Introduction to Coasts - GCSE Geography

Key Terms

• Constructive and Destructive Waves
• Fetch, Swash, and Backwash
• Longshore Drift
• Concordant and Discordant Coastlines
• Bay, Cove, Beaches, Deposition, Cliffs, and Erosion

Waves and Their Influence

• Waves significantly shape the UK's coastline.
• Formation: Waves are caused by wind blowing over the surface of the sea.
• Factors Affecting Wave Strength:
  • Duration the wind has been blowing.
  • Strength of the wind.
  • The distance the wave has traveled, known as fetch.

Types of Waves

Destructive Waves

• Characteristics:
  • Usually form in stormy conditions.
  • Larger, more powerful, with lots of energy.
  • Created by strong winds blowing over a long fetch.
  • Erode the coastline with a stronger backwash than swash.
  • High and steep shape, short in length.

Constructive Waves

• Characteristics:
  • Form in milder weather conditions.
  • Break on the shore and deposit materials.
  • Have a strong swash that carries materials up the beach and a weaker backwash.
  • Longer in length but shorter in height, almost flat.

Longshore Drift

• Process where sediment moves along the coast.
• Swash and Backwash:
  • Swash comes up the beach at an angle, backwash goes straight back out.
  • Direction of prevailing wind influences the swash direction.
• Diagram Tips: Use solid arrows for swash and dotted arrows for backwash.

Coastal Features

Concordant Coastlines

• Formation:
  • Layers of different rock types run parallel to the coast.
  • Hard rock protects softer rock behind it.
• Coves:
  • Form when hard rock is breached, allowing erosion of softer rock.
  • Example: Lulworth Cove in Dorset.

Discordant Coastlines

• Formation:
  • Bands of rock types are perpendicular to the coast.
  • Headlands (hard rock) and bays (soft rock) form.
• Process:
  • Softer rock erodes faster, forming bays.
  • Harder rock erodes slower, forming headlands.
  • Headlands then become more vulnerable to erosion.

Cliffs and Beaches

Cliffs

• Formation:
  • Formed through erosion and weathering.
  • Soft rock creates gentle slopes, harder rock creates steep cliffs.

Beaches

• Types: Sand, pebble, shingle, and mud beaches.
• Formation:
  • Made from eroded materials transported and deposited by the sea.
  • Constructive Waves:
    • Build up the beach profile.
  • Profile:
    • Sandy beaches have a gentle slope, pebble and shingle beaches are steeper.
  • Sediment size varies - larger sediments at the top, smaller at the bottom.
  • Transported by longshore drift and deposited by constructive waves.