UK physical Landscapes - Glacial landscapes Flashcards
When was the last glacial period?
Around 18000 years ago
What was the UK like during the last glacial period?
- there were glaciers in the north and west as far as the Severn Estuary - deep valleys and troughs
- land was permanently frozen in the south and east as permafrost
what is an ice age?
a period of long term cooling of the earth’s atmosphere, resulting in expansion of ice sheets and glaciers
what are the 2 periods of time in an ice age?
glacials (cooler periods) and intergalcials (warmer periods)
how much of the earth’s surface is covered by ice today?
10% - from ice sheets in Greenland and Antractica, high places like the Himalayas, and in the Arctic circle
what is the main form of weathering process and what does it do to the landscape?
- freeze-thaw weathering - mostly seasonal (freeze in winter, thaw in summer)
- it creates a jagged landscape, weakens rocks so they are easier eroded, and creates scree which is a powerful erosion tool under moving glaciers
describe freeze-thaw weathering
1) water enters cracks in the rocks
2) when it gets really cold, water freezes and expands by up to 9%
3) when it warms up the ice melts
4) this process repeats many times
5) the pressure of the ice expanding causes the rock to break after many cycles
what are the 2 main types of erosion processes?
- abrasion
- plucking
what is abrasion?
a sandpaper effect caused by rocks frozen into the glacier scouring the valley floor, leaving behind a smooth, polished surface and striations
what is plucking?
meltwater freezes rocks beneath the glacier into it. this rock is plucked away by the glacier as it moves downhill
what are striations?
scratches in the bedrock surface caused by a glacier moving using the process of abrasion
what are the 3 ways glaciers move?
- rotational slip
- basal slip
- internal deformation
what is rotational slip?
the circular movement of ice along a curved surface to enlarge and develop hollows
what is basal slip?
when meltwater lubricates the glacier enabling it to move downhill, mainly in summer months
what is internal deformation?
In winter, the glacier is frozen to the rock surface. The weight of the ice and effect of gravity cause ice crystals to change shape, which causes the glacier to move slowly downhill
how fast do glaciers move?
really slowly - only a few cm per year
how does a glacier transport sediment?
by bulldozing - when rock and debris in front of the glacier are moved downhill by the sheer force of the ice
what is the material transported by glaciers called?
moraine
where does glacial deposition occur?
wherever ice melts, usually at the snout (tip) of the glacier
what is glacial till?
the poorly sorted rock fragments left behind as a glacier retreats
what is glacial outwash?
well sorted sandy, gravelly material moved by glacial meltwater. larger rocks are deposited closer to the ice, fine material is further away
how does a glacier form?
1) Snowflakes fall and accumulate in a hollow on the side of a mountain
2) more snowfall - weight compresses snow -> firn ice
3) more snowfall - firn ice -> ice
4) ice looks blue - sall air is squeezed out under the pressure
5) ice doesn’t melt + more snowfall = glacier becomes bigger and heavier
6) force of gravity makes it move downhill very slowly
7) as the glacier moves it erodes the valley on either side + underneath, changing the landscape
What is a corrie?
a deep depression found on a hillside
also known as a cirque or cwm (Welsh)
how does a corrie form?
1) snow accumulates in a hollow and gets compressed into ice
2) glacier gets bigger - freeze-thaw above, plucking steepens back wall, rotational slip gouges out deep hollow, abrasion deepens the hollow
3) less rate of erosion at the end - ice is thinner - rock lip
4) after glacial period - armchair shaped hollow - the corrie
5) features - jagged summit, steep back wall (freeze-thaw weathering still happens), corrie lake (tarn)
what is an arête?
it is a knife edge ridge with a steep drop on either side
how does an arête form?
when two corries erode back to back and the land gets narrower
what is a pyramidal peak?
a sharply pointed mountain peak caused by glaciation
how does a pyramidal peak form?
when 3 or more corries erode back to back on a mountain leaving behind a peak
what are the main glacial valley landforms?
- glacial trough (U-shaped valley)
- hanging valleys
- truncated spurs
- ribbon lakes
how is a glacial trough formed?
1) before the glacier there was a V-shaped river valley
2) during glaciation, rock in the valley is removed (plucking + abrasion)
3) the glacial trough is formed - a steep sided, wide, flat-bottomed, U-shaped valley
how are hanging valleys formed?
