Coastal Dunes

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Slide 1

Coastal Environments

Sand Dune Systems

Slide 2

Coastal Dunes

Lindsey Wood, liw2, 022423830

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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.

Slide 3

Sand Movement

Lindsey Wood, liw2, 022423830

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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

Slide 4

Formation

Lindsey Wood, liw2, 022423830

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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

Slide 5

Classification

Lindsey Wood, liw2, 022423830

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Slide 6

Further Classification

Lindsey Wood, liw2, 022423830

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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

http://www.bbc.co.uk/wales/mid/fun/wallpaper/pages/ynyslas_sand_dunes.shtml

Ynyslas Dunes

dunes