Flashcards in Coastal Landscapes Deck (92):
What does weathering do?
Helps wear away the rocks but leaves weathered material in the situ
How many types of weathering is the and what are they?
3 and chemical, biological and mechanical
What is chemical weathering?
Rocks reacting with slightly acidic water e.g limestone reacting with carbonation
What is biological weathering?
This is the action of plants and animals causing the rock to split apart e.g tree roots widen in the cracks in rocks
What is mechanical weathering?
Water falls into the cracks in rocks and freezes, causing it to expand; over time the reappeared thawing and freezing causes the rock to break apart
What is mass movement on the coast?
Mass movement is the downhill movement of martial under the influence of gravity
What do types of mass movement vary according to?
Materials involved,ma mount of water in material and type of movement e.g sliding, slumping
What are the 4 different ways waves can erode the coast?
Abrasion, hydraulic action, attrition, solution
What is abrasion?
Breaking waves throw sand, pebbles and boulders against the coast during storms
What is hydraulic action?
The sheer weight and impact of water against the coastline, particularly during a storm, erodes the coast. Also waves compress air in joints in rocks forcing them apart
What is attrition?
Rocks and pebbles carried by waves rub together and break into smaller pieces
What is solution?
The chemical action of seawater dissolves some rocks
What do loose wet rocks do?
Slump Nader the gravity along the curved split planes
When does slumping happen?
It happens when the rock is saturated. Loose wet rocks slump down under the pull of gravity along curved slip planes
When does slumping often occur?
On clay coasts
What do waves transport?
They transport eroded material along the coast and deposit when they lose the energy to carry it further
What is left long shore Drift?
This is the process by which beach sediment can be transported along the coast by waves
How does longshore drift occur?
The direction of the prevailing wind will dictate the angle and direction in which beach sediment will move
The action of the wave swash forces the sediment up the beach at a 45 degree angle
The action of the backwash will bring the sediment back down the beach at a 90 degree angle
As waves hit the beach this zigzag process continues
What are the 4 different ways waves transport material?
Traction, saltation, suspension and solution
What does traction do?
(Wave transport) large boulders are rolled along the sea bed by waves
What is saltation
(Wave transport) smaller stones are bounced along the seabed
What is suspension?
(Wave transport) sand and small particles are carried along the flow
What is solution?
(Wave transport) some minerals are dissolved in seawater and carried along the flow
How is the coastal landscape shaped?
By the interaction of the different physical processes of weathering, mass movement and erosion
Name 3 types of soft rock
What is a destructive wave?
In a destructive wave, the swash is weak and the backwash strong. Material is dragged into the sea, eroding the coast. Destructive waves have high energy, and occur in stormy conditions
What are constructive waves?
In a constructive wave, material is deposited, building up the coast. Constructive waves have lower energy and occur in calm conditions
What does the unpredictability of the uk's weather and climate affect?
The rates of coastal erosion retreat, impacting on landforms and landscapes
What is the different impacts do coastal erosion have due to?
The four seasons, for example, cd temperatures in winter lead to freeze-thaw weathering
What are the effects of stormy weather
Storm frequency is high in many parts of the UK
Coasts are often subject to strong winds, increasing the eroding power of the waves, and heavy rainfall contributes to the mass movements
Frequent storms can damage coastal landforms like spits. Spurn head along the Holderness coast is at risk of being cut off from the mainland
Beach sediment can be removed from a reaction of coastline
Sand dunes can be removed by storms
where do prevailing winds come from in the uk?
What does prevailing wind from the south-west bring?
It brings warm moist air from the Atlantic and frequent rainfall,Munich contributes to weathering and mass movement on the coast
What is the definition of coastal erosion?
The breaking down and removal of material along the coast
What is the definition of coastal retreat?
When coastal erosion causes the coastline to move further inland
Explain how the uk's climate contributes to coastal erosion
The uk's climate is temperate maritime,Monica means winters are mild and and and summers are warm and wet. The prevailing wind from the south-west often brings rainfall to the country. The large amount of rainfall causes coastlines to be eroded through weathering, and can lead to mass movement and cliff collapse,Mohicans lead to coastal retreat. Storm frequency is high, which brings heavy rainfall and strong winds that increase the erosional power of waves. The seasonal nature of the climate means that rocks in the coast are subject to freeze-thaw weathering in winter, which adds to erosion
What distinctive landforms are there that have been caused by coastal erosion?
Headlands, bays, headland features and wave-cut platforms
Where do headlands and bays develop?
On coastlines with a mix of hard and soft rock
When do headlands and bays often occur?
Where cliffs have fault lines or joints
Hard rocks like chalk are often left jutting out in sea, forming what?
Soft rocks such a sands are eroded more quickly forming what?
Cliffs are common coastal features. Cliffs are shaped through weathering and erosion. Soft rock erodes easily to creat gently sloping cliffs. Hard rock erodes more slowly to create steep cliffs
When are stacks formed?
When an arch collapses (they are big rocks sticking out of the water)
When is a cave formed?
Formed when the waves erode a weakness in the rock such as a joint or a fault
When is an arch formed?
Formed when two caves erode back from either side of a headland and meet in the middle
What can the erosion of cliffs create?
What are wave-cut platforms?
Areas of flat rock at the base of the cliffs
What causes the formation of distinctive landforms including beaches, spits and bars
The process of deposition
What are beaches accumulations of?
Sand and shingle formed by deposition and shaped by erosion,transportation and deposition
What are can beaches be?
