Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Edexcel A Level Geography > Coasts EQ2 - Coastal landforms > Flashcards

Coasts EQ2 - Coastal landforms Flashcards

1
Q

What are the characteristics of constructive waves?

A
  • low wave height (less than 1m)
  • long wave length (up to 100m)
  • strong swash, weak backwash
  • low frequency (8-10 waves per min)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the characteristics of destructive waves?

A
  • wave height of over 1m
  • wavelength of around 20m
  • strong backwash and weaker swash
  • high frequency (10-14 per min)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is beach morphology?

A

The shape of a beach, including its width and slope (beach profile) and features such as berms, ridges and runnels. Also includes type of sediment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is fetch?

A

The uninterrupted distance across water over which a wind blows, and therefore the distance the waves have to grow in size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What factors does wave size depend on?

A
  • strength of wind
  • duration wind blows for
  • water depth
  • wave fetch
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are human changes that can cause beach profiles to change?

A
  • construction of dams blocking sediment supply
  • global warming creating more storms
  • coastal management intefering with sediment supply
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is hydraulic action and the influence of lithology on it?

A

Air trapped in cracks and fissures is compressed by the force of the waves crashing against the cliff face, causing blocks of rock to become dislodged.
Heavily jointed/fissured sedimentary rocks are therefore vulnerable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is abrasion and the influence of lithology on it?

A

Sediment picked up by breaking waves is thrown at the cliff face, which acts like a tool on the cliff, gradually wearing it down.
Loose sediment must be available for abrasion to be effective. Softer sedimentary rocks more vulnerable than hard igneous ones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is attrition and the influence of lithology on it?

A

Sediment is moved around by waves, causing collisions between particles to chip fragments off, causing sediment to become smaller and more rounded.
Softer rocks very rapidly reduced in size by attrition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is corrosion/solution and the influence of lithology on it?

A

Carbonate rocks (limestones) are vulnerable to solution by rainwater, spray from the sea and seawater (the rock gets dissolved).
Mainly affects limestones, vulnerable to solution by weak acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How does a blow hole form?

A

When a coastal cave turns upwards and breaks through the flat cliff top. Usually this is because of erosion of especially weak strata or the presence of a fault line.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How is a wave cut platform formed?

A
  1. Wave cut notch is eroded between high and low tide water marks, through erosion processes at a cliff face.
  2. The notch deepens by further erosion until the overlying material collapses by mass movement due to gravity, forming a cliff.
  3. The process repeats, and the position of the cliff retreats (coastal recession)
  4. The rock just below low tide level is always submerged, it’s uneroded as it’s never exposed to wave impact.
  5. As the overlying material is eroded, uneroded rock at low tide level is left as flat rock surface, the wave cut platform.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Explain the cave-arch-stack-stump formation process

A
  1. Weaknesses in rocks at a cliff face (joints, faults etc) are exploited by marine erosion from waves causing a sea cave to form
  2. This is accentuated by wave refraction, as energy is directed at lateral erosion of the headland
  3. Where a line of weakness extends right through the headland caves form on both sides. Marine erosion deepens the caves until they connect up, forming an arch.
  4. Undercutting of sides of arch leads to collapse of overlying material, eroding arch wider
  5. Weathering and sub aerial processes cause arch roof to collapse and this creates a stack
  6. Marine erosion at the base of the stack will form a notch on all sides until the stack collapses by blockfall - forming a stump
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How is a cliff formed?

A
  1. Marine erosion of land between the high tide and low tide mark by hydraulic action and abrasion forms a wave cut notch
  2. The notch deepens until the overlying rock collapses by mass movement due to the force of gravity.
  3. The exposed face forms a cliff.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What factors affect sediment transportation?

A
  • angle of wave attack
  • process of longshore drift
  • tides
  • currents
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the 4 processes of sediment transport, and the type of sediment they transport?

A
  1. traction - pebbles, boulders
  2. saltation - sand sized particles
  3. suspension - silt and clay particles
  4. solution - chemical compounds in solution
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is a swash aligned coast?

A

Where wave crests approach parallel to the coast, so there is limited longshore movement of sediment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is a drift aligned coast?

A

Where wave crests break at an angle to the coast, so there is consistent longshore drift and generation of elongated depositional features

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is gravity settling?

A

When sediment is deposited because the energy of transporting water becomes too low to move sediment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is flocculation?

A

Depositional process where clay particles clump together due to electrical or chemical attraction and become large enough to sink and are no longer suspended

21
Q

What is a spit and how is it formed?

A

A sand or shingle beach ridge extending beyond a turn in the coastline
Where the coast changes direction, longshore drift continues to deposit material in a zig zag motion in the direction of the prevailing wind

22
Q

What is a tombolo and how is it formed?

