what is mechanical weathering?
the breakdown of rock without changing its chemical composition.
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what is the main mechanical weathering that affects coasts?
freeze-thaw weathering
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when does freeze-thaw weathering happen and how is it done?
it happens when the temp alternates above & below 0 degrees. water gets into rock that has cracks, when the water freezes it expands. when the water thaws it contracts. repeating this widens and breaks up the rocks
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what is chemical weathering?
the breakdown of rock by changing its chemical composition. carbonation weathering is a type of chemical weathering that happens in warm and wet conditions
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how does carbonation weathering happen?
rainwater has carbon dioxide dissolved in it, which makes it a weak carbonic acid. carbonic acid reacts with rock that contains calcium carbonate, so the rocks are dissolved by rain water.
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what is mass movement and when does it happen?
the shifting of rocks and loose material down a slope. it happens when the force of gravity acting on a slop is greater than the force supporing it
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what does mass movement cause at coasts and when is it more likely to happen?
it causes coasts to retreat rapidly. and they're more likely to happen when the material is full of water.
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what are the two types of mass movement at coastal areas?
slides: material shifts in a straight line. slumps: material shifts with a roation.
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what type of waves carry out erosional processes at coastal zones?
destructive waves
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information about destructive waves?
they have a high frequency(10-14 waves per minute). they're high and steep. their backwash is more powerful than their swash, this means material is removed from the coast.
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how are wave-cut platforms formed?
waves cause most erosion at the foot of a cliff. this forms a wave-cut notch, which is enlarged as erosion continues. the rock above the notch becomes unstable & eventually collapses. the collapsed material is washed away.repeated collapsing forms it
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what is a wave-cut platform?
the platform that is left behind as the cliff retreats.
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where do headlands and bays form?
where there are alternating bands of resistant and less resistant rock along the coast. the less resistant rock is eroded quickly-this forms bays. the resistant rock is eroded more slowly and is left jutting out which forms headlands.
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how are caves, arches and stacks formed from headlands?
waves crash into the headland and enlarge cracks.Repeated erosion & enlargement of the cracks causes a cave to form.Continued erosion deepens cave until it breaks through headland-forming an arch.Erosion continues,The arch collapses-forming a stack.
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how are materials transported along the coast?
a process called longshore drift.
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explain is longshore drift ?
waves follow the direction of prevailing wind.They usually hit the coast at an oblique angle. the swash carries material up the beach, in the same direction as the waves.The backwash carries material down the beach at right angles, back towards sea.
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the four types of processes of transportation?
Traction, Suspension, Saltation and Solution
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what is traction?
large particles like boulders are pushed along the sea bed by the force of the water.
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what is suspension?
Small particles like silt and clay are carried along in the water.
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what is saltation?
pebble-sized particles are bounced along the sea bed by the force of the water.
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what is solution?
Soluble materials dissolve in the water and are carried along
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when does the amount of material thats deposited on an area of the coast increase?
when theres lots of erosion elsewhere on the coast, so theres lots of material available. or when theres lots of transportation of material into the area
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information about constructive waves?
they deposit more material than they erode. constructive waves have a low frequency (6-8 waves per minute). they're low and long. the swash is powerful and it carries material up coast. the backwash is weaker and doesnt take a lot of material back.
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where are beaches found?
between the high water mark and the lowest mark. they're formed by constructive waves depositing materials like sand and shingle.
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sand and shingle beaches have different characteristics - what are they?
sand beaches are flat and wide-sand particles are small and the weak backwash can move them back down the beach, creating a long gentle slope. shingle beaches are steep&narrow- shingle particles are large&the weak backwash cant move them.
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what are splits and how can it form a bar?
splits are beaches that stick out into the sea- they're joined to the coast at one end. if a spit sticks out so far that it connects with another bit of mainland, it'll form a bar. they're both formed by longshore drift.
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how arespits?
form at sharp bends in the coastline. longshore drift transports sand and shingle past the bend and deposits it in the sea. strong winds and waves can curve the end of the spit. the sheltered area behind the spit is protected from waves.
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how are bars 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.
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what are the economic impacts of coastal flooding?
loss of tourism, damage repair, loss of agricultural land.
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what are the social impacts of coastal flooding?
death, water supplies affected, loss of housing, loss of jobs.
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what are the environmental impacts of coastal flooding?
ecosystems affected, vegetation killed by water, increase erosion
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what are the political impacts of coastal flooding?
the government has to make policies to reduce the impacts of future flooding. they can do things like building more or better flood defences or they can manage the use of areas that might be flooded e.g by stopping people living there.
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hard engineering strategies to reduce flooding or erosion?
sea wall, rock armour, groynes
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soft engineering strategies to reduce flooding or erosion?
beach nourishment, dune regeneration, marsh creation or managed retreat.
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Other cards in this set

Card 2


what is the main mechanical weathering that affects coasts?


freeze-thaw weathering

Card 3


when does freeze-thaw weathering happen and how is it done?


Preview of the front of card 3

Card 4


what is chemical weathering?


Preview of the front of card 4

Card 5


how does carbonation weathering happen?


Preview of the front of card 5
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