Section C: physical landscapes in the UK

• How are waterfalls created? (Erosional)

  -soft rock is eroded quicker than hard rock, which creates a step

  -Erosion continues, and the hard rock is undercut, forming an overhang

  -Abrasion and hydraulic action erode to create a plunge pool

  -overtime, this gets bigger, increasing the size of the overhang until the rock is no longer supported and collapses
• How are interlocking spurs formed? (Erosional)


  -more vertical erosion than lateral erosion

  -this means the river cuts down into the valley

  -areas of hard rock which are harder to a road mean the river will bend around them to go to the path with the least resistance

  -This creates interlocking spurs of land
• How are gorges created (Erosional )


  -soft rock is eroded quicker than hard rock, which creates a step-Erosion continues, and the hard rock is undercut, forming an overhang-Abrasion and hydraulic action erode to create a plunge pool-overtime, this gets bigger, increasing the size of the overhang until the rock is no longer supported and collapses-as this continues the waterfall retreats upstream-a steep sided valley is left where the waterfall once was called a gorge
• How are flood planes formed? (Erosion + deposition)

  -erosion removes any interlocking spurs, creating a wide flat area on either side of the river

  -During a flood material being carried by the river is deposited as the river loses its speed and energy to transport material

  -overtime, the height of the floodplain increases as material is deposited on either side of the river
• How are levees formed? (Depositional)

  -Sediment that has been eroded upstream is transported downstream

  -When the river floods, the sediment spreads out across the floodplain

  -As the river loses energy, the largest material is deposited on the sides of the river bank and smaller material further away

  -After many floods, the sediment builds up to increase the height of the riverbanks, meaning that the channel can carry more water and flooding is less likely to occur in the future
• How are meanders formed?

  -As the river goes around a bend, most of the water is pushed towards the outside, causing increase speed and erosion

  -Lateral erosion on the outside bend causes undercutting of the bank to form a river cliff

  -on the inner bend is slower, causing the water to slow down and deposit, the eroded materials, creating a gentle slope

  -the buildup of material is a slip of slope
• How are oxbow lakes formed?

  -erosion on outside of a bend and deposition on inside, change the shape of a meander

  -Erosion narrows the neck of land within the meander and as the process continues, demanders, move closer together

  -When there is very high discharge after a flood, the river cuts across the neck, taking a straighter and shorter route

  -deposition will occur to cut off the original, leaving a horseshoe shaped oxbow lake
• How are headlands and bays formed (erosional)

  -Bands of soft rock, such as clay and sand are weaker, therefore can be eroded quickly forming a bay (usually within a beach)

  
  

  -Hard rock, such as chalk is more resistant to the process of erosion. When a soft rock is eroded inward, the hard rock sticks out into the sea, forming a headland.
• How are cliffs formed?

  they are shaped through a combination of erosion and weathering
• How are wave platforms formed?


  -see attack base of cliff between high and low watermark

  -Wave cut notch is formed by erosional processes, such as abrasion and hydraulic action, leaving a dent in the cliff at levels of high tide

  -As the notch increases size, the cliff becomes unstable and collapses, leading to the retreat of the cliff face

  -Backwash carries away, the eroded material, leaving a wave cut platform
• How are caves, arches ,stacks and slumps formed

  -cracks are widened in the headland through the erosional processes of hydraulic action and abrasion

  -As the waves continue to grind away at the crack, it begins to open up and form a cave

  -The cave becomes larger and cannot support itself, so breaks through the headland to form an arch

  -Base of the arch becomes wider through erosion until the roof becomes too heavy and collapses, leaving a stack

  -The stack is undercut at the base until it collapses to form a stump
• How are beaches formed?

  -material is transported by longshore drift

  -material is deposited by the sea when waves have limited energy

  -This means beaches often form in sheltered areas like bays
• How are spits formed?

  -sediment is carried by longshore drift

  -When there is a change in shape of coastline deposition occurs

  -along send rid of material is deposited which is the spit
• How are bars formed?

  A bar is formed when a spit joins two headlands together. The bar cuts off the bay between the headlands from the sea. This means a lagoon can form behind the bar.
• What is a wave?

  Ripples in the sea, caused by the transfer of energy from the wind blowing over the surface of the sea
• What is the fetch of a wave?

  The distance a wave has travelled
• What factors affect the size of a wave?

