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Paper 1 - Physical Landscapes in the UK > Coasts - Processes and landforms > Flashcards

Coasts - Processes and landforms Flashcards

1
Q

What is a wave?

A

A disturbance on the surface of the sea or ocean.

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2
Q

How do waves form?

A

Friction created by wind blowing over the surface of the sea.

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3
Q

What happens as waves approach the coast?

A

Their orbit becomes more elliptical due to friction with the seabed. The crest rises up and breaks on the shore.

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4
Q

What is fetch?

A

The distance the wind blows over water.

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5
Q

Which factors affect wave size?

A

The greater the fetch, the larger the wave. Stronger and faster winds create larger waves.

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6
Q

What are the features of constructive waves?

A

Swash stronger than backwash. Long wavelength. Low height and low frequency. Create beaches with a gently sloping profile.

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7
Q

What are the features of destructive waves?

A

Backwash stronger than swash. Destroy the beach. High wave frequency. Create a steep beach profile.

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8
Q

Define ‘swash’.

A

The water flowing towards a beach when a wave breaks.

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9
Q

Define ‘backwash’.

A

The movement of water down the beach, after a wave has broken.

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10
Q

Define ‘elliptical’.

A

Oval-shaped or egg-shaped.

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11
Q

What is weathering?

A

The breakdown of rock, in situ, by biological activity, chemical processes or weather-related factors.

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12
Q

What is mechanical weathering?

A

The breakdown of rock, without affecting its chemical composition e.g. freeze-thaw weather.

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13
Q

Explain how freeze-thaw weathering works.

A

Porous rocks hold water/allow it to pass through. The water freezes at night, expanding the cracks. This ice thaws in the daytime when temperatures rise. When ice thaws, water seeps further into the cracks. The crack expands further by water freezing at night. This processes repeats itself, breaking down the rock.

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14
Q

What is chemical weathering?

A

The breakdown of rock, changing its chemical composition e.g. through carbonation.

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15
Q

How does carbonation happen?

A

When slightly acidic rainwater comes into contact with limestone or chalk, it causes it to dissolve. A chemical reaction occurs, between the acidic rainwater and calcium carbonate in the limestone/chalk, forming calcium carbonate. Calcium carbonate is soluble and gets carried away.

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16
Q

What is biological weathering?

A

The breakdown of rock, by the actions of living organisms.

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17
Q

How might biological weathering occur?

A

Tiny bacteria, algae and lichens all produce chemicals that can help to break down the rocks they live on. Tree roots may prise apart rocks if they grow into the cracks of the rock. If roots grow, they may make cracks bigger and break up the rock.

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18
Q

Define ‘in situ’.

A

Describes something that remains where it is while being subjected to a process.

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19
Q

Define ‘algae’.

A

A simple, non-flowering, typically aquatic plant. They lack true stems, roots and leaves.

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20
Q

What is mass movement?

A

The downhill movement of cliff material, under the influence of gravity.

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21
Q

Which cliff material is susceptible to slumping?

A

Boulder clay.

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22
Q

How does slumping occur?

A

Rainfall causes boulder clay to become saturated. This causes the cliff to slump due to its weight (there is additional weight from the water it is holding). The debris from the slump is deposited at the bottom of the cliff. The debris is eroded by the sea, leaving the cliff exposed to coastal marine processes.

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23
Q

How do landslides occur?

A

Waves breaking at the foot (bottom) of cliffs form a wave-cut notch. Continued erosion increases the size of the notch. The weight of the cliff is too heavy to be supported, resulting in a landslide. The debris is deposited at the bottom of the cliff, providing temporary relief from erosion.

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24
Q

What is a rock fall?

A

Fragments of rock breaking away from a cliff face, often due to freeze-thaw weathering.

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25
Q

When do mudflows occur?

A

When saturated soil and weak rock flows down a slope. Mudflows typically affect cliffs made of boulder clay.

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26
Q

Define ‘boulder clay’.

A

A sort of ‘stony soil’. It is made of rocks, sand and gravel which were deposited by melting glaciers at the end of the ice age.

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27
Q

Define ‘saturated’.

A

Describes something that is completely full of water, to the extent that it cannot hold any more.

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28
Q

Define ‘slump’.

A

To fall suddenly.

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29
Q

Define ‘debris’.

A

Scattered pieces of material left over from something that has been destroyed.

30
Q

Name the 4 processes of coastal erosion.

A

Hydraulic action, Abrasion, Attrition, Solution

31
Q

What is hydraulic action?

A

When waves hit the base of cliffs, they force air into the cracks in the rock. When the wave retreats, air rushes out of cracks. The trapped air in cracks in the rock breaks the rock down.

32
Q

What is abrasion?

A

The sandpapering effect of pebbles grinding against rocky platforms, often causing them to become smoother.

33
Q

What is attrition?

A

This is where rock fragments, carried by the sea, knock into one another, causing them to become smaller and more rounded.

34
Q

What is solution?

A

This is when certain cliff types and rock types are eroded by weak acids present in the seawater.

35
Q

Name the 4 processes of coastal transportation.

A

Traction, Saltation, Suspension, Solution

36
Q

What is traction?

