Unit 3 Physical Landscapes in the UK - Coasts Flashcards

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1
Q

What is weathering?

A

The breakdown of rocks where they are

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2
Q

What is erosion?

A

When rocks are broken down and carried away by something

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3
Q

What is mechanical weathering?

A

The breakdown of rock being disintegrated rather than decomposed

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4
Q

Give an example of mechanical weathering

A

Freeze-thaw weathering

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5
Q

Explain freeze-thaw weathering

A
  1. It happens when the temperature alternates above and below 0°C
  2. Water enters rock that has cracks (e.g. granite)
  3. When the water freezes, it expands, which puts pressure on the rock
  4. When the water thaws, it contracts, which releases the pressure on the rock
  5. Repeating freezing and thawing widens the cracks and causes the rock to break up
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6
Q

What is chemical weathering?

A

Caused by a chemical reaction when rainwater hits rock and decomposes it or eats it away

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7
Q

Give an example of chemical weathering

A

Carbonation weathering

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8
Q

When does carbonation weathering happen? (type of chemical weathering)

A

In warm and wet conditions

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9
Q

Explain carbonation weathering

A
  1. Rainwater has carbon dioxide dissolved in it, which makes it a weak carbonic acid
  2. Carbonic acid reacts with rock that contains calcium carbonate (e.g. carboniferous limestone), so the rocks are dissolved by the rainwater
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10
Q

What is mass movement?

A

The shifting of rocks and loose material down a slope (e.g. a cliff)

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11
Q

When does mass movement happen?

A

When the force of gravity acting on a slope is greater than the force supporting it

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12
Q

How does mass movement affect coasts?

A

It causes coasts to retreat rapidly

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13
Q

When is mass movement most likely to happen?

A

When the material is full of water - water acts as a lubricant, and makes the material heavier

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14
Q

What does the shifting of material create on a slope? (mass movement)

A

A scarp (a steep ‘cut’ in the side of the slope)

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15
Q

What is a landslide?

A

When large blocks of rock slide downhill

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16
Q

How does a landslide occur?

A

A wave-cut-notch is created and as it grows bigger, the weight of the cliff becomes to much to support, causing a landslide

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17
Q

What is a rockfall?

A

When bits of rock fall off the cliff face

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18
Q

How does a rockfall occur?

A

Often due to freeze-thaw weathering

19
Q

What is a mudslide?

A

When saturated soil (soil filled with water) and weak rock flow down a slope - in a straight line

19
Q

How does a mudslide occur?

A

Typically occurs when cliffs are made up of boulder clay

20
Q

What is saturated soil?

A

Soil filled with water

21
Q

What is slumping?

A

Saturated soil slumps down a curved surface

22
Q

How does slumping occur?

A

Soft boulder clay is eroded due to hydraulic action, abrasion, and rainfall.

When layers of boulder clay is left behind by melting glaciers, it causes the cliff to slump

23
Q

What is the definition of coastal erosion?

A

The actions of waves wearing away the rock along the coastline and removing the coastal sediments

24
Q

What is hydraulic action?

A

When waves crash against rock and compress the air into the cracks. This puts pressure on the rock - repeated compression widens the cracks and causes bits of rock to break off

25
Q

What is abrasion?

A

When eroded particles in the water scrape and rub against the rock (cliff), removing small pieces

26
Q

What is attrition?

A

When eroded particles in the water smash into each other and break into smaller pieces. Their edges get rounded off as they bash into each other

27
Q

What is solution? (process of erosion)

A

When weak carbonic acid in seawater dissolves rock, like chalk and limestone

28
Q

How is a wave created?

A

When wind blows over the surface of the sea

29
Q

How is the power of a wave determined?

A

The greater the fetch, the more powerful the wave

30
Q

What is the fetch (power of wave)?

A

The distance the wind blows over the sea

31
Q

Describe the features of destructive waves

A
  • High frequency (11 to 15 waves per minute)
  • Rear up to form towering waves
  • Tall and steep wave height
  • Strong backwash
  • Weak swash
  • Sand and shingle pulled down the beach; removing material
32
Q

Describe the features of constructive waves

A
  • Low frequency (6 to 9 waves per minute)
  • Low and long wave height
  • Weak backwash
  • Strong swash
  • Little erosion
33
Q

What is traction?

A

When large particles like boulders are pushed along the sea bed by the force of the water

34
Q

What is saltation?

A

When pebble-sized particles are bounced along the sea bed by the force of the water

35
Q

What is suspension?

A

When small particles float in the water

36
Q

When does deposition occur?

A

When water carrying sediment loses energy and slows down

37
Q

When is the amount of material deposited on an area of coast increased?

A
  • When there’s lots of erosion elsewhere on the coast (so more material is available)
  • When lots of material is transported into the area
38
Q

Which kind of wave has more deposition than erosion?

A

Constructive waves
- they drop more material than they remove

39
Q

What is longshore drift?

A

Where material such as sand and pebbles is transported along the coast by wave action in a zig-zag pattern

40
Q

What is deposition?

A

The laying down of materials, such as sand and pebbles, which are being transported by the sea

41
Q

Explain longshore drift

A
  1. Waves follow the direction of the prevailing wind (strongest wind)
  2. They usually hit the coast at non-right angles
  3. The swash carries material up the beach, in the same direction as the waves
  4. The backwash then carries material down the beach at right angles, back towards the sea
  5. This process repeats, making material zig-zag along the coast
42
Q
A