1) smaller tributary glacier flows towards main glacier
2) since they were smaller they didn’t go as deep as the main glacier
3) after melting - a smaller U-shaped valley is formed above the main valley, often with spectacular waterfalls
How are truncated spurs formed?
1) there is a V-shaped river valley with interlocking spurs initially
2) the glacier bulldozes through the valley
3) any land that juts out is removed, forming truncated spurs - blunt-ended, sloping ridges which descend from the flank of a valley
How are ribbon lakes formed?
1) the glacier erodes areas of softer rock deeper than areas of hard rock
2) once the glacier has melted there is a depression in the base of the glacial trough
3) meltwater sits in the depression, leaving a ribbon lake - a long narrow lake in the glacial trough
What are the 3 depositional and transportation landforms to know?
- Erratics
- Drumlins
- Types of moraine
what are moraines?
accumulations of rock and debris that have distinct shapes
what are the 4 types of moraine?
- ground
- medial
- lateral
- terminal
describe ground moraine
it is material that was dragged under the glacier that is left behind after the glacier melts
describe lateral moraine
it forms on the side of a glacier and is mostly made of scree that has fallen from the edges of the valley
describe medial moraine
When a tributary glacier joins a bigger one, 2 lateral moraines merge into 1, forming a ridge in the middle when ice melts
describe terminal moraine
lots of material builds up at the end of the glacier - it marks the maximum extent of ice coverage
what are drumlins?
- found in low-lying areas
- made of till
- they look elongated with one blunt end (facing up valley) and one tapered end (facing down valley)
- groups of drumlins = basket of eggs/swarms
- dimensions: length = 1-2km, width = 500m, height = 50m
how are drumlins formed?
1) glacier is carrying material - it is overloaded and struggles to carry it as it is near the end and melting
2) small obstacles like rocks lead to moraine being deposited around them - ice can’t overcome them and carry material
3) moraine moulds itself around the obstacle - blunt end = deposited material upstream of ice, tapered end = ice flowed over obstacle and moraine trails behind
4) when ice moves over it shapes the drumlin depending on direction of flow
what are erratics?
a large boulder resting on a different type of rock (transported and deposited by a glacier)
eg. granite from the Isle of Arran found in North Devon
why are erratics helpful?
they are good indicators of patterns of former ice flow and by doing that you can work out where the erratic came from
what are the main economic activities that happen in glaciated areas?
- farming
- tourism
- forestry
- quarrying
why does farming take place in previously glaciated areas?
- in upland areas glaciers scoured away soil and vegetation - soil is now thin and acidic
- good for grazing - sheep can tolerate the cold, wet, wind and poor vegetation
- summer - sheep graze on steep valley slopes and mountains
- winter - sheep are cared for on the valley floor
- valley soil is thicker and more fertile because of glacial till - valleys are flatter, warmer and sunnier so better suited to arable farming
give an example of farming taking place in a glaciated area
- Grasmere, Lake District - sheep farming
- central and eastern England - productive farming of wheat, barley, potatoes and other crops
êwhy does tourism take place in previously glaciated areas?
- The UK’s glaciated upland areas with spectacular scenery attract tourists who enjoy outdoor activities and cultural heritage
- it provides employment for 1000s and can be the area’s main source of income
what is an example of tourism in a glaciated area?
Aviemore (near the Cairngorm Mountains, Scotland)
- one of the UK’s main mountain activity centres
- activities: mountain biking, skiing, climbing, walking on footpaths, watching, photographing or drawing the wildlife
why does forestry happen in previously glaciated areas?
- conifers are well adapted for mountainous regions - they can cope with acidic soils in upland areas
- conifers can be left to grow for 20-30 years before being felled for ‘soft’ wood - useful for timber in construction and paper making
what is an example of forestry in a glaciated area?
Loch Lomond and Trossachs National Park, Scotland
- large plantations of coniferous trees
- focus on promoting the spread of native woodland
why does quarrying happen in glaciated areas?
