Cold environments Flashcards
1
Q
Three main reasons why an environment may be cold
A
High altitude
High latitude
Continentality (in the middle of a continent)
2
Q
Why are high latitudes cold?
A
They receive less solar radiation
3
Q
Why are high altitudes cold?
A
Because air temperature decreases with increasing altitude. (6-10 degrees colder every 1000m you go)
4
Q
Why are middles of continents cold?
A
In summer the land heats up quickly, sea slowly, in winter the land cools quickly and sea cools slowly, so in winter the sea heats the coasts but not the centre of continents.
5
Q
Where are glacial environments found?
A
High altitude and high latitude
6
Q
2 main types of glaciers
A
valley and corrie
7
Q
What are ice sheets?
A
Domes of ice covering huge areas of land
8
Q
Example of glacial environment at high latitude…
A
Antarctic ice sheet and Greenland ice sheet (both above 60 degrees latitude)
9
Q
Example of glacial environment at high altitude…
A
Himalayan mountain range
10
Q
Why are glacial environments not found at centre of continents?
A
Not enough snow
11
Q
Where are periglacial environments found?
A
High altitude, high latitude and in centre of continenents
12
Q
What is a periglacial environment?
A
Places where the temperature is frequently or constantly below freezing, but not covered by ice. They contain a layer of permafrost on or below the surface.
13
Q
Where are alpine environments found?
A
at high altitudes - above the tree-line. Often found above the tree-line in mountain ranges e.g. Himalayas
14
Q
What is an alpine environment?
A
Cold areas of land at an altitude above the tree-line
15
Q
What other conditions may be present in alpine areas?
A
Periglacial - may exist above and below tree-line
Glacial - may exist even higher up
16
Q
Where are polar environments found?
A
Around the poles (one at North, one at South)
17
Q
What are the two polar environments called and why are they cold?
A
Arctic - High latitude (66 degrees North)
Antarctic - High latitude (66 degrees South)
18
Q
What is the areas around North Pole made of, and what happens to it in Winter and Summer?
A
Sea ice (frozen sea water) - Area of sea ice shrinks in Summer, leaving open sea, and refreezes in Winter
19
Q
What environments can the Arctic include?
A
Glacial environments e.g. Greenland ice sheet
Periglacial environments e.g. Northern Russia.
20
Q
2 other reasons why Antarctica is cold?
A
High altitude - in some places the ice is so thick it reaches an altitude of over 4000m
Continentality - Interior is cold as the centre is hundreds of km away from sea.
21
Q
What environment is found in Antarctica?
A
Glacial e.g the Antarctic ice sheet
22
Q
What are the inputs of a glacier?
A
Snow
Condensation of water vapour
Sublimation of water vapour to ice
Bits of rock collected when the glacier calves away the landscape
23
Q
What are the stores of a glacier?
A
Ice
Meltwater (can be subglacial, englacial or supraglacial)
Debris
24
Q
What are the outputs of a glacier?
A
Ice can melt and flow out of glacier as meltwater
Surface snow can melt and evaporate
Ice and snow can sublimate to water vapour
Snow can be blown away
With glaciers that end at the sea, blocks of ice fall from the snout of the glacier into water to create icebergs, this is called ‘calving’.
25
What is a glacial budget?
The balance between a glaciers inputs and outputs.It shows whether the glacier will advance or retreat
26
How does the glacial budget change throughout the year?
In summer ablation is greater as more melting will occur, in winter there's more accumulation than ablation.
27
How will this affect the mass balance over a year?
The glacier may advance in winter but retreat in summer, so the volume of water in the glacier will stay the same.
28
How has the glacial budget changed over several years?
Temperatures in 19th century were colder than the 18th century so the glaciers would advance. However 20th century temperatures are higher meaning glaciers tend to retreat.
29
How do glaciers form?
1) Snow settles. It has a loose fluffy consistency
2) The weight of more snow falling on top turns the snow into denser, more granular snow called firn.
3) Air is squeezed out and particles of ice are compresses together
4) Ice melts and refreezes in air spaces, making the ice more dense.
30
In warm based glaciers the base is warmer than the melting point of ice, why?
Because of heat from friction caused by the glacier moving. Or because of geothermal heat from the earth.
31
What effect does a warm base have?
The ice at the base of the glacier melts and the melt-water acts as a lubricant, making it easier for the glacier to move downhill. Ice at the surface may also melt and move down through the glacier, lubricating it even more. Lots of movement means lots of erosion.
32
Explain the movement in cold based glaciers.
The ice is frozen to the base of the valley, so there's very little movement. Cold based glaciers cause very little erosion.
