Coasts part 2

• Types of biological weathering

  plant roots and animals
• How is plant roots a type of weathering

  -seeds collect in cracks by wind or birds

  -the seeds (if conditions are right) will develop into plants

  -eventually the plant becomes a tree and the roots will become so large that they make the crack bigger
• How are animals a type of weathering

  -animals such as badgers and moles dig/burrow down into rocks which will enlarge the cracks or weaken the rock making it easier to collapse
• Type of chemical weathering

  acid rain
• How is acid rain a type of weathering

  -rainwater absorbs CO2 from the air and becomes slightly acidic

  -contact with alkaline rocks e.g. chalk and limestone causes the rock to dissolve
• What is mass movement

  The downward movement or sliding of material under the influence of gravity
• What are the 4types of mass movement

  rockfall

  mudflow

  landslide

  rotational slip
• What is rockfall


  Fragments of rock break away from the cliff face, often due to freeze-thaw weathering.
• What is a landslide


  the sliding down of a mass of earth or rock from a mountain or cliff.
• What is mudflow


  Saturated soil and weak rock flows down a slope
• What is rotational slip


  Slump of saturated soil and weak rock along a curved surface
• Case study for mass movement

  Scarborough 1993

  -60m of cliff slipped onto the beach near Scarborough, North Yorkshire

  -Took with it part of the Holbeck Hall Hotel

  -The hotel was left on the cliff edge so had to be demolished

  -land can no longer be used

  -nearby houses aren't safe to live in

  -jobs were lost
• What are the 4 main processes of coastal erosion

  Abrasion:

  rocks hitting the cliff surface

  Attrition:

  rocks hit under each other

  Hydraulic action:

  pressure of water

  Solution:

  chemicals dissolve
• Why is coastal erosion important

  -causes landslides

  -cost of the damage it causes

  -damage to property/infrastructure, transport and agriculture

  -land isn't accessible so tourism isn't possible

  -coastal retreat (land moving back water moving forward)
• What is a prevailing wind?


  The main direction the wind is travelling
• First stage of the process of longshore drift

  1- the direction of the prevailing wind influences where the start of longshore drift is and the direction it occurs in
• Second stage of the process of longshore drift

  2-The waves approach the beach at an angle (influenced by direction of prevailing wind)
• Third stage of the process of long shore drift

  3- Then the swash carries the sediment up the beach at the same angle as the breaking wave
• Fourth stage of the process of long shore drift

  4- next the backwash moves the sediment down the beach by gravity
• Fifth stage of the process of long shore drift

  5-this continuous zigzag movement carries sediment down the beach by gravity
• Sixth stage of the process of long shore drift

  6- Overtime the process of long shore drift causes depositional landforms along the coastline
• How do the waves transport material

  Through the process of longshore drift