A

A sand or shingle bar that attaches the coastline to an offshore island.
Formed due to wave refraction around an offshore island that creates an area of calm water and deposition between the island and the coast

23
Q

What is a barrier beach/bar and how is it formed?

A

A sand or shingle beach connecting two areas of land with a shallow water lagoon behind.
Forms when a spit extends across a bay to connect two headlands.

24
Q

What is an offshore bar/berm and how is it formed?

A

Ridges of sand or shingle running parallel to the coast in an offshore zone
Formed from sediment eroded from the coastline by destructive waves which is then dragged back by the backwash – which stops at a shallower point. Transport offshore is halted by friction with the sea bed.

25
Q

What is a cuspate foreland and how is it formed?

A

Cuspate forelands extend outwards from the shoreline in a triangular shape
Formed by accretion and progradation of sand and shingle. Waves are incident from two directions/longshore drift from two directions causes the deposition of sand in a triangle.

26
Q

What is a storm ridge and how is it formed?

A

Storm ridges consist of the largest material thrown up by the swash of strong waves in a storm – much higher than the reach of normal tides.

27
Q

What are cusps and how are they formed?

A

Cusps are semi circular depressions formed by a collection of waves reaching the same point. The curved shape causes swash to concentrate in the small bay formed in the centre, while the backwash drags material back down the middle.

28
Q

What are berms and how are they formed?

A

Berms are a series of smaller ridges on a beach formed by the deposition of sediment by spring high tides or storm waves.

29
Q

What is a hooked/recurved spit and how does it form?

A

A spit whose end is curved landward, into a bay or inlet
The seaward/distal end of the spit naturally curves landward into shallower water. The ‘hook’ may be made more pronounced by waves from a secondary direction to the prevailing wind.

30
Q

What is a sediment cell?

A

A linked system of sources, transfers and sinks of sediment along a section of coastline

31
Q

What is dynamic equilibrium and how is it reached?

A

Dynamic equilibrium is reached when inputs of sediments from the source region are balanced by the amount being deposited in sinks. It is dynamic because although it is in balance, there’s a constant movement of sediment through the sediment.

32
Q

What is negative feedback?

A

When a system returns to equilibrium following a change in the system.

33
Q

What is positive feedback?

A

When an initial change within a system brings about further change in the same direction.

34
Q

What are some examples of sources, transfers and sinks?

A

Sources - offshore bars, cliffs
Transfers - beaches, parts of dunes, salt marshes
Sinks - spits, cuspate forelands

35
Q

What is weathering?

A

The in situ breakdown of rocks by chemical, mechanical or biological agents. It does not involve any movement

36
Q

What is erosion?

A

The breakdown of rock due to the action of some external force, which then transports the eroded material to a new location

37
Q

What is mechanical weathering?

A

Rocks being broken down due to the exertion of a physical force, it does not involve any chemical change

38
Q

What is chemical weathering?

A

The interaction of rock with mineral solutions (chemicals) to change the composition of rocks.

39
Q

What is biological weathering?

A

The weakening and subsequent disintegration of rock by plants, animals and microbes

40
Q

What are some examples of mechanical, chemical and biological weathering?

A

Mechanical - freeze thaw, salt crystallisation
Chemical - carbonation, hydrolysis, oxidation
Biological - plant roots, rock boring

41
Q

What is mass movement?

A

The downslope movement of rock and soil

42
Q

What is a fall?

A

Rockfalls or blockfalls are a rapid form of mass movement where a rock fragment breaks away and either drops vertically or bounces downslope.
Initiated by mechanical weathering or marine erosion (wave cut notches, undercutting)

43
Q

What is a topple?

A

Forward rotation of rocks about a pivot point.
Where rock strata have a very steep seaward dip, undercutting by erosion will lead quickly to instability and blocks of material toppling seaward

44
Q

What is a rotational slide/slump?

A

Rock failure and movement along a curved rock plane.
Occurs in rock that is weak, unconsolidated or have complex geology. Facilitated by the presence of water (lubricates and adds weight).

45
Q

What is a flow?

A

When weak rocks such as clay or unconsolidated sands become saturated, lose their cohesion and flow downslope.

46
Q

What is a rotational scar?

A

A fresh, curved, unweathered and unvegetated rock surface on the cliff face

47
Q

What is a talus scree slope?

A

A fan shaped mound of material, formed from an accumulation of angular blockfall debris

48
Q

What is a terraced cliff profile?

A

Where the cliff profile is stepped due to lithology or fractures in the rock

49
Q

What type of rock does slumping/sliding occur in?

A

Slumping = unconsolidated sediments
Sliding = consolidated sediments

Edexcel A Level Geography (27 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions