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Distinctive Landscapes (Case study: The Jurassic Coast (Landforms…

- - - - mechanical
      - chemical
      - Biological
    - - sliding
      - Slumping
    - - abrasion
      - hydraulic action
      - Attrition
      - solution
    - - traction
      - saltation
      - suspension
      - solution
  - - - Coastline faces the wave attack with discordant beds of sediment
      - Wave attack causes hydraulic action and attrition which causes the cliff to retreat
      - Less resistant rocks are eroded at a faster rate to create bays,
        More resistant rocks stick out to sea as headlands
      - During calm periods the sheltered bays allow deposition of beaches
    - - Hydraulic action affects headlands by eroding weak faults in the rocks
      - a wave-cut notch is created
      - This is eroded to become a cave
      - The cave is eroded by hydraulic action, corrosion, abrasion and attrition to become an arch
      - Eventually the arch collapses under its own weight, leaving a stack standing on its own
      - Weathering and erosion undercut the stack and it collapses to form a small stump
    - - Spit
        
        A long narrow piece of land
        
        One end joined to the mainland, projects out into the sea or across an estuary
        
        Made of sand and/or shingle
      - Tombolo
        
        A spit that joins an island to a mainland
      - Bar
        
        a spit develops across a bar where there is no strong flow of water from the landward side
        
        Sediment reaches across to the other side
- - - - Found in North and West
      - Harder rocks which resist erosion, eg. slate, granite, limestone
      - Many are glaciated
      - Steep gradient
      - Cooler and wetter climate
      - Harsh climate, thin soils => Rough vegetation, forestry
      - Land uses: sheep farming, quarrying, tourism
    - - Found in South and East
      - Softer rocks, eg. chalk, clay, sandstone
      - Flatter, gently rolling hills
      - Warmer and drier climate
      - Fertile soils=> grassy meadows, deciduous forests
      - Land uses: quarrying, tourism, dairy and arable farming
      - Contains most urban areas and industries
- - - - gap eroded in Portland limestone
      - Soft clay behind is easily eroded
      - Chalk cliffs prone to slides and slumps
    - - Formed on Portland limestone headland
      - waves opened up a crack –> cave –> arch
      - Arch is being gradually broken down by mechanical, chemical and biological weathering
    - - tombolo joining Isle of Portland to the mainland
      - change in direction of headland
        => longshore drift deposits material as a spit
        => spit joins up with an island creating a tombolo
    - - Erosion of softer clay in between hard chalk and limestone
      - Material carried from south to north and vegetation at north stabilises the cliffs
      - Can still be prone to slumps
    - - Chalk in between two areas of soft rock
      - Arch collapsed to form a stack – Old Harry
        And a stump – his wife
      - Combination of hydraulic action, abrasion, salt weathering, carbonation weathering and biological weathering
  - - - winter temp: 3°c
        => limited freeze-thaw weathering
        => salt weathering dominates
    - - prevailing wind from SW, long fetch bring storms
        => hydraulic action and abrasion undercutting cliffs, promoting mass movement
    - - heavier rocks
      - promotes mass movement
      - eg. Jan 2016 Storm Frank => cliffs collapsed