Marine processes

• What is coastal erosion a manifestation of?

  Energy from the sun converted by wind
• What are the main erosion processes in coastal environments?

  1. Hydraulic action
  2. Corrosion
  3. Abrasion/corrasion
  4. Attrition
• What is hydraulic action in coastal erosion?

  Sheer force of water crashing against coastline
• What is cavitation in the context of coastal erosion?

  Compression of air in sea-facing joints
• What does corrosion involve in coastal processes?

  Waves carrying pebbles with force
• How does abrasion occur in coastal environments?

  Pebbles grind along a rock platform
• What is attrition in coastal erosion?

  Rocks carried by sea knock against each other
• How do wave characteristics affect coastal erosion?

  • Steep destructive waves have more erosive power
  • Waves breaking at cliff bases cause maximum erosion
  • Offshore breaking waves lose energy and cause less erosion
• What is Old Harry in Dorset?

  A headland formed by wave erosion
• How do spring tides affect coastal erosion?

  They expand the zone of wave attack
• What is the effect of neap tides on coastal erosion?

  They create a smaller zone of wave attack
• What role do currents play in coastal processes?

  • Longshore and rip currents move large quantities of material
  • They can influence erosion and deposition patterns
• How do onshore winds affect coastal environments?

  They erode fine beach sand to form dunes
• What is the relationship between fetch and wave energy?

  Longer fetch increases wave energy potential
• How high can some sand dunes in the Gobi Desert reach?

  More than 400 metres
• What is the role of sediment supply in coastal erosion?

  • Continual sediment supply is necessary for erosion
  • Oversupply can protect the coast from erosion
• How does platform width affect erosion?

  Larger platforms expose more area to erosion
• What are the effects of larger platforms on wave energy?

  • Wider platforms dissipate wave energy better
  • They provide more space for energy to dissipate
• How does rock resistance influence coastal erosion?

  Hard rocks erode slowly, forming stable cliffs
• What type of rock is granite?

  Hard rock highly resistant to erosion
• What happens to soft rocks like sandstone in coastal environments?

  They erode easily and form unstable cliffs
• What is Lowmoor Point?

  A headland with softer rock like shale
• How does rock structure affect coastal erosion?

  • Well-jointed rocks are susceptible to erosion
  • Horizontal structures produce steep cliffs
  • Rocks dipping away from the sea create gentle cliffs
• What type of rock is chalk?

  Soft, white, porous sedimentary rock
• How does offshore topography affect wave characteristics?

  Steep seabeds create high, steep waves
• How does the orientation of a coast affect erosion?

  • Head-on coasts face more erosion
  • Parallel coasts allow for dune formation
  • Sheltered beaches are protected from harsh waves
• What effect does the direction of fetch have on wave strength?

  Longer fetches generate stronger waves
• How does fetch influence where waves contact the coastline?

  It affects the force and impact of waves