Spits, Bars & Sand Dunes

Geography: AQA GCSE, topic 3.2.11

Bars, Spits and Sand Dunes

In addition to beaches, the deposition of sediment can create bars, spits, and sand dunes.

Spits are piles of sand that create sheltered zones on the coast.
When the coast changes direction at an estuary (where a river meets the sea), longshore drift continues to move sediment across the inlet.
The river doesn't let the longshore drift completely join to the coast on the other side because the river has the energy to move the sediment.
Spits are the long fingers of sand sticking out from one side on a coastline. They often have marshland forming in the sheltered zone.

A bar is created when a spit grows across a bay.
Lagoons (saltwater pool separated from the ocean) are often created behind a bar.

Sand dunes are hills of sand created at the back of a beach.
The wind blows deposited sand up the beach. Objects like wood, driftwood or human rubbish can block the wind, leading to hills of sand.
The hills of sand can allow plants and vegetation to grow.
This leads to more sand building up.
Older sand dunes (hills) are called mature dunes.
Newer sand dunes are called embryo dunes.