Coastal Landscapes and Processes

• Salt crystals grow inside cracks, causing them to expand and break apart
• what is chemical weathering?

  It's the breakdown of rock by changing its chemical composition.
• How does carbonation weathering work?

  1. Rainwater had carbon dioxide dissolved in it, which makes it a weak carbonic acid. 2.
• Abrasion


  Pebbles grinding along a rock platform, much like sandpaper. Over time the rock becomes smooth.
• Attrition


  Rocks that the sea is carrying knock against each other. They break apart to become smaller and more rounded.
• Solution


  Sea water dissolves certain types of rocks. In the UK, chalk and limestone cliffs are prone to this type of erosion.
• Hydraulic action


  The sheer power of the waves as they smash against the cliff. Air becomes trapped in the cracks in the rock and causes the rock to break apart.
• Solution


  Minerals in rocks like chalk and limestone are dissolved in seawater and then carried in solution. The load is not visible.
• Suspension


  Small particles such as silts and clays are suspended in the flow of the water.
• Saltation


  Small pieces of shingle or large sand grains are bounced along the sea bed.
• Traction


  Pebbles and larger material are rolled along the sea bed.
• Lowland areas in the UK

  • Made from sedimentary rocks
• Upland areas in the UK

  • Made from metamorphics and igneous rocks
• UK upland landscape around 300 million years ago

  1. Tectonic plates caused magma under intense pressure to rise through the Earth's crust

  2. Some magma reached the surface level

  3. Some magma cooled and solidified underground
• UK's downlands


  • Formed of harder sedimentary rocks which are less resistant to erosion
• UK downlands


  • North and South Downs in south east England
  • Hills formed of chalk with even softer clay in the valleys between
• Glacial Processes


  1. Glaciers eroded u-shaped valleys (glacial abrasion) during the last ice age

  2. The Lake District is littered with ground moraine (material that was carried in the base of the glacier and then deposited)
• High Precipitation


  Lots of streams draining water from the land
• The Weald is drier

  Less streams
• Post Glacial River Processes


  1. Misfit rivers (too small) flow at the bottom of u shaped valleys

  2. Dry valleys formed in the last Ice age

  3. During the Ice age, the chalk froze and became impermeable, therefore water formed streams on the surface

  4. When the climate warmed, water could soak into the chalk again and most valleys were left dry
• Slope Processes


  1. Rock falls are quite common, happening when pieces of a rock from a weathered cliff fall

  2. Slumping has occurred at the coast, often after long periods of rainfall

  3. At the junction where the permeable rock meets an impermeable rock such as clay the saturated soil and weaker rock slumps and slides down the cliff
• Clay vales


  • Frequently found at the foot of chalk escarpments
• Escarpment


  A long cliff formed by the erosion of folded rocks
• Scarp slope


  The steeper side of an escarpment
• Dip slope


  The gently sloping side of an escarpment
• Coastal processes


  1. Over time headlands are eroded to form caves, arches, stacks and stumps

  2. Sand and pebbles are deposited in bays

  3. This is because the waves retract around the headland
• Hard engineering examples 


  Groynes, Seawalls, Rip Raps
• Soft Engineering examples 


  Beach nourishment, Managed Retreat
• Sea Walls and How they work

  concrete walls about 3-5 metres high built at the foot of cliffs. They reflect waves from being less destructive 
• Sea Walls costs and disadvantages

  Can be obtrusive and unnatural to look at and can restrict access to the beach. They are also very expensive to build and maintain. They can increase erosion at the beach 
• Sea Walls Benefits and advantages

  They are effective at stopping the sea, They often include a promenade or a walkway
• Groynes and How they work

  Groynes trap sand and stop longshoredrift
• Groynes coast and disadvantages

  Interrupting the movement of sediment and can have an impact further along the coast. Rock Groynes can be unsightly
• Groynes benefits and advantages

  They are quick to contract. They stop sediment and broaden the beach. A bigger beach can attract more tourist
• Rip Rap and how it works 


  absorbs wave energy do waves are weaker when they hit the cliff
• Rip raps Costs and disadvantages:

  The boulders are usually from other regions from abroad transportation. The cost can be high. They do not fit in with the local geology. They can impede access the the beach
• Rip rap Benefits and advantages:

  The boulders face the waves to break dissipating their energy and protecting the cliffs. They can quickly be put in place. Relatively easy and cheap
• Beach nourishment and how it works

  Makes the beach bigger so more wave energy is absorbed before waves hit the beach
• Beach nourishment costs and disadvantages

  Areas of the beach have to be fenced of prohibiting access. It takes time for the dune and vegetation to become established
• Beach nourishment and advantages

  Helps the dunes to develop and maintaining a natural coastal environment. Popular with people and wildlife. Relatively cheap.