Coastal Processes

• Mechanical weathering


  natural weather events cause rocks to break down
• Freeze Thaw (Mechanical Weathering)


  water in cracks freezes, causing rock to expand and exerts pressure
• Pressure Release (Mechanical Weathering)


  top rocks are eroded causing bottom rocks to expand and fracture
• Thermal Expansion (Mechanical Weathering)


  heat causes rock to expand and contracts when cooled. Frequent changes causes cracks
• Salt Crystalisation (Mechanical Weathering)


  Salt solution seeps into rock which forms crystals causing rock to disintergrate
• Chemical weathering


  rock breaks down due to chemical reactions
• what are 3 examples of chemical weathering?


  oxydisation

  solution

  carbonation
• Biological weathering


  rock erodes due to plants and animals
• How do tree root break down rock? (Biological Weathering)


  tree roots grow into cracks in the rock and exerts pressure
• How do organic acids break down rock? (Biological Weathering)


  Plant and animal litter cause soil to become acidic which reacts with the minerals in the rock
• Mass Movement


  forces act on materials on a slope causing them to fall
• Rock Fall (Mass Movement)


  weathering causes cliff rocks to detatch amd fall to the foot of the cliff
• Rock Slides (Mass Movement)


  undercutting by waves remove support
• Erosion (Marine Processes)


  breaking waves are able to erode at a coastline
• Abrasion (Marine Erosion)


  waves throw rocks at cliffs
• Attrition (Marine Erosion)


  rocks collide when being transported
• Hydraulic action (Marine Erosion)


  air trapped in rocks and expands
• Pounding (Marine Erosion)


  breaking waves exert pressure on rocks
• Solution (Marine Erosion)


  water disolves minerials in the rocks
• Transport (Marine Processes)


  waves move sediment
• Solution (Marine Transport)


  sediment disolves
• Suspention (Marine Transport)


  small sediment carried by current
• Saltation (Marine Transport)


  heavy sediment gets carried and then dropped... repeats
• Traction (Marine Transport)


  large sediment rolls along the seafloor
• Marine deposition when?


  ... loss of energy

  ... no moving water at the top of the swash

  ... low energy environments
• Erosion (Fluvial Processes)


  similar to waves but includes weathering and mass movement
• Transport (Fluvial Processes)


  Same as waves
• Deposition (Fluvial Processes)


  as river enters the sea it loses volacity and energy. Also, when clay particles meet sea water flocculation occurs, causing it to sink.
• Erosion (Aeolian Processes)


  sand gets picked up by wind and moved away. Dry sand is easier to erode than wet.
• Transport (Aeolian Processes)


  wind carries sand by saltation or traction
• Deposition (Aeolian Processes)


  when wind speed falls due to surface friction and deposits sediment. This occurs inland due to vegetation.