Jurassic coast case study

case study: coastal landscape

• This case study will be about the Jurassic coast in Dorset.

location and geology

• Geology: chalk
• Location of Studland bay:
• located at the east end of the Jurassic coast, near Swanage, Poole and Bournemouth.
• The Jurassic coast stretches along 45 miles of coastline, between Exmouth (in Devon) and Swanage (in Dorset).
• It is on a discordant coastline
• a discorded coastline is when the geology alternates between strata (bands) of hard and soft rock.
• climate: warm, dry summers with mild, wet winters, salt crystals are the main form of mechanical weathering.

Landforms

• old Harry- collapsed arch, erosional landform, made of resistant chalk, eroded by carbonation and erosion mainly, although biological weathering also plays part in it.
• Durdledoor- arch, erosional landform, made of hard limestone, erosion due to waves caused a crack in the headland, which became a cave, which became an arch.
• Lulworth Cove- cove/small bay, erosional landform, made of limestone and clay, the limestone was eroded, leaving place for the clay to be eroded and carried away, vulnerable to rock slides and mass movement
• Chesil Beach- spit which became a tombolo, depositional landform, made of sandstone, caused by longshore drift, the spit eventually reached the isle of Portland, becoming a tombolo.
• Swanage Bay- cliffs +bay, erosional landform made of gravel and soft clay, caused by longshore drift and erosion, the slumping is caused by weathering.

what impacts have human activities had in shaping the landscape?

• Industry and tourism:
• Quarrying- limestone is a valuable material in construction, quarries take out limestone and leave exposed rock behind, this rock is vulnerable to chemical weathering and erosion.
• Material- In the 60's gravel was removed from Chesil beach (for construction) at a faster rate than the sea could replenish it, this caused the beach to retreat
• Tourism- Dorset is a popular tourist destination, the footpaths on top of the cliffs are worn out and the plants may be trampled and worn away, exposing soil and rock under it to weathering and erosion due to wind and rain.

coastal management: hard engineering

• 2 examples of hard engineering:
• Sea wall:
• advantages- can also protect from coastal flooding+ lasts a long time
• Disadvantages- expensive, waves bounce off it and erode material on the beach instead
• Rock armor:
• advantage: rocks are cheap and efficient
• Disadvantage-unattractive and can make the beach dangerous

coastal management: soft engineering

• Beach nourishment
• involves taking materials from other beaches and using them to maintain the beach line of one beach.
• advantages- keeps the beach's appearance + cheap
• disadvantages- needs to be replaced every 20 years or so + can damage other beaches were material comes from.