Processes and factors responsible for distinctive coastal landforms.

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  • Created by: hamishc
  • Created on: 26-04-16 16:18
How do waves form?
As wind blows over the ocean, friction occurs causing energy to be transferred creating waves. As the waves move towards shallow coastal waters, the drag on the seabed slows the base of the wave, causing increased height until the wave breaks.
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What are the factors affecting waves?
Wind direction, wind strength, fetch.
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What is swash?
A body of water pushed up the beach after a wave is broken, causes deposition.
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What is backwash?
The movement of water back down a beach after a wave has reached its highest point, causing erosion.
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What are constructive waves?
Have long wavelength, and short wave height, stronger swash than backwash resulting in deposition and the formation of ridges.
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What are destructive waves?
Have short wavelength, large wave height causing waves to crash onto the beach with large amount of energy, causing strong backwash and therefore erosion.
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How do storm surges occur?
When the following factors coincide: High tides, strong onshore winds creating high wave energy, low pressure weather allowing sea to expand.
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What are the 3 types of coastal erosion?
hydraulic action, abrasion/ corrosion, attrition.
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What is hydraulic action?
When the cliff-face is attacked, breaking waves force air into cracks in the cliff surface, compression of air has the power to loosen and break away rock.
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What is abrasion/ corrosion?
When sand/ sediment is picked up and hurled by waves at the cliff face, most rapid form of coastal erosion.
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What is attrition?
Rocks and pebbles are constantly collided with each-other, reducing the size and roundness of beach material as impacts smooth away rough edges.
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What are the 2 types of coastal weathering?
Solution, wetting/ drying.
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What is solution?
Chemical reaction occurs between slightly acidic sea and calcium based rocks such as chalk, this causes the calcium to ionise and dissolve into the sea water, where it is carried away.
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What is wetting/ drying?
When weaker rocks like clay are found in the coastal splash zone, they prone to expansion and contraction as they become wet and dry out, this causes weakness and disintegration in the rock, allowing marine processes to erode more easily.
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How do slumps and rockfalls occur in coastal environments?
When abrasion from wave action undercuts and weakens the base of the cliff, this can lead to whole sections of the cliff collapsing as a slump or rockfall.
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Difference between resistant and non-resistant rock in the formation of coastal landforms.
More resistant rocks such as limestone erode slowly producing spectacular cliff features, whilst weaker rocks like clay have less structural strength resulting in a low cliff profile, mudslides and slumping.
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What is a concordant coastline and how does it affect landforms?
A coast where rock types run parallel to the sea. Results in straighter coastlines with fewer distinctive landforms.
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What is a discordant coastline and how does it affect landforms?
A coast where rock types run at a right-angle to the sea. Resulting in more headlands and bays as the types of rock erode at different rates causing outcrops.
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What is lithology of rock?
Mineral composition, cracks, joints, coherance of different rocks. It is what determines the level of resistance the rock has.
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Other cards in this set

Card 2

Front

What are the factors affecting waves?

Back

Wind direction, wind strength, fetch.

Card 3

Front

What is swash?

Back

Preview of the front of card 3

Card 4

Front

What is backwash?

Back

Preview of the front of card 4

Card 5

Front

What are constructive waves?

Back

Preview of the front of card 5
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