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Coastal questions


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Coastal questions

  1. 1. Coastal questionsYear 9
  2. 2. Contrast the process of freeze thawweathering with chemical weathering. (sp)Freeze thaw weathering involves temperature changearound freezing point so that water in a crack in the rockwill freeze and expand.Subsequent thawing will lead to pressure exerted on side ofcrack being released.Eventually, after repeated freezing and thawing angular bitsof rock will break off. No change is involved in the rockitself, it just gets smaller.This is unlike chemical weathering where under especiallywarm and wet conditions the composition of the rockchanges completely e.g. limestone.2 x 1 for describing each type, 1 for clear contrast
  3. 3. Mass movement is common in the area shown in Figure 20.What role does mass movement have on coasts such as that inFigure 20?Shifting of loose material downa slope as one may be seen as ameans of rapidly transformingthe coast / cliffs (1) viasliding / slumping (1).The coast will retreat. (1)There will be a new supply ofmaterial on the beach (1) whichcan then be transported vialongshore drift (1)2 x 1/ 1 +1
  4. 4. Mass movement is a process affecting the coastalzone. Describe this process.(3 marks) S 2010Mass movement occurs when loose material onthe land surface (1) moves downslope (1) due togravity (1) sliding and slumping (1).This is often fast and sudden (1) as withlandslides (1) when the base of the cliff hasbeen eroded, making the cliff unstable (1).With a landslide, the whole column of materialmoves in one go (1), slumping is similar, but thisinvolves a curved movement (1).
  5. 5. Explain how and why cliff collapse occurs in somecoastal locations. (S03) 4 marksLevel 1 1 – 2 marks Basic statementse.g. destructive strong waves erode the land• rain saturates rocks, the rocks are soft.Level 2 3 – 4 marks Clear statements, considers how andwhye.g. at Holderness the cliffs are very soft (w) and easilyeroded by destructive waves (w). The cliffs areundercut and eventually the overhang collapses (h).Heavy rain may also saturate the boulder clay (w)causing slip planes to form along which the cliffcollapses.(mass movement) (h)(4 marks)
  6. 6. 1.Give two differences between destructivewaves and constructive waves. (2 marks)Any 2 valid differences relating to thefrequency, steepness, height,relative importance of swash/backwash.
  7. 7. Mark with an arrow and label three landformsshown on this coast.
  8. 8. Explain the formation of a cliff and wave cut platform (4 m)Explain the formation of a wave cut platform (S06) 6 marks•Waves attack between low water mark and highwater mark;•base of cliff eroded through hydraulic actionand abrasion,•wave cut notch formed•notch gets bigger and the cliff overhangs•as erosion continues, overhang collapses.•The cliff retreats and flat area of rock at baseis exposed, forming the wave cut platform.
  9. 9. Either:Draw and label a diagram to show how a stackmay develop at the end of the headland (S04) 2marksExplain how wave action and other processes willhelp to create the features shown on yourdiagram (S04) 4 marksExplain the formation of a sea stack (S08) 6marks
  10. 10. Draw and label s diagram to show how a stack maydevelop at the end of the headland (S04) 2 marks
  11. 11. Explain how wave action and other processes will help to createthe features shown on your diagram (S04) 4 marksLevel 1 Basic (1-2 marks)• Basic points made, may only consider wave action e.g.wave action will erode the cliff and cause the arch tocollapse.Level 2 Clear (3-4 marks)• Clear and makes reference to wave action and otherprocesses e.g. hydraulic action, the great power ofthe water widens cracks to form caves and leadsto the roof of an arch collapsing. This may be helpedby weathering e.g. freeze-thaw widening cracks.
  12. 12. (i) On the figure below, a sea stack has been labelled.Mark with an arrow and label three other landforms resultingfrom coastal erosion.Three different landforms should be identified – cliff, wave cutplatform, headland, bay, cove, stump (only small feature).
