Chapter 3 - Coastal Systems & Landscapes - Complete Flashcards
(121 cards)
1
Q
What are the 5 inputs into the coastal system? t wf sc w w
A
- Tides
- Wave refraction
- Sea currents
- Waves
- Wind
2
Q
What are the 2 outputs from the coastal system?
A
- Sediment removal
- Energy
3
Q
What are the 4 processes in the coastal system? E L W C
A
- Erosional landforms
- Longshore drift
- Waves
- Coast
4
Q
What are the 2 stores in the coastal system?
A
- Beach (Landscape)
- Deposition
5
Q
What are the 4 factors which keep beaches in dynamic equilibrium?
A
- The supply of sand.
- The energy of the waves.
- Changes in the sea- level.
- The location of the shoreline.
6
Q
What is the sand supply in dynamic equilibrium?
A
Input and output of sand into the beach must be equal.
Sand is food for beaches and gives shorelines protection from waves.
Being starved of sand can cause higher rates of erosion.
7
Q
What is the waves in dynamic equilibrium?
A
The erosion action of a wave is greatest when the wave is high. The angle at which they strike a beach and how much sand they are carrying can also influence the rate of erosion.
8
Q
Define the 4 causes of sea level change?
A
- Eustatic
- Isostatic
- Tectonic plate activity
- Thermal expansion (50% responsible)
9
Q
What is the location of the shoreline in dynamic equilibrium?
A
Shorelines move back and forth between storms and their location can either increase or decrease erosion rates.
10
Q
Define how the wind is created?
A
- Created by air moving from areas of high pressure to low pressure.
- Strong winds generate powerful waves, has prevailing winds causing higher-energy waves.
11
Q
Define how waves are created?
A
- Waves created by wind blowing over surface - circular motion.
- The effect of a wave on the shore depends on its height.
12
Q
Define constructive waves?
A
They are created in calm weather and are less powerful than destructive waves.
13
Q
Define destructive waves?
A
Are created in storm conditions. They are created from big, strong waves when the wind is powerful and has been blowing for a long time.
14
Q
Define tides?
A
Are the regular rise and fall of sea levels, the gravitational pull of the moon and sun cause the tides.
15
Q
Define currents?
A
General flow of water in one direction - caused by wind, water temperature or salinity.
16
Q
Define high energy coast?
A
- Receive high inputs of energy from large powerful waves.
- Caused by strong winds, long fetches and steeply shelving offshore zones.
17
Q
Define low energy coast?
A
- Receive low inputs of energy from small gentle waves.
- Caused by gentle winds, short fetches and gently sloping offshore zones.
18
Q
Define sediment budget?
A
The amount of sediment that enters and exits.
More enters then positive sediment budget
More exits then negative sediment budget
19
Q
Define sediment cells (littoral cells)?
A
Coastline between two headlands which is a closed system.
Movement of sediment is contained in cell.
11 cells in England & Wales
20
Q
Define abrasion?
A
Waves pick up small rocks and throw them at the cliff, breaking off more rocks.
This is when pebbles grind along with a rock platform, much like sandpaper. Over time the rock becomes smoother and worn.
21
Q
Define hydraulic action?
A
This is the sheer power of the waves as they smash against the cliff, the air becomes trapped in the cracks in the rock and causes the rock to break apart.
22
Q
Define cavitation?
A
As waves recede, the compressed air expands violently, again exerting pressure on the rock and causing pieces to break off.
23
Q
Define wave quarrying?
A
When high energy, tall waves hit the cliff face they have the power to enlarge joints and remove chunks of rock in one go through vibration.
24
Q
Define solution?
A
minerals are dissolved in the water and carried along in solution. Suspension - fine light material is carried along in the water. Saltation - small pebbles and stones are bounced along the river bed.
25
Define attrition?
When rocks that the river is carrying knock against each other, they break apart to become smaller and more rounded.
26
```
Define the 5 transportation processes?
