classifying coasts

  • Created by: sana.2000
  • Created on: 04-05-19 10:14
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  • classifying coasts
    • role of geology
      • geology
        • resistant coastlines - e.g. Cornwall
          • withstand winter storms without suffering from rapid erosion
            • from the atlantic ocean
          • older rock
            • resistant to erosive power
              • could lead to differential erosion
            • igneous e.g. Granite
            • Older compacted sedimentary rock e.g. Old red sandstone
            • metaphoric rock e.g. Slate and Schists
        • coastal plains
          • younger sedimentary rocks
            • chalks
            • clay
            • sand/sandstone
          • low, flat relief
            • the wash
      • coastal morphology
        • concordant
          • e.g. Isle of Purbeck (Southern Coast) - Lulworth Cove
            • Purbeck Limestone - resistant **** weaknesses joints (Headland)
              • Wealden beds - mainly unconsolidated clay less resitant
                • Chalk - strong and resistant to erosion - formed cliffs and headlands
        • Discordant
          • e.g Isle of Purbeck (Eastern Coast)
            • The Foreland - created Headlands
              • chalk
            • swanage bay - breated bays
              • unconsolidated clay
    • high energy coastlines
      • erosional landforms
        • headlands
        • cliffs
        • shoreline platform
      • high energy environment
        • In UK from Atlantic facing-coasts - powerful waves
          • coast of cornwall
        • high
          • rate of erosion exceeds rate of deposition
          • powerful waves
    • low energy coastlines
      • less powerful waves
      • landforms
        • beaches
        • spits
        • coastal plains
          • low flat relief
    • balance between erosion and deposition
      • dominate process creates landform
        • longshore drift (deposition)
          • angle at which waves apporach the beach
          • tides
            • tidal range - relative difference between high and low tide
          • current
      • erosional landforms
        • cliffs
        • stacks and stumps
        • shoreline platform
        • headland and bays
          • cuspate foreland
      • erosional processes
        • Abrasion/corrasion
          • waves pick up material chip away at the cliff foot
        • Hydraulic action
          • water compresses into cracks
            • forms joints and cracks
        • Corrasion
          • weak acid in water dissolves alkine rock
        • attrition
          • rock particles collide and leads to abrasion
      • depositional landforms
        • cuspate foreland
        • beach
          • swash aligned
          • drift aligned
        • spit
          • recurved spit
          • double spit
        • bars
          • offshore bar
          • barrier beaches
        • Tombolos
        • stabilisng depositonal landforms
          • sandunes
          • salt marshes
      • Marine Transport (Coastal sediment)
        • Traction
          • large and heavy rocks roll along sea bed
        • saltation
          • smaller and lighter rocks 'bounce' along the seabed
        • suspension
          • lighter sediment carried by water
        • solution
          • dissolved sediment
    • sea level change
      • Eustatic Change
        • when the sea level itself rises or falls
          • glacial periods - preciptation falls as snow forms ice sheets that store water - leads to Sea level falls
            • end of glacial period - ice sheets melt
              • stored water falls in rivers and the sea and the sea level rises
        • global
      • Isostatic Change
        • land rises or falls relative to the sea
          • glacial period the weight of the sheets makes theladn sink (isostatic subsidence)
          • As ice begins to melt end of period its weight lets land rise (isostatic recovery)
        • UK- Isostatic recovery - land in north and west in rising during last ice age
          • UK - south and east - Rivers pour water and sediment into the thames estuary. the weight of sediment causes the crust to sink and relative sea levels to rise
        • UK - south and east - Rivers pour water and sediment into the thames estuary. the weight of sediment causes the crust to sink and relative sea levels to rise
      • Past tectonic Activity
        • local titlting of land
        • uplift of mountain ranges and coastal land at destructive and collision plate margins
      • emergent coastline landforms (fall in sea level)
        • raised beach (isostaic recovery)
          • relic cliffs
      • submergement land forms
        • Rias
        • Dalmation coastlines
          • formed by concordant coastlines
        • Fjords

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