33
What is basal sliding?
Meltwater underneath a glacier allows the glacier to slide over the ground. It is the main way that warm based glaciers move.
34
Why is flow faster around an obstruction than downstream?
There's more melting around protruding bits of rock because there is pressure on the ice so melting point decreases. Meltwater can refreeze downstream so the glacier will slow down.
35
What is rotational flow?
Glacier move in an arc shape in a hollow, this is called rotational flow
36
What is internal deformation?
Where the ice bends and warps to flow downhill like a liquid. Its caused by ice crystals shifting past each other. Its the main way cold based glaciers move.
37
What is extensional flow?
At the head of the glacier the valley is steep, so there is a strong gravitational force pulling the ice downwards. This makes the ice move quickly, when ice moves quickly there's more tension which causes the ice to fracture into layers, these layers then slip downwards.
38
What is compressional flow?
Lower down the valley the glacier is moving more slowly. The faster ice from the head of the glacier pushes down on the slower ice and compresses it. The high pressure causes the ice to fracture into layers, these then slip forwards.
39
What are the three main things that determine the speed at which a glacier flows?
Gradient of valley floor
Thickness of ice
Temperature at base of glacier
40
What parts of the glacier moves the fastest?
Surface and middle (see page 38)
41
What is a bergschrund?
When the glacier pulls away from the back wall the tension creates a large semicircular crevasse at the back of the glacier called a bergschrund.
42
What is plucking?
Ice in contact with rock surfaces can melt slightly then refreeze around protruding bits of rock. When the glacier moves forward it plucks the rock away.
43
What is abrasion?
Debris carried along by the glacier can scrape material off the valley walls and floor.
44
What is frost shattering?
Meltwater from snow gets into cracks in the valley walls and then freezes. When it freezes it expands so exerts a pressure on the rock and bits of rock get broken off.
45
What are the three ways that debris is carried in a glacier?
Subglacial
Englacial
Supraglacial
46
What is till?
The unsorted mixture of the material deposited by the glacier. Till points in the direction that the glacier is flowing.
47
What is lodgement till?
Till that is spread onto the valley floor beneath the ice by moving glaciers
48
What is ablation till?
Till dropped by a glacier as it melts
49
Why do glaciers normally form on one side of a mountain peak?
Because one side gets least sun and coldest winds, this means that there will be more accumulation and less ablation on this side.
50
What is an arête?
A steep sided ridge - it is formed when two glaciers flow in parallel valleys
51
What is a pyramidal peak?
A pointed mountain peak with at least 3 sides - it is formed when three or more corries form back to back.
52
What is a glacial trough?
A steep sided valley with a flat bottom, formed by the erosion of V-shaped river valleys by glaciers
53
What is a hanging valley?
valleys formed by tributary glaciers, they erode the valley floor much less deeply because they are smaller than the main glacier. So when the glacier melts the valley gets left much higher than the glacial trough, you can get waterfalls from hanging valleys.
54
What is a truncated spur?
Formed when ridges of land that stick out into the main valley are cut off by the glacier as it passes through.
55
What are valley steps?
Formed when glacier erodes the valley floor more deeply in places, this happens when another glacier joins it or where there's softer rock.
56
What is a tarn?
A lake that forms in a corrie after a glacier has retreated.
57
What is a ribbon lake?
Long, thin lake that forms after a glacier has retreated. Form in dips caused by erosion of less resistant rock.
58
What is a fjord?
Long, deep inlets that form when a valley that's been eroded by a glacier is flooded by sea level rise after ice has melted.
59
What is a roche moutonnee?
Hard mass of rock on the valley floor, the stoss side is smooth because it was smoothed by abrasion as the glacier went over it. The lee side is steep and rough where the glacier plucked at it.
60
How wide and tall can a roche moutonnee be?
3m high and 8m wide
61
What are the three types of moraine and describe each one.
Lateral moraine - Deposited where the sides of the glacier was
Medial moraine - Deposited in the centre of the valley where two glaciers converge
Terminal moraine - Builds up at the end of the glacier
62
What are drumlins?
Half-egg shaped hills of till, up to 1500m long and 100m high. Stoss end is wide and tall and lee side is narrow and low
63
What are erratics?
Boulders that have been carried a long way by glaciers and dropped in an area of different geology.
64
Why do melt water streams cause more erosion than normal rivers of the same size?
Because the pressure of the ice means that melt water streams flow very quickly, so they carry lots of material that erodes the landscape.
65
What happens to the meltwater channels after the glacier retreats?
The deep meltwater channels are left with very shallow streams running through them.
