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N5 Physical Geography: Glaciation / Conflicts Topic Revision
Transcript of N5 Physical Geography: Glaciation / Conflicts Topic Revision
Freeze-thaw / Frost Shattering
Water in cracks in the rock freezes and expands by 9%, forcing the crack to widen. When the ice melts (thaws) more water can get into the crack and freeze again. The process repeats making the crack bigger and the pieces of rock are eventually broken off.
Glacial ice freezes into the cracks and crevices made by the freeze-thaw process and as the glacier moves, loose pieces of rock are pulled or torn out.
Abrasion occurs when pieces of rock debris that are embedded in the ice rub away at the rocks on the valley floor and sides like 'sandpaper'.
Formation of a Corrie
Snowfall builds up in a north-facing hollow in a mountainside. Over time, 30-40 years, it compacts to form firn and eventually glacial ice. The backwall is steepened through freeze-thaw (EXPLAIN PROCESS) and plucking (EXPLAIN PROCESS). This plucked moraine from backwall deepens the corrie through the process of abrasion (EXPLAIN PROCESS). After glaciation, the ice melts and can leave a Corrie-Loch or Tarn. The rock-lip acts as a natural dam. Freeze-Thaw continues on the steep backwall causing lots of weathered rock to create a 'scree-slope'.
Formation of Arêtes and Pyramidal Peaks
When two adjacent corries erode backwards or sideways towards each other, the land between them becomes narrower, until a rocky, knife-edged ridge called an arête is formed. The ridge is sharpened by frost shattering.
If three or more corries develop on the sides of a mountain, a pyramidal peak or horn may be developed. This has steep sides and several arêtes radiating from the central peak.
FOR BOTH EXPLAIN FORMATION OF A CORRIE
Formation of U-Shaped Valleys
Rivers in mountains carved out V-shaped valleys. A glacier flowed down the old V-shaped river valley. The ice eroded the sides and floor of the valley through plucking (EXPLAIN PROCESS) and abrasion (EXPLAIN PROCESS). This deepened and widened the valley into U-shape. The U-shape Valley formed has a wide, flat valley floor with very steep sides. As the ice has all melted rivers begin to flow through these valleys. The rivers are too small for the size of the valley and are called 'misfit streams'
Formation of a Hanging Valley
When the valleys are occupied by ice, less ice is found in the tributary valley. Less ice results in less erosion. After glaciation, the tributary valley is left hanging above the floor of the main valley. This is known as a hanging valley. The valley often contains a river which results in a waterfall into the main valley.
SIMILAR TO U-SHAPED BUT SMALLER GLACIER!
ARETES / PYRAMIDAL PEAKS
Remember to look for the words 'cirque', 'cwm', 'tarn', 'lochan'
FEATURES PRODUCED BY GLACIAL EROSION
GLACIAL FEATURES ON A MAP
Look out for horseshoe shaped contour lines on the map
Closely packed contour lines as arêtes are steep. You may also see bare rock symbol. Pyramidal peak will have three or more corries backing onto it. They can often be seen as triangular on the map with a point summit.
Closely packed contour lines at the sides of the valley with very few on the flat valley floor.
Contour lines will look like a u-shaped valley but the contours will suddenly stop and will be cut by the steep sides of the main valley. Truncated spurs often have almost right-angled contours lines, by the hanging valleys.
Remember that these revision Prezi's are designed to be used alongside your class notes. Use them to remind yourself about topics prior to an assessment or before your final exam - they are not intended as a single source of revision!
Conflicts in National Parks
National Parks are very popular places. However, it is difficult to protect the National Parks and encourage tourists and keep local people happy. Conflicts happen when one group of people use the environment which upsets another group of people in the area.
'National Parks' are scenic or historically important areas of countryside protected by the government for the enjoyment of the general public and/or the preservation of wildlife. The aims of National Parks are shown opposite:
What are the conflicts?
Conflicts can take place between a number of different land users, such as, tourists and local people; tourists and other tourists and tourists and farmers.
An example of a conflict is water skiers and fishermen on Lake Windermere. The motor boats create waves on the water, noise and water pollution. This can damage the serenity of the area and also scares fish and other wildlife.
'National Parks' are cared for by government led bodies, such as 'Lake District National Park'. However, there are also voluntary bodies, such as 'National Trust' who encourage volunteering to create and maintain path networks, plant local tree species etc. Bodies like the National Trust also educate people on the importance of National Parks and how to care for them.
Who looks after National Parks?
Walkers leave gates open allowing animals to escape
Tourists VS Farmers
Farmers hang signs asking people to close the gate behind them
Stone walls / dykes damaged/vandalised
Voluntary bodies (e.g. National Trust) protect areas of land and buildings, maintain walls and footpaths
Farmers may restrict access to walkers at certain times, e.g. lambing season
Park rangers liaise with different land users to minimise problems
Noise disturbs wild animals
Visitor centre staff aim to educate the public about the 'Countryside Code'
Tourists VS Locals
Litter bins removed in the hope that people take their own litter home
Increased traffic congestion at peak times
One-way systems (Ambleside), pedestrianised areas (Keswick), Park n ride and improved public transport
Footpath erosion causing visual pollution
National Park officers can build stone paths to reduce footpath erosion and put up signs to direct walkers
More noise and air pollution from increased traffic
Rail and bus services have been improved to reduce the number of cars in the national park