coastal landforms

• spit


  1) swash moves up the beach at an angle of the prevailing wind (LSD)

  
  

  2) backwash moves down the beach at 90° to coastline due to gravity (LSD)

  
  

  3) zigzag movement (LSD) transports sediment along the beach

  
  

  4) deposition causes the beach to extend, until reaching a river estuary

  
  

  5) change in prevailing wind direction forms a hook

  
  

  6) sheltered area behind spit encourages deposition, therefore a salt marsh forms

  
• headlands and bays


  1) the coast would be made up of alternating bands of rock

  
  

  2) when the waves approach, the soft rock is eroded more quickly so it will retreat and for a bay

  
  

  3) hard rock is much more resistant to erosion so it will stick out forming a headland

  
  

  erosion usually consists of abrasion and hydraulic action

  
• cliffs and wave-cut platforms

  1) the sea attacks the base of the cliff

  
  

  2) a wave-cut notch is formed by erosion (HA + ABRASION) - this is a dent in the cliff usually at the level of high tide

  
  

  3) as the notch increases in size, the cliff collapses due to instability, and retreats

  
  

  4) backwash carries away eroded material leaving a wave-cut platform

  
  

  5) process repeats over time, cliff continues to retreat

  
• caves → arches → stacks → stumps


  prior - cracks formed due to HA

  
  

  1) CRACKS are widened in the headland through erosion (HA + ABRASION)

  
  

  2) as erosion continues from the waves, the CRACK is opened up to form a CAVE

  
  

  3) CAVE becomes larger and eventually breaks through the other side of the headland to form an ARCH

  
  

  4) base of ARCH becomes wider over time through further erosion, until gap is so big, roof collapses into the sea leaving a STACK

  
  

  5) STACK is undercut at the base until it collapses leaving a STUMP

  
• bar + lagoons


  same formation as spit but is across a bay

  
  

  - sediment is continually deposited along the coastline

  
  

  - the sediment eventually joins up with the other side of the bay

  
  

  - joins up the two headlands together

  
  

  a LAGOON is left behind which is a shallow lake behind the bar