  13. 13. (ii) Explain the formation of a sea stack.There is a line of weakness in a cliff face – e.g. ajoint or a crack which is eroded by the sea toeventually form a cave. Hydraulic action and abrasionare particularly responsible for making the cavebigger. The rock must be relatively hard, made fromlimestone or chalk or otherwise it would simplycollapse forming a slump. If there are two caves oneither side of the headland, continued erosion willresult in a hole being formed, joining the caves toform an arch. As further erosion takes place, theroof of the arch will eventually collapse, as it cannotbe supported. The seaward end of the arch will forma sea stack – an isolated piece or pieces of rock,separate from the headland.
  14. 14. Level 1 (1-2 marks) Basic statements with limited sequencee.g. sea attacks the rock,hollow is formed, gets bigger and rock abovefalls.Level 2 (3-4 marks) Clear, more developed answer with clearer,more completesequence and more appropriate terminologye.g. waves attack a headland and erode a crack in the rock. A cave isformed due to abrasion. This gets bigger and forms an arch whichcollapses leaving a sea stack.Level 3 (5-6 marks) Detailed, well developed answer with clearand complete sequence; appropriate terminology, clearly linkssequence to landforme.g. waves attack a crack in a headland. This is enlarged to forma cave by the pounding of the waves compressing air in therock face and abrasion where material carried by the wateris flung against the cliff. In this way, the cave is made biggerand, if there is one on either side of the headland, an arch willresult when they join. Continued erosion will wear away therock supporting the arch and this will collapse. This will leavean isolated piece or pieces of rock separated from the headland– a sea stack.
  15. 15. Photo of Hurst Castle spit in Hampshire. Describethe spit and explain how it was formed (S09) 6marks
  16. 16. Description should refer to:• It is attached to the land at one end.• It is long and thin• Appears to be composed of sand.• It is wider and hooked at the end.• There is an area of calm water and deposition / smallislands behind it / north of it.Explanation should refer to:• The bend in coastline where spit begins.• Deposition continues to follow the direction of thecoast,• The importance of longshore drift in supplyingmaterial to the spit.• The curve at the end is due to change in winddirection / current.
  17. 17. Level 3 (Detailed) (5-6 marks)Developed answer with clear and complete sequence; appropriateterminology. Clearly links sequence to landform. Description andexplanation are fairly well balanced.The spit begins where the coast changes direction. It is attachedto the land here. Deposition continues along the coast in theoriginal direction of the coast and the long, thin area ofdeposition (the spit) is formed. Longshore drift is responsible forthis. Material is moved along the beach in the direction of theprevailing wind – here they will be south westerly so dominantdirection of movement will be eastwards. The end is wider andis hooked as it moves towards the coast. An area of calm waterand deposition is found behind the spit. It curves due to asecond wind direction affecting the currents across the openwater.
  18. 18. Explain why sea level is expectedto rise (3 marks) S2010• Increase in sea level due to melting of ice sheets (1)+1 for detail on locations of these (1).• Recognition that this will remove water stored ina frozen state (1) on land and enable it to flow to thesea increasing amount of water in the sea (1).May relate to underlying cause – global warming (1)and causes of this, e.g. increase in carbon dioxide (1)and reasons for this (1).• Thermal expansion due to warming sea due to globalwarming
  19. 19. Use a case study to describe economic effects ofcoastal flooding. 4 marks (2010)Economic effects likely to relate to:loss or damage to•areas•businesses•food crops in subsistence economy;•cash crops exports•impact on tourismneed to try to protect and costs incurred in this.
  20. 20. Level 1 (Basic) (1-2 marks)Simple, listed points.Will refer to some effects may be drift into non – economic ones.Crops will be destroyed. People will lose their food supply and land.They will have nowhere to live. Parts of cities will be flooded.Businesses will be lost and people will lose their jobs.Level 2 (Clear) (3-4 marks)Points are developed and linked.Focus on economic effects.Refers to case study.As sea level rises, low lying parts of the UK will be flooded. Parts ofthe fertile Fens will be lost and people will lose their businesses. Cropproduction will fall – cereals and vegetables will be affected. Areasnext to the Thames in London, including the Houses of Parliament willbe flooded. The City will be affected and jobs could be lost. It will costa lot of money to try to protect the coast from rising sea levels – inorder of £10 billion.