S
S
S
T
L
```
- Solution
- Saltation
- Suspension
- Traction
- Longshore drift
27
Define SOLUTION as a transportation process?
- Substances that are dissolved get carried along in the water.
28
Define SALTATION as a transportation process?
- The force of the water causes pebbles & gravel to bounce along the sea bed.
29
Define SUSPENSION as a transportation process?
very fine material, like silt & clay particles, is whipped up by turbulence and carried along in the water.
30
Define TRACTION as a transportation process?
Very large particles like boulders are pushed along the sea bed by the force of the water.
31
```
Define the 4 sub-aerial weathering processes?
SC
FT
C
W&D
E
```
- Salt crystallisation
- Freeze-thaw
- Chemical
- Wetting & drying
- Exfoliation
32
Define the sub-aerial weathering process SALT crystallisation WEATHERING?
- Caused by saline water.
- Saline water enters cracks in rocks at high tide.
- Tide goes out, rock dries and salt crystals form expanding rock.
33
Define the sub-aerial weathering process Freeze-thaw weathering?
- Temperature fluctuates
- Water enters cracks
- Cold temperature freezes water expanding in rocks.
- Over time weakens rock to break.
34
Define the sub-aerial weathering process Chemical weathering?
- Breakdown of rock by changing its chemical composition.
| - Carbon dioxide in the atmosphere dissolves in rainwater forming weak carbonic acid which reacts with the rock.
35
Define the sub-aerial weathering process wetting & drying?
- Some rocks contain clay.
| - Clay gets wet, it expands and pressure breaks off rock.
36
Define weathering?
Breakdown of rock in SITU.
37
Define 3 types of general weathering categories?
- Mechanical (Physical)
- Biological
- Chemical
38
Define mass movement?
Shifting of material downhill due to gravity.
39
```
Define the 5 types of mass movement?
R
L
R
M
S
```
- Rotational slumping (shifts with a rotation)
- Landslides (Shifts in straight line)
- Rockfalls (material breaks up and falls
- Mudflows (Material flows down slope)
- Soil creep
40
Define unconsolidated rocks?
Are prone to collapse as there's little friction between particles to hold them together.
41
Define the 3 coastal landforms caused by EROSION?
- Cliffs & wave-cut platforms
- Headlands & bays
- Caves, Arches & stacks
42
Define how cliffs & wave-cut platforms are formed?
- Form as sea erodes the land, cliffs retreat.
- Eventually, a notch is formed at high watermark.
- Rock above becomes unstable and collapses creating wave-cut platform.
43
Define how headlands & bays are formed?
- Bands of alternating hard & soft rock are perpendicular to shoreline.
- Soft rock is eroded quickly forming a bay, harder rocks eroded less quickly and sticks out like headland.
44
Define how caves, arches & stacks are formed?
- Weak areas eroded to form caves.
- Caves on small headland will form an arch.
- Arch collapses forming stack.
45
Define the 6 coastal landforms caused by DEPOSITION?
- Beaches
- Spits
- Offshore bars & tombolos
- Barrier islands
- Sand dunes
- Estuary mudflats & saltmarshes
46
Define how Beaches are formed?
- Constructive waves deposit sediment on shore.
| - Shingle beaches are steep and narrow
47
Define how Spits are formed?
- Longshore drift to deposit material across river mouth leaving bank of sand sticking out in the sea.
- Changes in wind direction can cause spit to curve around a bit.
- Multiple recurved ends of spit called a compound spit.
- Area behind spit is sheltered from waves causes mudflats and saltmarshes to form.
48
Define how Offshore bars & tombolos are formed?
- Bars formed by spit joining two headlands together.
- lagoon forms behind bar.
- A bar that connects the shore to an island is called a tombolo.
49
Define how Barrier islands are formed?
- Barrier islands are long, narrow islands of sand that run parallel to shore and are detached from it.
- Formed by last ice age from rapid sea-level rise.
- Lagoon or marsh formed behind barrier islands sheltered from wave action.
50
Define how Sand dunes are formed?
- Formed when sand deposits by longshore drift are moved up the beach by wind.
- Sand trapped by driftwood or berms. vegetation stabilises sand and plants and grasses grow.
- Older dunes migrate inland and embryo dunes form onshore.
- PLANT SUCCESSION - plants make area more hospitable for other plants.
51
Define how Estuarine mudflats & saltmarshes are formed?
- Mudflats and saltmarshes formed in sheltered, low-energy environments.
- As silt and mud deposited by the river or tide.
- Mudflats colonised by vegetation that survives high salt levels and submergence form the tide.
52
Define the 2 states sea-level change can be in?
- Eustatic
| - Isostatic
53
Define Eustatic sea-level change?
- Caused by change in volume of water in the sea or shape of ocean basin.
- Effects are GLOBAL
- Changes in climate
- Increase in temperature causes melting ice sheets rising sea levels.
- Decrease in temperature causes more precipitation to fall as snow, increases water stored in glaciers, decreases sea level.
54
Define Isostatic sea-level change?
- Caused by vertical movements of land relative to sea.
- Downward movement of land causes sea to rise locally, uplift of land causes sea level to rise.
- Effects are LOCAL.
- Uplift or depression due to melting ice sheets.
- Subsidence of land due to shrinkage after abstraction of groundwater.
- tectonic processes.
55
Define how climate change affects sea levels in terms of greenhouse gases?
- Global temperatures risen over last century
- Higher concentration of greenhouse gases in atmosphere, absorbing outgoing long-wave radiation so less is lost to space.
- More energy is trapped and planet warms up.
- Melting ice and rising sea levels.
56
Define the impacts of climate change on coastal areas?
- Storms more frequent and intense
- Sea level rise continues
- More frequent flooding
- Submergence of low-lying islands
- Changes in the coastline
- Contamination of water sources and farmland
57
Define how sea levels falling impacts coastlines of Emergence?
- Raised beaches are formed(above high water mark)
- Exposes wave-cut platforms
- The cliffs above raised beaches no longer eroded by sea
58
Define how sea levels rising impacts coastlines of Emergence?
RI
FJ
DA CO
- RIAS are formed where river valleys are partially submerged.
- FJORDS are drowned glacial valleys, shallow mouth by deposition.
- DALMATIAN COASTLINES are where valleys lie parallel to the coast, an increase in sea level can form them.
59
Describe how erosional processes create and alter landforms over time?
- Individual landforms combine to make landscapes
| - Change existing landforms
60
What are the areas that are protected by coastal management and defensive projects?
Protect:
- Homes
- Businesses
- Environment
- Tourist destinations
- High-value land
61
Define the 4 options for coastal management?
- Hold the line
- Advance the line
- Do nothing
- Managed realignment
62
Define the 2 sustainable management strategies for coasts?
- Shoreline management plans
| - Integrated coastal zone management
63
Define shoreline management plans as a sustainable coastal management strategy?
- Coastline is split into stretches by sediment cells, each cell a plan is devised for how to manage it.
- Each cell can choose to hold, advance or retreat the line or do nothing.
64
Define integrated coastal zone management plans as a sustainable coastal management strategy?
- Considers all elements of the coastal system when making a plan.
- Try using natural resources.
- Different uses considered - fishing, industry, tourism.
- Local, regional & national levels of authority all have an input on the plan.
65
Describe a shingle beach?
- Strong swash moving sediment up beach.
- Larger rocks at top, less erosion.
- Weak backwash.
66
Define swash-aligned beach?
- Smoothly curved, concave beaches.
- Low energy
- Form headlands & bays
67
Define drift-aligned beach?
- Produced where waves break at angle to coast.
- Swash occurs at angle.
- Backwash runs perpendicular to beach.
- High energy
68
Define a landscape?
- Are the bigger/entirety of the sea, coast, countryside.
69
Define a landform?
