Coastal Procesess

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  • Created by: tolulaz
  • Created on: 06-12-15 16:09

Coastal Weathering and Erosion

Coastal Weathering

Salt weathering - water evaporates leaving salt crystals, which can expand and fracture rock

Biological weathering - burrowing animals and roots from trees/plants can break up 

Coastal Erosion

Hydraulic action - waves trap air in cracks in the rock. Pressure of water and compressed air causes rock to crack

Abrasion - particles in waves crash againt cliffs and break bits off

Attrition - particles in waves crash against each other

Solution - seawater slowly dissolves cliffs

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Coastal Transportation

The process of transportation along coastal areas is called longshore driftLongshore drift is the process of waves transporting material along a coastline. Longshore drift only occurs when waves hit the beach at an angle due to prevailing wind direction. 

The swash of the waves carries material up the beach at an angle. The backwash then flows back to the sea in a straight line at 90°. This movement of material is called transportation.

(http://upload.wikimedia.org/wikipedia/commons/thumb/f/fb/Longshore_drift.svg/800px-Longshore_drift.svg.png)

Waves and tidal currents can also carry material through solution (dissolved minerals), suspension (small particles carried in water), saltation (load bounced along sea bed) and traction (load rolled along sea bed)

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Coastal Deposition

When the sea loses energy, it drops the sand, rock particles and pebbles it has been carrying. This is called deposition. Deposition happens when the swash is stronger than the backwash and is associated with constructive waves.

It is likely to occur when:

  • waves enter an area of shallow water
  • waves enter a sheltered area, eg a cove or bay
  • there is little wind
  • there is a good supply of material
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