66
What is 'braiding' and why does it happen?
When meltwater streams are flowing away from the glacier they often split into lots of mini streams that cross over each other. This is because when the meltwater if flowing more slowly (e.g. in winter) it cant carry it's load so it deposits its sediment on the ground and splits into two streams to get around it.
67
What's the difference between fluvioglacial and glacial deposits?
Fluvioglacial deposits are sorted and glacial deposits are unsorted.
68
What is an outwash plain?
A layer of gravel, sand and clay that forms in front of where the snout of the melting glacier used to be.
69
What are kettle holes and how are they formed?
Blocks of ice that have broken off from the glacier can get surrounded and partly buried by the fluvioglacial deposits. When the blocks of ice melt, they leave holes in the outwash plain, called kettle holes.
70
What are eskers?
Long, winding ridges of sand and gravel that run in the same direction as the glacier. They're deposited by meltwater streams flowing in tunnels underneath the glacier. When the glacier retreats the stream dries up and the load remains as an esker.
71
What are kames?
Mounds of sand and gravel found on the valley floor. Meltwater streams on top of the glaciers collect in depressions and deposit layers of debris. When the ice melts the debris is dumped onto the valley floor.
72
What are kame terraces?
Piles of deposits left against the valley wall by meltwater streams that run between the glacier and the valley sides. They are sorted.
73
How is a delta formed?
Pro-glacial lakes can form in front of glaciers when the flow of meltwater streams gets dammed by terminal moraine. As meltwater streams flow into the lake they are slowed down so the stream deposits it's load on the ice.
When the ice melts these deposits are dumped onto the valley floor as delta kames.
74
What is permafrost?
Permanently frozen ground with a top layer that can melt in the summer
75
What temperatures are needed for continuous and discontinuous permafrost to exist?
Continuous - Mean annual temperature below -5 degrees
| Discontinuous - Mean annual temperature below 0 degrees for at least 2 years.
76
What is solifluction?
The layer of permafrost is impermeable, if the active layer melts the water cant go anywhere, so it becomes waterlogged. This means that the water will flow wherever there is a gradient.
77
How do ice wedges form?
1) When temperatures are very low in winter the ground cracks and cracks form in the permafrost
2) When temperatures increase in spring, the active layer thaws and meltwater seeps into the cracks.
3) The water then freezes in the crack forming an ice wedge
4) Frost contraction in following years can re open cracks and more water can seep in, causing the crack to widen each year
78
How does frost heave happen?
1) Water freezing in the ground can make humps in the surface
2) When the active layer freezes in winter, the ice forms in a lens shape
3) In fine grained soil the ice lifts up the surface, this is called frost heave
79
Why do ice lenses also form under rocks?
Because rocks lose heat quicker than the soil around them, so when temperatures drop its colder around the stones.
80
What are the two ways that patterned ground can be formed?
Frost heave - stones can get pushed to the surface, when they get there they roll down to the edges of the mounds forming patterns around them
Frost contraction - Causes the ground to crack in polygon shapes, the cracks get filled in with stones, forming patterned ground.
81
Outline what nivation is
When snow gets into a hollow in the ground it can increase the size of the hollow. It does this by frost shattering. Also slopes collapse because they are waterlogged and they've been eroded, eventually the hollow becomes deeper and wider, this can form nivation hollows which can be the beginning of a corrie.
82
How does solifluction cause lobes to form?
The waterlogged active layer flows easily over the frozen layer underneath, Solifluction lobes are formed when one section of the soil is flowing faster than the soil around it (e.g. because it is on a steeper part of the hill)
83
What are pingos?
A pingo is a conical hill with a core of ice. Can be up to 80m high and 500m wide.
84
What is the difference between open and closed system pingos?
Open system - form where there is discontinuous permafrost.
| Closed system - form where there is continuous permafrost where there is a lake at the surface.
85
How are open system pingos formed?
Groundwater is forced up from lower unfrozen layers, through gaps in the permafrost, this water collects together and freezes, forming a core of ice that pushes the ground upwards.
86
How are closed system pingos formed?
The lake insulates the ground beneath it, so it remains unfrozen, when the lake dries up the ground is no longer insulated and the permafrost advances around it. This causes water to collect in the centre of the unfrozen ground, eventually the water freezes forming a core of ice that pushes the ground upwards.
87
What happens if the ice in a pingo thaws?
The pingo collapses, leaving behind a pond of meltwater surrounded by ramparts (walls of soil)
88
What 3 resources can be found in cold environments?
