topic 2b: coastal landscapes and changes Flashcards
1
Q
What is the coastal environment?
A
The interface (zone) between the sea and the land where marine and terrestrial processes combine to produce a variety of landforms.
2
Q
Define marine and terrestrial.
A
Marine - anything to do with the sea; Terrestrial - anything to do with the land.
3
Q
Why is a coastline regarded as an open system?
A
It receives inputs and outputs are transferred.
4
Q
What are biogenetic inputs?
A
Shells and marine fossils (things that were living but are now dead).
5
Q
What are the three components of the coastal system?
A
- Inputs
- Processes
- Outputs
6
Q
List the inputs in the coastal system.
A
- Energy
- Sediment
- Human activities
7
Q
What processes occur in the coastal system?
A
- Erosion
- Longshore drift
- Deposition
8
Q
What are the outputs of the coastal system?
A
- Erosional and depositional landforms
- Loss of wave energy
9
Q
What does it mean for a coast system to be in dynamic equilibrium?
A
It experiences negative feedback due to the wide range of processes that interact with it daily.
10
Q
What is scree?
A
Material that has fallen off the cliff.
11
Q
What are the two types of farming mentioned?
A
- Pastural - animals
- Arable - crops
12
Q
What can cause rapid changes in the coastline?
A
Increased energy in natural processes or impacts of human activities not being carefully considered.
13
Q
What determines where wave action takes place?
A
Tidal range.
14
Q
What occurs in offshore areas?
A
- Offshore currents and longshore drift move sediment up the coast
- Dredging for sand and gravel for construction.
15
Q
What is the foreshore?
A
The lower beach which is exposed at low tide and covered during high tide.
16
Q
What are the characteristics of backshore?
A
- Where weathering and mass movement occur
- Building of coastal defenses against erosion
- Upper beach with berms.
17
Q
Define estuary.
A
Where the mouth of a river meets the sea.
18
Q
List the types of coastlines.
A
- Valentine
- Rocky
- Sandy
- Estuarine
19
Q
What are the characteristics of a rocky coastline?
A
- Receding, small beach, large cliffs of varying heights
- Landforms: caves, wave cut platforms
- Abrupt transition from land to sea.
20
Q
What defines a sandy coastline?
A
- Sand dunes
- Depositional landforms
- Dune vegetation stabilizes the coastline.
21
Q
What is a high energy coastline characterized by?
A
- Destructive waves
- Long fetch
- Storm conditions.
22
Q
What are the characteristics of low energy coastlines?
A
- Constructive waves
- Short fetch
- Calmer conditions.
23
Q
What is beach morphology?
A
The surface and shape of the beach and how it changes.
24
Q
What happens to beach profiles during winter?
A
- Destructive waves occur more frequently
- Stronger backwash erodes berms.
25
What type of waves are constructive waves?
* Strong swash
* Weak backwash
* Beach gain.
26
What causes waves?
Waves are caused by wind.
27
What is wave refraction?
The separation of energy due to the depth of water as waves approach a headland.
28
What influences tidal range?
* The gravitational pull of the moon
* The shape of the coast.
29
What are concordant coasts?
Coasts where layers of different rock types run parallel to the coastline.
30
What is a Haff coastline?
A coastline with a very long bar creating a lagoon behind it.
31
Describe a Dalmatian coastline.
A series of offshore islands running parallel to the coastline due to rising sea levels.
32
What defines discordant coastlines?
Alternating rock types perpendicular to the coastline.
33
What is lithology?
The physical properties of rock.
34
Explain the significance of bedding planes.
Natural gaps between strata caused by gaps of time during the rocks' formation.
35
What is a syncline?
The downward fold in rock.
36
What is a pioneer species?
Specialized plants that begin to grow in an area of initially bare sediment.
37
What is required for sand dune development?
* A large supply of sand
* Strong wind
* An obstacle to trap sand.
38
What characterizes embryo and foredunes?
* Small, fragile dunes
* Scattered plants
* Waxy leaves and halophytes.
39
What are yellow dunes?
* Wind continues to destroy and rebuild dunes
* Long tap roots stabilize sands.
40
What defines grey dunes?
* More humus content
* Surface lichens
* Multiple plant species coexist.
41
What is a dune slack?
Low lying land after grey dunes that may be flooded if there is a high water table.
