✅3.1.3.2 - Systems and Processes Flashcards Preview

Physical geography - A level AQA > ✅3.1.3.2 - Systems and Processes > Flashcards

Flashcards in ✅3.1.3.2 - Systems and Processes Deck (63)
Loading flashcards...
1
Q

What are some of the sources of energy in the coastal system?

A

Wind
Waves
Currents
Tides

2
Q

How does the wind provide energy?

A

Strong winds move the water surface and create waves

Winds with large fetches can transfer more energy

3
Q

How do waves provide energy?

A

Waves have powerful errosive energy, can destroy features

Moves sediment around, creates as well as destroys

4
Q

How do currents provide energy?

A

Can move sediment on the sea floor

More material on and off coastline regularly, great force

5
Q

How do tides provide energy?

A

Moves sediment up the beach and down again, carries material

Dictates where waves can get to, location of the energy

6
Q

How does the sun provide energy?

A

It causes differences in air pressure due to different rates of heating, when then creates wind

7
Q

How is wind energy formed?

A

By air moving between areas of different pressure

8
Q

How are powerful winds created?

A

The greater the difference in air pressure gradient, the faster the wind speed and the more powerful

9
Q

What are the factors impacting the size of waves?

A

Strength of the wind
The fetch
Duration of the wind

10
Q

How does wind strength impact waves?

A

The stronger the wind, the more power and energy the waves have and so the more powerful and potentially destructive they are.

11
Q

What are some terrestrial features affecting the coastal system?

A

Tectonics
Sediment supply
Sub aerial processes
Fluvial processes

12
Q

What are some marine features affecting the coastal system?

A
Wave shape/size
Fetch
Wave direction
Tides
Sea level change
13
Q

What are some human features affecting the coastal system?

A
Development
Sea defences
Tourism and recreation
Pollution
Global Warming
Conservation
14
Q

What are some atmospheric features affecting the coastal system?

A
Winds
Temperature
Precipitation
Solar energy
Glaciation
15
Q

How are waves formed?

A

By energy passing through the water, causing it to move in a circular motion

16
Q

What do waves transmit?

A

Energy, not water

17
Q

What are wind driven waves caused by?

A

Frictional drag between the wind and the surface water

18
Q

How do waves change as they approach the shore?

A

Disturbance to the circular motion beneath the surface leads to a more horizontal movement and the wave breaks

19
Q

What are the features of constructive waves?

A

Add material to coastline
Low wave with long wavelength
Strong swash

20
Q

What are the features of destructive waves?

A
Tall in relation to length
Remove material from coastline
Common in winter
Strong backwash
Never reach the backshore
Causes cliff face erosion
21
Q

What are orthogonals?

A

Lines of wave energy

22
Q

What are high energy coastlines like?

A

Rocky, ocean facing coasts where waves are powerful

23
Q

What types of landforms tend to be on high energy coasts?

A

Wave cut platforms and headlands

24
Q

What are low energy coastlines like?

A

Sandy, estuarine and where waves are less powerful as the coast is sheltered

25
Q

How do rates of deposition and erosion compare at high energy stretches of coast?

A

Rate of erosion exceeds rate of deposition

26
Q

How do rates of deposition and erosion compare at low energy stretches of coast?

A

Rate of deposition exceeds rate of erosion

27
Q

What types of landforms tend to be on low energy coasts?

A

Beaches, spits and coastal plains

28
Q

What is a sediment cell?

A

A stretch of coastline within which sediment movement is more or less contained

29
Q

What are sediment cells usually bordered by?

A

2 large headlands

30
Q

What can sediment cells be further subdivided into?

A

Sediment subcells

31
Q

What are some example sources of sediment?

A

Rivers
Cliff erosion
Offshore sediment
Wind

32
Q

How do rivers act as a source of sediment?

A

Fluvial sediment often accounts for the vast majority of coastal sediment as it is deposited in the river mouths and estuaries, where it is reworked by waves, tides and currents

33
Q

How does cliff erosion act as a source of sediment?

