Coastal Landscapes in the UK

  • Created by: tobyf
  • Created on: 11-05-18 00:15
How is rock broken down?
Freeze-thaw weathering: water gets into cracks, freezes and expands, then thaws and contracts, releasing pressure the rock. Carbonation weathering: rainwater is a weak carbonic acid and reacts with rock that contains calcium carbonate, dissolving it
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Types of mass movement?
Rockfall (material breaks up and falls down slope), mudflow (saturated soil flows down slope), landslide (large bits of rock fall downhill), rotational slip (saturated soil slumps down a curved surface)
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Processes of wave erosion?
Hydraulic action: sheer force of waves/air compresses into cracks and applies pressure. Abrasion: eroded particles scrape and rub against rock, removing small pieces. Attrition: eroded particles smash together, breaking into smaller fragments.
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Destructive/constructive waves differences?
Destructive waves: carry out erosional processes, high frequency, high and steep, backwash more powerful than swash. Constructive: low frequency, low and long, swash more powerful than backwash, deposit material.
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How are wave-cut platforms formed?
Waves erode the foot of the cliff, causing a wave-cut notch. This continues to grow, until it becomes unstable and collapses. The collapsed material is washed away, forming a wave-cut platform - it is enlarged as the process repeats.
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How are headlands and bays formed?
Alternating bands of hard (more resistant) and soft (less resistant) rock. The soft rock is eroded quickly, forming a bay with a gentle slope. The hard rock is eroded slowly and is left jutting out, forming a headland. They have steep sides
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How are caves, arches and stacks formed?
Headlands have weaknesses like cracks. Waves crash into headlands, enlarging cracks by hydraulic power and abrasion. These cracks enlarge, forming a cave, then an arch. Erosion wears away rock supporting the arch, making it collapse, forming a stack
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Explain longshore drift
Prevailing wind causes waves to hit beach at an oblique angle. Swash carries material up the beach in the direction, backwash carries material down the beach at right angles. Over time, material zigzags across the beach
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Four processes of transportation?
Traction: large particles like boulders pushed along sea bed. Saltation: pebble-sized particles bounced along sea bed. Suspension: small particles like silt carried along in water. Solution: soluble materials dissolve in the water, are carried along
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What increases deposition?
When there's lots of erosion elsewhere along the coast, so lots of material is available; there's lots of material transported into the area; low energy waves that carry material but don't sweep as much away
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How does deposition form beaches?
They are formed between the high and low water mark by constructive waves depositing sand and shingle. S
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Difference between sand and shingle beaches?
Sand beaches: flat and wide. Sand particles are small, weak backwash moves them back down beach, creating a long, gentle slope. Shingle beaches: steep and narrow. Shingle particles are large, weak backwash cant move them back down beach - steep slope
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How are spits formed?
Form at sharp bends in coastline (river mouth). Longshore drift transports sand and shingle past bend, into sea. Strong winds curve the end of the spit. Sheltered area protected from waves, material accumulates and plants grow - mud flat/salt marsh
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How are bars formed?
Formed when a spit joins two headlands together. Bar cuts off bay between headlands from the sea. A lagoon can form behind the bar.
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How are sand dunes formed?
Sand deposited by longshore drift, moved up beach by wind. Obstacles (driftwood) cause wind speed to decrease so sand deposited, is colonised by plants/grasses, which stabilises sand (embryo dunes). Oldest dunes migrate inland (mature dunes), are 10m
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Name a n example of a wave-cut platform, spit, caves/stacks, headland/bay, sand dunes, arch and bar/tombolo from the Dorset coast
Wave-cut platform: Kimmeridge Ledges. Spit: Sandbanks. Caves/stacks: Old Harry Rocks. Headland/bay: Pevril Point & Swanage Bay. Sand dunes: Studland. Arch: Durdle Door. Bar/tombolo: Chesil Beach
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Difference between hard and soft engineering?
Hard: man-made structures built to control the flow of the sea and reduce flooding and erosion. Soft: schemes set up using knowledge of the sea and its processes to reduce the effects of flooding and erosion
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Explain what Sea Wall and Gabions do
Sea wall: hard wall that reflects waves back to sea. Prevents erosion/flooding, but expensive. Gabions: wire cages filled with rocks built at foot of cliffs. Reduce erosion, cheap, easy to build, ugly and can corrode
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Explain what Rock Armour and Groynes do
Rock armour: boulders piled up along coast. Reduces erosion/flooding, fairly cheap, can be removed by strong waves, need replacing. Groynes: Fences built at right angles to coast. Wider beaches, stops flooding/erosion, cheap, starve beaches elsewhere
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Explain what Beach Nourishment & Reprofiling and Dune Regeneration does
BN&R: sand/shingle added to upper part of beach. Wider beaches, slows waves, stops flooding/erosion, expensive, must be repeated. Dune Regen: creating/restoring dunes by nrshmnt/vg. Stops flooding, vg cheap, limited to small area, nrshmnt expensive
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What is Managed Retreat?
Removing current defences, allowing sea to flood land behind. Over time this will become marshland, which protects land behind from flooding/erosion. Cheap/easy - no maintaining. New habitats. Could have negative effect on farmers as land is lost
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Lyme Regis - location and reasons for protection? Cost of coastal management?
Small (4,000 people) town in south coast of Dorset. UNESCO World Heritage Site. Popular tourist resort (10,000/day in summer). Risk of re-activating ancient landslides. Infrastructure at risk: 144 properties, 900m of A3052 + gas supply. Cost: £50 mil
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Lyme Regis - management strategies?
Stabilising land behing beach by fixing it to rock below with 1000+ pins. New drainage systems into the cliff. 2 new sea walls. 390 tonnes of rock armour from Norway. Beach replenishment w/ sand+shingle from France. New jetties to act as groynes.
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Lyme Regis - positives/benefits?
For every £1 spent, town has gained £4.46 worth of benefits from protected area. 480 homes saved from damage/loss of access. Defences protected Lyme Regis from recent winter storms (2014). Larger, replenished beach has increased tourism
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Lyme Regis - limitations/conflict?
Disruption to town during construction, tourists put off. Sea wall may be increasing erosion further down coast. Sand/rock armour from France+Norway - high transportation costs + carbon footprint. Preventing landslides prevents fossil discoveries
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Other cards in this set

Card 2

Front

Types of mass movement?

Back

Rockfall (material breaks up and falls down slope), mudflow (saturated soil flows down slope), landslide (large bits of rock fall downhill), rotational slip (saturated soil slumps down a curved surface)

Card 3

Front

Processes of wave erosion?

Back

Preview of the front of card 3

Card 4

Front

Destructive/constructive waves differences?

Back

Preview of the front of card 4

Card 5

Front

How are wave-cut platforms formed?

Back

Preview of the front of card 5
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