1
Q
Define coast
A
A narrow zone, where land and sea overlap and directly interact
It is an open system
2
Q
Name 3 types of systems
A
- Closed system
- Open system
- Isolated system
3
Q
Define boundary
A
The outer edge of a system/ the zone between one system and another
4
Q
Name the inputs of a coast
4 Sub-Categories
A
- Atmospheric: Precipitation, Climate Change, Solar Energy
- Marine: Waves, Tides, Storm Surges
- Rock/Land: Sediments, Rock type/structure, Tectonic activity
- People: Human activity, Coastal management
5
Q
Name the processes of a coast
A
- Weathering + Mass Movement
- Erosion
- Deposition
These processes are responsible for forming different coastlines/landscapes -> rock shores, sandy beaches, coastal wetlands etc.
6
Q
Name the outputs of coast
A
- Ocean currents + Rip tides
- Sediment transfer
- Evaporation
7
Q
Define input
A
Material or energy moving into the system from outside
8
Q
Define output
A
Material of energy moving into the system from outside
9
Q
Define energy
A
Power or driving force
energy associated w/ flowing water, the effects of gravity on cliffs and moving air
10
Q
Define stores/components
A
Individual elements or parts of a system
11
Q
Flows/transfers
A
The links or relationships between the components
12
Q
Define positive feedback
A
Where a flow/transfer leads to an increase in growth
13
Q
Define negative feedback
A
Where a flow/transfer leads to decrease of decline
14
Q
Define dynamic equilibrium
A
A state of balance within a constantly changing system
15
Q
Give an example of a positive feedback loop at the coast
A
1) Rock is eroded
2) Falls into sea
3) Becomes tool for erosion
4) Rock is eroded
16
Q
Give an example of a negative feedback loop at the coast
A
1) Constructive waves deposit sediment
2) Beach’s steepness increases
3) Backwash is stronger than swash -> destructive waves occur
4) Beach’s steepness decreases
5) More ideal for constructive waves
Helps the system reach dynamic equilibrium
17
Q
Name the stores/components in a coast
A
- Beach
- Sand dunes
- Spits
- Bars
- Headlands + Bays
- Nearshore Sediment
- Cliffs
- Wave-cut notches + platforms
- Caves, arches, stacks + stumps
- Salt Marshes
- Tidal flats
- Offshore bars
18
Q
What are the four parts of the littoral zone?
From back of beach to front of beach
A
1) Backshore
2) Foreshore
3) Nearshore
4) Offshore
19
Q
Where does low-tide reach in the littoral zone?
A
Back of nearshore
20
Q
Where does high-tide reach in the littoral zone?
A
Back of foreshore
21
Q
Where does maximum spring tide reach in the littoral zone?
A
Middle of backshore
22
Q
What zone is the area outside the influence of waves?
A
Offshore
23
Q
What zone is the intertidal area between high and low tide?
A
Foreshore
24
Q
What zone is usually beyond the influence of wave action but can be affected during storm events?
A
Backshore
25
What zone is the breaker zone where friction between the seabed and the waves causes them to break?
Nearshore
26
What is the link between coastal systems and other natural systems?
Coastal systems are interlinked with other physical and human systems
| e.g. Human coastal areas suffering from more severe flooding
## Footnote
e.g. Carbon Cycle -> Global Warming -> Sea Level Change -> Coastal Ecosystems
27
Give an example of how the carbon system and coastal system link
Marine organisms use carbon to build calcium carbonate (shells) contributing to sediment formation
28
Give an example of how the water system and coastal system link
Rivers deliver water, sediment and dissolved material to the coast
29
What are the sources of energy along a coast?
Sun + Wind which creates waves
30
What 3 factors affect wave energy?
- Strength of wind - determined by pressure gradient
- Duration of wind
- Fetch
31
How does wind work?
It is the movement of air from high pressure to low pressure: the bigger the gradient, the stronger the wind
32
How do waves form?
1) Water gets shallower + circular orbit of the water particles changes to elliptical shape
2) Wavelength + velocity decreases, wave height increases -> water backs up from behind + rises to a point where it breaks
33
What are the charactersitics of a constructive wave?
