glacial environments Flashcards
what is meant by the glacial budget 5 points
- the glacial budget refers to the balance between inputs of a glacier (precipitation in the form of snow) and outputs (water) over A YEAR
- if accumulation exceeds ablation the budget is positive
- if ablation exceeds accumulation the budget is negative
- the budget shows whether the mass of the glacier has increased/decreased
- showing if it will retreat / advance
Explain the physical characteristics of vegetation in cold environments 5
- Differs in each environment (glacial/polar/periglacial/alipine)
- Glacial: covered by ice permanately so no exposed soil - algae and moss on glacier in sumer
- Polar very few plants some possess on rocks and few grasses in warmer areas
- periglacial: grow slowly and not tall - near poles only mosses
- alpine seasonally exposed soil means plants can grow e.g alpine flowers
Outline the impact of basal temperature on glacial processes 4
- Cold base glaciers basal temperature is below melting point of ice so there is very little melting
2 the glacier is frozen to the valley floor so moves very little - warm based glaciers basal temp is above melting point of ice so bases melt
- this acts as a lubricant allowing movement to occur and cause erosion
Explain the development of warm based glaciers 4
- occur in areas where surrounding temperatures are high as a result of environmental conditions
- basal temperature is above melting point of ice so melting occurs
- the melting ice forms meltwater which acts as a lubricant allowing the glacier to move
- where the glacier is thicker, there is more melting as the melting point falls
Outline the erosional processes involved with the formation of glaciers /corries
- plucking
- abrasion
- frost shattering
Explain the development of cold based glaciers 4
- These glaciers still move but due to internal deformation/flow rather than basal slippage
- T he ice crystals within the glacier orientate themselves in the direction of ice movement. This allows ice crystals to slide past one another
- At the head of the glacier the ice moves by extensional flow
- Lower down it moves by compressional flow
Assess the potential challenges and opportunities for future development in a glaciated landscape you have studied beyond the UK
intro: describe alaska and how its a glaciated landscape
1. opportunities
- oil and gas
-minerals
-fishing
-tourism
2. challenges
environmental conditons
inaccesibility
buildings/infrastructure
3. assess the extent - human responses
Assess the relative importance of water and ice in the development of landscapes of glacial and periglacial deposition
intro: dependant on the geographical location meltwater creates despositaionl features whereas ice creates erosional features
1. fluvioglacial features
2. erosional features
3. combo of both in periglacial
Outline the formation of moraine
- Moraines are formation of till that has been left behind by a glacier
- Moraine is unsorted
- Different types
- lateral
- medial
- terminal
Outline how sediment is sorted in glacial outwash planes
- an outwash plain forms as meltwater flows out of a glacier depositing sediment at the front of the snout
- Sediments sorted into layers dependant on weight
- Gravel is bottom layer as its the heaviest
4 Clay forms the top layer as it is the lightest and is carried the furthest away
- Outline the role of meltwater in the formation of kames and kame terraces
- Kames are mounds of sand and gravel found on the valley floor
- Material transported by meltwater streams may be deposited in crevasses, in hollows on the ice surface 3. 3. 3.Once the ice melts, the material is dropped in a heap on the valley floor
- Kame terraces are formed by meltwater streams desposting sediment along the margins of ice sheets or glaciers and are sorted into layers
Assess the role of climate in the formation of fluvioglacial landscapes
- increase in temperatures above freezing temperature which causes the ice to melt in glaciers
2It is here that ablation and glacial retreat often occurs. 3. 3Without the increase in temperatures there could be no melting and development of landscapesT
4the melting ice leads to the formation of kames, eskers andoutwash plains
5.climate change/human impact causing acceleration in development
explain what is meant by mass movement with reference to solifluction and frost creep
- Occurs when ground begins to thaw
- Ground becomes waterlogged and heavy and flows easily - water can’t drain away- solifluction
- Solifluction produces lobe formations as one section of soil moves quicker than the other
- Also occurs due to regularly freezing and thawing
- Frost creep- water expands when it freezes so soil particles forced upwards at right angles
- when it thaws the soil particles move vertically downwards
outline how ice wedges are formed
- Temperatures drop very low in winter and when the ground contracts cracks form in the permafrost
- in the summer when the active layer thaws - meltwater seeps into the cracks
- the permafrost is still frozen so water freezes in the cracks
- each year the crack can reopen and widen the ice wedge
outline the characteristics of patterned ground
- • Patterned ground often takes the form of geometric shapes on the land
- Can happen by frost heave: water underneath stones freezes and expands forcing stones upwards
- Frost contraction: ground cracks in polygonn shapes - cracks get filled with stones forming polygon shapes
