rock.
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Spur:
A projection of land from a ridge or mountain. Truncated spurs are those which have been eroded in their lower parts by glaciers.
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Ribbon lakes:
Long, linear lakes which fill a glaciated trough such as Lake Windermere in the Lake District.
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Hanging Valley:
A small U-Shaped valley, formed by a small glacier that joins and hangs above a large U-Shaped valley formed by a larger glacier.
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Scree:
Angular sediment that collects at the foot of a mountain range or cliff. The rock fragments that form scree are usually broken off by the action of freeze-thaw weathering.
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Moraines:
Lines of loose rock fragments which have been weathered from the valley sides above the ice and have fallen downslope onto the ice. Depends on; the amount of material carried, the rate of ice movement, the rate of ablation and amount of meltwater.
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Fjords:
Fjords are glacial troughs below or partly below sea level.
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Isostatic Uplift:
The rising of the land when the weight of a glacier has been removed as a result of deglaciation.
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Unstratified material:
Glacially deposited material which is unsorted, variable in size and has no distinct layers.
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Erratics:
Large boulders of different rock to the local geology that are dumped by the ice, usually on flat land.
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Ablation:
The removal of material (ice,debris) from a glacier such as by melting, evaporation or sublimation.
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Drumlins:
Oval mounds of till a few metres long, deposited where friction between the ice and the rock floor was stronger than the adhesion between the till and the ice.
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Varved Clays:
A distinctive banded layer of silt and sand deposited in lakes near the margins of ice sheets.
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Eskers:
Elogated ridges or coarse, stratified fluvioglacial material. The material was deposited in subglacial meltwater tunnels during a period of lengthy ice stagnation.
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Kames:
Kames are irregular mounds of bedded sands and gravels arranged in a chaotic manner.
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Patterned ground:
Frost heaving moves larger stones to the surface. Fine grained material forms the raised core, while the stones form the edges of the pattern.
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Pingos:
Pingos are isolated, conical hills. They form as a result of the movement and freezing of water under prssure.
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Dry valleys:
During the periglacial period limestone and chalk became impermeable and water flowed over their surfaces. High rates of river erosion occured but at the end of the periglacial period the ground became permeable and the valleys were left dry.
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Springmelt:
The flooding that occurs in spring as a result of melting winter snow.
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Scree slopes:
Slopes composed of large quantities of angular fragments of rock. They have an angle of rest and this is the angle at which the slope is stable and no further mass movements occur. Large upland surfaces of angular rocks are called blockfields.
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Perennials:
Plants living for several years.
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Plant adaptations:
Low-lying = insulation beneath snow, warmer microclimate. Large underground root structure - store food over winter. Lower optimum photosynthesis rate = maximised growing season.
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Net primary productivity:
The rate of production of biomass that is available for consumption by herbivores - the next trophic level in the ecosystem.
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Animal adaptations:
Low temperature = High quality fur insulation and increased metabolic rates. Short summer = birds migrate. Snow/harsh winters = some animals hibernate beneath snow.
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Soils:
Nutrients are limited because rates of weathering are slow, contain angular fragments of rock due to freeze-thaw action and frost heave, oxygen is lost resulting in ferrous compounds, waterlogged (gleyed) leads to an acidic humus.
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Podzol:
Light-coloured soil found under coniferous forests and on moorlands where rainfall exceeds evaporation. The constant downward movement of water leeches nutrients from the upper layers, making podzols poor agricultural soils.
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Human impacts on the environment:
Permafrost can be destoryed by heat from buildings, pipelines, changes in vegetation cover and the impact of vehicles and machinery. Thermokast=sibsidence as ice melts.
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Opportunities for development:
Resource exploitation, agriculture, recreation and tourism.
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Challenges for development:
Environmental constraints, costs/remote locations, and conflicts with indigenous populations.
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Agriculture in cold environments:
Short growing season of just 90 days, long days are challenging and most cultivated plants are not adapted to such long hours of sunlight, gleyed soils are poor quality. Some geothermal energy has successfully heated greenhouses.
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Energy and mineral extraction:
Difficult because permafrost is unstable for the construction of structures, some pipes are buried, some are suspended and some are built along roads. Pollution is a major problem as oils break down very slowly in the cold conditions.
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Other cards in this set

Card 2

Front

Glacial Environments:

Back

Contain snow and ice all year round.

Card 3

Front

Periglacial Environments:

Back

Preview of the front of card 3

Card 4

Front

Insolation:

Back

Preview of the front of card 4

Card 5

Front

Orographic Rainfall:

Back

Preview of the front of card 5
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