Geography
Coasts
Coastal Erosion
[Date]
Today I will:
- Know the key terms
- Know how a bay and wave cut platform is formed
Geography
Coasts
Processes of Erosion at the Coastline
1. Hydraulic Action: Waves crash against a cliff and drive water under great
pressure into cracks in the rock. This pressure squeezes the air and as the wave
falls back the air expands explosively, loosening pieces of rock.
2. Corrasion: Corrasion (or abrasion) occurs when stones and pebbles are
picked up by waves and thrown against the cliff, causing erosion.
3. Solution: Salty sea water chemically dissolves rocks. This is most noticeable
on chalk and limestone cliffs.
4. Attrition: Rock fragments (stones and pebbles) hit against each other and so
are reduced in size.
Geography
Coasts
The force of the swash and backwash
determines whether the waves are
constructive waves or destructive waves.
Swash:
The water which
rushes up the
beach is called
swash.
Backwash: As the wave
loses its momentum,
energy is transferred
back to the sea – this
return flow is called
backwash.
Geography
Coasts
If the swash is weaker than the backwash (destructive wave), very little
material is carried up the beach. With a strong backwash, material will
be removed and the beach will decrease in size.
Geography
Coasts
Wave-cut platform
Cliff
Geography
Coasts
Geography
Coasts
Geography
Coasts
Bay
Headland
Geography
Coasts
Geography
Coasts
Geography
Coasts
Geography
Coasts