coastal landscapes in the UK + UK landscape Flashcards
what are the two different types of weathering
chemical and mechanical
what is mechanical weathering
the breakdown of rock without changing its chemical composition
what is an example of mechanical weathering that affects coasts
freeze-thaw weathering
how does freeze thaw weathering happen
- happens when temp alternates above and below 0 degrees
-water enter a rock that has cracks
- when the water freezes it expands which puts pressure on the rock
- water thaws and contracts - releasing pressure
- process keeps happening which causes the rock to break up
what is chemical weathering
chemical weathering is the breakdown of a rock by changing is chemical composition
what is a type of chemical weathering
carbonation
what happens in carbonation
- rainwater has carbon dioxide dissolved in it which makes it a weak carbonic acid
- carbonic acid reacts with rocks that have calcium carbonate so the rocks are dissolved by rainwater
what is mass movement
the shifting of rocks or loose material down a slope when the force of gravity acting on the slope is stronger than the force supporting it.
what does mass movement do to coasts
causes them to retreat rapidly
can create a scarp ( a steep cut in the side of the slope)
when is mass movement more lilley to hape
when the material is full of water
what is a slide in mass movement
when material shifts in a straight line along a slide plane
what is a slump in mass movement
material roates along a curved slip plane
what are rock falls in mass movement
material breaks up often along beddding planes and falls down a slope
draw slides,slumps and rockfalls
what are the two types of waves
destructive and constructive
what is the fetch
the distance the wind blows over the sea
what creates waves
when the wind blows over the surface of the sea
what is the wave like if it has a greater fetch
it is a stronger wave
what are storm surges
temporary sea level rises caused as string winds push water onshore
which type of wave erodes the coast
destructive waves
which type of wave deposits material
constructive waves
what is the back wash
water moving down the beach
what is the swash
water moving up the beach
what are the characteristics of a destructive wave
- high frequency
- high and steep
- backwash is stronger than swash so material is removed
what are the characteristics of a constructive wave
- low frequency
- low and long
- stringer swash than backwash so material is deposited
what are the three types of coastal erosion?
hydraulic power
abrasion
attrition
what is hydraulic power
waves crash against rock and compress air in cracks
which puts pressure on rock
the repeated compression widens the cracks and causes rocks to break off
what is abrasion
eroded particles scrap on rock, removing small pieces
what is attrittion
eroded particles in the water collide and break into smaller pieces and become more rounded
waves follow the direction of the
prevailing wind ( most common wind)
how is material transported along the coast
by long shore drift
what is long shore drfit
- waves follow direction of prevailing wind
- usually hit coast at a oblique angle
- swash carries material up beach in the same direction as the waves
- back wash carries material back down the beach at right angles towards the sea
- and overtime material travels in zig-zags across the coast
what are the four processes of transportation
traction
saltaion
suspension
solution
what is traction
large boulders are pushed along the sea bed by the force of the water
what is saltation
pebble sized particles bounce along the sea bed by force of water
what is suspension
small particles like slit are carried along by the water
what is solution
soluble materials like limestone dissolve in the water and are carried along
when does deposition occur
when the water loses energy and slows down
coasts build up when the amount of deposition is ________ than the amount of __________
deposition
erosion
the amount of material deposited on an arena of a coast is increased when:
- theres alot of erosion else where on the coast so there is more material available
- when lots of material is transported into an area
where do the uks upland areas tend to be
in the north and west
where do the uks low land areas tend to be
in the south and east
what are the two different types of coastlines that coastlines can be
concordant or discordant
what influences the type of erosional landforms develop on the coastline
the rock type and geological structure
what are joints and faults in rocks and what does it mean when it comes to erosion
cracks and weaknesses in the rock and it means the rock erodes more quickly
what is an example of a hard rock
granite
what is an example of a soft rock
sandstone
what is a discordant coastline made up of
bands of alternating hard rock and soft rock that are at a right angle to the coastline
what is a concordant coastline made up of
bands of alternating hard rock and soft rock that are parallel to the coastline
what type of coastlines do headlands and bays form on
discordant coastlines
how are headlands and bays formed
made up of alternating bands of less resistant rock and resistant rock
- less resistant rock is eroded faster forming a bay with a gentle slope
- reistsant rock erodes slwoer so it juts out forming a headland with steep sides
when headlands are eroded what do they form
caves,arches and stacks
how are caves, arches and stacks formed
- the resistant rock in hedlands has weaknesses like crack
