glaciers 2 Flashcards
what is till?
-an unsorted mix of rocks, clay and sand
-usually transported as supraglacial and glacial material
-is deposited when the ice melts
-can be used to identify where the glacier travelled from
what is englacial transportation?
-material inside the glacier
-debris enters through crevasses
Englacial Moraine
-material within the ice that adds to terminal moraines
what is subglacial transportation?
-material underneath the glacier
-debris enters through abrasion and plucking
Subglacial Moraine
-material under the ice that is transported within meltwater
what is supraglacial transportation?
-material on the surface of the glacier
-debris comes from freeze thaw weathering or avalanches
Supraglacial Moraine
-material on the surface that adds to lateral and medial moraines
formation of an erratic
-large boulder that has been deposited
-geology is different to the deposited area - has been moved a long way
-has been transported by a glacier
formation of a drumlin
-forms when a glacier moves over the moraine in the valley
-can’t entrain the moraine because it doesn’t have enough energy
-can’t erode the resistant rock in the moraine
what is a lateral moraine?
-formed by frost shattered materials that have fallen of the valley walls onto the glacier
-long embankments of material along the sides of the valley
what is a medial moraine?
when 2 glaciers join together so 2 lateral moraines join to form a medial moraine, which occurs in the centre of the glacier surface
what is terminal moraine?
-occurs across the valley floor in a high mound
-often crescent shaped which corresponds with the snout of the glacier
-marks the furthest point a glacier reached
what is a recessional moraine?
-these mounds of material mark the retreat of a glacier
-each recessional moraine indicates a period of retreat
-these may be removed by future advances
what is a push moraine?
-develop due to climate change
-if the climate deteriorates enough for the glacier to advance the already deposited moraine will be pushed into a mound
what is a glacial moulin?
a hole in the glacier created by meltwater
what is the importance of meltwater?
-transports moraine subglacially, allowing erosion to take place
-assists basal sliding
-erodes channels and forms rivers
-can refreeze, binding the base of the glacier to bedrock
formation of an outwash plain/sandur
-created by erosion and deposition
-located at the snout of a glacier
-meltwater streams deposit gravel, sand and clay throughout the summer
-can freeze over winter, causing freeze thaw weathering
-larger material is deposited close to the glacier
formation of a braided stream
-seasonal melt variants causes fluctuations in sediment load
-excess sediment deposited during low discharge obstructs flow
-usually found on outwash plains
-the channel braids as it looks for a more efficient path
formation of an esker
-formed by subglacial flow
-long ridge of sediment running in direction of flow
-made of sorted sand and gravel
formation of a kame
-a hill or hummock composed of stratified sand and gravel laid down by glacial meltwater
-deposited along the front of a slowly melting or stationary glacier
-will collapse when the ice retreats
formation of a kame terrace
-sorted sand and gravel forming along the sides of a glacier
-deposited by meltwater streams flowing along the sides of the ice
-warm rock melts the ice close to it, forming a long depression along which a meltwater stream can flow
formation of a proglacial lake
-a lake developed immediately infront of the glacier
-sediment deposition will occur on the lake bed
-dammed by a terminal moraine
formation of a kettle hole
-dead ice is left on an outwash plain by a retreating glacier
-meltwater streams bury blocks of ice under sediment deposits
-the ice melts and leave a depression in the outwash plain called a kettle hole
formation of glacial lakes and varves
-lakes on the fringes of the ice are filled with layered deposits
-a varve is a layer of silt lying on top of a layer of sand, deposited over a year
-can be used to show past climates and warmer/cooler periods
-finer silts deposit in winter, heavier deposits form in spring
what are glacial deposits?
-unstratified (no layers)
-unsorted
-angular material of various shapes and sizes from physical weathering and erosion
what are fluvioglacial deposits?
-stratified (layers)
-sorted
-smooth, rounded material
why are cold environments fragile?