  Strength of winds

  Fetch of a wave

  Wind durations

  How long, they cross, large expanses of water
• Main features of a wave:

  
• Characteristics of a constructive wave

  Wave frequency: low, 8 to 10 waves per minute

  Wave height: under 1 m

  Wave lengths: long wavelength

  Type of wave (plunging or spilling): spilling

  Strength of swash: strong

  Strength if backwash: weak

  Beach sediment - gain or loss: sediment buildup on beach
• Characteristics of destructive waves:

  Wave frequency: high, 13 to 15 waves per minute

  Wave height: large, one to 5 m

  Wave lengths: short wavelength

  Type of wave (plunging or spilling): plunging

  Strength of swash:weak

  Strength if backwash: strong

  Beach sediment - gain or loss: removes sediment from beach
• What is weathering?


  Break up and breakdown of rock by the action of rainwater, extreme temperatures and biological activity
• What is mechanical weathering?

  Break up of rock without changing its chemical composition.

  
  

  Freeze thaw weathering is the primary type of mechanical weathering that affect coasts.
• Freeze thaw weathering


  Done, when rocks are porous or permeable and water enters the rock and freezes the ice expands by around 9%, causing pressure in the rock until it cracks repeating this can cause the rock to break up
• Chemical weathering by carbonation

  Because one slightly acidic (carbonic) rain or seawater, comes in contact with sedimentary rock, such as limestone or chalk, causing it to dissolve a chemical reaction occurs between the acidic water and calcium carbonate forming calcium bicarbonate, which is soluble and is carried away in solution. Carbonation happens in warm, wet condition.
• What is mass movement?

  Downhill movement of cliff material under the influence of gravity
• Types of mass movement

  rockfall, landslide,mudslide , slumping
• What is longshore drift?


  Movement of material along the shore by wave action. It happens when waves approach the beach at an angle with swash, carrying material up and along the beach and backwash, carrying material back down to the beach at right angles.
• What is the direction of prevailing wind in the UK?

  south west
• When does coastal deposition occur?

  When waves don't have enough energy to transport sediment

  Swash is stronger than the backwash

  Waves into shallow water

  Little wind

  Good supply of materials
• Discordant coastlines


  Coast with many types of rock with perpendicular, layers of geology, more likely to form headlands and bays
• Concordant coastlines


  Coast with only one rock type, more likely to form straight coasts
• How do headlands and bays form?

  Form along coast, which have alternating band of more resistant rock and less resistant rocks

  Where the rock is more resistant it will be eroded less, leaving a headland that sticks out to sea

  The less resistant rock is eroded more quickly by abrasion (where pebbles and rocks are hurled at the cliff by destructive waves, weakening the rock) and hydraulic action (where waves compressed air into cracks in the rock and blast it apart)

  This leads to the formation of a sheltered bay and sediment from the eroding headland, helps to form a beach. The headland protects the beach from the full force of the waves and attrition breaks down the boulders into pebbles and eventually sand to form the beach.

  The headland is now exposed to the full force of the wave and its vulnerable to erosion
• Cliff erosion and wave cut platforms:

  
• Caves, arches, stacks and stumps:

  
• How is a beach formed?

  Deposition is the main process that creates a beach This occurs where waves have less than on exposed headlands limited energy and so beaches often form in sheltered areas such as bays where wave energy Here waves are likely to be constructive where the swash is dominant and a backwash weaker so that material is left on the beach rather than being taken away by the waves pebbles to fine sands Over the time this beach material will accumulate in the sheltered bay and may be composed of different sediments from Beaches are under constant change from processes like longshore drift Beaches can also grow over time when constructive waves dominate or even shrink in size during winter periods in the UK when we are more likely to get storms and destructive waves
• What is a sand dune?


  Small ridges or hills of sand found at the top of the beach
• What happens at the embryo dune?

  Closest to the sea, where the soil is a yellow colour and very alkaline. there aren't many plants here as the soil is very salty.

  
  

  Saltation move sand around and deposit it.

  
  

  Prickly saltwater is a pioneer species are found there which is adapted to live due to waxy leaves and deep roots. It acts as a shield causing more sand to be deposited and grows the sand dunes

  
  

  Is a mobile dune
• What happens at the Foredune?

  Sand accumulated

  Sand Couch grass and lime grass found there

  Is a mobile dune
• What happens at the yellow dune?

  Yellow sand due to the clearest sand found there

  30 to 40 years old

  Maram grass, traps, sand and stabilisers to dune

  Is a mobile dune
• What happens at the fixed dune?

  Grey sand

  Not as salty so vegetation changes

  Mosses and Lycomes help give it a grey colour

  Sea buckthorn, and Dewberry found as there is more organic matter (humus) in soil