Coastal depositional features Flashcards
What is coastal deposition?
When the sea drops or lays down material, including sand, sediment and shingle, on the beach
What is a beach?
The accumulation of sediments (sand, gravel, shingle) on the shore along the coast
What is a spit?
A long, narrow accumulation of sand with one end attached to the mainand and the other projecting at a narrow angle into the sea or partly across a river estuary
How are beaches formed?
Sand and shingle are transported along the coast by longshore drift until they reach an area where the water is sheltered and the waves lack energy, such as a bay. The material is temporarily deposited to form a beach
How are spits formed?
- Longshore drift of sand occurs along the coast until the coastline changes direction at a river mouth
- Material is deposited in a long strip out to sea, forming a spit
- It builds up across the river mouth, or bay
Why might a spit have a hooked lateral?
If the wind direction changes, the wave direction changes. This causes the end of the spit to curve and form a hooked end called a lateral
Why is there a salt marsh behind the spit?
The area behind the spit is sheltered from wind and the waves lack energy. Deposition occurs and a salt marsh is formed.
What is a bar?
Forms when a spit grows across a bay and joins two headlands ,leaving a lagoon behind it
How are bars formed?
- Longshore drift of material occurs along the coast until the coastline changes direction across a bay.
- Material is deposited across the bay
- This blocks of the sea behind it and forms a lagoon
What is a tombolo?
A long stretch of sand joining an island to the mainland. Forms when a spit joins an island to the mainland
How is a tombolo formed?
- Longshore drift of material occurs along a coast until the coastline changes direction.
- Material is deposited in a long strip out to sea, forming a spit.
- The spit grows out of the mainland and joins an island to form a tombolo.
