Glaciers Flashcards
How does high latitude make environments cold
Higher latitudes get colder as less solar radiation (heat from sun)
What are three factors that make environments cold
High latitude. High altitude. Continentality.
How does high altitude make an environment cold
Colder as air temperature decreases with altitude
How does continentality make environments cold
Far from sea so sea warms costal areas only and not areas in middle of continent
What are glacial environments
Areas of land permanently covered by ice
What is latitude altitude and continentality like in glacial environments
High latitude; Antarctic ice sheet above 60* latitude. High altitudes. Can’t form in middle of continents as not enough snow
What is the definition of a periglacial environment
Temperature below 0* but not covered by ice and has a layer of permafrost
How does latitude, altitude and continentality affect the distribution of periglacial environments
High latitude eg Canada. High altitude. Interior of land masses.
What is the definition of an alpine environment
Cold areas of land above the treeline
How does latitude and altitude affect the distribution of periglacial environments
Always high altitude eg above treeline on himalayas. any latitude eg Rockies in north America
Where is the arctic
North pole
How is the arctic defined
Arctic circle which is 66*N
What’s the area around the land in the arctic like
Sea ice which partially melts each summer but freezes in winter again
Where is Antarctica
South pole
How is Antarctica defined
10* January isotherm as this is hottest month here
Why is antarctica cold
High altitude, up to 4000m high. Interior of land mass cold due to effect of continentality
What are the 4 inputs to glaciers
Snow. Condensation. Sublimation. Rock.
What is sublimation
The change from a gas to a solid without passing through the liquid stage
What are 3 stores in a glacier
Ice. Meltwater. Debris.
What are 5 outputs of glaciers
Meltwater. Surface snow melting and evaporating. Ice and snow sublimating to water vapour. Snow blown away. Calving.
What’s meltwater
Ice melting and flowing out of the glacier
What’s calving
Blocks of ice fall from the front of a glacier into the water, which creates an iceberg lettuce
What’s accumulation
The input of snow and ice
What’s ablation
The output of water from a glacier
What’s the glacial budget show
The balance between accumulation and Ablation over one year
What’s the zone of accumulation
Where there is more accumulation than ablation
What is the zone of ablation
Where there is more ablation than accumulation
Whats the equilibrium point
Where accumulation and ablation are equal
What’s a positive regime/positive mass balance
Where there is more accumulation than ablation over the year so the glacier grows and advances forwards
What’s a negative regime/negative balance
Less accumulation than ablation so the glacier shrinks and retreats
How do the seasons affect ablation and accumulation
In summer more ablation and more accumulation in winter
How are glaciers formed
Snow settles and more snow compacts it and it’s now dense and called firn. Squeezes air out and ice compresses together. Water melts and refreezes In the air spaces making the ice even more dense.
How are glaciers classified
By the temperature of the base, which is where the ice touches the valley floor
What is a warm based glacier like
Base is warmer than melting point of ice.
Why do warm based glaciers move more easily
Ice at the bottom melts and the meltwater acts as a lubricant so the glacier can more downhill more easily.
What type of glacier erodes more and why
Warm based because there’s more movement
What are cold based glaciers like
Base temperature below ice melting point so little movement
What is basal sliding
Meltwater underneath glacier allows it to slide over the ground and this is the main way warm based glaciers move
How does pressure affect glacial movement
More melting around protrusions as more pressure so ice can melt at temperatures below 0*c. Meltwater freezes downstream where there’s less pressure so flow tends to be faster round obstructions and slower downstream
What’s rotational flow
Glaciers move in an arc shape when they’re in a hollow due to basal sliding
What’s internal deformation
Ice bends and warps to flow downhill like a liquid. This is the main way cold based glaciers move.
What’s extensional flow
The valley is steep at the top of a glacier so there is a strong gravitational force pulling the ice downwards so it moves quickly. This means there’s more tension so the ice fractures into thick layers which then slip downwards
What’s compressional flow
Low down a glacier the ice moves slowly as its not very steep. Faster ice from the head of the glacier pushes down on the slower ice, compressing it. This pressure causes the ice to fracture into layers which then slip forwards.
