L5 headlands


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L5 headlands

  1. 1. Erosional landforms: Headlands
  2. 2. Coast The maximum distance over which waves can travel is known as the… Fetch One of the erosion processes that involves large waves hurtling beach material at a cliff is called…….. Corrasion The landform created along stretches of less resistant coastlines (i.e. areas made of clay) are known as……. Bays The name given to waves with a weak swash but strong backwash is…… Destructive The process that involves beach material being dropped is more technically known as…. Deposition What is the name given to the predominant force affecting the coastal landscape of the UK……. Prevailing Winds The process that carries material up and down the beach is known as……. Longshore Drift What is the name of the process that carries / returns wave energy back down the beach Backswash The erosion process that breaks up large boulders into small particles by bumping them against each other is known as….. Attrition The areas of land left protruding into the sea as they are more resistant to wave erosion are called….. Headlands The force of waves compressing air into cracks in a cliff is an erosion process called… Hydraulic Action Coastlines can dissolved by salts and acids in seawater. This is also known as…. Corrosion The narrow contact zone between land and sea is more commonly called the… Match the keyword with its meaning
  3. 3. Headland landforms The different properties of rocks means they are more or less resistant to erosion. This means they will change shape in different ways. Watch the animation of headland landforms being created. headland animation
  4. 4. Pop-up headlands Follow the instructions to make a pop-up headland that shows caves, arches, stacks, etc.
  5. 5. http://www.flickr.com/photos/sacherfire/21711 3480/
  6. 6. 1 You need your template. This will represent a chalk headland.
  7. 7. 2 Using a blue crayon -colour the outsidehorizontal strips- theserepresent the sea.
  8. 8. 3 Using a green crayon- colour the middle horizontal strip- this represents the top of the headland- exposed to weathering.
  9. 9. 4 Just above the horizontal blue lines- shade a grey line- make sure it reaches the top of the wave-cut notch. This represents wave action between high and low tide.
  10. 10. 5 Carefully cut out all the black areas on the template- with the exception of the wave- cut notch. Don’t cut off your stump!
  11. 11. 6 It should look like this...
  12. 12. 7 Using a ruler, carefully fold the horizontal lines.
  13. 13. 8 Like this...
  14. 14. 9 Glue along the two blue horizontal strips- on thereverse!
  15. 15. 10 Position the green strip overthe centre fold of your book.Gently glue down the bluehorizontal strip- the one withthe stump.- Practice yourpositioning first.
  16. 16. 11 Carefully practice folding the model... are the folds the right way?
  17. 17. 12 Finally, glue the final blue strip down. Practice the positioning first...
  18. 18. 13 Gently close your book...
  19. 19. 14 Magic...
  20. 20. 1 2 3 4 5 6 Add a label alongside your pop-up showing what they are: fault, wave-cut notch, cave, arch, stack, stump
  21. 21. Complete the sentences Hydraulic action affects headlands by eroding weak ............ in the rocks. Firstly, a .............. ..................... is created. This is eroded more over time to become a ........... Hydraulic action, corrosion, abrasion and attrition work to erode the cave to become an ................. Eventually the arch ............... under its own weight This leaves a ................ standing on its own Over time, weathering and erosion ................. the stack and it collapses to form a small ................. . stump collapses undercut arch stack faults (cracks) wave-cut notch cave
  22. 22. Cliffs and wave-cut platforms Cliffs are steep rock faces along the coastline, they form along coastlines with resistant harder rocks such as chalk Wave-cut platforms are rocky ledges on the beach left behind after a cliff collapses. They become smooth over time with erosion.
  23. 23. CLIFFS AND WAVE-CUT PLATFORMS So how do cliffs and wave-cut platforms form?  The erosion of a cliff is greatest at its base where large waves break - hydraulic action, abrasion and attrition constantly undercut the foot of the cliff  This forms a dent called a wave-cut notch  The cliff face is also affected by abrasion as rock fragments are hurled against the cliff by the breaking waves.  The undercutting continues and eventually the overhanging cliff becomes so heavy it collapses downwards - this process continues over time and the cliff gradually retreats inland and becomes steeper.  As the cliff retreats, a gently-sloping rocky platform is left at the base, this is known as a wave-cut platform which is exposed at low tide.
