Geography - AQA - GCSE - Physical - Coasts

Geography - AQA - GCSE - Physical - Coasts

1. Processes

   • Erosion
     • Corrosion
       • Dissolving because of acidity in water
     • Corrasion/Abrasion
       • Rock rubbing against other rocks
     • Attrition
       • Rock hitting other rocks
     • Hydraulic action
       • Sheer force of water against rocks
   • Mass Movement
     • Rotational slumping
       • Large areas of land falling very quickly
         • Material shifts with a rotation
     • Mudflow
       • Saturated soil falling slowly
         • Material shifts in a straight line
     • Rockfall
       • Rocks falling usually due to freeze thaw weathering
         • Material shifts vertically
     • Landslide
       • Rocks rolling downhill
         • Material shifts in a straight line
   • Weathering
     • Chemical
       • Acidic rain corroding
     • Biological
       • Animals burrowing into cliffs
         • Roots of plants in cliffs
     • Physical
       • Freeze thaw
         • Water in cracks freeze and expand, splitting rocks and cliffs
       • Exfoliation
         • During the day, heats up and at night, cools down, expanding and contracting and then cracking

2. Landforms

   • Wave-cut Platform
     • Wave-Cut Notch
       • Example
         • Caused by high and low tide
     • Example
       • Wave-cut notch leaves cliff undercut
         • Cliff collapses leaving area of land where cliff once was
           • Repeats and leave platform
   • Headland
     • Cave
       • Arch
         • Stack
           • Stump
             • Example
               • Stack is eroded down to make stump
           • Example
             • The top of the arch collapses, leaving stacks
         • Example
           • A cave is eroded all the way through
       • Example
         • Where a fault in a cliff is eroded
     • Example
       • Harder rock that doesn't erode as easily
   • Bay
     • Beach
       • Example
         • Less wave energy in bays because of wave refraction so deposition occurs
     • Example
       • Softer rock that erodes easier than the harder rock
   • Spit
     • Example
       • Prevailing wind means longshore drift occurs, taking sediment away from the coast. Occasionally, a secondary wind kicks in and curls the end of the spit around. The process repeats. If there is an estuary, the spit stops
   • Bar
     • Tombolo
       • Example
         • A bar that connects the mainland to an island
     • Example
       • A spit that has grown across a bay, undisturbed, joining the two headlands. There is a lagoon on one side
   • Cove
     • Example
       • Fault in hard rock is eroded, with soft rock behind the hard rock
         • Soft rock is further eroded to form a cove

3. Case studies

4. Waves

   • Constructive
     • Weak backwash
       • Strong swash
         • Short waves
           • Long length waves
             • Deposition occurs
               • Low frequency
   • Destructive
     • Strong backwash
       • Weak swash
         • High waves
           • Small length waves
             • Erosion occurs
               • High frequency
   • Terms
     • Fetch - Distance of water over which the wind has blown to produce a wave.

5. Longshore drift

   • The prevailing wind carries sediment along the beach

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