Cliffs

• What is our hard rock cliff example and what rock type is it

  Beachy Head near South Coast

  Chalk cliffs

  
• What are the inputs of sediment and energy for Beachy Head

  Wind and Waves:

  • direction of fetch= southwest and it travels across English Channel and is approximately 150-200km
  • prevailing wind comes from South west

  Tides:

  • The tidal range is between 4-5 m
  • the speed of tidal currents can reach up to 2-3 knots
• What are the controls on the coastline for Beachy Head

  • Well jointed rock (pressure release may have opened up the bedding planes and joints)
  • Material deprived from rock fall will be eroded by attrition and eventually removed by longshore drift
  • 90m high hard, chalk cliffs with vertical upper profile
  • chalk has crumbly appearance as a result of weathering (carbonation and physical weathering e.g freeze thaw)
  • Evidence of huge rock fall- hundreds of thousands of tonnes of chalk vertically joins the cliff to the lighthouse
• What is our soft rock cliff example and what rock type is it

  Holderness Coast

  boulder clay cliffs

  
• What are the inputs of sediment and energy for Holderness coast

  Wind and Waves:

  • fetch can be up to 500-600 km
  • Prevailing wind direction is generally from the north-east across North Sea

  Tides:

  • The tidal range typically ranges between 4-6m
  • tidal currents considered to be moderate to strong reaching speeds of up to 1.5 to 2 m per second
• What are the controls on the coastline for Holderness Coast

  • Boulder clay is weak unconsolidated rock that cannot maintain a steep profile
  • There is a jumble of mud and small rocks= could be evidence of an earthflow or mudflow
  • the beach sediment is rounded in by marine processes of erosion (abrasion & attrition)