Glaciation

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Definition of a glacier
Mass of land ice that deforms under its own weight and flows downhill
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Definition of a system
Has inputs and outputs as well as processes that store, transfer and transform the matter
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How much do snowflakes weight??
~0.1g per cubic cm
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How much does Neve weigh??
~0.5g per cubic cm
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How much does glacier ice weigh??
~0.9g per cm
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How long does it take for a glacier to form in Alaska??
5 years (10 m)
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How long does it take for a glacier to form in Greenland/ Antarctica??
100s of years (greater depths)
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What are the inputs of a glacier??
Snowfall, avalanches, rock debris, potential energy
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What are the stores/ transfers of a glacier??
Water as ice and heat energy
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What are the outputs of a glacier??
Evaporation and sublimation,melt water, rock debris, calving, melt water, wind
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Definition of accumulation zone
Towards high elevation head of a glacier where inputs exceed outputs over the year
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Definition of Equilibrium zone
Towards centre of glacier where inputs and out puts are equal
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Definition of ablation zone
End or snout of glacier where out puts higher than inputs
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When will the north pole be nearly iceless??
2100
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When wil the majority of ice in Greenland be depleated by 50% ??
3000
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Short term causes of climate change
Burning fossil fuels, sun spots, volcanoes,farming, population growth,ocean currents, land fill, plague, asteroids
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Long term causes of climate change
Tilt of earth's axis, plate tectonics, orbit around the sun, evolution of life, salt changes in ocean, the moon
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Definition of Perihelion
When Earth is closest to the sun
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Definition of Aphelion
When the Earth is furthest from the sun
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What is the tilt of the Earth??
23.5
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Eccentricity cycle
Shape of orbit changing, ~100,000 years, changes intensity of insolation, present variation = 6.7%
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Obliquity cycle
Tilt of the Earth's axis, 22.1 - 24.5 degree shift, ~41,000 years, affects intensity of seasons, currently decreasing
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Procession of the equinoxes
Wobble of the axis, ~23,000, changes position of seasons, Opposite to today 13,000 years ago
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Definition of stadials
Cold periods
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Definition of interstadials
warm periods
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When was there ocean current issues in the younger dryas??
12,800 and 11,500
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What is another name for an ocean current which sinks??
Thermohaline conveyor belt
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What % decrease can a volcano cause in the energy recieved at the Earth's surface??
5 -10 %
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When did the Toba volcano erupt??
74,000 years ago
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How much ash and sulphur was produced??
2,800 cubic Km (height of 32 Km)
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What temp. decrease occurred due to Toba??
Northern hempisphere dropped by 3 - 5 C
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How long is a sunspot cycle??
11 years
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What years were there crop failures in Europe due to sunspots??
France - 1693-94, Norway - 1695-96, Sweden - 1696-97
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What % of the population did the famines claim??
10%
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How much did temps. decline in this period??
0.4 C but 0.8 C in some areas
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Gangotri Glacier facts
30.2 Km long and 0.5-2.5 Km wide, retreated >850 m in past 25 years
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How much carbon is stored in Permafrost??
500 Gt
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How much Methane is released annually??
40 Mt
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If the temp. rises by 4 C how much methane will be released??
45 - 65%
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Definition of Basal sliding
Whole glacier slides over the overlying bedrock
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Definition of Internal deformation
Ice crystals deform within the glacier due to the stresses acting upon them
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Cold based glacier facts
High latitudes, Antarctica and Greenland, ~-20 to - 30 C, Internal deformation
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Warm based glacier facts
Low latitudes/ high altitudes, pressure melting can occur, 80-90% of movement = basal sliding 10-20% = internal deformation, 20 -300 m a year movement
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Definition of Pressure melting
The temp. below 0 C that ice can melt due to pressure - 1 C for every 100 Kg/cm3
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Definition of Regelation
Pressure on ice turns it to water but when said pressure is released it refreezes
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Definition of ice creep
Displacement of ice grains relative to each other
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Definition of internal slippage
Layers of ice within the glacier slipping over each other
