Coastal Environments

1
Coastal Environments

• Sand Dune Systems

2
Coastal Dunes

• Temperate latitudes. Accumulation of windblown
  sediment needed in backshore zone.

• UK - around 7-8 of coast has vegetated dunes.
  

• Needs vegetation, low rainfall, strong winds and
  abundant sand.

3
Sand Movement

• Saltation
• sand blown downwind. Transfers energy through
  other grains.
• 75 of sand moved by this method.
• Surface Creep
• By product of saltation.
• Pushed along sand surface
• Must be dry

4
Formation

• Embryo dunes
• obstacle forces deposition of sand

Embryo
Fore
Grey

• Foredunes
• embryo dunes coalesce laterally

• Grey dunes
• includes 1st, 2nd, 3rd dune ridges etc. Growth
  of foredunes

5
Classification
6
Further Classification

• Bay Dunes eg. Studland
• Spit Dunes eg. Ynyslas, see right
• Hindshore Dunes eg. Merthyr Mawr
• Ness or Forland Dunes eg. Tentsmuir

• Offshore Island Dunes eg. Scott Head

Ynyslas Dunes
dunes
http//www.bbc.co.uk/wales/mid/fun/wallpaper/pages
/ynyslas_sand_dunes.shtml
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