  24. 24. Using the keywords below and the diagrams from p6 ‘Tomorrow’s Geography’, produce a four picture step- by-step storyboard explaining the processes that produces a wave cut platform. High Tide Low Tide Wave Cut Notch Corrasion Retreat Wave cut platform Cliff Hydraulic Action
  25. 25. Wave cut platforms Copy the exam question into your books, then answer it: “With reference to erosion processes, explain how wave-cut platforms are formed” {4marks}
  26. 26. How does geology influence landforms? The different properties of rocks means they are more or less resistant to erosion. This means they will change shape in different ways. Watch the animation of a headland being formed. animation.html
  27. 27. Jurassic Coast: Swanage Bay  Differing rock hardness is picked out and exaggerated by wave action.  The hard rocks form headlands and the softer rocks form bays.  Currents are weaker in the bays so beach sediments are deposited.
  28. 28. What can you tell from the map? The map above shows the stretch of coastline to the west of Lulworth Cove. The features along this stretch provide excellent examples of landforms forming on destructive coastlines. What features can you identify?
  29. 29. What can you tell from the map? What feature is this? ................... .... What feature is this? ................... ........ What feature is this? ................... ........
  30. 30. YOUR CASE STUDY: Erosion landform Old Harry Rocks The Old Harry Rocks are two chalk stacks located at on the Dorset coast in England About 4 km NE of Swanage The rocks are part of the Jurassic Coast The cliff is chalk, with some bands of flint, which have been gradually eroded over the centuries, Some of the earlier stacks have fallen away (Old Harry's original wife fell in 1896), while new ones have been formed. Old Harry and his Wife
  31. 31. Old Harry Rocks Watch the animation
  32. 32. Old Harry Rocks story cards Read the information cards you have been given Cut them up, and stick them in to your books in an order that tells the story of what created Old Harry and his wife. Order: 1)Introduction to Old Harry Rocks (background info, location) 2)What created Old Harry, step-by-step
  33. 33. The headland is to the north of Swanage Bay. Hydraulic action and abrasion takes place. The area is known as the Isle of Purbeck. It is on the Jurassic Coast. Chalk is a more resistant rock than clay. The wave-cut notch undercuts the cliff above, making it unstable. The stack is still eroded and will eventually collapse and become a stump. A column of rock is left standing on its own. This is a stack. Most of this area is clay. Most wave erosion happens at the base of the cliff. Wave erosion takes place between the high tide mark and low tide mark. The arch eventually collapses under it’s own weight. A wave-cut notch is eroded along the cliff base between high and low tides. Because the headland juts out in to the sea, it takes the full force of wave erosion. When chalk is formed, it contains joints which means it has areas of weakness. Wave erosion picks out the areas of weakness in the chalk cliffs and splits rocks apart in to cracks. Caves develop on both sides of the headland. Old Harry already lost one ‘wife’ in 1896 when she collapsed. Small cracks are formed. Small caves are formed. Wave erosion enlarges the caves. Old Harry Rocks are in Dorset. Several lines of weakness go right through the headland cliff, wave action can erode these. Caves are eroded so far back in to the headland that they meet in the middle and a hole is created that goes through. This creates an arch. Further erosion causes the arch to enlarge and become unstable. The headland is made of chalk. Chalk does not crumble away as easily as clay. This stack is called ‘Old Harry’. Caves, arches and stacks cannot be formed in clay. Old Harry’s wife is a stump. She was created when a stack collapsed a long time ago.
  34. 34. Homework reminder Extended homework sheet This does not mean leave it to the last minute Each week I want an update on what you have found out so far. This should be a detailed project Due: See www.priorygcse.wordpress.com for help
  35. 35. Keyword bingo Match up the keyword with my description 5 in a row You must also be able to explain the keyword in your own words to win