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UK physical (coasts) - Coggle Diagram
UK physical (coasts)
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Weathering
Solution - acids contained in sea water will dissolve some types of rock such as chalk and limestone
Mechanical - the breakdown of rock without a change in chemical composition. Freeze-thaw is the most important in coastal areas
Attrition - waves smash rocks and pebbles on the shore into each other, causing them to become smaller and rounder
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Abrasion - bits of sand and rock in waves grind down cliff surfaces like sandpaper and are thrown at cliff surfaces, breaking them apart
Mass movement - the shifting of rocks and loose material down slope when the force of gravity is greater than the supporting forces
Hydraulic action - waves trap air in joints and cracks in the cliff. This puts pressure on the rock and over time it breaks up.
cliff collapse
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human actions
building on the cliff top adds a load, which can weigh down the weakened cliff
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rockfalls - fragments of rock break away from the cliff face, often due to freeze-thaw weathering
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The lake District
main weathering process
the main weathering process is related to fragments of rock known as scree which are created by freeze-thaw weathering which is where cracks in the rock are filled with rain water, and as the temperature drops, the water freezes and expands, making the crack bigger and it then melts and the process repeats until the rock is pushed apart and becomes scree
effects of glaciation
the glciers created u-shaped valleys and hollows which are now filled by lakes. Glaciation means rivers now flowin the valley bottom and they are small compared to their valleys so are called misfits. These deposit silt and mud known as alluvium making the ground good for farming
slope processes
the slope processes are when scree fragments are unstable so move easily during rockfalls, and landslides are common and due to the large amounts of rain it adds to the weight of the rock so it falls easily
description & geology
along one lake, wastewater lake, the climb is 2750 over peaks of igneous rocks in this upland landscape. The ground is rough and in the Lake District is England's largest mountain Scafell Pike
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The Weald
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description & geology
some areas consist of undulating hills (gently rolling). The Weald was once a dome of folded rock which formed an anticline (arch) which has been eroded and weathered
effects of glaciation
during the Ice Age water in the chalk froze making it impermeable and then freshwater formed rivers and when the climate warmed the water seeped into the chalk
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rock types
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metamorphic - formed from igneous or sedimentary rock that is changed by heat or pressure deep in the earth
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sedimentary - made of layers of sediment (bits of crumbled rock, dead animals and chemical deposits) compressed together
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The north of the UK is mostly made up from harder igneous and metamorphic rock, whereas the south and east are made up from soft sedimentary rocks. (separated by Tees Ex line)
waves
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constructive waves - build up the beach with a stong swash, smaller backwash with a frequency of 6-8 per minute
swash - movement of a wave up the beach at an angle, due to the wind
destructive waves - smaller swash, stong backwash which leads to the erosion and destruction of beaches, with a frequency of 9-12 per minute
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Malham Cove
geology - the limestone is formed in more tropical seas when creatures died and were compressed from in the sea bed to rock. Calcium carbonate then crystallised, cementing fragments of rock together, which was overtime placed underneath existing rocks
tectonic process - the rocks were uplifted from below the sea into mountains creating fault lines and slopes
glaciers - glaciers widened and deapened making u-shaped valleys which then melted and made waterfalls and rivers
The South Downs
Forestry
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many of the hazel and chestnut trees are no longer managed traditionally so are overgrown and causing quality to decline
a large % of woodland makes up the South Downs National Park with many ancient trees and diverse wildlife
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coastal area, created 65M years ago by tectonic activity, dries out quickly because of chalk grassland which is one of the best habitats in England, used for cattle and farming, and has 40 species of plant in 1 square meter
farming
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income from farming supports the local economy (agriculture makes up 6% of national park employment)
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coastlines
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discordant
forms bays and headlands when the soft and hard rock layers run alongside, perpendicular to the coast
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Christchurch bay
cliff collapse
sliding
when large chunks of rock slide down the slope quickly without any warning. this can make it very dangerous to walk along the beach under the cliffs
slumping
comon where the cliffs are made of clay. The clay becomes saturated during heavy rainfall and oozes down towards the sea as part of debris flow
location
Christchurch is found on the south coast near Bournemouth and is a 16km stretch of coastline. This is exposed to waves from across the Atlantic ocean witha fetch of 3,000, causing the cliffs to have eroded at a rate of 1-2m per year. This area is densly populated with many coastal towns and the tourism is key to the local economy. In 2007 the beach huts along the coastline were evacuated due to a danger of cliff collapse
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coastal management
soft engineering
sand dunes
Adv - attractive, sheap, natural process
Dis - time consuming, limited access, storms cause damage
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salt marshes
Adv - cheap, habitat for wildlife, long term
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beach nourishment
Adv - bigger beach, attractive, natural process
Dis - no protection of cliffs, frequent renewal of sand
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managed retreat
Adv - no repairs, natural method
Dis - no protection, coast will erode and flood
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hard engineering
groynes
wood - £10,000 each / rock - £125,000 each
Adv - builds up beach, makes beach wider, provides calmer waters
DIs - needs repairs, no defence on strong waves, terminal groyne syndrome
rock armour
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Adv - easy to install, cheaper than sea wall
Dis - unnatractive, needs repairs, may contain rats
sea wall
Adv - deflects waves, strong, effective, long lasting, dissipates energy
Dis - expensive, repaired regularly, damages the sea bed
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gabions
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Adv - effective, cheaper than sea wall
Dis - not attractive, inconvenient for tourists, rats can occupy spaces
Intergrated Coastal Zone Management (ICZM) is a plan to protect the whole coastline from flooding and erosion
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Flooding
2013-2014 floods
In 2013-2014, there was a higher rainfall in the south of England (up to 225% of 1981-2010 average), particularly the south east corner such as London, Brighton and Southhampton where it more than 200% than the average. It was lighter in the north around 90-130% more than average but there is more in the east than the west. Wales and Scotland normally have more rainfall since they have higher ground, which leads to more condensation as air rises
Impacts of the flooding
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2 people killed - one droned, one crushed in a car by debris
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weathering - the physical, chemical and biological breakdown of solid rock by the action of weather or plants
