Coasts

Types of waves

·       Constructive waves - Transportation and deposition

+  Low energy

o   Strong swash

o   Weak backwash

·       Destructive waves - Erosion

+  High energy

o   Weak swash

o   Strong backwash

Headlands and Bays

·       Headlands - Hard, resistant rock (Chalk)

o   Slow erosion

·       Bays - Soft, less resistant rock (Clay)

o   Rapid erosion

Eg. Dorset coast

Types of Erosion

Hydraulic action -  waves enter cracks creating pressure, causing it to weaken and break open

Abrasion  - pebbles, sand are thrown at cliff, which grinds it down

Corrosion - chemicals from the sea reacts with cliff causing it to dissolve

Attrition - Rocks smash together and thrown at cliff

Erosion of cliffs

o   Hard rock cliffs (chalk)

·       Sea erodes the base of cliff to create a wave-cut notch

·       Eventually there is no support for rock and weathering has weakened it, so it collapses.

·      …