A

Can be extremely important locally in areas with soft rock where sand and clay are easily eroded

34
Q

How does offshore sediment act as a source of sediment?

A

Can be transferred into the coastal zone by waves, tides and currents. When sea levels rose at end of last ice age, large amounts of coarse sediment was moved to South coast and formed landforms

35
Q

How does wind act as a source of sediment?

A

In glacial or hot environments, wind blown sand can be deposited in coastal regions. Sand dunes are semi dynamic features at the coast that represent both accumulation of sand and potential sources

36
Q

What might dictate the amount of sediment input into a sediment cell at any given time?

A

The amount of rainfall, and therefore fluvial sediment
Destructive/constructive waves
Season
Amount of weathering

37
Q

How does water depth affect wave refraction?

A

As water depth decreases, there is a reduction in wave velocity and the waves are bent towards that part of the shoreline where they are moving most slowly

38
Q

How do headlands affect wave refraction?

A

The higher relief and therefore shallower water off the headlands slows the approaching wave.
Wave crests converge onto headlands, increasing the energy released by the breaking wave in the bay

39
Q

What happens to the energy where orthogonals diverge?

A

The energy per unit wave crest decreases

40
Q

What are processes which shape the coast?

A
Chemical/Physical weathering
Deposition
Erosion
Mass movement events
Transfer processes
41
Q

What are some marine processes?

A

Transportation, erosion and deposition

42
Q

What are some sub-ariel processes?

A

Weathering, mass movement

43
Q

What is traction?

A

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

44
Q

What is suspension?

A

Small particles like silt and clay are carried along in the water

45
Q

What is saltation?

A

Pebble sized particles are bounced along the sea bed by the force of the water

46
Q

What is solution?

A

Soluble materials dissolve in the water and are carried along

47
Q

How does a high energy coast affect transportation?

A

Small particles easily transported whilst larger and heavier material is deposited. Shingle beaches formed

48
Q

How does a low energy coast affect transportation?

A

Even the smallest material is deposited forming mudflats and salt marshes

49
Q

What is hydraulic action?

A

Refers to the impact on rocks of the sheer force of the water. This can exert enormous pressure upon the rock

50
Q

What is wave quarrying?

A

A braking wave traps air as it hits a cliff face. The air is compressed into any gaps causing huge pressures. As the water retreats there is an explosive effect of the air pressure being released

51
Q

What is abrasion/corrosion?

A

Eroded material being thrown against the rock by the waves. Also conducts erosion of wave cut platforms due to movement of material back and forth

52
Q

What is attrition?

A

Rocks which are carrying out abrasion are slowly worn down into smaller and rounder particles

53
Q

What is a concordant coastline?

A

Rocks on these coastlines run parallel to the sea

54
Q

What is a discordant coastline?

A

Rocks on these coastlines run perpendicular to the sea

55
Q

What is a cliff profile?

A

The gradient of the cliff face, responsible for whether the cliff has a steep gradient

56
Q

What are factors influencing the rate of cliff retreat?

A

Rock type, geographical location and climate/season

57
Q

What is biological weathering?

A

The breakdown of rocks by organic activity, such as by plant roots and water running through decaying vegetation

58
Q

What is chemical weathering?

A

Involves chemical reactions dissolving the rocks such as through acid rain, oxidation and solution

59
Q

What is mechanical/physical weathering?

A

The breakup of rocks without ant chemical changes taking place, such as via freeze thaw or salt crystallisation

60
Q

What features do cliffs with horizontal bedding planes have?

A

A stable profile with a steep cliff face

61
Q

What features do cliffs with downward tilted bedding planes have?

A

Very stable with slow rates of erosion as the cliff is supported by deeper running strata

62
Q

What features do cliffs with upward tilted bedding planes have?

A

A cliff profile similar to the angle of the tilt and frequent mass movements when the base of the cliff is eroded

63
Q

What features do cliffs with weathering joints have?

A

Very vulnerable to erosion as gravitational pull is created and cracks make them fragile