Formation of Coastal Landforms

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The formation of coastal landforms is a captivating spectacle of nature’s creative forces. These dynamic landscapes, where the land meets the sea, are shaped by a delicate dance between erosion and deposition, geological processes and oceanic currents. From the dramatic cliffs of rugged coastlines to the serene beauty of sandy shores, coastal landforms tell stories of Earth’s ever-changing surface. Understanding this intricate process is not just a matter of geological curiosity; it’s about unraveling the forces that have shaped our coastlines for millennia and continue to do so today. As we embark on this exploration, we’ll journey through the transformative power of waves, tides, and geological processes, gaining insights into the mesmerizing formation of coastal landforms and their vital role in our planet’s geology, ecology, and human societies.

The waves are one of the most powerful forces involved in the change of coastal areas. These waves are brought about by winds blowing over the surface of the water. Waves are produced by the friction created by the wind. This friction produces a swell in the water. The wind energy makes the particles of water to rotate inside that swell and this takes the wave forward.

Water particles only move forward in small circles as waves pass. When waves hit the coasts it releases the energy on shorelines. The movement of the surface water very rarely affects the still deep bottom water of the oceans. As a wave come near the beach, it slows down. This is due to the friction between the moving water and the sea floor. The wave breaks when the depth of water is even less than half of the wavelength of the wave.

The size and energy of a wave are affected by :

  1. The period for which wind blowing over the sea surface.
  2. The power of the wind
  3. Fetch – the distance travelled by a wave.

When the wave hits the beach, it is called swash and when the same wave returns into the sea, it is called backwash.

There are two types of waves that affect the coastal regions and bring about change.

1. Constructive waves

Features of constructive waves

  • Swash is stronger than backwash.
  • It is flat and low in height
  • Long wavelength
  • The strong swash takes the sediments to the beach and form berm.
  • These are formed in calm water and are less strong than destructive waves.
  • These waves bring sediment with them and deposit on the beach and further build them.

2. Destructive Waves

  • The backwash is stronger than the swash.
  • Storms help in the formation of destructive waves.
  • The strong winds blowing over a long period support destructive waves.
  • A long fetch and high wave energy is one of the main features of destructive waves.
  • They induce the erosional process along the coast.
  • The waves are high and steep and have a shorter wavelength.
Wave types play a major role in the formation of coastal landforms

The destructive and constructive waves give rise to two kinds of processes in the coastal areas:

  1. Coastal Erosion
  2. Coastal Deposition

Coastal Erosion

The wearing down and breaking of rocks and other material along the coastline is called coastal erosion. This erosion is the result of destructive waves that wear down the coastline in a number of ways :

  1. Hydraulic action – Air trapped in the cracks and joints of the cliff face get compressed when a wave hits the cliff which causes erosion.
  2. Abrasion – Waves bring bits of rock and sand with them which grind the surface of the cliff and cause erosion.
  3. Attrition – The rocks and pebbles on the shore grind against each other when waves hit them resulting in the breakdown of these rocks and pebbles.
  4. Solution – Some rocks like chalk or limestone are easily dissolved by acids contained in the seawater.

Transport

Waves hit the shore at some angle and go back at 90 degrees.

There is a variety of material which is transported from one place to another through waves. This movement is called transportation. This material is generally:

  • Eroded from the cliff.
  • Transported by longshore drift.
  • Brought by constructive waves.
  • Carried to the coastline by rivers.

The continuous backwash and swash transport the sediments and other material sideways along the coast. This type of movement of material is called longshore drift. It happens in a zigzag manner.

Coastal Transportation

Waves and tides transport sediments in four ways. Further, these contribute to the movement of sediment by longshore drift.

Coastal Deposition

Sediments settle down when the sea loses its energy. This is called deposition. Stronger swash and a weak backwash with constructive waves contribute to coastal deposition.

Deposition occurs when:

  • Waves enter an area of lesser depth.
  • Waves hit a sheltered area like a bay.
  • A weak wind
  • The amount of material to be transported is in good quantity.

Frequently Asked Questions

What geological processes contribute to the formation of coastal landforms like beaches, spits, and barrier islands?

Coastal landforms result from erosion, deposition, and sediment transport by waves, tides, and currents.

Explain the formation of coastal caves, arches, and stacks through coastal erosion and weathering processes.

Coastal caves form when waves erode weaknesses in rock, arches result from further erosion, and stacks are remnants of collapsed arches.

Describe the development of coastal deltas and estuaries and their ecological significance in supporting diverse ecosystems.

Coastal deltas form at river mouths, providing fertile soil and habitats for various species. Estuaries are vital transition zones between freshwater and marine environments.

How do coastal landforms like lagoons and fjords form, and what makes them unique in terms of their physical and ecological characteristics?

Lagoons form behind barrier islands, while fjords result from glacial erosion. They both offer distinct ecosystems and recreational opportunities.

Discuss the impact of sea level rise and climate change on coastal landforms and the challenges faced by coastal communities.

Rising sea levels can lead to erosion, increased storm surges, and coastal flooding, posing threats to infrastructure and ecosystems.

Cite/Link to This Article

  • "Formation of Coastal Landforms". Geography Revision. Accessed on March 29, 2024. https://geography-revision.co.uk/gcse/agriculture/formation-of-coastal-landforms/.

  • "Formation of Coastal Landforms". Geography Revision, https://geography-revision.co.uk/gcse/agriculture/formation-of-coastal-landforms/. Accessed 29 March, 2024.

  • Formation of Coastal Landforms. Geography Revision. Retrieved from https://geography-revision.co.uk/gcse/agriculture/formation-of-coastal-landforms/.