Coastal Zone Flashcards
(38 cards)
What is weathering
The breakdown of rocks in one place
What is erosion
Breakdown of rocks that was then carried away
What are tides caused by
The magnetic pull of the earth, the moon and the sun
What is the fetch
The distance across which the wind blows. The bigger the fetch, the bigger the wave
What factors affect the size of a wave
- How long the wind has been blowing
- The strength of the wind
- How far the wind has travelled (the fetch)
What two types of wave reach the coast
Constructive and destructive
What does a constructive wave do
Build up the beach and dump sand, pebbles on the shore
- Swash is more powerful than backwash
- Longer wavelength than wave height
- Which beach at a rate of eight a minute or less
What is the coastal zone
The point where the land meets the sea
What does a destructive wave do
It takes material away
- Greater weight height than wavelength
- Back wash is stronger than swash
- Destructive waves reach beach at a rate of 10+ per minute
- formed by a storm (mainly during winter)
What are the three processes of weathering
- Mechanical or physical weathering
- Chemical weathering
- Biological weathering
What is mechanical/physical weathering?
The breakdown of rocks which doesn’t involve any chemical changes taking place-build up a rock at the bottom of the hill or Cliff is known as scree
E.g. Frost shattering all freeze thaw
Exfoliation/onion peel
What is chemical weathering
Weathering that involves a chemical change taking place. Breakup of rock involving chemical changes e.g. acid rain or carbonation
What is biological weathering
Weathering caused by living organisms e.g. tree roots and borrowing animals
Methods of coastal erosion
- Corrosion/solution
- Corrasion/abrasion
- Attrition
- Hydraulic action
- Wave pounding
What is corrosion/solution
- Occurs when the seawater is slightly acidic and reacts with dissolved rocks e.g. limestone, chocolates
- Sea water becomes acidic from the CO2 being dissolved from the air, fish, seaweed and algae…
What is corrasion/abrasion
- Caused by wearing away of rocks being flung at the cliff face
- During storms huge quantities of rocks will be thrown at/where down the cliffs
What is attrition
- Pebbles in waves constantly knock against each other
- Gives fairly smooth and around rocks
What is hydraulic action
- As waves hit the cliffs, water is forced into little cracks, displacing/pushing the water the back.
- When the wave retreats the air expands(pops) to fill the space, therefore sending out a little soundwaves (vibrations)
- if this happens thousands of times a day, it can cause the rock to disintegrate
What is wave pounding
Sheer force of the water hit in the cliff. Greatest force in storms
What coastal features are formed as a result of erosion
- Headlands/bays
- Cliffs, undercutting/wave cut notch
- Caves
- Arches
- Stacks, stamps, Reefs
- Wave cut platform
What is differential erosion
- Takes place at different rates on the coast as there are different types of rocks
- this means there will be different times of the erosion-soft rocks get a eroded first
- Hard rock forms headlines
- Soft rock forms bays
Give me two examples of cliffs
- White Cliffs of Dover
- Seven sisters in Suffolk
Give me two examples of wave cut platform
- Birling Gap, Sussex
- Robin Hood Bay, Yorkshire
What happened at Barton on Sea
In 2008 the cliffs collapsed as a result of sliding and rotational slumping