Whales, seals and fish - e.g. in Northern Russia whales and seals are hunted for their skins, meat and blubber, while its fishing industry is one of the largest in the world
Minerals - gold in Canada and Alaska has led to establishment of towns based around mining
Oil - Alaska has a lot of oil so oil companies have moved there to exploit it
89
How has tourism developed in Antarctica?
In 1992 number of tourists = 6700
| In 2007 number of tourists = 46000
90
Why do cold environments have fragile ecosystems
Harsh climate...
- Short growing season (where there is enough light and warmth for plants to grow) means that plants don't have a lot of time to recover if they are damaged
- Plants and animals are adapted to the cold environment so its hard for them to adapt if the environment changes
- Decay is slow because it is cold so pollution is broken down slowly
91
What is tundra?
Areas where it's too cold for trees to grow, either because of high altitude or high latitude (e.g. Greenland, Northern Russia)
92
How can fishing damage the ecosystem?
Can disrupt food chains (e.g krill fishing is depleting food supplies for whales and penguins)
Overfishing of a species can cause it to become extinct
Bottom trawling (dragging nets along the sea bed) can cause light levels to drop and also can catch species that arent the target species
93
How can oil extraction damage the ecosystem?
Oil spills can occur during transport, causing ocean species to be killed.
Oil can be spilled from the pipelines
94
How can tourism damage the ecosystem?
Large cruise ships increase pollution levels
| Tourism development can damage wildlife e.g. roads and hotels can disrupt habitats leading to reduced biodiversity
95
How can mining damage the environment?
Mining can lead to ground and surface water contamination, either by chemicals used during mining or by the materials being mined. Also mining produces both solid waste and waste-water which has to be disposed of.
96
Who are the inuit people?
A group of native tribes who live in the tundra in Northern parts of Greenland and Russia. Their way of life involves hunting and fishing - they eat the meat and make clothes and shoes from the fur and skin of the animal.
97
Why did Europeans take an interest in tundra areas in the 17th century?
Because of the opportunities for hunting whales and seals. Seals were hunted for their warm fur and oil - the oil was used as a lamp fuel. Whales were mainly hunted for their oil, which was used to make candles and margarine.
98
Why did the arrival of newcomers have a negative effect on the inuits?
Because they brought new diseases with them, so lots of inuits were infected and died e.g. in late 19th century 90% of an inuit tribe were killed by diseases like TB and flu.
Also increased amounts of whale and seal hunting reduces the number available for inuits to catch.
99
How can development in cold environments be made more sustainable?
National parks - Allows tourism while protecting the environment.
Fishing quotas - Prevent overfishing
Oil pipes - automatic shut off valves in order to minimise oil spills if pipes are damaged.
100
What is a wilderness area?
An area that has been unaffected by large scale human activity
101
Why does the Antarctic have a fragile ecosystem?
1) Very little water available - inland areas receive less than 166mm of precipitation per year
2) It's very cold - average temperature is -49 degrees
3) Very little sunshine in winter meaning that very few species can survive there
4) It takes a long time to recover from damage due to the conditions
5) sea ecosystem is fragile - if one species' population decreases it affects other species in the food chain, e.g. if the population of krill decreases it affects the whale population
102
What valuable resources does Antarctica have?
1) Around 300 species of fish and eight species of whale in the waters around Antarctica
2) Antarctica has very attractive scenery
3) Large underground deposits of coal and iron ore
4) Large reserves of oil underneath the Southern Ocean
103
Why is oil extraction and mining banned in Antarctica?
Because of the huge environmental impacts
104
What is the Madrid protocol?
Part of the Antarctic Treaty, the Madrid protocol came into force in 1998, banning all oil extraction and mining - ban is in force for 50 years - some people think it will be lifted in 2048 due to the need for minerals and oil.
105
Why is whaling banned in Antarctica?
Whaling was allowed in Antarctica, but caused a decrease in population - 100 years ago there were around 250,000 blue whales in Antarctica, now there are fewer than 1000.
106
What is the Antarctic treaty?
An agreement set up in 1961 by 12 countries to come up with laws to protect it. Includes many protocols to prevent certain activities.
107
How is tourism in Antarctica controlled?
Antarctic treaty prevents discharge of oil and plastic from cruise ships.
No more than 100 passengers are allowed on shore at any one time and only one ship is allowed at a landing site at a time.
108
How is scientific research in Antarctica controlled?
Protocol came into force in 1998 protecting Antarctica from damage by scientific research e.g. litter must be taken with you and sewage must be treated before disposing.
109
Why does illegal fishing happen?
It is hard to police the seas in Antarctica, in 2003 it was estimated that 2622 tonnes of patagonian toothfish were caught illegally.