What’s the three things that affect the speed of glaciers
Gradient of valley floor. Thickness of the ice. Basal temperatures.
How does the gradient of the valley floor affect the speed of a glacier
If its steeper it’s faster as pressure causes melting
How does th thickness of the ice affect the speed of glaciers
More pressure if thick so more melting so faster flow
How ds basal temperature affect how fast a glacier flows
If its warm based more movement as more meltwater which allows basal sliding
How do crevasses form
Form due to stress on the ice, eg extensional/compressional flow or calving.
How does a bergschrund form
Tension caused by the glacier pulling away from the ice attached to the back wall makes a semicircular crevasse that reaches the base
What’s plucking
Ice in contact with rock thaws slightly then refreezes around the rocks. When glacier moves forwards it pulls the rock out
What’s abrasion glacier style
Debris carried along by the glacier can scrape material off the valley walls and floor
What’s meltwater erosion
Where glaciers produce a lot of meltwater which creates streams that cause fluvial erosion
What’s frost shattering
Frost shattering breaks rocks off the back and side of valley. Meltwater from snow gets into cracks and freezes. It expands so bits of rock get broken off
What’s debris
The material a glacier has gathered
What’s supraglacial
Surface of glacier
What’s englacial
Within glacier
What’s subglacial
At base of glacier
What’s till in general
Unsourced material deposited by the glacier. Can be called boulder clay. Points in the direction the glacier is flowing
What’s lodgement till
Till spread onto valley floor by glaciers
What’s ablation till
Till dropped as a glacier melts, usually near the snout
Describe a corrie
Bowl shaped or armchair shaped hollow
How is a corrie formed
Snow collects in a hollow and turns to ice. Basal sliding abrasion and plucking deepen the hollow. Frost shattering and plucking steepen the back wall. When ice is thick enough it flows over the lip and downhill as a glacier.
Describe an arête
Steep sided ridge between two valleys
How is an arête formed
Two glaciers flow in parallel valleys. They erode the sidesformijg a sharp ridge between them
Describe a pyramidal peak
Pointed mountain top with three or more sides
How do pyramidal peaks form
3 or more corries form back to back and their back walls meet to make the mountains peak. In an exam you’d need to say how a corrie is formed first
Describe a glacial trough/u shaped valley
Steep sided valley with a flat bottom!
How are glacial troughs/u shaped valleys formed
Formed by the erosion of v shaped valleys. As the glacier erodes them it makes them deeper and wider
Describe a hanging valley
High level valleys on a mountain face
How are hanging valleys formed
By tributary glaciers which are small so erode valley floor less deeply so when glaciers melt the valleys are at a higher level than the glacial trough
How are truncated spurs formed
When ridges of land that stick out into the valley are chopped off as the main glacier moves past
Describe valley steps
Steps in the glacial trough/u shaped valley floor
How are valley steps for,ed
When glacier Erodes the valley mor deeply eg if the rock is less resistant
What are tarns
Lakes in corries
How do tarns form
After glacier has retreated. Can be meltwater
Describe ribbon lakes
Long thin lakes like one of those balloons
Describe the formation of ribbon lakes
Form in dips caused by erosion of less resistant rock
What’s a fjord
Long deep inlet
Describe the formation of a fjord
Form where a valley floods due to sea level rise after the ice has melted
Describe a Roche moutonnée
Resistant mass of rock on valley floor. Upstream side is called stops and smooth. Downstream called lee and rough
Describe the formation of a Roche moutonnée
More resistant rock so didn’t erode. Stoss smoothed by abrasion and lee rough due to plucking
What’s moraine generally
Formations of till deposited by glacier
What’s lateral moraine
At the sides of a glaciers
What’s medial moraine
In centre of valley where two glaciers meet
What’s terminal moraine
At end of glaciers in semicircles
Describe a drumlin
Half egg shaped hills of till up to 1500m long and 100m high. Often form in groups eg ribble valley in Lancashire. Upstream Stoss wide and tall downstream lee narrow and low
Describe the formation of a drumlin
Nobody actually know but they guess it’s when the till was streamlined when the glacier readvanced over it
Describe erratics
Boulders carried a long way by a glacier and deposited in a area of different rock type. Eg some in east England carried from Norway during the ice ages… Yay..
