Distinctive Landscapes

• The physical characteristics of lowland areas include:

  • Generally formed from softer rocks, such as chalk, clay and some sandstone
  • The landscape is flatter, with gentle rolling hills
• The uses of lowland areas include:

  • Quarring
  • Tourism
  • Dairy and Arable farming
  • Most urban areas and industries are located here
• The physical characteristics of upland landscapes include:

  • Formed of harder rocks that resist erosion, e.g slate, granite and some limestone
  • Gradient of the land is often steep
• The uses of upland areas include:

  • Sheep farming
  • Quarring
  • Tourism
  • Some upland areas are used for forestry
• A landscape comprises all the visible features of an area of land. It can contain both natural features and man-made features.
• A natural landscape is a landscape with more physical features, such as mountains or forests
• A built landscape is a landscape with more human features, just like a town or a city
• Mechanical weathering is the breakdown of rock without changing its chemical composition
• Freeze-thaw weathering is an example of mechanical weathering. It happens when the temperature alternates above and below 0C. Water gets into cracks. When the water freezes it expands, which puts pressure on the rock. When the water thaws it contracts, which releases the pressure on the rock. Repeated processes of this eventually cause the rock to break up.
• Chemical weathering is the breakdown of rock by changing its chemical composition.
• Biological weathering is the breakdown of rock by living things.
• Mass movement is the shifting of rocks and loose material down a slope. It happens when the force of gravity acting on a slope is greater than the force supporting it
• There are four processes of Erosion:

  • Hydraulic action: Along coasts, waves crash against rock and compress the air in the cracks
  • Abrasion: Eroded particles in the water scrape and rub against a rock in the sea bed, cliffs, or river channel, removing small pieces and wearing them away
  • Attrition: Eroded particles in the water smash against each other and break into small fragments.
  • Solution: Dissolved carbon dioxide makes river and sea water slightly acidic. The acids reacts chemically with some rocks, dissolving them
• Transportation is the movement of eroded material
• There are 4 processes of transportation:

  • Traction: Large particles are pushed along the river bed
  • Suspension: Small particles are carried along by water
  • Saltation: Pebble-sized particles are bounced along the river bed.
  • Solution: Soluble materials dissolve in the water and are carried along
• Deposition is the dropping of material
• Headlands and bays form where there are alternating bands of resistant and less resistant rock along a coast.

  • The less resistant rock(e.g. clay) is eroded quickly and this forms a bay, which have a gentle slope
  • The resistant rock(e.g. chalk) is eroded slowly and is left jutting out, forming a headland, which have steep sides

  
  

  CONSIDER SWANAGE BAY(a bay)
• • Headlands are usually made out of resistant rocks that have weaknesses like cracks
  • Waves crash into the headlands and enlarge the cracks(mainly by hydraulic action and abrasion)
  • Repeated erosion(abrasion and hydraulic action) 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, an isolated rock that separates from the headland

  CONSIDER OLD HARRY'S ROCK(STACK)/DURDLE DOOR(ARCH)
• Beaches are formed by constructive wave depositing material like sand and shingle(rounded rock material).
• Formation of a spit:

  • Spits form when there is a change in direction of the coastline.
  • The process of longshore drift occurs when the prevailing wind blows at an angle to the coastline.
  • Longshore drift will then deposit the sediment in the sea,, in which then an extension of the sediment is formed
  • If there is a change in wind direction, a curved end of the spit can be formed.
  • Salt marshes would be produced behind the spit, meaning plants can grow there
  • Sand dunes would be formed on the spit.

  CONSIDER CHESIL BEACH( JURASSIC COAST)
• Longshore drift:

  • Waves follow the direction of the prevailing wind, which hit the coast at an 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 but towards the sea
  • Overtime, material zigzags along the coast
• Formation of a V-shaped valley:

  • Vertical erosion causes the sides of the channel to deepen
  • Weathering loosens material of the slope
  • Mass movement moves loosen material down the slope
• CASE STUDY: Jurrasic coast

  PSD - Geology

  Headlands and bays:

  1. Discordant coastline
  2. Contains clay(for swanage bay) and sand
  3. Wave refraction at headland

  Caves, arch and stack:

  - Discordant coastline

  - Chalk( Old Harry's rock)

  - Solution affects chalk
• CASE STUDY: Jurrasic Coast

  PSD - Climate

  • Temperature - The coast has warm, dry summers(around 21 degrees in July) and mild;wet winters( average temperature in about 3 degrees). Salt weathering is the dominant form of weathering , usually in summer.
  • Annual temperature = 10 degrees to 12 degrees.
  • Wind- prevailing wind from the south- west. High chances of stroms
  • Rainfall - Annual rainfall = Apprx 800mm
• Explain how management has impacted the coastal landscape.

  Groynes- Strong wooden structures sticking out into the sea

  Advantages

  • They trap sand causing the beach to widen and gives more protection to the coastline behind from erosion
  • Prevents loss of beach material
  • They produce an attractive beach for tourists. Not the most expensive

  Disadvantages

  • They can be seen as unattractive
  • Can cause erosion further along the beach
  • Needs regular maintenance
• Formation of a meander:

  • The current(the flow of water) is faster on the outside of the bend because the river channel is deeper(less friction to slow the water down)
  • So more erosion takes place on the outside of the bend, forming river cliffs
  • The current(the flow of water) is slower on the inside of the bend because the river channel is shallower(more friction to slow the water down)
  • So eroded material is deposited on the inside of the bend, forming slip-off slopes
  • The erosion of the river cliff and the deposition of the slip off slipes causes the river to bend,forming a meander
• 
  

  Ox-Bow lakes are formed from Meanders:

  • Erosion causes the outside bends of the meander to get closer, until there is only a small bit of land left between the bends
  • The river breaks through this land, usually during a flood and the river flows along the shortest course
  • Deposition eventually cuts off the meander, forming an ox-bow lake
• Why do meanders migrate across valleys?

  • Meanders migrate due to deposition and erosion
  • These geomorphic processes tend to make the meander neck more narrower, making the river to flow in a straight and faster course.
  • As the river flows, it eventually breaks the meander neck, forming a straight channel, seperating the meander
• CASE STUDY: River Wye

  Plynlimon hills

  Geology

  • Cambrian mountains are 2500 feet high and made of hark, impermeable rock, e.g. shales and gritstone - the increased rate of surface runoff has created steep v-shaped valleys

  Climate:

  • High rainfall of 1400mm per year- most rain in January 157mm. High rainfall results in high levels of erosion
  • Cold temperatures in winter , which leads to freeze thaw weathering