Ice On The Land
- Created by: Georgie
- Created on: 25-03-16 16:26
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- Ice On The Land
- Landforms resulting from erosion
- Ribbon Lake
- Long, thin lakes that form after a glacier retreats.
- They form in hollows where the softer rock was eroded more that the surrounding her rock
- Long, thin lakes that form after a glacier retreats.
- Ribbon Lake
- Landforms resulting from transportation
- Drumlin
- Elongated hills of glacial deposits- the largest ones can be over 1000m long, 500m wide and 50m high
- They are round, blunt and steep at the upstream end and tapered,pointed and gently sloping at the downstream end
- Found in Ribbon Valley, Lancashire
- Moraine
- Lateral
- long mound of material deposited where the side of the glacier was
- Medial
- ound of material deposited in the centre of a valley where two glaciers meet (two lateral moraine join together)
- Terminal
- build up at snout of glacier and deposited as semicircular mounds
- Ground
- thin layer of material deposited over a large surface area as a glacier melts
- Lateral
- Drumlin
- Processes of erosion
- Abrasion
- weight of the ice scores the valley floor an d sides using the angular material rock trapped beneath the ice
- results in a smoothand often shiny rock surface
- scratches caused by large rocks beneath the ice can often be seen -striations
- Plucking
- when meltwater beneath the glacier freezes bonds the glacier base to the rocky surface below.
- The process leaves behind a jagged rocky surface
- Abrasion
- Freeze-Thaw weathering
- 1) water gets into cracks rocks
- 2) The water freezer and expands, putting pressure on the rock
- 3) The ice then thaws, releasing the pressure
- 5) it produces angular rock fragments
- 4) Process repeats and bits of rock break off
- Processes of movement transportation
- Rotational slip
- slippage of ice along a curved surface
- Bulldozing
- The pushing of deposited sediment at the snout by the glacier as it advances
- Deposition
- when the ice carrying the material (such as rocks and earth) melts the material is dropped on the valley floor
- occurs when the ice is overloaded with material
- Rotational slip
- Pleistocene
- last ice age
- it was a thick ice sheet that acted as a mirror and reflected heat this means the cooling effect was more visible
- ice covered 30% of the earths surfaced spread south
- Birmingham was a mile and a half under ice
- During ice ages there are cooler periods called glacial periods
- when the ice advances to cover more of earths surface. each one lasts 100,000 years
- in between the glacial periods are warmer periods called interglacial periods
- when the ice retreatscover less of earths surface. lasts around 10,000 years
- evidence of changing temperature
- chemical
- chemical composition of ice and marine sediments changes temperatures changes
- can be used to work out how GLOBAL TEMPERATURES has changed in the past
- ice and sediment build up over thousands of years
- samples taken at different depths show show temps over thousands of years
- the records show a pattern of increasing and decreasing temps, which caused ice to advance and retreat
- chemical composition of ice and marine sediments changes temperatures changes
- Geological
- same landforms created by glaciersin the past
- This shows that some areas that aren't covered in ice today were covered in ice in the past this means temps were lower
- same landforms created by glaciersin the past
- chemical
- present extent of ice coverage
- about 10% of earths surfaces covered by ice
- the only ice sheets are the ones in Greenland and Antartica
- Impacts of glacial retreat
- Environmental
- increase in natural hazards- flooding, rockslide and avalanches- destroy habitats/ disrupt food chains
- meltwater contributes to rising sea level- destroy costal habitats by causing flooding
- Harmful pollutants can be trapped in glacier ice - rapid melting releases them back into environment polluting rivers and lakes
- Social
- water supply to some settlements reduced
- Disruption toe power supplies from HEP leave some people with unreliable power supply
- if businesses shut down local people will have to more away to find work
- ice no longer available for recreational use for locals e.g. ice climbing
- unreliable snowfall means that there might not be enough snow for winter sports
- Environmental
- Landforms resulting from erosion
- Case Study for a retreating glacier: Rhône
- Background
- in swiss alps
- 7.8kn long
- been retreating since 19th century
- Evidence of retreating
- Pictures
- two pictures taken of the glacier in 1900 and 2008 show the different size and position of the glacier
- Monitoring Data
- The length of the glacier has been measured since 1879 and since then there has been a decrease in length
- Amount of meltwater
- As glacier retreats it produces more meltwater. Meltwater has formed a new lake infront of the glacier which has been increasing in size- glacier has been melting more rapidly
- Pictures
- Cause
- Global Warming
- melts the snout of the glacier which causes it to retreat
- Global Warming
- Background
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