coastal processes and landscapes

• two main coastal landscapes

  rocky coasts, coastal plain
• characteristics of rocky coastal landscapes

  -result from resistant geology

  -often in a high energy environment where erosion > deposition

  -occupy about 1000km of uk coast, mostly N and W

  -cliffs which vary in height, low or high relief
• characteristics of coastal plain landscapes

  -relatively flat

  -low relief areas where deposition > erosion

  -areas adjacent to the sea

  -often contain freshwater wetlands + marshes due to poor drainage of the flat landscape

  -its littoral zone is composed of sand dunes, beaches, mudflats and salt marshes

  -may be estuarine or sandy

  -most of uks S and E coastline
• how are rocky coastal landscapes formed

  formed in areas of resistant geology which erode and weather slowly

  due to the high energy environment, there is constant erosion which removes/transports eroded and deposited sediment

  cliff is slowly eroding
• how are coastal plains formed

  form in low energy environments

  have a net accumulation of sediment

  sediment from offshore sources are transported by waves/tides/currents to the coastline

  or

  sediment from terrestrial sources are transported by rivers/glaciers/wind/mass movement

  
  

  usually form by coastal accretion, this is often accelerated as plants grow in shallow water which traps sediment and forms organic deposits when they die

  
  

  coastal plains can also form when change in sea levels, usually a fall, exposes a flat continental shelf
• what is coastal accretion

  The deposition of sediment at the coast and the seaward growth of the coastline, creating new land.
• what is high/low relief

  high relief are tall cliffs, eg 318m Hangmans cliff in north devon

  
  

  low relief are short cliffs, eg 3m cliffs at chapel port in cornwall
• What is dynamic equilibrium?

  where erosion = deposition
• define weathering


  breakdown of rock in situ
• define erosion


  breakdown of rock and immediate transport by eroding agent
• marine processes that can affect the coast

  wave erosion: hydraulic action, abrasion, attrition, saltation
• terrestrial processes that can affect the coast

  weathering, mass movement, wind + river erosion
• what is the sub-aerial process

  combination of weathering and mass movement
• define mass movement


  downslope movement of material due to gravity
• what is a clastic rock

  rocks made of fragments cemented together (sedimentary rocks eg sandstone and clay)
• define unconsolidated


  sedimentary rocks with very weak cementation eg gravels and sands
• define consolidated


  rocks with mineral particles of different sizes cemented together with heat and pressure eg igneous rocks