Coasts
Definitions:
Wave types Wavelength – distance between 2 crests
Wave height – distanced from trough to crest
Factors that affect the energy of a wave: Wave frequency – how many waves pass a fixed point
- Strength of the wind Crests – top of the wave
- How long the wind has been blowing Trough – low point between 2 crests
- Distance of ocean which the wind blows over Fetch – the distance of ocean which the wind blows over
Swash – up the beach
Backwash – down the beach
Constructive wave Destructive wave
Tides are the rise and fall of sea levels
They are caused by gravitational forces exerted on the Earth by the moon and the sun
The wind turns tides into waves – energy exerted on ocean from gravitational pull
Processes of erosion
,Coastal transportation
Weathering
Mechanical weathering:
Freeze thaw weathering
Onion skin weathering
Chemical weathering:
Carbonation – weak acids attack rocks
Hydration – water swells and expands the rock
Coastal processes
Rotational cliff slumping
,Caves arches and stacks
The formation of bays and headlands
Concordant coastline – where there is one type of rock along a
coastline, with few bays and headlands
Discordant coastline – where there are multiple types of rock along a
coastline, there are bays and headlands
Swanage bay was formed due to the erosion of soft clay occurring at a
faster rate than the chalk or limestone. As a result, this also forms
headlands at the sides of the bay at Ballard Point and Durlston Head.
Erosion of cliffs
Dunraven bay, Wales - wave cut platform
Coastal deposition
landforms
Deposition takes place in low energy environments where the flow of water slows down and sediment can’t be
carried anymore so is deposited
sandy beaches – gentle sloping profiles, sheltered bays
low energy deposits sand and sediment
pebble beaches – steeper profiles, where cliff have been eroded
high energy washes away finer sand leaving behind larger pebbles
, Formation of a spit
Spurn Head
Sand dunes
1. The sea brings sediment to the beach and then the wind redistributes that sediment. When the wind
encounters obstacles, this creates low energy so it is deposited
2. This builds up sand at the front of the dune system forming embryo dunes
3. Over time, tough plants known as pioneers such as marram grass take root on the dune. Their root
systems help to stabilise the sand and fix it in place
4. As the plants die off, they add nutrients and humus to the sand dune, improving the soil so more complex
plants can move in, such as brambles
5. Eventually the climatic climax vegetation is reached – oak, deciduous forest
As you go further inland from the coast, the vegetation becomes stronger and covers larger areas. This is because
of the organisms making the soil more fertile over time. In addition, the build up of the smaller plants make the
sand and soil sturdier to allow bigger plants to grow.
Formation of a bar
Slapton sands
Definitions:
Wave types Wavelength – distance between 2 crests
Wave height – distanced from trough to crest
Factors that affect the energy of a wave: Wave frequency – how many waves pass a fixed point
- Strength of the wind Crests – top of the wave
- How long the wind has been blowing Trough – low point between 2 crests
- Distance of ocean which the wind blows over Fetch – the distance of ocean which the wind blows over
Swash – up the beach
Backwash – down the beach
Constructive wave Destructive wave
Tides are the rise and fall of sea levels
They are caused by gravitational forces exerted on the Earth by the moon and the sun
The wind turns tides into waves – energy exerted on ocean from gravitational pull
Processes of erosion
,Coastal transportation
Weathering
Mechanical weathering:
Freeze thaw weathering
Onion skin weathering
Chemical weathering:
Carbonation – weak acids attack rocks
Hydration – water swells and expands the rock
Coastal processes
Rotational cliff slumping
,Caves arches and stacks
The formation of bays and headlands
Concordant coastline – where there is one type of rock along a
coastline, with few bays and headlands
Discordant coastline – where there are multiple types of rock along a
coastline, there are bays and headlands
Swanage bay was formed due to the erosion of soft clay occurring at a
faster rate than the chalk or limestone. As a result, this also forms
headlands at the sides of the bay at Ballard Point and Durlston Head.
Erosion of cliffs
Dunraven bay, Wales - wave cut platform
Coastal deposition
landforms
Deposition takes place in low energy environments where the flow of water slows down and sediment can’t be
carried anymore so is deposited
sandy beaches – gentle sloping profiles, sheltered bays
low energy deposits sand and sediment
pebble beaches – steeper profiles, where cliff have been eroded
high energy washes away finer sand leaving behind larger pebbles
, Formation of a spit
Spurn Head
Sand dunes
1. The sea brings sediment to the beach and then the wind redistributes that sediment. When the wind
encounters obstacles, this creates low energy so it is deposited
2. This builds up sand at the front of the dune system forming embryo dunes
3. Over time, tough plants known as pioneers such as marram grass take root on the dune. Their root
systems help to stabilise the sand and fix it in place
4. As the plants die off, they add nutrients and humus to the sand dune, improving the soil so more complex
plants can move in, such as brambles
5. Eventually the climatic climax vegetation is reached – oak, deciduous forest
As you go further inland from the coast, the vegetation becomes stronger and covers larger areas. This is because
of the organisms making the soil more fertile over time. In addition, the build up of the smaller plants make the
sand and soil sturdier to allow bigger plants to grow.
Formation of a bar
Slapton sands