What are meltwater streams
Streams of meltwater in tunnels under a glacier and out Of its snout
Tell me about how meltwater streams erode stuff
Fluvial erosion but cause more erosion than rivers of same siZe would as pressure of the ice means it flows quickly.
What is permafrost in general
Permanently frozen ground, may have an active layer which melts in summer
What’s the difference between continuous and discontinuous permafrost
In continuous permafrost all the ground is frozen
What is solifluction
Gradual downhill slumping of saturated soil and rock
What’s frost contraction and when does it occur
Occurs when temperatures drop very low in winter. The ground contracts and cracks form in the permafrost
How are ice wedges formed
In spring the active layer thaws and meltwater seeps into cracks formed by frost contraction. The permafrost layer is still frozen so the water in the cracks freezes, which is called an ice wedge
Whats frost heave
When water in the ground freezes and makes humps on the surface
How do ice lenses form
They form under stones as stones lose heat faster than the soil, so colder beneath stones. As the Ice expands the stones get pushed up and the ice lense stops the stone from slipping down
How does patterned ground form
Stones get pushed to the surface by frost heave. Once they reach the surface they roll down to the edges of mounds so they form circles.
When do store stripes form
If mounds are on a slope the stones roll downhill and form lines
When does polygon shaped patterned ground form
When the mounds are close together. Frost contraction causes the ground to crack in polygon patterns on the surface. The cracks are filled in with stones, forming the polygon patterned ground
What are fluvioglacial deposits like
It’s where the meltwater streams deposit the sediment on the valley floor, it’s sorted, unlike glacial deposits
What are outwash plains
Layers of gravel sand and clay that form in front of where the glacial snout used to be. This is because gravel is heaviest so closest to snout, then sand then clay
What are kettle holes
Blocks of ice from the glacier can get partially buried by fluvioglacial deposits. When they melt they leave holes in the out wash plains and these are called kettle holes
Describe an esker
A long winding ridge of sand and gravel that runs in the same direction as the glacier
Explain the formation of eskers
Deposited by meltwater streams in tunnels underneath the glacier. Wen the glacier retreats the load remains as an esker, so this cn show you where the glacial tunnel used to be
Describe kames
Mounds of sand and gravel found on the valley floor
Explain the formation of kames
Meltwater steams on top of glaciers collect in depressions and deposit layers of debris. When the ice melts this is dumped onto the valley floor.
Describe kame terraces and their formation
Piles of debris against valley walls. Sorted into layers as meltwater stream deposits heaviest load first. So gravel at bottom and sand on top
How do proglacial lakes form
In front of glaciers eg when meltwater streams become blocked by terminal moraine
Explain the formation of delta kame
As meltwater streams flow into proglacial lakes they slow and deposit sediment on the ice. When ice melts delta is dumped on valley floor and called a delta came
Describe a pingo
Conical hill with a core of ice. Can be up to 80m high and 500m wide.
How do open system pingos form
There’s discontinuous permafrost. Groundwater is forced through gaps between areas of permafrost. The water collects together and freezes, forming a core of ice that pushes the ground above it upwards
How are closed system pingos formed
In areas of continuous permafrost where there’s a lake at the surface. The lake insulates the ground so the area below it is unfrozen. When the lake dries up the ground isn’t insulated and the permafrost moves around it. The watcollects in the unfrozen part then freezes, pushing the ground above it upwards
What resources in cold environments attract development
Whales seals and fish for fishing and whaling etc. minerals so mining eg in Canada and Alaska. Oil eg in Alaska. Attractive scenery so more tourists eg antarcticas tourism is rising. Some have potential for hydroelectric power, Norway supplies 99% power in this way
What is a fragile ecosystem
An ecosystem that would struggle to recover from any damage
Why is Antarctica/other cold environments a fragile ecosystem
Short growing season restricted to when enough light and warmth so plants can’t recover if damaged. Plants and animals adapted to cold conditions so can’t survive if environment changes. Decay is slow so pollutants remain in environment for a long time
How can fishing damage cold environments
Disruption of food chains eg fishing krill in southern ocean means less for pengywengys. Overfishing of a species can cause it to become extinct if it’s population depletes a lot. Disrupts the ecosystem eg bottom trawling reduces light levels and catches multiple species rather than just one type of fish
How does hydroelectric power development damage cold environments
Hydroelectric dams can block migratory paths so fish can’t reach breeding grounds so numbers decrease. Heat up water which can endanger fish used to colder temperatures.