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Is weathering insitu or contains movement??
Insitu
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Is erosion insitu or contains movement??
Includes the transportation and removal of sediment
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Freeze thaw weathering occurs when the temp. fluctuates either side of what ??
0 C
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How much does water expand by when it freezes??
9%
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What are the dimensions of a Roche Moutonne??
1-5 m high and 5-20 m in length
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Definition of striations
Scratches on hard bedrock, glacial abrasion
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Definition of chatter marks
Small intermittent chips/fractures/gouges in the bedrock formed from basal debris
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Definition of polished rock
Sand and silt in basal in basal ice acts as sandpaper, no angular fragments
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Definition of supraglacial debris
Surface debris
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Definition of englacial debris
Debris with in the glacier
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Definition of subglacial debris
Basal debris
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Definition of proglacial debris
Debris in front of the glacier
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What are the dimensions of an esker??
200 m high, 3 Km wide and 100 Km long
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How much land surface can some sandurs cover??
1300 Km2
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Definition of Permafrost
Permanently frozen ground which has been frozen for at least 2 years
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What % of the exposed land in the northern hemisphere is covered in Permafrost??
25%
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What temps. are needed for permafrost??
Below 0 C normally lower than -5 C
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How thick can permafrost be??
1500 m
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Definition of active layer
Thin soil layer that freezes and thaws every year and is 30 -200 cm thick
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How wide and deep can ice wedges be??
2 -3 m and ~10 m deep
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What are the dimensions of a pingo??
3 to 70 m high and 30 to 1000 m diameter
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Definition of Talik
Area of unfrozen ground surrounded by permafrost
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Definition of Cryostatic pressure
Pressure exerted on soil or rocks by the freezing of water
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Definition of artesian groundwater flow
Water that reaches the surface under natural pressure of an aquifer
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Randa rock slide facts
Switzerland, April 18th 1991, ~15 million m3 of rock slid, 33 m3 fell 600 m, 33 buildings destroyed, 1.3 Km stretch of Definition of river blocked
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Definition of avalanche
Falling mass of snow that may contain rocks, soil or ice
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How many people go to ski resorts each year??
>300 million
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What % go to the Alps??
45%
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What % go to America??
21%
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What % go to Asia and the Pacific??
14%
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What % go to Western Europe??
11%
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What % go to Eastern Europe and Central Asia??
9%
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Ski related deaths
Past two decades - number of deaths has increased, 1991 - ??deaths, >30 a year now (most in Europe
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What are the annual losses in the USA due to avalanches??
~$1 million
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What are the annual losses in Switzerland due to avalanches??
~£20 million
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Galtur glacier facts
Austia, February 1999, 4 m of snow, 170,000 tonnes of snow involved, 80 m/s-1, 31 killed, 7 buildings destroyed, $20 million spent on avalanche protection
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Brunei GLOF facts
1994, 20 killed, 100s of glacial lakes (25 dangerous)
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Lake Thorthomi facts
53 million m3 of water, could have flood 3x as big as 1994 - 117 buildings, 362 people, 16 historical monuments and 5.2 Km of road will be effected
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Nepal lake facts
effects up to 60 miles away, swamp homes and field with 15m thick rubble, growing by 47m a year (3x faster than any other lake)
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How much money do Alaska have to pay a year for road repairs??
~$35 million
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Trans - Alaskan pipeline facts
400 miles long, $800 million additional cost, $8 billion in total, 8x higher price than traditional pipes, breaks could cost $2 million per mile, 3m above the ground, sleepers allow 1.5 m horizontal movement
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By how much have the methane emissions from the Arctic increased??
31% (2003 - 2007)
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What temp. increase may occur in permafrost regions??
10 C by 2090
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How far north could permafrost shift??
500 Km
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Other cards in this set

Card 2

Front

Definition of a system

Back

Has inputs and outputs as well as processes that store, transfer and transform the matter

Card 3

Front

How much do snowflakes weight??

Back

Preview of the front of card 3

Card 4

Front

How much does Neve weigh??

Back

Preview of the front of card 4

Card 5

Front

How much does glacier ice weigh??

Back

Preview of the front of card 5
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