- upland areas are made up of hard, resistant rock - crushed and used for construction like to build roads
- lowland areas have sand and gravel deposits
give an example of a glaciated area where quarrying takes place
- Cairngorms National Park - proposal to extend quarrying at Dalwhinnie - good employment but bad for the environment and tourism
- Pennine Hills - limestone quarrying for the chemical industry - improving soils and making cement
where is Cadair Idris?
- within Snowdonia National Park - to the south
- Snowdonia National Park is in North Wales
- about 20km from Porthmadog
- about 12.5km from the coast
what glacial landforms are present at Cadair Idris?
- corries (cwm on maps)
- arêtes (craig on maps)
- pyramidal peaks
what was the proposed plan at Kirkstone Pass?
to build 3 16m high wind turbines in Kirkstone Pass, one of the Lake District’s most remote valleys, to power a pub that relied on diesel generators
did the plan for Kirkstone Pass go ahead and why?
- yes, it was completed in 2012 for £150000
- the Friends of the Lake District supported the scheme - it was better to power the pub with green energy and helped secure the future of the pub and its employees
what are the arguments against wind farms in the Lake District?
- they spoil the natural landscape
- fewer tourists in the area - affects local economy
- house prices might fall - views are spoiled by the turbines
what was the Glenridding zip wire proposal about?
- proposed in 2014 by Windermere-based company Treetop Trek
- 4 parallel 1-mile long zipwires over Glenridding in Patterdale
- disused Greenside mine -> fields above Glenridding
why were people opposed to the Glenridding zipwire proposals?
- concerns over conservation
- threats to the area’s views, tranquility and natural environment
- negative impact on tourism
- there’s already enough to do outdoors
did the Glenridding zipwire proposals go ahead?
no, there was too much opposition
how does quarrying lead to conflict?
- pollution of land and rivers - habitat destruction
- spoils landscape - less tourists
- noise pollution - from process and transport
how does tourism create conflict?
- tourists drop litter and erode footpaths when they don’t stay on them
- they scare sheep, trample on crops and leave gates open - farmers get angry
- farmland is used for tourism stuff like gift and coffee shops instead of farming
- people get holiday homes - house prices go up and become too expensive for locals
how does farming create conflict?
- grazing sheep remove vegetation
- conservationists want the area to be more natural
- conflict with tourists over access to farm sites
how does forestry create conflict?
- harvesting trees = chopping trees = habitat destruction
- coniferous trees don’t support as many species as natural woodland
where is the Lake District?
- in the county of Cumbria in England
- near the Scottish border
- near the coast (Irish Sea)
what are the physical attractions of the Lake District?
- water sports, cruises and fishing at lakes like Windermere and Ullswater
- mountains like Helvellyn and Scalfell Pike are popular with walkers and bikers
- adventure activities like abseiling, grge walking and rock climbing
what are the cultural attractions of the Lake District?
- popular scenic towns and villages like Ambleside
- landscape has inspired poets like Wordsworth and writers like Beatrix Potter
- home of Beatrix Potter is a National Trust site
- moments like Muncaster Castle at Ravenglass
what are the social impacts of tourism?
- 20 million tourist in 2018
- 83% of tourist come by car - congestion
- high house prices - 20% are holiday lets/second homes
- most tourism jobs are seasonal and poorly paying
what are the economic impacts of tourism?
- Tourists spent £3 billion in 2019 supporting hotels, shops and restaurants
- gives 65000 jobs
- new businesses like adventure tourism give locals jobs
- congestion slows business communication
What are the environmental impacts of tourism in the Lake District?
- Honeypot sites are overcrowded
- footpaths are damaged
- pollution from cars and boats damaged ecosystem
- walkers damage farmland and dogs disturb livestock
What areas need to be managed because of tourism in the Lake District?
- footpath erosion
- traffic congestion
What is the Go Lakes Travel programme?
It is a £6.9 million initiative to encourage sustainable travel
What is included in the Go Lakes Travel programme?
- building dual-carriageways around the Lake District
- improve public transport + traffic management - reduce congestion
- develop integrated walking + cycling networks +wheelchair access
- creating transport hubs
- expanding park and ride schemes - connect car parks with popular villages and foopaths
How is footpath erosion managed in the Lake District?
- Upland Path Landscape Restoration Project + Fix the Fells - repair paths and replant native plants
- still 100s of Kms of footpaths that need ongoing maintenance