- waves crash into headlands and water englarges teh cracks ( hydraulic power)
- repeated erison makes a cave form
- contiuned erosion makes the cave deeper until it breaks through the other side and creates a arch
- erosions wears away the arch until it collapses leaving a stack
what is a example of a arch
durdle door,dorset
what is an example of a stack
Old harry, dorset
what are beaches formed by
deposition
how are wave cut platforms formed
- erosion at the bottom of the cliff creates a wave - cut notch - enlarges over time
- repeated erosion makes rock above collapse
- eroded material is washed away and a new wave cut notch is formed
- after repeated collapses the cliff retreats leaving a wave cut platform
what type of wave are beaches formed by and why
constructive waves
becuase the swash is more powerful than the back wash so more deposition happens
what type of waves are sand beaches formed by
low energy waves - sand particles are small so weak back wash can move them down the beach making the beach wide
are sand beaches flat and wide or steep and narrow
flat and wide
what type of waves are shingle beaches made from
high energy waves - sand particles are washed away and shingle is left behind. shingle builds up to make a steep slope
are shingle beaches flat and wide or steep and narrow
steep and narrow
where do spits form
at sharp bends in the coastline (e.g) the river mouth
how are spits formed
long shore drift transports sand and shingle past the bend and deposits it in the sea
strong winds and waves can curve the end of a spit - recurved end
the area behind a spit is sheltered from waves,so material accumulates and plants are able to grow
- over time sheltered area can become a mud flat or salt marsh
where do bars form
when a spit joins two headlands together
how are bars formed
a spit joins two headlands together
the bay between headlands is cut off from the sea
a lagoon can form behind the bar
how are sand dunes formed
when sand deposited by long shire drift is moved by the beach by wind
how are embryo dunes formed
obstacles like drift wood decrease wind speed so smaller dunes are formed call embryo dunes
how do plants help build up dunes
embryo dunes are colonised by plants like marram grass. the roots of vegetation stabilise the sand,encouraging more sand to accumulate there
what are the three different sizes of sand dunes
embryo
foredunes
mature dunes
what are dune slacks
smalls pools that can form in hollows between dunes
what is hard engineering
man-made structures built to control the flow of the sea and reduce flooding and erosion
what is soft engineering
schemes set up using the knowledge of the sea and its processes to reduce the effects of flooding and erosion
what are the different types of hard engineering coastal managment
sea wall
gabions
rock armour
groynes
what is a sea wall
a wall made of hard material like concrete that reflect a wave’s power back out to sea
what is gabions
a wall made up of wire cages filled with rocks, usually built at the foot of cliffs
what is rock armour
boulders that are piled up along the coast
what do groynes do
wooden or stone fences that are built at right angles to the coast. they trap material transported by long shore drift
what are the two types of soft engineering strategies in defending the coast
beach nourishment and reprofilling
dune regeneration
what is beach nourishment and reprofilling
sand and shingle from elsewhere or from lower down the beach thats added to the upper parts so beaches
what is dune regeneration
creating or restoring dunes by nourishment or by planting vegetation to stabilise the sand
what are the benefits of sea walls
it prevents erosion of the coast
prevents flooding
what are the cons of a sea wall
has to built all along a towns coastlines
expensive to build and maintain
creates a strong backwash that erodes under the wall
what are the benefits of gabions
they absorb the wave energy
reduce erosion
cheap defense
what are the cons of gabions
unattractive
wire cages can corrode over time
what are the benefits of rock armour
absorb wave energy
reduce erosion and flooding
fairly cheap
what are the cons of rock armour
boulders can be moved by strong waves so they need to be replaced
what are the benefits of groynes
create wider beaches which slow the waves
gives greater protection from erosion and flooding
fairly cheap
what are the cons of groynes
starve beaches further down the coast making them narrower
narrow beaches lead to greater erosion
what are the benefits of beach nourishment and reprofilling
creates wider beaches which slows waves
gives greater protection from flooding and erosion
what are the cons of beach nourishment and reprofilling
taking material from seabed can kill microorganisms - coral
very expensive
has to be repeated
what ar ethe benefits of dune regeneration
create a barrier between alnd and sea and absorb wave energy,preventing flooding and erosion
cheap - stabilisation
what are the cons of dune regeneration
the protection is limited to a small area
nourishment is expensive
what is managed retreat
removing current defences and allow sea to flood land behind
over time land will become marshland protecting land behind it from flooding
what are the pros of managed retreat
cheap and easy
doesn’t need maintaining
creates new habitats for animals
what are the cons of managed retreat
flooding farmland affects livelihoods of farmers
saltwater can have a negative affect of ecosystems
What is Lyme Regis?
