Coastal Landorms & Flashcards
What is longshore drift
Waves approach the coast at an angle because of the direction of the prevailing wind. The swash will carry the material towards the beach at an angle. The backwash, then flows back to the sea down the slope of the beach. The process repeats itself along the coast in the zigzag movement.
How are spits formed?
- a spit is an extended stretch of sand or shingle, cutting out into see from the land.
1) sediment is carried by longshore drift
2) when there is a change in shape of the coastline, deposition occurs.
A long thin ridge of material is deposited. This is the spit
3) a hooked end can form, if there is a change in wind direction
4) waves cannot get past a spit therefore, the water behind a spit is very sheltered. Silts are deposited to form salt, marshes or mudflats.
How is a bar formed?
Sometimes a spit can grow across the bay and join two headlands together. They can trap shallow lakes behind the bar. These are known as lagoons. lagoons, do not last forever, and may be filled up with sediment.