- Generated by distant weather systems
- Low, surging waves w/ long wavelength
- Strong swash, weak backwash
- Beach gain
- Gentle beach profile, but will build up beach and make it steeper
- Wave energy is absorbed by the beach
34
What are the charactersitics of a destructive wave?
- Generated by local storms
- High, plunging waves w/ short wavelength
- Weak swash, strong backwash
- Beach loss
- Steeper beach profile, but will flatten the beach overtime
- Little wave energy is absorbed by the beach
35
What factors influence wave type?
- In summer, more constructive waves - In winter, more destructive waves
- Constructive waves may become destructive when storm begins
- Climate change may increase storm frequency in UK
- Coastal management may affect beach type
36
Define **tides**
Changes in water level of seas and oceans caused by gravitational pull of the moon (+sun)
37
How many high and low tides does the UK experience each day?
2 high and 2 low tides
38
What is the **tidal range**
The relative distance between high and low tide
39
Why is there a higher tidal range for spring tide?
The sun and moon are in line at full moon/new moon -> Gravitational pull act together to create higher high tides + lower low tides
40
Why is there a lower tidal range for neap tide?
Moon is at right angle to sun -> gravitational pulls act against each other to create lower high tides and higher low tides
41
How do tides affect inputs, outputs and proccesses?
High tidal range = powerful tidal currents = transport sediment
Determine the height and duration of wave processes on beach or cliff
## Footnote
e.g. lead to wave-cut notch
42
How do rip currents form?
1) Series of plunging waves cause temporary build-up of water at top of beach
2) Once met with resistance from breaking waves, backwash is forced just below surface following troughs and inundations in beach profile
3) Fast-flowing offshore surge of water can drag people into deep water
43
Name the characteristics of a high-energy coastline
- Rocky coast
- Erosion rates exceeds deposition rate
- Destructive waves
- Erosional landforms
44
Name the characteristics of a low-energy coastline
- Sandy coastline
- Deposition rate exceeds deposition rate
- Constructive, less powerful waves
- Depositional landforms
45
Explain **upwelling**
1) Surface winds blow away warmer surface water
2) Deeper, colder nutrient rich water takes its place (good for phytoplankton -> more fish)
Conditions are optimal when wind blows along shore
46
What are 4 characteristics of the Peruvian coastal upwelling system?
4°S - 40°S
Winds sustain upwelling process all year
20% of world's industrial fish for only 0.02% of ocean surface
(High productivity for fish)
47
Define **sediment cell**
A defined area of coastline, usually between two prominent headlands, where inputs and outputs of sediment are theoretically balanced
48
What are the characteristics of a sediment cell?
- A theoretical closed system
- Sediment is largely contained
- Sediment transported in system via LSD
- Sediment is being redistributed along sources and sinks
- Headlands and estuaries provide boundaries of sediment cell
- The 11 cells around the English + Welsh coastline can be further divided into sub-cells
49
Define sediment budget
The balance between the sediment being inputs (sources) and outputs (sinks) from the coastal system (sediment cell)
50
Name 6 sediment sources
- Rivers
- Cliff erosion
- Wind
- Glaciers
- Offshore
- Longshore Drift
51
What is meant by the term dynamic equilibrium in relation to a sediment budget?
There is a balance between inputs and outputs
52
Describe a flow chart to explain a positive sediment budget
1)More material added than removed = net accretion
2)Positive budget / surplus of sediment
3)Shoreline builds towards sea
53
Describe a flowchart to explain a negative sediment budget
1) More material removed than added
2) Negative budget / deficit in sediment supply
3) Shoreline retreats landward
54
How can human activity affect sediment budget?
Management:
**Hard engineering** - groynes
**Soft engineering** - beach nourishment
55
How long do sand dunes, sandbanks and beaches store sediment?
- SD = years to decades
- SB = 5k - 10k years
- B = 2 to 10 years
56
Why does wave refraction cause?
