Geography: Coastal Landsapes in the UK

Weathering
1. Mechanical
  1. Happens when temperature alternates above and below 0 C. Water gets into rock that has cracks. When the water freezes it expands, putting pressure on the rock.
2. Chemical
  1. Rainwater has carbon dioxide dissolved in it, making it a weak carbonic acid. Carbonic acid reacts with rock that contains calcium carbonate, so the rocks are dissolved by the rainwater,
Processes of Erosion
1. Hydraulic Power
  1. Waves crash against rock and compress their air in cracks, putting pressure on the rock. repeated compression widens the cracks and makes bits of rock break off
2. Abrasion
  1. Eroded particles in the water scrape and rub against rock, removing small pieces.
3. Attrition
  1. Eroded particles in the water smash into each other and break into smaller fragments. Their edges get rounded off as they rub together.
Waves erode cliffs to form Wave-cut Platatforms
1. Waves cause most erosion at bottom of cliff. As it erodes, a wave-cut notch is make, which enlarges as erosion continues. The rock above the notch becomes unstable and collapses. The collapsed material is washed away and a new wave-cut notch forms. Repeated collapsing results in the cliff retreating. A wave-cut platform is the platform that's left behind as the cliff retreat
Destructive Waves
1. High frequency (10-14 waves per minute)
2. High and steep
3. Backwash is more powerful than the swash, which means the material is removed from the coast
Headlands and Bays
1. Soft rocks have low resistance to erosion and hard rocks have high resistance.
2. They form where there are alternating bands of resistant and less resistant rock along a coast. The soft rock is eroded quickly and this forms a bay. The hard rock is eroded more slowly and it's left jutting out, forming a headland.
Headlands form caves, arches and stacks
1. Headlands are usually made of resistant rocks that have weaknesses like cracks. Waves crash into the headlands and enlarge the cracks mainly by hydraulic power and abrasion. Repeated erosion and enlargement of the cracks causes a cave to form. Continued erosion deepens the cave until it breaks through the headland forming an arch. Erosion continues to wear away the rock supporting the arch, until it eventually collapses. This forms a stack.
Transportation
1. Longshore drift: Waves follow the direction of the 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 then carries material down the beach at right angles back towards the sea. Over time, material zigzags along the coast.
2. Traction
  1. Large particles like boulders are pushed along the sea bed by the force of the water.
3. Saltation
  1. Pebble sized particles are bounced along the sea bed by the force of the water.
4. Suspension
  1. Small particles like silt and clay are carried along in the water
5. Solution
  1. Soluble materials dissolve in the water and are carried along
Coastal Landscape: Dorset
1. Durdle Door - Arc
2. Lulworth Cove - Small Bay
3. Chesil Beach - A tombolo formed by longshore drift
4. Swanage and Studland Bay and The Foreland - Two bays and a headland
Coastal Management
1. Hard Engineering
  1. Sea Wall
  2. Gabions
  3. Rock Armour
  4. Groynes
2. Soft Engineering
  1. Beach Nourishment and Reprofiling
  2. Dune Regeneration

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Geography: Coastal Landsapes in the UK

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	Created by Blerta Morina almost 6 years ago