Paper 2: Coastal Landscapes Flashcards
Name the three types of weathering
Biological
Chemical
Mechanical
biological weathering
Living things break down rock
Plant roots can biologically weather a rock by pushing cracks apart
Mechanical weathering
Chemical composition of rocks stays the same
Freeze thaw weathering - water expands when it freezes - when it fills the cracks, it expands, putting pressure on rock and freezing + thawing will wear down the rock
Chemical weathering
The chemical composition of rocks changes
When the climate is warm and wet, carbonic dioxide can dissolve in rain to create a ‘carbonic acid’.
The carbonic acid in rainfall hits rocks and dissolves the parts of the rock made of calcium carbonate.
This also breaks down rock
What is mass movement?
Mass movement describes the movement of rocks on a hill or cliff. These movements are caused by weathering, erosion, and gravity. Small changes over time can mean that a cliff’s centre of gravity hangs over the sea, instead of over land
What are slides?
Slides are when material moves down a slope in a straight line.
What are rock falls?
Rockfalls are when the cliff (materials) break and crumble down the cliff.
What are slumps?
Slumps are when a slip plane forms under the cliff. The cliff then slumps down in layers.
What are the two main types of wave?
Constructive and destructive
What are constructive waves?
Constructive waves deposit material on coastlines because their swash depositing things on the beach is stronger than their backwash dragging things from the beach
Constructive waves are small waves that are not very tall above the surface of the ocean
What are destructive waves?
Destructive waves are taller and more frequent than constructive waves
Destructive waves cause most of the erosion of coastlines.
Destructive waves have a stronger backwash than swash, meaning they drag more material away from the coastline than is deposited on the shore
What is deposition?
Deposition describes the sea putting (depositing) solid material from the sea onto the land on the coastline.
Constructive waves deposit material on coastlines because their swash depositing things on the beach is stronger than their backwash dragging things from the beach
How do destructive waves erode the coast?
Hydraulic power: The force of wave actually breaks the rock itself.
Abrasion: The material and rock being carried by the sea damages the coastal rock.
Attrition: The bedload collides with itself, eroding it
Features of UK climate that impact rates of coastal erosion and retreat
Rainfall
Prevailing wind
Storm frequency
Seasonality
What are the terms given to cracks and weaknesses in rocks?
Joints and faults
Name the two types of coastline
Concordant
Discordant
What type of area are headlands and bays formed in?
Areas that have alternate areas of hard and soft rock facing the sea
What type of rock has lots of cracks and joints?
Soft rock
Why does clay erode quicker than chalk?
Clay is a softer rock
Concordant coastlines
Concordant coastlines have a layer of soft rock, then a layer of harder rock, then a layer of soft rock next to each other.
Discordant coastlines
Discordant coastlines have alternating chunks of hard rock and soft rock at 90 degrees to the coast. The sea’s waves will hit both hard rock and soft rock when they meet the coast.
How does seasonality impact climate on coastal erosion and retreat?
Temperature changes and the range of temperatures that rock is exposed to can affect erosion and weathering.
E.g freeze thaw weathering
How does rainfall impact climate on coastal erosion and retreat?
At times of heavy rainfall, soil can become saturated, and mass movements may be more likely.
After heavy storms, chemical weathering may be more likely to happen.
Heavy rainfall is often accompanied by storms and destructive waves.
How does prevailing winds impact climate on coastal erosion and retreat?
The prevailing winds affect where sediment is carried.
Strong prevailing winds can lead to lots of destructive waves.
Winds from the Atlantic Ocean hit the south-west of England.
How does storm frequency impact climate on coastal erosion and retreat?
Many parts of the UK are frequently hit by storms.
If storms happened more often, then erosion and weathering would happen more quickly.
At what kind of coastline do bays form?
Discordant coastline
Over time, cliffs are eroded by destructive waves resulting in what?
Wave - cut platforms
What is left behind after cliffs retreat due to erosion?
Wave - cut platform
What is needed for headlands and bays to form?
Bands of hard and soft rock
What type of rock are headlands made of?
Resistant rock
As headlands are eroded what types of landforms can be created?
Caves
Arches
Stacks
How are caves formed?
There are cracks, joints, and weaknesses in rocks.
When cracks get wider (because of hydraulic action, abrasion or attrition), they can become large enough to create a cave.
How are arches formed?
Caves can be eroded from one side of the rock through the other.
This creates an arch.
You can see right through an arch to the other side of the rock.
Durdle Door (Dorset), Bow Fiddle Rock (Scotland), and the Green Bridge of Wales (Pembrokeshire) are the 3 most famous arches in the UK.
How are stacks formed?
When the top of an arch collapses because of gravity, a column called a stack is left behind.
What type of waves is responsible for most of the erosion that takes place at the base of cliffs?
Destructive waves