coasts

• What is the littoral zone?

  The wider coastal zone including adjacent land areas and shallow parts of the sea just offshore
• Why are the backshore and foreshore sections the ones that concern us the most? (2)

  - its where the greatest human activity occurs

  - it's where the physical processes of erosion, deposition, transport and mass movement largely operate
• What are the short term factors that varies the littoral zone? (3)

  - individual waves

  - daily tides

  - seasonal storms
• What are the long term factors that varies the littoral zone? (2)

  - changes to sea level

  - climate change
• What are the two formation processes?

  - primary coasts are dominated by land-based processes such as deposition at the coast from rivers or new coastal land formed from lava flows

  
  

  - secondary coasts are dominated by marine erosion or deposition processes
• What are the two coasts that are relative to sea level change?

  - Emergent coasts where the coasts are rising relative to sea level, for example due to tectonic uplift

  
  

  - submergent coasts are being flooded by the sea, either due to rising sea levels or subsiding land
• What are the three coast names with different tidal ranges? (0-2m, 2-4m, >4m)


  - (0-2m) Microtidal coasts

  - (2-4m) Mesotidal coasts

  - (>4m) Macrotidal coast
• What are the features of a Cliffed coast? (3)

  - the transition from and to sea is abrupt

  - at low tide, the foreshore zone is exposed as a rocky platform

  - the cliffs here are vertical, but cliff angles can be much lower
• What are the features of a Sandy coastline? (2)

  - at high tide the sandy beach is filled, but the vegetation dunes are not

  
  

  - dune vegetation plays a crucial role in stabilising the coast and preventing erosion
• What are the features of an estuarine coastline? (3)

  - extensive mud flats, cut by channels, are exposed at low tide but filled at high tide

  
  

  - closer to the backshore the mud flats are vegetated, forming a salt marsh

  
  

  - this type of coastline gradually transitions from land to sea
• What is the definition of coastal recession?

  it is another term for coastal erosion
• What are the three major rock types?

  - igneous

  - sedimentary

  - metamorphic
• What are some examples of igneous rocks? (3)

  - granite

  - basalt

  - dolerite
• What are some examples of metamorphic rock? (3)

  - slate

  - schist

  - marble
• What are some examples of sedimentary rock? (3)

  - sandstone

  - limestone

  - shale
• How fast does igneous erode and why?

  they erode very slowly because they are crystalline, so the interlocking crystals make a strong, resistant rock. They have limited point of weakness, due to not having many joints, making it harder to erode.
• How fast do metamorphic rocks erode and why?

  quite slow, as they are crystalline also. Many metamorphic rocks have their crystals orientated in one direction, which produces weakness.
• How fast does sedimentary erode and why?

  moderate to fast, as most sedimentary rocks are geologically young rocks and tend to be weaker.
• What does impermeable mean?

  doesn't let water through
• What does permeable mean?

  allows water through it
• What does Porous mean?

  can hold water in the spaces within the geology
• What is a fault on a cliff?

  a vertical point of weakness going all the way through the cliff
• What is a bedding plane on a cliff?

  a horizontal point of weakness
• What is a joint on a cliff?

  a vertical point of weakness found between bedding planes
• Why does vegetation stabilise sediment? (3)

  - the roots of plants bind sediment particles together making them harder to erode

  - when submerged, plants growing in sediment provide a protective layer so the surface of the sediment is not directly exposed to moving water and therefore erosion

  - plants protect sediment from wind erosion by reducing wind speed at the surface due to friction with the vegetation
• What are the two types of plants that grow on the coast and where will you find them?

  - halophytes can tolerate salt water, either around their roots or spray from the sea

  
  

  - xerophytes can tolerate very dry conditions, like on sand dunes where the soil retains very little water
• what does plant succession mean?

  it refers to the changing structure of a plant community over time as an area of initially bare sediment is colonised by plants
• What is a sand dune ecosystem called?

  Psammosere
• What is a salt marsh ecosystem called?

  Halosere
• How are waves formed?

  They are formed by friction between wind and water, with some energy from the wind being transferred into the water. The force of the wind blowing on the surface of the water generated ripples, which grow into waves if the wind is sustained.
• What does wave size depend on? (4)

  - Strength of wind

  - Duration for which the wind blows

  - Water depth

  - Wave fetch
• Describe what happens to a wave as it hits the shoreline

  As a wave approaches the shore, the wave length decreases and the wave height increases. They then break in shallow water because the crest of the wave moves forward faster than the wave trough due to friction with the sea bed. Eventually the wave crest outruns the trough and the wave topples forward and breaks
• What is the difference in summer and winter with the waves?

  In summer they are constructive and sediment is dragged onshore, whereas in winter they are destructive and sediment is dragged offshore
• What is beach morphology?

  The shape of a beach, including its width and slope (the beach profile) and features such as berms, ridges and runnels. It also includes the type of sediment (shingle, sand, mud) found at different locations on the beach.
• How does human interference change beach profiles over time? (3)

  - sediment supply from rivers is reduced, mainly due to the construction of dams on rivers that traps sediment upstream

  
  

  - often a result of coastal management in one place means it has an effect on processes further along the coast

  
  

  - if global warming affects an areas weather patterns, a storm can bring more destructive waves and the winter version of beach profiles would be more common
• What is hydraulic action/ wave quarrying?

  It's when air is trapped in cracks and fissures and gets compressed by the force of waves crashing against the cliff face. This forces the cracks to open wider.
• How does hydraulic action influence lithology? (2)

  - sedimentary rocks with many fissures become very vulnerable

  - very hard igneous rocks may attack its cracks and erode it
• What is the process of abrasion (corrasion)?

  Sediment is picked up by breaking waves and thrown at the cliff face. This chisels away at the surface and gradually wears it down.
• How does abrasion (corrosion) influence lithology? (2)

  - loose sediment is used, like shingle or pebbles

  - softer sedimentary rocks are more vulnerable than hard igneous ones
• What is the process of attrition?

  It acts on already eroded sediment. As sediment moves around in water, they collide with each other mean they are chipped down so the sediment gets smaller and more round over time.