Coasts

• What are concordant coastlines characterized by?

  Rock layers parallel to the coast
• How do concordant coastlines protect less resistant rock?

  By having a harder outer layer
• What shape is created when waves break through on concordant coastlines?

  Crescent shaped
• What defines discordant coastlines?

  Alternating rock types at right angles
• What landforms are created by discordant coastlines?

  Headlands and bays
• What type of waves have a strong swash?

  Constructive waves
• When do constructive waves typically occur?

  In calm weather and summer months
• What is the effect of destructive waves on sediment?

  They erode sediment from the beach
• When do destructive waves typically occur?

  In poor weather and winter months
• What are sub-aerial processes?

  Actions occurring above sea level
• What is erosion in the context of coastlines?

  Wearing away of rock along the coastline
• What are the four types of erosion on coastlines?

  Hydraulic action, abrasion, attrition, solution
• What landforms are created by coastal erosion?

  Headlands, bays, caves, arches, stacks, stumps
• What is transportation in coastal processes?

  Movement of material along the shore
• What is deposition in coastal processes?

  The putting down of material
• What is longshore drift?

  Movement of beach sediment at an angle
• How does backwash affect sediment movement in longshore drift?

  It pushes sediment down at a right angle
• What can happen to a beach due to longshore drift?

  It can move in the direction of the current
• What can longshore drift lead to?

  Formation of estuaries, lagoons, or islands
• What type of waves impact Christchurch Bay?

  Waves from the Atlantic
• Why are the waves at Christchurch Bay powerful?

  They have a long fetch
• What materials make up the cliffs at Christchurch Bay?

  Sandstone and clays
• Why are the cliffs at Christchurch Bay easily eroded?

  They are made of permeable rock
• What happens to water in the cliffs at Christchurch Bay?

  It infiltrates easily and saturates the cliffs
• What are coastal gorges known as?

  Chines
• What has decades of erosion caused at Christchurch Bay?

  Cliff edge to retreat by tens of metres
• What is the risk to buildings near the cliffs at Christchurch Bay?

  They may be very close to the cliff edge
• What has happened to coastal defences in some areas of Christchurch Bay?

  They have failed
• What issue has poor planning around Barnston on sea created?

  Terminal groyne syndrome
• What is terminal groyne syndrome?

  Groyne traps sediment on one side
• What happens to the other side of the beach in terminal groyne syndrome?

  It is starved of sediment