How does oil extraction damage cold environments
Oil spills can occur during transport, eg in 1989 over 40 million tonnes of oil leaked which killed birds and fish
How can tourism damage cold environments
Cruise ships can cause pollution. Tourists disrupt wildlife and damage habitats so there’d a reduced biodiversity
How can mining damage cold environments
Ground and surface water contamination due to chemicals used in mining or released from the mines. Mining produces solid waste and wastewater that needs to be disposed of and if not done properly this pollutes the surrounding area
What affect did development of cold environments have on the locals
90% of a tribe of Canadian Inuits died due to disease as had not been exposed to it to build up an immunity. Whaling and fishing reduces amount available for natives. Have to rely on government help as no qualifications, 50% Inuits unemployed
What does development have to do to be sustainable
Not deplete resources or cause long term environmental damage
What are three ways of helping development be more sustainable in cold environments
National parks allow tourism whilst protecting the environment eg Denali national park in Alaska. Fishing quotas to limit amount caught. Oil pipes had automatic shut off valves to minimise spills if pipes are damaged
What is the definition of a wilderness area
An area that has been unaffected by large scale human activity
How large is antarctica
14 million km2. Contains 90% of worlds ice
What are the two largest ice sheets in Antarctica
Ross shelf and Ronne shelf
Why is Antarctic fragile (basic reasons)
Little available water for plants. Very cold. Very little sunshine in winter.
What’s a fact about rainfall in Antarctica
Less than 150mm of rain per year so classified as a desert
What’s the average temperature in Antarctica
-49*
Why is the sea ecosystem in Antarctica fragile
If the population of one species decreases it affects other species in the food chain, eg if krill die there’s not enough for fragile
What are four of antarcticas natural resources
Around 300 species of fish and 8 species of whales. Very attractive scenery. Large underground deposits of coal and iron ore. Large reserves of oil underneath southern ocean around Antarctica
What is the Antarctic treaty and when was it set up
12 countries signed to agree to protect Antarctica as it is fragile. 1961. Treaty contains protocols and conventions that control or prohibit activities.
What does the Antarctic treaty say about oil extraction and mining
It’s banned but due to be reviewed in 2048.
What does the antarctic treaty say about whaling
Commercial hunting was prohibited in 1994 but some is still allowed for scientific research. It used to be allowed but drastically reduced the whale population to only 1000 in the Antarctic.
Do a lot of tourists visit antarctica
Yes obviously, 45,000 in 2007-2008 season
Do a lot of researchers visit antarcrica
5000 in summer and 1000 in winter
How does the Antarctic treaty control tourism
Prohibits discharging of oil from ships. IATO (international association of Antarctica tour operators) say no more than 100 passengers on shore at a time
How does the Antarctic trea control scientific research
Scientists have to remove most of their waste from the area and treat sewage before disposing of it into the sea
How does the Antarctic treaty control the impact of fishing
Quotas so there are limits on things such as krill.
What’s a nivation hollow
In a hollow the ice can melt and refreeze repeatedly. When it freezes it expands so frost shattering breaks off rock at the base. Slopes collapse because they’re waterlogged and have been eroded, and the material is washed away by meltwater. The hollow becomes deeper and wider and this is called a nivation hollow.
What’s a solifluction lobe
The waterlogged active layer flows over the frozen layer beneath. Solifluction produces lobe formations where one section is moving faster than the other, eg if it’s on steeper ground.