-tundra can take 50 years to return to former state
-damage to the ecosystem can take a long time to recover
-limited rainfall limits plant growth
-cold temperatures
-short summers and long winters
antarctica and southern ocean human activities
-sealing and whaling
-maritime transport
-mining and oil extraction
-scientific research
-tourism
-chemical waste and sewage dumping
arctic basin human activities
-sealing and shaking
-maritime transport
-mining, oil and gas extraction
-forestry
-caribou herding
-tourism
-small scale hunting and fur trapping
alpine regions human activities
-forestry
-energy production (HEP)
-transport routes
-tourism
-agriculture
siberia human activities
-finding and hunting
-military bases
-oil, gas and coal extraction
-fresh water supply
-forestry
-mining
-fur trapping
why is there a limited range of human activities?
-settlements are remote, isolated and have limited access
-a limited range of living and non-living resources
-limited biodiversity is not sustainable
-large fluctuations of energy held in each trophic level of the food chain
-human disruption to the biome can have a long lasting impact
causes of climate change
-changes in solar activity
-earths orbit
-meteorite impact
-volcanic activity
-changes in ocean circulation
-emission of greenhouse gases
-deforestation
how can climate change affect cold environments?
-snow and ice are melting at an increasing rate -> rising sea levels
-accelerated ocean warming
-stronger winds and currents
-accelerated shoreline erosion in arctic communities
-endangering species
physical challenges for human occupation and development
-very low temperatures
-short summers
-short growing season
-snow lying for long periods
-low precipitation levels
-thin, stony, poorly developed soils
-permafrost
-surface thaw in summer causes waterlogging
-blizzards
adaptions made by indigenous people
-traditional economic activities of hunting, fishing, herding and fur trading
-live in low population densities
-only take the resources they require
-cultural norms that promote the protection of the environment
human challenges for human occupation and development
-shortage of labour and skills
-increasing unpredictability of climatic events
-remoteness and inaccessibility
-lack of permanent jobs
-limited educational opportunities
-absence of modern conveniences
-feeling of economic and politic neglect
-impacts from outside on natural resources
traditional adaptions
-small family size (low birth rate)
-nomadic
-driftwood and deal skin huts in summer
-travel by umiaks in summer
-travel by dog sled in winter
-snow holes and igloos in winter
-settled communities build log and sod houses
-use all parts of a carcas
-safely eat raw meat
-hunt, gather and preserve food throughout summer
contemporary adaptions
-new building methods protect the permafrost and prevent building subsidence
-houses are elevated on piles driven into the permafrost
-large buildings are built on aggregate pads
-buildings are insulated to reduce heat transfer
-utilidors have been built
oil and gas exploration in cold environments
-large amounts of exploration within arctic circle
-greenpeace demonstrate against them
-could have major environmental consequences if not managed
-BP and shell are the main TNCs
Trans-Alaska pipeline
-boomtowns grew (Fairbanks)
-boosted the Alaskan economy
-increased tourist numbers
-increase in crime
-overstretched infrastructure
-Fairbanks mcdonald’s became no2 for sales
-construction workers moved in
-house prices rose
-films were filmed in the area
-tax rates reduced
prudhoe bay
-oilfield in north Alaska
-largest oilfield known USA (86,418 ha)
-held 25 billion oil barrels (around 2 billion remain)
-major oil spill in 2006
-oil spill was undetected for 5 days
-BP was fined $20 million
-happened in winter months
-limited impact on tundra
-oil was vacuumed up and remaining oil was scraped from surface
Trans-Alaska pipeline system
-in 2015 output reduced to 500,000 barrels per day
-pipeline will be operational until 2075
-Alaskan law states that the pipeline must be removed and the landscape returned to it’s natural state
Arctic National wildlife refuge ANWR
Kaptovik, Alaska
-indigenous people - no alcohol
-many are in favour of oil development as it provides money and jobs
-big communal freezer for whale meat-> supplied by oil company
Arctic National wildlife refuge ANWR
Guitchen people
-depend on caribou hunting
-worried that caribou migration patterns will change if oil development takes place
Arctic National wildlife refuge ANWR
Alberta, Canada
-oil tar sands
-forest removed, sand heated using fossil fuels to extract tar (oil)
-water pollution from ‘tailing ponds’
