1.1.9: Variations in coasts over time Flashcards

1
Q

Fast timescale: changes in seconds

2 examples

A

High- energy storm activity

Rapid mass movement

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2
Q

Seasonal changes

example

A

Changes in beach profile

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3
Q

Changes over millennia

example

A

Sea-level change

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4
Q

Rapid mass movement

A

Sudden rockfalls, landslides and slumps create changes in cliff-face profiles and retreating cliffs, with the loss of land and possibly buildings.

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5
Q

High energy storm events

A

Causes an increase in wave energy, resulting in wave erosion and transportation

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6
Q

What can high energy storm events / tsunamis causes

3

A
  • removal of large amounts of beach sediment, changing the profile or removing it altogether
  • destruction or breaching of sand dunes
  • coastal flooding
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7
Q

Seasonal changes influencing a beach profile
UK Summer
5

A
fewer storms
less frequent high wind speeds
lower- energy waves
wave predominantly constructive
sediment moved onshore, building up the beach
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8
Q

Berm

A

A beach terrace formed by low energy waves.

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9
Q

Seasonal changes influencing a beach profile
UK Winter
5

A
More storms
High winds more frequent
Higher- energy waves
Destructive waves more frequent
Sediment moved offshore, lowering the beach profile
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10
Q

Sea level change

2 types

A

Eustatic

Isostatic

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11
Q

Eustatic change

A

A global change in the volume of water in oceans

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12
Q

Isostatic change

A

A localised change in the relative sea level.

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13
Q

Causes of eustatic change

3

A
  • during a glaciation period more water is frozen = resulting in a fall in sea level
  • global warming of the climate increases the melting of continental ice sheets = causes rise in sea level
  • warming of oceans causes the volume of water to expand = creating a rise in sea level
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14
Q

Causes of isosatic change

2

A

The upward or downward movement of land masses

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15
Q

What causes the upward movement of land masses

A

Melting ice removes the weight and the land slowly rises = relative fall in sea level (isostatic recovery)

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16
Q

What causes the downward movement of land masses

A

During the glacial period the weight of the ice causes the land to sink into the crust making sea level appear relatively higher

17
Q

Impacts of rising sea levels on landforms

3

A

flood lower-lying parts of the coast
deltas, spits and beaches disappear under water or due to increases rates of erosion
river floodplains and valleys flood to form rias and fjords

18
Q

Ria

A

A flooded river valley which becomes a broad river estuary

19
Q

Fjords

A

If the flooded valley is a glaciated U-shaped valley a fjord is formed

20
Q

Features of fjords

A

Very deep, flat bottomed and steep sided, u-shaped

21
Q

Threshold

A

Shallower entrance of a fjord

22
Q

Skerry

A

A small, rocky island is created when the sea level rise doesn’t cover the threshold

23
Q

Raised beaches

A

Beaches are no longer affected by waves and are left stranded above the new sea level

24
Q

Relict cliffs

A

The former cliff lines and landforms left stranded above the new sea level

25
Q

Degraded cliffs

A

New version relict cliffs which have been eroded by sub-aerial processes and now are covered in vegetation and are no longer undercut.

26
Q

Falling sea levels form which landforms

A

raised beaches
relict cliffs/ degraded cliffs
marine terrrace

27
Q

Marine terrace

A

the wave-cut platform appears raised above sea level to form a marine terrace

28
Q

Marine terrace use

A

agriculture

29
Q

Example of isostatic recovery

A

The western coast of Scotland has an isostatic recovery rate of 2mm per year and possesses many of these features