- Are individual components of the landscape
| - Cliffs, beach, wave-cut platform.
70
```
Define the 7 processes which erode a headland into a stump?
H
A
S
SA
SC
C
O
```
- hydraulic action
- abrasion
- solution
- sub-aerial
- salt crystallisation
- carbonation
- oxidation
71
Define discordant coast?
- Bands of different rock perpendicular to coast.
- Weak rock erodes forming bay.
- Headland & bays formed here.
72
Define concordant coast?
- Bands of different rock parallel to coast.
| - Hard outer rock erodes and soft rock behinds it erodes faster forming coves.
73
Define geomorphology?
- Shape of the coastline
74
Define a berm on a beach?
- Series of long ridges running parallel to sea.
| - Make various hide tide marks in each gradient.
75
Define a cusp on a beach?
- Cresent shaped indentations into the beach.
| - Waves get parted at head of cusp and circle round backwash.
76
```
Define the order of sand dunes formation?
E
F
Y
G
S
M
```
- Embryo
- Fore
- Yellow
- Grey
- Slack
- Mature
77
Define backshore?
Is the area between the high tide mark and the cliff/headland.
78
Define foreshore?
Is the area lying between the High tide mark and the Low tide mark.
79
Define nearshore/inshore (same thing)?
Is the area between the Low tide mark and the low tide break line.
Where the waves cease to have any influence on the land around them
80
Define offshore?
Is the area beyond the low tide break line and then out to sea.
81
Define swash zone?
The area where a turbulent layer of water washes up the beach following the breaking of a wave.
82
Define surf zone?
The area between the point where waves break, forming a foamy, bubbly surface and where the waves then move up the beach as swash in the swash zone.
83
Define breaker zone?
The area where waves approaching the coastline begin to break, usually where the water depth is 5 to 10m.
84
Define fetch?
Area of ocean or lake surface over which the wind blows in an essentially constant direction, then generating waves.
85
Define storm beach?
Is a type of shingle beach that is often hit by heavy storms, strong waves and winds batter storm beaches into narrow steep landforms.
86
Define wave refraction?
Wave refraction involves waves breaking onto an irregularly shaped coastline, e.g a headland.
87
Define Longshore Current (Littoral drift)?
Are generated when a train of waves reach the coastline and release bursts of energy.
88
Define rip currents?
Is a strong flow of water running from a beach back to the open ocean, sea, or lake.
89
Define upwelling?
Is a process in which deep, cold water rises toward the surface, water that rises to the surface is typically colder and rich in nutrients.
90
Define Spring Tide?
Occur when the moon is either new or full and the sun, the moon and the earth are aligned.
When this is the cause their collective gravitational pull on the earth’s water is strengthened.
91
Define neap tides?
7 days after a spring tide, when the sun and moon are at right angles to each other. During full or new moons, which occur when the earth, sun and moon are nearly in alignment.
92
Define Sub-Aerial Processes?
Refer to the processes of weathering and mass movement.
Weathering is the breaking down of rock in situ. It can be divided into mechanical and chemical weathering.
93
Define Marine Deposition?
When the sea loses energy, it drops the material it has been carrying.
94
Define Aeolian Deposition?
Sediment transported by wind, formed by interaction of airflow with the sediments.
95
Define Surface Creep?
A stage in the wind erosion in which sand grains are moved along the ground surface by the impact of other grains in saltation.
96
Define Oxidation as a form of chemical weathering?
Occurs when oxygen reacts with minerals such as calcium and magnesium to form iron oxide. Iron oxide is reddish-brown in colour and causes the decomposition of rock.
97
Define hydration as a form of chemical weathering?
chemical bonds of the mineral are changed as it interacts with water.
98
Define hydrolysis?
Takes place when acid rain reacts with rock-forming minerals such as feldspar to produce clay and salts that are removed in solution. The only common rock-forming mineral that is not affected is quartz, which is a chemically resistant mineral.
99
Define carbonation as a form of chemical weathering?
