KQ1: Causes of Landforms

Effectiveness of coastal processes
1. Geology (rock type and structure)
2. Aspect
  1. Direction of coast in relation to waves
3. Sea level change
  1. 250m higher than 10,000 years ago
4. Time
5. Human Activity
Weathering Processes
1. Salt crystallisation
  1. When sea water enters cracks in the rock and then dries, leaving behind salt growths which prise the cracks apart
2. Wetting and drying
  1. When rocks are periodically wetted and dried, clay minerals expand causing rocks to break up
3. Frost shattering
  1. When water enters cracks and freezes, it expands, shattering rocks or expanding cracks
4. Heating and Cooling (insulation weathering)
  1. Thermal expansion and contraction of rocks (usually the face) can cause onion skin weathering, as a layer of rock will be eroded and another exposed
5. Oxidation
  1. CO2 gas in the atmosphere reacts with rain water making it acidic, and the solution removes Al and Fe from the rocks, leading to disaggregation
6. Chelation
  1. The decay of organic matter causes acid to enter rocks, wearing it away
Mass Movements
1. Slides
  1. Saturated weathered material moving down a slope under the influence of gravity
2. Falls
  1. Dislodged material falls to the base of cliff, usually caused by undercutting
3. Slumps
  1. Involves a whole segment of the cliff moving down-slope along a saturated shear-plane
4. Flows
  1. When extremely saturated mud flows down a cliff
5. Creeps
  1. The gradual downhill movement, under the force of gravity, of soil and loose rock material on a slope
Marine Processes
1. Erosion Processes
  1. Hydraulic Action
  2. Abraision
  3. Corrosion
  4. Attrition
2. Transport Processes
  1. Swash
    1. Body of water pushing up a beach after a wave has broken
  2. Backwash
    1. The movement of water back down a beach after it has reached its highest point
Geology
1. Lithology
  1. Limestone
    1. Cemented and strong
  2. Sandstone
    1. Resistant but weak if poorly cemented
  3. Clay/Mudstone
    1. Weak, easily saturated and eroded
  4. Granite
    1. Resistant due to interlocking crystals
  5. Boulder Clay
    1. Mixture of grain sizes, weak
2. Structure
  1. Bedding planes, joins and faults
    1. Allow water to enter rock and expose more cliff face to sub-aerial processes
  2. Poorly cemented (porous)
    1. More succeptable to weathering due to permeability
  3. Plan-form
    1. Discordant coasts expose more rock to weathering than concordant coasts

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KQ1: Causes of Landforms

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	Created by sophie.c.cook over 10 years ago