Causes energy to be concentrated around headlands and dissipated in bays, accounting for erosive features at headlands and deposition in bays
## Footnote
this leads to a negative feedback loop as coastline continues too change
57
Define **erosion**
The wearing away and removal of material by water e.g. rivers + waves, wind + ice
58
Define **weathering**
Sub-aerial processes occurring above the waterline leading to the disintegration and decomposition of rock and thus influencing the nature of landforms and the character of the landscape
59
What are the types of marine erosion?
- Corrasion
- Abrasion
- Attrition
- Hydraulic action
- Corrosion/Solution
- Wave Quarrying
- Cavitation
60
What factors affect rate of erosion?
- Waves
- Rock type (lithology)
- Geological structure : fissures, joints, cracks, faults
- Presence or absence of beach
- Subaerial processes
- Coastal management
61
What are the 3 categories of weathering?
- Mechanical (physical)
- Biological
- Chemical
62
Name 3 types of mechanical weathering
- Freeze-thaw (Frost shattering)
- Salt crystallisation
- Wetting + drying
63
Name 4 ways biological weathering can occur
- Thin plant roots grow into cracks and grow
- Water running through decaying vegetation becomes acidic
- Birds and animals dig burrows in cliffs
- Marine organisms (piddocks) burrow into rocks or secrete acids (limpets)
64
Name 3 types of chemical weathering
- Carbonation
- Oxidation
- Solution
65
Define **landform**
Natural, physical features found along the coastline
66
Define **landscape**
A section of coastline that comprises of various landforms
67
Explain **cavitation**
Collapse of **bubbles in waves** crashing into and receding from cliffs and other solid rock features causing **energetic pressure waves** which break up the rock and enlarge joints and fissures in the rock
68
Explain **corrasion**
Sand and pebbles are picked up by the sea from an offshore sediment sink or temporal store and hurled against the cliffs at high tide, causing the cliffs to be eroded.
Erosive power factors : shape, size, weight and quantity of sediment + wave speed
69
Explain **corrosion/solution**
The mildly acidic seawater causes alkaline rock (e.g.limestone) to be eroded
70
Explain **wave quarrying**
Waves exert pressure of 30 tonnes/m^2. Directly pulls rocks away from cliff face. It hammers the rocks surface, shaking and weakening it and leaving it open to attack from hydraulic action and abrasion.
71
What is the rate of erosion for **igenous** rock + why?
Very slow: <0.1cm/year
Interlocking crystals allow for high resistance to erosion
| Examples: Granite + Basalt
72
What is the rate of erosion for **metamorphic** rocks + why?
Slow: 0.1-0.3 cm/year
Crystal orientated in the same direction, resisting erosion
| Examples: Slate, Schist, Marble
73
What is the rate of erosion for **sedimentary** rocks + why?
Very fast: 0.5-10cm /year
Lots of faults making htem weak and vulnerable to erosion
| Examples: Limestone
74
Explain **carbonation**
1) Rainwater absorbs carbon dioxide from the air to form weak carbonic acid.
2) Reacts with calcoum carbonate in rock (limestone + chalk) forms calcium bicarbonate, which is easily dissolved
3) Cooler temp of rainwater, more CO2 absorbed (Carbonation more effective in winter
75
Explain **oxidation**
The reaction of iron-rich rock minerals with oxygen to form rusty red powder -> more vulnerable to weathering
76
Explain **salt crystallisation**
1) Salt water evaporates and leaves salt crystals
2) They grow and exert stresses in the rock, causing it to break up
Salt can also corrode rock
77
Explain **wetting and drying**
Rocks rich in clay expand when wet + contract when drying -> causes cracks + breaks up
78
Define **mass movement**
The gradual or sudden movement of sediment downhill under the force of gravity
Occurs when shear stress exceeds shear strength
79
Name the four categories of mass movement
- Creep/Heave
- Flow
- Slide
- Fall
80
What factors affect the type of mass movement?
