Glaciation - Physical Flashcards
What is abrasion?
Where bits of rock stuck in the ice grind against the rock below the glacier, wearing it away. (Sandpaper effect)
What is plucking?
When meltwater at the base, back or sides of a glacier freezes onto the rock. As the glacier moves forward it pulls pieces of rock out
What is freeze thaw weathering?
1) . Where water gets into cracks of rock
2) . The water freezes and expands, putting pressure on the rock.
3) . The ice thaws, releasing the pressure. If the process is repeated it can make bits of rock fall off
What are the characteristics and processes of glacial movement?
1) . Glacier ice forms snow that has been compressed, into granules of ice
2) . As weight of the ice accumulates, gravity causes it to flow over and down the mountains
3) . The surface of the glacier cracks as the glacier move over the uneven valley floor
4) . Glacier slides over the underlying rock in a process called basal flow. The ice changes the way it moves in response to the changes in the gradient of the slope; this is internal deformation.
5) . As glacier moves down, the sides and valley floor are eroded by plucking and abrasion. As a result, a big amount of eroded material are left on the floor, this is callard ground moraine
6) . In lowland areas, the climate is warmer. As ice flows it begins to melt
7) . Then end point of the glacier is called the snout. Large amounts of meltwater pour off the snout and can carry debris beyond here
What is an Arête?
Narrow, steep sides ridges formed when glaciers flow in parallel valleys. The glaciers erode the sides of the valley, which sharpens the ridge between them giving it a jagged profile
What is a pyramidal peak?
A pointed mountain peak with at least three sides. Its formed when three or more back to back glaciers erode a mountain
What are truncated spurs?
Cliff like edges on the valley side formed when ridges of land (spurs) are cut off as the glacier moves past
What are hanging valleys?
Valleys formed by tributary glaciers that flow into the main glacier. The glacial trough eroded much more deeply by the large glaciers, so when the glacier melts the valleys are left a higher level.
What are glacial troughs?
Steep sided valleys with flat bottems. They start off as a v-shaped river but change to a u-shape as the glacier erodes the sides and bottom with processes including abrasion making it wider and deeper.
What are ribbon lakes?
Long, thin lakes that form after a glacier retreats. They form in hollows where softer rock was eroded more that the surrounding harder rock
What are corries?
Begin as hollows containing a small glacier. As ice moves by rotational slip, it erodes the hollow into a steep sided shape with a lip at the bottem end. (When ice melts it can leave a small circular lake called a tarn)
What is transportation?
When glaciers move material over very large distances.
What is bulldozing?
When material is frozen in the glacier, on the surface or pushed in front of it; basically when ice pushes loose material ahead of the glacier
What is till?
as a glacier slowly retreats it leaves behind a bed broken rock fragments called till
What is deposition?
When the ice carrying the material melts, the material is deposited on the valley floor; mostly occurs at the snout
What are most glacial deposits not?
Not sorted by size and weight
What is outwash?
Very fine material such as sand and gravel can get washed away by small meltwater streams;
- the sediment is well sorted with bigger rocks being depositied closer to the ice and finer material carried many KM’s away.
What is moraine?
Landforms made out of till dropped by the glacier as it melts
What is lateral moraine?
Forms at the edge of the glacier. It is mostly scree material that has fallen off the valley sides due to freeze-thaw weathering. When ice melts the moraine forms a low ridge on the valley side
What is medial moraine?
When a tributary glacier joins the main glacier, two lateral moraines will merge to produce a single line of sediment that runs down the centre of the main glacier.
- On melting, the medial moraine forms a ridge down the centre of the valley
What is terminal moraine?
Huge amounts of material pile up at the snout of the glacier to form a high ridge. This represents the furthest extent of the glacier’s advance.
- As the ice melts & retreats up the valley, these festures are eroded from the valley floor and depositied as semicircular mounds as ice retreats
What is ground moraine?
The eroded material dragged underneath the glacier and left behind when the ice melts, often forms uneven hilly ground
What are drumlins?
Smooth egg shaped hills that are found in clusters on the floor of a glacial trough
How are drumlins formed?
They’re made of moraine that has been streamlined and shaped by the moving ice, they usually have blunt end which faces up valley and a more pointed end facing down valley. This indicates the direction of movement of a glacier
What are erratics?
An erratic is a large boulder that is out of place, resting on a different type of rock. Mostly large erratics were probably transported on or im glaciers
What opportunities do upland areas provide for farming?
Soils are thin and acidic due to glaciers scouring away vegetation and soil, the area is ideal for grazing animals like sheep
What opportunities do lowland areas provide for farming?
the lowland areas may be covered by a thick layer of till, which with a sunnier climate is a well suited environment for intensive arable farming
What opportunities do upland areas provide for forestry?
They are well suited for forestry. Large plantations of conifer trees have been planted in the UK, they are well adapted to cope woth acidic soils.
- Conifers can produce soft wood which can be used in the timber in the construction industry or making paper
What opportunities do upland areas provide for quarrying?
Made of hard, resistant rock; this can be quarried & crushed to provide stone used in the contruction industry and building roads.
- Limestone makes up much of the pennine hills, used for chemical industry or making cement
What opportunities do lowland areas provide for quarrying?
Glacial deposits of sand& gravel are valuable in the construction industry
What opportunities do upland areas provide for tourism?
Provides employment for 1000’s of people and glacial scenery attracts tourists who enjoy outdoor activities & cultural heritage
Where is the Lake District?
North west cumbria in England. Became a national park in 1951. It is famous for its mountains, hills and lakes
What physical attractions are there in the Lake District?
1) . Lakes like windermere offer water sports cruises and fishing
2) . Mountain landscapes with peaks like Helvellyn are popular for walking & mountain biking
3) . Adventure activities include abseiling and rock scrambling
What cultural/historical attractions are there in the Lake District?
1) . Landscape inspired writers & poets eg william wordsworth
2) . Beatrix potter author of peter rabbit lived close to lake windermere; her home is now a national trust attraction
3) . Scenic towns and villages eg grasmere are popular
What are the social impacts of tourism?
1) . In 2014, 14.8 million tourists visited, this supports shops, hotels and restaurants
2) . Jobs in tourism are mostly seasonal, poorly paid and unrealiable
What are the economic impacts of tourism?
1) . New businesses like adventure tourism provides jobs
2) . Traffic congestion slows down business communications
What are the environmental impacts of tourism?
1) . Honeypot sites and footpaths show signs of overcrowding eg footpath erosion & litter
2) . Pollution from vehicles & ships can damage ecosystems
How is traffic congestion in tourism managed?
- Several dual carriageways built to improve access
- Park and ride schemes have been expanded for tourists
- Traffic calming measures eg speed bumps are used in villages
How is footpath erosion managed in tourism?
- Projects such as ‘upland path landscape restoration’ have repaired and resurfaced paths with local stone
- ‘Fix the fells’ repair mountain paths with methods like stone pitching which create a hard wearing surface
what are the problems with quarrying, tourism, and water storage?
- Quarrying - can lead to pollution of land and rivers and spoil the themselves
- Tourism - can cause conflict with local landowners over access to land. local people may be affected by traffic congestion and rising house prices
- water storage - building reservoirs can conflict with environmental interests and require the flooding of farmland
