beaches and sand dunes

Question 1

what is deposition?

Answer 1

when material being transported by the sea is dropped due to a loss in energy.

Question 2

why does deposition occur?

Answer 2

•its linked with constructive waves, when the swash is greater than the backwash
•deposition occurs when the sea transporting sediment loses energy and slows down

Question 3

what is a beach?

Answer 3

the area of deposited material bwtween the low water line to the limit of storm waves.

Question 4

what are 2 types of beaches?

Answer 4

•sandy beaches
•shingle beaches

Question 5

how are sandy beaches usually formed?

Answer 5

•a sandy beach is usually formed in a sheltered bay
•low energy, constructive waves transport material to the shore
•as the swash is stronger than the backwash, material is moved onto the shore
•they have a gentle profile

Question 6

how are shingle beaches formed?

Answer 6

•usually formed on more exposed beaches that tend to be steep and often pebbly
•higher energy waves remove the sand leaving the larger shingle behind

Question 7

what are sand dunes?

Answer 7

small ridges or hills of sand found at the top of a beach (away from the waves).

Question 8

what conditions for sand dunes need to form?

Answer 8

•large supply of sand
•large, flat beach
•an onshore wind
•an obstacle for the dune to form against e.g. seaweed

Question 9

how are sand dunes formed?

Answer 9

1.wind transports sand across a beach through saltation (the bouncing of particles along the beach by wind).
2. deposition occurs around obstacles such as rocks or seaweed.
3. overtime the sand builds up creating small embryo dunes.
4. these dunes are stabilised by vegetation such as marram grass, the long roots bind the sand together.
5. then they develop into foredunes and yellow dunes. overtime, the rotting vegetation adds organic matter to the sand and so more vegetation is able to grow, smaller dunes form in front.