Straight or curved
Have are curved beaches formed?
By waves refracting, or bending, as they enter a bay
What can beaches have on them?
Sand or pebbles (shingle)
Where are shingle beaches usually found?
Found where cliffs are being eroded and where waves are powerful
What are Ridges in a beach parallel to the sea called? What does it show
They are called berms and the one highest up the beach shows where the highest tide reaches
What are spits?
Spits are narrow beaches of sand or shingle that are attached to the land at one end. They extend across a bay or astute or where the coastline changes direction.
How are spits formed?
They are romped by longshore drift powered by a strong prevailing wind
Explain how a bar is formed
A bar forms in the same way as a spit, with longshore drift depositing material away from the coast, until a long ridge is built up. But, unlike a spit, a bar then grows all the way across a bay, so that a stretch of water is cut off and damed to form a lagoon
What is sand and minerals carried by waves deposited by?
What different factors influence depositions?
Sheltered spots (e.g bays)
Gentle gradient offshore causing friction
They all reduce wave energy
Explain how longshore drift transports material along the coastline
The direction of material movement is determined by the prevailing wind direction. Waves approach the coastline at an acute angle, bringing sediment onto the beach in the swash. Sediment is then dragged back to the sea in the backwash, under the force of gravity at a right angle. The process continues in a zigzag pattern, moving along the beach.
What do the geological structure of coasts, rock type, and wave action all influence?
They all influence coastal landforms
What affects how fast coastal erosion occurs?
What are created when soft rock and hard rocks occur together?
What are the characteristics of soft rock such as clay?
Soft rock is easily eroded by the sea
Cliffs will be less rugged and less steep than hard rock coasts
Soft rock landscapes include bays
What are the characteristics of hard rock, such as granite?
Hard rock is resistant to all types of erosion
Cliffs will be high, steep and rugged
Hard rock landscapes include wave-cut platforms and headlands where caves, arches and stacks are formed
What are concordat coasts?
Concordat coasts are made up of the same rock type
What are discordant coasts?
On discordant coasts, the rock type alternates, forming headlands and bays
Describe rocks with joints and faults
Joints are smaller cracks; faults are larger.
Both make rock more prone to erosion.
Rocks with more joints and faults are eroded more quickly
Name 3 hard rocks
The ways in which humans use coastal environments can landscapes what does this affect?
People and the environment
What does urbanisation have an impact on in coastal landscapes?
Weight of buildings makes cliffs more vulnerable
Changes to drainage increase soil saturation
Raises interest in protecting coastal landscapes
How does agriculture affect coastal landscapes?
Increases soil erosion
Creates wildlife habitats
How does the industry have impact on coastal landscapes?
Increases air, noise and visual pollution
Can destroy habitats for birds, animals and sealife
Brings wealth and jobs to an area
What are the effects of coastal recession and flooding?
Wildlife habitats destroyed
Cliffs become dangerous for walkers
Disruption to communication networks - roads and railway lines - creating difficulties for commuters
Decreasing value of properties and difficulties in obtaining home insurance
Loss of businesses (caravan parks, cafes, golf courses) from disappearing cliffs
Increased deposition further along the coast
Loss of people's homes
Explain how coastal recession and flooding can affect people
One of the ways coastal recession can affect people is through the loss of homes. Many of the villages on the edge of the U.K. Coastline are disappearing, losing homes to the power of the sea. Transport systems can be disrupted and damaged, especially important railways that run along the coastlines. This prevents people from making journeys or means long detours are needed, which cost time and money. Farmers lose valuable farmland due to coastal recession, which means they lose income. In areas where homes have been flooded, people may have to pay more for home insurance, making it more expensive to live there
There are advantages and disadvantages to different coastal management techniques why do they need to be given careful consideration?
Because of the changes that can happen to the landscape
What can alter wave patterns, resulting in increased erosion further along the coast?
Soft or hard techniques
What can many hard engineering techniques spoil?
The visual landscape
What are the pros and cons of a sea wall?
Protects cliffs and buildings
More expensive - £5000-£10 000/m
What are the pros and cons of groynes?
Prevent sea removing sand and cheaper - £2000/m of timber
Exposes other coastal areas
What are the pros of rip rap?
Rocks absorb wave energy and are cheaper - £1000-3000/m
What does soft engineering aim to do?
To work with nature to help maintain the coastline
Name 3 types of hard engineering
Rip rap defences
Name two types of soft engineering
What are the pros of beach replenishment?
Sand reduces wave energy
Cheaper - £2000/m
What are the pros and cons of an offshore reef?
Waves break on reef and lose power
May interfere with fishing
More expensive - £5000/m
Where is Holderness coast?
East Yorkshire coastline
What is the significance of Holderness?
Soft Boulder clay is easily eroded, susceptible to slumping after heavy rainfall; chalk is more resistant (flambourough Head)
Exposed to strong waves (fetch) from the North Sea
On the Holderness coast what is happening with coastal erosion?
A combination of strong waves (especially during storms) and rock type ensure the coast is eroded rapidly
On the Holderness coast what is happening with mass movement?
Clay frequently slumps from the cliffs after rainfall
On the Holderness coast what is happening with transport and where does deposition happen?
Strong waves move the eroded material away from the coastline, deposition happens further south
What human processes are at work on the Holderness coast?
Hard engineering on parts of the coast have protected areas from erosion and cliff collapse
Hard engineering in some places has prevented transport, making erosion worse in other places