Coasts

• How can the coast be classified in terms of systems?

  As an open system
• What types of systems can coasts transfer outputs to?

  Terrestrial, atmospheric, or oceanic systems
• In what context should the coast be considered a closed system?

  During scientific research and coastline management
• What are sediment cells?

  Sections of coast considered closed systems
• How many sediment cells are there in England and Wales?

  Eleven sediment cells
• What are the components of sediment cells?

  • Sources: Where sediment originates (e.g., cliffs)
  • Through flows: Movement of sediment via longshore drift
  • Sinks: Locations where sediment is deposited (e.g., beaches)
• What does dynamic equilibrium in a sediment cell mean?

  Input and output of sediment are balanced
• What is a negative feedback loop in the coastal system?

  It lessens changes, restoring equilibrium
• What is a positive feedback loop in the coastal system?

  It exaggerates changes, making the system unstable
• How can physical and human actions affect sediment cells?

  They can change the dynamic equilibrium
• How does a storm create a negative feedback loop?

  Storm waves erode the beach, then deposit sediment
• What happens to a beach after a storm in terms of sediment?

  Excess sediment is deposited as an offshore bar
• What is the littoral zone?

  The area of the coast affected by wave action
• What factors affect the littoral zone?

  • Short-term: Tides and storm surges
  • Long-term: Sea level changes and climate change
• What are the subzones within the littoral zone?

  • Backshore: Above high tide level
  • Foreshore: Where most wave processes occur
  • Offshore: The open sea
• What does Valentine's Classification describe?

  The range of coastlines that can occur
• What causes an advancing coastline?

  Land emerging or deposition being prominent
• What is erosion in the coastal context?

  The removal of sediment from a coastline
• What causes a retreating coastline?

  Land submerging or erosion being prominent
• What are the main processes of coastal erosion?

  • Corrasion
  • Abrasion
  • Attrition
  • Hydraulic Action
  • Corrosion (Solution)
  • Wave Quarrying
• What is corrasion?

  Sand and pebbles erode cliffs at high tide
• What is abrasion?

  Movement of sediment wears down the shoreline
• What is attrition?

  Rocks and pebbles wear down by colliding
• What is hydraulic action?

  Waves force air into rock cracks, causing erosion
• What is wave quarrying?

  Breaking waves exert pressure to erode cliffs
• What is corrosion in coastal erosion?

  Acidic seawater erodes alkaline rocks like limestone
• What conditions lead to the highest erosion rates?

  High waves, perpendicular approach, and high tide
• How does rock resistance affect vulnerability to erosion?

  Clastic rocks are more vulnerable than crystalline rocks
• What factors influence a rock's vulnerability to erosion?

  • Type of rock: clastic vs. crystalline
  • Amount of cracks and fractures
  • Lithology of the rock
• What are the types of rocks and their erosion rates?

  • Igneous: Very slow (<0.1 cm/year)
  • Metamorphic: Slow (0.1-0.3 cm/year)
  • Sedimentary: Very fast (0.5-10 cm/year)
• What erosional landforms are created by coastal processes?

  • Caves, Arches, Stacks, Stumps
  • Wave-cut notch and platform
  • Retreating Cliffs
  • Blowholes
• How do caves, arches, stacks, and stumps form?

  Through marine erosion on pinnacle headlands
• What creates a wave-cut notch and platform?

  Marine erosion at the base of a cliff
• What is longshore drift (LSD)?

  • Sediment transported along the coast
  • Waves hit the beach at an angle
  • Sediment moves up in swash and down in backwash
• What is a blowhole?

  A channel for waves to travel into a cliff
• What causes retreating cliffs?

  Repeat wave-cut notches and platforms
• What determines the angle of wave approach in longshore drift?

  The direction of the prevailing wind
• What are the processes of sediment transportation?

  • Traction: Large sediment rolls along seabed
  • Saltation: Smaller sediment bounces along seabed
  • Suspension: Small sediment carried in water
  • Solution: Dissolved material carried in water
• What is the impact of wave angle on sediment transportation?

  Swash-aligned limits drift; drift-aligned enhances it
• When does deposition occur?

  When a wave loses energy and sediment is heavy