Studied by 1 personlength of jurassic coast
95 miles
age of jurassic coast
185 million
geology of old harry
cretaceous chalk
found on headland
on discordant coastline
explain the influence of geology on old harry
chalk is more resistant that surrounding clay and sands
this creates a chalk headland due to differential erosion
headland sticks out of coast = wave refraction attacking headland
cretaceous chalk has lots of lines of weakness which are exploited by weathering and erosion
explain the influence of climate on old harry
stormier climate now = more erosion on old harry
geology of swanage bay
clay and sands
found on discordant coastline
explain the influence of geology on swanage bay
softer rock than surrounding geology = quicker erosion
bay is therefore cut inland and at a lower elevation than surrounding headlands
waves are constructive as they have a lower energy in the bay due to wave refraction of headlands
constructive waves = more deposition
more deposition = beach
geology of durdle door
portland limestone
found on concordant coastline
influence of geology on durdle door
durdle door withstands erosion better tan softer bands of rock surrounding it
limestone has joints and bedding planes = more susceptible to weathering
influence of climate on durdle door
warmer climate = less freeze-thaw weathering
spray from ocean = constant wetting and drying cycle
limestone is soluble and suffers from carbonation = more solution and chemical weathering
geology of swanage beach
clay and sands from soft eroded rock
limestone from neighbouring durlston head
erosion to the south
explain the influence of climate on swanage beach
two neighbouring headlands refract wave energy = beach with constructive waves
constructive waves = deposition
eroded sediment from headlands is deposited on swanage beach
longshore drift transports sediment south due to south-west prevailing winds
name of tombolo on jurassic coast
chesil beach
length of chesil beach
18 miles
geology of chesil beach
sand and shingle beach from sediment deposited from further up coastline
shape of coastline allows lagoon to form behind tombolo
explain the influence of climate on chesil beach
prevailing wind determines direction of LSD
calmer water allows for deposition across bend in coastline
this allows the tombolo to form
explain the impacts of humans building hotel on geomorphic processes
major slip in 2012 meant drainage pipes were implemented to stop a slip plane being created on impermeable clay
this decreased mass movement on this area of the jurassic coast
number of wooden groynes on jurassic coast
18
when were the wooden groynes on jurassic coast built
2005
when and how much was the last beach replenishment on the jurassic coast
90,000 m³ in 2005
when was the concrete sea wall on the jurassic coast built
1920
explain the impacts of groynes on geomorphic processes
limits LSD
encourages deposition in swanage bay
explain the impacts of the concrete sea wall on geomorphic processes
limits hydraulic action and abrasion on coastline
explain the impacts of beach replenishment on geomorphic processes
increases amount of deposition on swanage beach
increases rates of transportation as more sediment is available
explain the pros and cons of management strategies on jurassic coast
aggressively defending the coast has built up sediment and protected the landscape behind
defences have been costly - all sea defence projects are multi million pound projects
explain the pros and cons of groynes on jurassic coast
groynes 'starve' sediment from places beyond the final groyne
wooden groynes are starting to fall apart already so are less effective
groynes so successful they are overtopping - so much sediment has been deposited and trapped
explain the pros and cons of beach replenishment on jurassic coast
beach replenishment needs redoing every 20 years
beach replenishment is expensive for larger beaches
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