- Slope angle
- Geology: lithology + structure
- Vegetation cover + type
- Saturation of ground
- Human activity
- Weathering
- Earthquakes
81
Name 6 types of mass movement
- Soil Creep
- Solifluction
- Mudflows + Earthflows
- Landslide
- Landslip/slump
- Rockfall
82
Explain the process of soil creep
- Heave caused by expansion + contraction of soil
- 2 mechanisms: freeze-thaw + wetting&drying
83
Explain the characteristics of **soil creep**
- 1mm/yr - 1cm/yr
- Continuous process - most prominent in winter
- Unlikely to be hazardous
84
What are the impacts of soil creep?
- Terracettes
- Tension gashes in road
- Tilted fences/poles
85
Explain the process of solifluction
- Winter: permafrost + regolith frozen
Summer: Low layer stays frozen, top layer thaws = waterlogged = flows as active layer
- Heave&flow
86
Explain the characteristics of **solifluction**
- 5cm-1m/yr
- Seasonal movement
- Occurs in preglacial environments (tundra)
- Solifluction lobe formed
87
Explain the process of **mud/earthflows**
Water gets trapped in the rock, increasing pore water pressure, which forces rock particles apart and leads to slope failure
88
Explain the characteristics of **mudflows
- 1cm/day - 1m/sec
- Higher water content = faster
- Common after heavy rain + where there's less vegetation
- Unconsolidated or weak rock
- Significant hazard
89
Describe **metamorphic** rocks
rocks which have been physicially and chemically altered due to heat and/or pressure
90
Describe **sedimentary** rocks
rocks formed from the deposition of sediment shells
91
Describe **igneous** rocks
Rocks formed from cooling magma/lava
92
Define rock **structure
The way rocks are geologically arranged
93
Define **lithology
The make-up of each rock type
94
Name 6 lithological characteristics
- Strata
- Bedding planes
- Joints
- Folds
- Faults
- Dip
95
Define **strata
Layers of rock
96
Define **bedding planes
Horizontal, natural breaks in strata, caused by gaps in time during periods of rock formation
97
Define **joints
Vertical fractures caused either by contraction as sediments dry out or by earth movements during uplift
98
Define **folds
Formed by pressure during tectonic activity, which makes rocks buckle and crumple
98
Defnie **dip
The angle at which rock strata lie (horizontally, vertically, dipping seaward/landward)
98
Define **faults
Formed when the stress or pressure to which a rock is subjected, exceeds its internal strength (causing it to fracture)
98
Define **impermeable
A material that does not allow water to pass through it or be stored in it
99
Define **permeable
A material that allows water to pass through it and be stored in it
100
Define **porous
A rock or soil where water moves into and is stored in pore spaces
101
Define **pervious
A rock or soil where water moves along cracks or joints
102
What are **geos** and their characteristics?
Linear clefts in a sea cliff that reflect marine erosion along a line of weakness
- Long, narrow slots develop
- Can form through cliff collapse
103
Define **traction
Rolling of large and heavy rocks along the seabed
104
Define **suspension
Lighter sediment is suspended within the water
105
Define **saltation
Smaller material being bounced along the seabed
106
Define **solution
Dissolved materials carried by the sea
107
Name 4 methods of transportation
- Traction
- Saltation
- Suspension
- Solution
108
What is meant by the term **aeolian processes**?
The processes by which wind erodes, transports, and deposits sediment
109
What factors can influence landform type?
- Geological structure + lithology
- Presence of beach
- Wave refraction
- Wave energy
110
What factors affect rate of retreat?
- Weathering + Mass movement
- Rock type
- Wave energy
111
112
What are 2 categories of beaches?
- Swash-aligned
- Drift-aligned
113
Name - landforms of **deposition**
- Beach
- Spits
- Tombolo
- Offshore bars
- Barrier beaches
- Sand dunes
- Estuarine mudflats and saltmarshes
113
114
Describe what a **dalmation coastline** is
Unique landforms of coastal submergence/eustatic change name after the Croatian Adriatic dalmation coastline
Formed by changes to volume of water in ocean where fold hills and valleys lie parallel to one another along a coastline. Valleys are flooded and tops remain above sea level appearing as a series of long, thin islands, running parallel to coastline separated by narrow sea channels called sounds
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