Lyme Regis is a historic town in Dorset, southwest England.
What natural phenomenon affects the sea cliffs at Lyme Regis?
Powerful waves from the south west erode the sea cliffs, causing them to collapse.
What significant event occurred in May 2008?
About 400 m of cliff slipped between Lyme Regis and Charmouth.
What risks do properties on the eastern side of Lyme Regis face?
Many properties have been damaged by landslides, slumps, and waves breaching the sea walls.
How much of the coastline at Lyme Regis is managed using hard engineering strategies?
Around 1 km of the coastline at Lyme Regis is managed using hard engineering strategies.
Why is the coastline at Lyme Regis managed?
The coastline is managed because of the population, tourism, and economic factors.
What is the population of Lyme Regis?
Lyme Regis has a population of over 3600 people.
How many tourists visit Lyme Regis each year?
Around 500,000 tourists visit each year.
What would have happened to the A3052 road without management?
Around 900 m of the A3052 road would have been lost within 50 years.
What is the economic impact of tourism in Lyme Regis?
About £42 million was spent by tourists in 2015.
What could threaten the historic town centre and tourism industry in Lyme Regis?
Erosion of the coast could threaten the historic town centre and the tourism industry.
What protective measures are in place in Lyme Regis?
Parts of Lyme Regis are protected by sea walls and rock armour.
What was Phase I of the Lyme Regis protection scheme?
Phase I, completed in 1995, involved building new rock armour on the eastern end of the sea front.
What were the key components of Phase II of the Lyme Regis protection scheme?
Phase II, completed in 2007, included replenishing and stabilising sand and shingle beaches, extending existing rock armour at Beacon Rocks, realigning North Wall Rockery, and improving drainage systems to reduce water build-up and prevent landslides. It cost £26 million.
What was the purpose of Phase III of the Lyme Regis protection scheme?
Phase III was meant to prevent landslides to the west of Lyme Regis but was never carried out due to high costs.
What did Phase IV of the Lyme Regis protection scheme entail?
Phase IV, completed in 2015, cost £19.5 million and included 390 meters of sea walls and rock armour to protect roads into the town.
What positive effects did the coastal management scheme have on Lyme Regis?
The improved beaches are thought to have increased trade by up to 20%, the rock armour absorbs wave energy protecting the harbour, and people feel more secure buying property due to easier insurance against coastal erosion and landslides.
What conflicts arose from the coastal management scheme in Lyme Regis?
Conflicts include increased traffic, litter, and noise pollution from greater tourist numbers, the defences preventing exposure of important fossils, and some residents believing the solution was expensive for a short-term fix, as the defences may need rebuilding in around 60 years.
where are the uks upland areas
in the north and west of the country
what are the upland areas formed of
hard igneous and metamorphic rocks that are resistant to erosion
where are the uks low land areas
in the south and east
what are the low land areas formed of
softer,sedimentary rocks that erode more easily
where are most cities in the uk
in low land areas and often on the uks main rivers - london,liverpool
what type of coastline does dorest have
concordant and discordant
what are the erosional landforms in dorset
Arch (Durdle Door)
Stack (Old Harry)
Bay (Swanage and Studland Bays)
Headlands: Durlston Head
Cove: Lulworth Cove
Wave cut platform: Kimmeridge Beach
on which type of coast line is the landforms on the Dorset coast
discordant
