Coastal erosion and landforms thus formed

  • The sea performs the function of erosion and deposition through sea waves, aided by currents, tides and storms in coastal areas.
  • The erosive work of the sea depends upon
      • size and strength of waves
      • seaward slope
      • height of the shore between low and high tides
      • composition of rocks
      • depth of water
  • The wave exerts a pressure to the magnitude of 3000 to 30,000 kilograms per square kilometre.
  • This wave pressure compresses the air trapped inside rock fissures, joints, faults, etc. forcing it to expand and rupture the rocks along weak points.
  • This is how rocks get worn down under wave action.
  • Waves also use rock debris as instruments of erosion. These rock fragments carried by waves themselves get worn down by striking against the coast or against one another.
  • The solvent or chemical action of waves is another mode of erosion, but it is pronounced only in case of soluble rocks like limestone and chalk.

The marine landforms can be studied under erosional and depositional categories.