A

Large pebbles and boulders rolled along the seabed.

37
Q

What is saltation?

A

Small stones and pebbles bounced and hopped along the seabed.

38
Q

What is suspension?

A

Fine material floating and hanging in the water, carried along by its flow.

39
Q

What is solution?

A

Dissolved materials carried along in the water’s flow.

40
Q

What is longshore drift?

A

The main way in which material is moved along the coast.

41
Q

How does longshore drift work?

A

Waves approach the beach at an angle. Swash carries material up and along the beach. Backwash carries material back down the beach at right angles, as a result of gravity. This process slowly moves material along the beach in a zig-zag motion.

42
Q

What is deposition?

A

The dropping of material that was being transported by waves.

43
Q

Why does deposition occur?

A

Due to reduced wave energy.

44
Q

What causes wave energy to reduce, resulting in deposition?

A

Waves entering an area of shallower water. Waves entering a bay. When there is little wind. When a river or estuary flows into the sea. When there is more material than waves have the energy to transport.

45
Q

What is a landform?

A

A natural feature of the Earth’s surface, created by natural processes.

46
Q

How does rock type influence coastal landforms?

A

Limestone, chalk and granite are tougher and more resistant than other rock types so they take longer/more energy to erode.

47
Q

How does geological structure influence coastal landforms?

A

Tectonic pressure can cause some rocks to snap, creating lines of weakness. These lines of weakness can be carved out by marine processes.

48
Q

How are headlands and bays formed?

A

Headlands formed along discordant coastlines. Less resistant rock is eroded faster, creating bays. More resistant rock is eroded slower, leaving headlands which jut out into the sea.

49
Q

What is a discordant coastline?

A

A coastline along which bands of hard and soft rock stick out at a right angle to the coastline.

50
Q

What is a concordant coastline?

A

A coastline where the same rock type runs along the whole length of the coastline.

51
Q

What are the features of bays?

A

They are sheltered so they tend to have sandy beaches, resulting from deposition of material because waves lose energy when they enter the bay.

52
Q

What is a wave-cut platform?

A

A wide, gently sloping platform found at the base of a cliff, extending into the sea.

53
Q

How is a wave-cut platform formed?

A

The sea (through hydraulic action & abrasion) attacks cracks at the foot of a cliff, creating a wave-cut notch. The notch becomes larger due to continued erosion. The unsupported rock above collapses, causing the cliff to retreat. Material from the collapsed cliff face is eroded and transported, leaving a wave-cut platform behind. Over time, abrasion may cause the wave-cut platform to become smoother.

54
Q

How are headlands eroded over time?

A

Cracks in headlands are opened up by hydraulic action & abrasion, transforming cracks into caves. Caves are eroded by the same processes, eroding all the way through to the other side of the headland. An arch forms. Hydraulic action at the base of the arch and freeze-thaw weathering on the roof of the arch cause the roof to collapse, leaving a stack. Wave-cut notches on either side of the base of the stack leave it unable to support its own weight. It collapses into the sea to form a stump.

55
Q

What is a spit?

A

A long finger of sand or shingle, jutting out into the sea from the land.

56
Q

Where do spits form?

A

On coastlines where there is significant longshore drift?

57
Q

How do spits form?

A

Where a coastline changes direction and bends sharply, longshore drift continues in the direction of the original coastline and deposits sediment in the sea. As sediment builds up, it starts to form an extension from the land, creating a spit. A change in wind direction can cause the spit to curve. If the spit curves due to strong winds or tidal currents, it is known as a recurved end. If the wind direction changes back, the spit will continue to extend outwards in its original direction. There may be a number of recurved ends to mark previous positions of the spit.

58
Q

What forms behind the spit?

A

A saltmarsh, due to the water being sheltered and mud being deposited.

59
Q

Why are saltmarshes important?

A

They are habitats for migrating birds.

60
Q

What is a bar?

A

A ridge of sand or shingle that joins two headlands, either side of a bay.

61
Q

When are bars formed?

A

When longshore drift causes a spit to grow right across the mouth of a bay.

62
Q

What is an offshore bar?

A

A bar that forms in the sea. It forms as a result of a gently sloping coastline, causing deposition of sediment because the sea encounters friction with the seabed.

63
Q

Define ‘saltmarsh’.

A

An area of flat, wet ground which is often flooded by salt water.

64
Q

Define ‘migrating’.

A

Moving from one habitat or area to another, according to the seasons.

65
Q

Where is the Dorset Coast?

A

In the south of England?

66
Q

Why is the Dorset Coast significant?

A

Its geology represents 185 million years of history.

67
Q

Which landforms can be found at Swanage?

A

Headlands and bays. Swanage Bay is formed from soft clay. Durlston Head (a headland) is formed from limestone and Ballard Point (another headland) is formed from chalk.

68
Q

What kind of coastline can be found at Swanage?

A

Discordant.

69
Q

What kind of coastline is found on the south coast?

A

Concordant. Limestone forms a relatively straight section of coast.

70
Q

Define ‘lagoon’.

A

A body of water separated from the sea by a bar.

Paper 1 - Physical Landscapes in the UK (4 decks)

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