Sand
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Sand

Dune Formation. How are they formed?. Working in small groups, try to work out how the sand dunes shown in the picture developed?. TV Clip: BBC Learning Zone. Sand dune formation and movement - the Dune of .

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Sand




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Presentation on theme: "Sand"— Presentation transcript:

Slide1

Sand

Dune Formation

Slide2

How are they formed?

Working in small groups, try to work out how the sand dunes shown in the picture developed?

Slide3

TV Clip: BBC Learning Zone

Sand dune formation and movement - the Dune of

Pilat

Duration

: 05:29

The Dune of

Pilat

in France is the highest sand dune in Europe. The loose sand constantly moves and the dune migrates away from the sea until it meets a pine forest inland

.

Slide4

The Dune of Pilat: 500m wide, 3km long, 140m high.

Sand supplied from the Atlantic

The forest acts as a barrier

The initial / fore dunes are moving constantly away from the sea

Slide5

A sand dune needs the following three things to form:

1. A large amount of loose sand in an area with little vegetation2. A wind or breeze to move the grains of sand3. An obstacle that causes the sand to lose momentum and settle. This obstacle could be as small as a rock or as big as a tree.Where these three variables merge, a sand dune forms.

Activity: Draw a diagram to explain how a sand dune forms

Slide6

Beach at Low Tide

Sand

accumulates on the beach from

longshore

drift.

At

low tide, the sand dries out allowing the prevailing winds to move the loose sand up the beach.

If there is

a large tidal

range, then there is more time for the sand to dry out.

Slide7

Embryo Dune

Sand

needs an

obstruction

to accumulate around.

Seaweed

, dead seabirds, driftwood and other detritus may all serve this purpose.

Slide8

Fore Dune

The first plants to colonise the

foredunes

are

Apodasmia

similis

.

.

Slide9

Yellow Dunes

The yellow dunes begin to show a greater diversity of plants as conditions become more favourable. As plants die and decay, a humus layer builds up and this traps both water and nutrients.

Slide10

Mature Dunes

The most mature dunes are found several hundred metres from the shore. Left undisturbed these dunes develop a soil which can support shrubs and trees.

Slide11

Management

The dunes may eventually need to be protected by the local authority.

This

often means fencing off at least part of the dune

system.

This allows damaged dunes to recover and/or ecologically important sections to be protected.

Public

access to beaches may be via fenced-off pathways. Along the footpaths, information boards can be used to educate the public about why the dune system is important and how they can avoid damaging it.

Slide12

Slide13

Sand Dunes around the world

Saraha, Africa

Slide14

Slide15

New Zealand