Coastal Erosion There are a number of ways in which coasts are eroded:

Authors Avatar

Jeremy Spiteri      -----      How To Combat Erosional and Depositional Coastal Features

Coastal Erosion

        There are a number of ways in which coasts are eroded:

  •  Abrasion  is the wearing away of shoreline by material carried by the waves
  • Hydraulic impact or quarrying  is the force of water and air on rocks
  • Solution  is the wearing away of base-rich rocks, especially limestone, by an acidic water. Organic acids aid the process
  • Attrition  is the rounding and reduction of particles carried by waves

In addition there are many forms of weathering

  • Salt weathering  is the process by which sodium and magnesium compounds expand in joints and cracks thereby weakening rock structures.
  • Freeze-thaw  is the process whereby water freezes, expands and degrades jointed rocks.
  • Water layer weathering  refers to the tidal cycle of wetting and drying
  • Biological weathering  is carried out by mollusks, sponges and urchins, and is very important in low energy coasts.

Rapid erosion occurs on rocks with weakness, which might develop into sea caves. If two sea caves meet, an arch is formed, and so on, until a stack and a stump are produced. These features are largely determined by the location of the weakness in the rock, and variations in the wave energy caused by refraction on the headland. These are relatively small-scale features and, ob a regional scale, headlands and bays relate to differences in geological structure and resistance.

Join now!

The profile of a cliff depends upon a number of factors including:

  • Geological structure
  • Subaerial and marine processes
  • Amount of undercutting
  • Rates of removal
  • Stage of development

Rocks of low resistance are easily eroded and are unable to support an overhang. Jointing may determine the location of weakness in the rock, just as the angle of dip may control the shape of the cliff. Past processes are also important. In areas affected by periglaciation, beveled cliffs are found.

Coastal Deposition

        Deposition occurs when the supply of sediment exceeds ...

This is a preview of the whole essay