Coastal Landforms
Beaches
Sand dunes
Spits
They are found on coats between the high and low water marks
They are formed by constructive waves depositing material
Sand and shingle beaches in different ways
Shingle beaches are created by high energy waves and are steep and narrow - sand particles are washed away but larger shingle is left behind. The shingle particles build up to create a steep slope
Sand beaches are created by low energy waves and are flat and wide- sand particles are small so the weak backwash can move them back down the beach, creating a long gentle slope
Bars
Longshore drift transports sand and shingle past the bend and deposits it in the sea
Strong winds and waves can curve the end of the spit (forming a recurved end).
Spits form at sharp bends in the coastline e.g at the river mouth
The area behind the spit is sheltered from waves, so material accumulates and plants are able to grow
A bar forms when a spit joins two headlands together
The bay between the headlands gets cut off from the sea
Offshore bars can for if the coast has a gentle slope - friction with the sea bed cause waves to slow down and deposit sediment offshore , creating a bar that is not connected to the coast
This means a lagoon can form behind the bar
Sand dunes are formed when sand is deposited by longshore drift is moved up by the beach by the wind
Obstacles cause wind speed to decrease so sand is depositied, forming small embryo dunes
Dune slacks (small pools) can form in hollows between dunes
Embryo dunes are colonised by plants e.g. Marram grass. The roots of the vegetation stabilise the sand, encouraging more sand to accumulate there. This forms foredunes and eventually mature dunes, New embryo dunes form in front of stabilised dunes