Coast GW1(Coastal processes+Coastal landforms)

Coastal processes
1. Coastal Erosion
  1. Hydraulic action
    1. Waves traps air in the rock joints and is compressed by oncoming waves,exerting presssure on joints,cause joints to weaken & rocks shatter
  2. Abrasion/Corrasion
    1. Sediments are carried by waves and are hurled against the coast.Loosened sediments knock and scrape against coastal cliffs.Weakens surface and breaks down the coast.Powerful enough to undercut a cliff.
  3. Attrition
    1. Rocks break down into smaller pieces & become smoother and more rounded over time.
  4. Solution/Corrosion
    1. Sea water react chemically with water-soluble minerals in coastal rocks.For exp,limestone are easily eroded by carbonic acid.Weakens rocks and rocks will eventually disintegrate.
2. Sediment Transport
  1. Longshore drift
    1. Beach drift
      1. Resultant Zig-Zag movement of the sediments
    2. Longshore current
      1. Currents that flow parallel to the coast
3. Sediment deposition
  1. Low wave energy like constructive waves allows the deposition of sediments.It vary in type and size,resulting a variety of beaches
Coastal landforms
1. Depositional coast
  1. Beaches
    1. Form from loose sand,gravel,pebbles,broken shells etc.
    2. Fine sand = gentler gradient;Coarse sand = steeper gradient
    3. Constructive waves
  2. Spits&tombolos
    1. Longshore Drift > direction of coastline changes abruptly > LSD continue to transport sediments from original direction > Sediments accumulated appear above water surface > spit > continue to extend from mainland to another island > Tombolo
2. Erosional coast
  1. Cliff & shore platform
    1. Cracks/Joints > Notch > Cave > Roof of cave collapse > steep cliff > Abrasion/Hydraulic action attack base > Overhanging cliff > Overhanging cliff collapse > Cliff retreat inland > Gentle sloping sloping shore platform formed
  2. Headland & bay
    1. Less resistant rock
      1. Bays
    2. More resistant rocks
      1. Headlands
  3. Caves,arches & stacks
    1. Joints and faults > Hydraulic action > Cave > Join caves to form arch > roof of arch collapse > Stack

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Coast GW1(Coastal processes+Coastal landforms)

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	Criado por Hui Yuan mais de 9 anos atrás