Occurs when carbon dioxide from moisture in the air reacts with carbonate minerals found in rock. This creates acid which breaks down rock.
100
Define Rotational slumping/slip?
Rocks slide along a concave-upward slip surface with rotation about an axis parallel to the slope.
Rotational movement causes the original surface of the block to become less steep, and the top of the slump is rotated backwards.
101
Define runnels?
Form parallel to the shoreline in the foreshore zone.
| Are disrupted by channels that help to drain the water down the beach.
102
Define berms?
Terrace of a beach that has formed in the backshore, above the high tide water mark.
103
Define cusps?
Beach cusps are shoreline formations made up of various grades of sediment in an arc pattern. The horns are made up of coarser material and the embayment contains finer sediment.
104
Define Psammosere ecosystem?
A seral community, an ecological succession that began life on newly exposed coastal sand. This is the climax community, defined as the point where a plant succession does not develop any further because it has reached equilibrium with the environment, in particular the climate.
105
Define Embryo Dunes?
Formed when sand is deposited within discrete clumps of vegetation or individual plants.
It starts with the establishment of dune‐building plant species above the high water line.
106
Define Flocculation?
refers to a process by which a solute comes out of a solution. As the sediment is dropped the charged particles, such as clays and polymers, clumps together to form flocs.
107
Define the order which the beach goes in (fore, off, near, back)
Backshore, foreshore, nearshore, offshore
108
Define how the coast is a natural system?
- Has inputs of energy & sediment.
- Components of erosional landforms & landscapes.
- Components of depositional landforms & landscapes
- Outputs of energy, sediment removal.
109
```
Define the 5 geomorphological processes?
C
E
T
D
W
```
- Change of landforms
- Erosion
- Transportation
- Deposition
- Weathering
110
Define the sub-aerial weathering process exfoliation?
| Onion peel
Rock under high pressure expands and then cooled by the sea causing rapid contraction, outer layer cracks (onion peel).
111
Define the sub-aerial weathering process Biological weathering?
Growing plant roots widen cracks in concrete & coastline.
Piddock bird drills holes in rocks.
Puffin excavate nests in rock.
112
Define SOIL CREEP as a type of mass movement?
Very slow movement (1cm/year) is dislodged by raindrops or wave splash & freeze-thaw & wetting & drying.
113
Define ROTATIONAL SLUMPING as a type of mass movement?
Heavy rainfall infiltrates unconsolidated soil, impermeable soil traps water adding weight, undercutting causes collapse of soil.
114
Define ROCK FALLS as a type of mass movement?
Weaknesses exposed & can't support weight so rocks fall.
115
Define LANDSLIDES as a type of mass movement?
Unconsolidated rocks like sandstone usually been lubricated and slides.
116
Define MUDFLOWS as a type of mass movement?
Excessive amounts of rainfall saturate soil and creates mudflow down a hill.
117
Define RUNOFF as a type of mass movement?
Intensive rainfall, impermeable surface transports fine material.
118
# Define locations of a:
- Cave O
- Arch S
- Stack N
- Wave-cut platform WS
- Headlands & bays S
- Old Harry rock
- Swanage
- The Needles
- West Somerset
- Swanage Bay
119
# Define locations of a:
- Spit & compound spit H
- Tombolos C
- Offshore bar H
- Barrier Islands L
- Bar (Barrier beach) S
- Sand dunes A
- Salt marshes/mudflats K
- Hurst Castle
- Chesil beach joining Isle of Portland
- Hordle Cliff
- Long Island
- Slapton Sands
- Ainsdale
- Keyhaven Marshes (Hurst Castle)
120
Define the 3 factors in the development of cliff profiles?
- Lithology (physical properties of rock)
- Structure (rocks run parallel, perpendicular, joints)
- Geomorphology (shape of the coastline (refraction))
121
How long ago was the sea level 120m below current level?
How long ago was the sea level 50m below current level?
20,000 years
| 10,000 years