42
What is brackish water?
A mixture of salty and fresh water.
43
What happens in the first stage of salt marsh development?
* Initial colonizers develop on mud flats
* Vegetation slows the movement of water.
44
What role does cord grass play in salt marshes?
It helps build up salt marshes by binding the mud and increasing height.
45
What happens to the height of the mud flats in Stage 2?
The height of the mud flats will increase, so the time of submergence is shorter.
## Footnote
Eg. 6-8 hours per tidal cycle
46
What plant species is mentioned in Stage 2 that aids in building salt marshes?
Cord grass
## Footnote
Cord grass has two root systems: fine surface roots and deeper roots.
47
How much does cord grass help to build up the salt marshes per year?
At least 5cm per year.
48
What type of vegetation develops in Stage 3 of salt marsh succession?
A deep mat of surface vegetation develops.
49
Which species begins to grow in Stage 3 of salt marsh development?
Sea lavender.
50
What are salt pans?
Small areas where there are pools of salt water, preventing plant growth.
51
In Stage 4, what types of species can survive due to the increased height of the salt marsh?
Reeds and rushes.
52
What complex feature can form in Stage 4 of salt marsh development?
Complex creek systems.
53
What happens to the salt marsh in Stage 5?
It becomes high enough and dry enough for trees like ash and elder to grow.
54
What is the relationship between tree growth and biodiversity in Stage 5?
As trees dominate, lesser species may be killed off due to competition, leading to little biodiversity.
55
What type of erosion involves waves causing rocks to smash into each other?
Attrition.
56
What is abrasion in the context of coastal erosion?
The material picked up by waves hits the cliff and gradually wears it away.
57
What is hydraulic action?
Waves force trapped air into gaps in the cliff, weakening and eroding it.
58
Define solution/corrosion in the context of coastal erosion.
Salts and acids in seawater dissolve the rock gradually.
59
What is lithology at the coast?
The geological composition that affects erosion rates.
60
What are the four types of sediment transportation?
* Suspension
* Traction
* Saltation
* Solution
61
What is longshore drift?
The process that impacts where sediment moves across the beach.
62
What factors affect longshore drift?
* Size and volume of sediment
* Beach management
* Tides
* Strength of prevailing winds
* Currents
63
What conditions lead to coastal deposition?
* Sediment accumulation exceeds removal
* Speed of water slows down
* Water percolates into the beach
* Human intervention slows movement.
64
How does gravity settling contribute to sediment deposition?
It occurs when the energy of transporting water is too low to move sediment.
65
What is flocculation?
The clumping of very small particles (e.g., clay) due to electrical or chemical attraction.
66
What is a beach?
A landform created due to shallow water and wave refraction.
67
What is a spit?
A sand and shingle extension beyond a curve in the coastline.
68
Define a tombolo.
A sand or shingle bar that attaches the mainland to an offshore island.
69
What is a bar in coastal geography?
A sand or shingle beach connecting two areas of land with a lagoon behind it.
70
What is a recurved/hooked spit?
A spit that curves landward.
71
What is a cuspate foreland?
Triangular shaped features extending from a shoreline formed by joining spits.
72
What is a storm beach?
A high berm built up by swash from high spring tides.
73
What does weathering refer to?
The breakdown of rock by chemical, mechanical, and biological agents in situ.
74
What is the difference between weathering and erosion?
Weathering does not involve movement, while erosion transports eroded material.
75
What is mechanical weathering?
Rocks break down due to physical force without chemical change.
76
What is freeze-thaw weathering?
Water seeps into cracks, freezes, expands, and breaks the rock.
77
Define chemical weathering.
Involves chemical reactions that generate new physical compounds.
78
What is carbonation in weathering?
Dissolution of limestone due to rainfall.
79
What role do plant roots play in biological weathering?
They grow in cracks and fissures, forcing rocks apart.
80
What is mass movement?
The downhill movement of weathered material under gravity.
81
What are the types of mass movement?
* Soil creep
* Rock fall
* Topple
* Translational slide
* Slumping
* Flow
82
What is soil creep?
Very slow downhill movement of individual particles.
83
What creates rotational scars?
Caused by slumping where large amounts of material slowly rotate down a cliff.
84
What are terraced cliff profiles?
Profiles created by slumping that leave steps in the cliff.
