Coastal systems & landscapes Flashcards
What are the 2 landforms of coastal erosion?
Cliffs and wave cut platforms
Cliff profile features
What are the 3 factors affecting the development of cliffs and wave cut platforms?
Rock type
Wave energy
Coastal morphology
What landforms form on coastlines of emergence?
Raised beaches
Wave cut platforms
What are marine features that are left above the high tide level called?
Relict features
Why may raised beaches appear as grassy terraces?
Once above the high tide line they are subject to vegetation succession
What landforms form on coastlines of submergence?
Rias and fjords
Dalmatian coasts
How do fjords form?
Glaciers erode to create steep-sided U-shaped valleys.
Sea level rises relative to the land, flooding the glacial valleys.
Why are fjords often shallower at the mouth than further inland?
Glaciers can overdeepen their valley
What are the 2 different types of sea level change?
Isostatic
Eustatic
What is isostatic sea level change?
Changes in sea level as a result of the changing level of the land.
What is eustatic sea level change?
Changes in sea level as a result of the changing level of water in the oceans.
On what scale does isostatic sea level change occur?
Local/regional
On what scale does eustatic sea level change occur?
Global
How quickly are sea levels rising?
3.2mm per year
What is the main reason for current sea level rise?
Thermal expansion
What are the 3 causes of isostatic change?
Tectonic activity
Glaciation
Post-glacial readjustment
What are the 2 factors affecting the development of mudflats and saltmarshes?
Energy of coastlines
Tidal range
What type of energy coastline do estuarine landforms form on?
Low energy coastlines
What kind of succession is the formation of saltmarshes?
Halosere
How do mudlfats form?
- Saltwater flowing into an estuary at high tide brings large amounts of fine sediments.
- This meets the slow river which is carrying fine silts and clays.
- Flocculation occurs when the two flows meet, resulting in large clay particles sinking to the bed.
- At low tide this mud is exposed in the intertidal area with water flowing in channels between the mudflats.
How do mudflats develop into saltmarshes?
Low lying vegetation begins to grow on the mudflats.
This slows currents leading to further deposition.
Pioneer species colonise the area.
Gradual colonisation by other plants forms a dense mat of vegetation up to 15cm high.
Vegetation growth slows currents further, leading to more mud and silt accumulation.
The mudflats are submerged for an increasingly shorter period of time so become a saltmarsh.
Give an example of a pioneer species on mudflats.
Spartina
What is flocculation?
Where fine particles settle out of suspension
Why are sand beaches gently sloped?
Sand grains are small and easily compacted so little water percolates through. The majority of water moving up the beach therefore also returns through backwash which smooths and flattens the beach.
Why does shingle tend to be at the top of the beach?
It takes high energy storm waves to deposit the larger material.
What are the 2 classifications of beaches?
Swash-aligned
Drift-aligned
What type of system is the coast?
Open system as it receives inputs from outside the system and transfers outputs away from the coast and into other systems.
What are the main 3 types of coastal inputs?
- Marine
- Atmosphere
- Humans
What are flows/transfers?
The processes that link inputs, outputs & stores of a system
What’s the littoral zone?
Part of sea that is close to the shore
Landforms of coastal deposition [8]
- Beaches
- Spits
- Barrier beach/bars
- Tombolo
- Offshore bars
- Coastal vegetation
- Sand dunes
- Estuarine Mudflats and Saltmarshes
What are systems made up of?
- Inputs
- Outputs
- Stores
- Flows
- Boundaries
What are inputs?
When matter/energy is added to the system
What are outputs?
When matter or energy leaves the system
What are stores?
Where matter or energy builds up
What are flows?
When matter or energy moves from one store to another
What are boundaries?
The limits of the system
What is negative feedback?
When a change in a system causes the opposite effect, nullifying the effects
What is positive feedback?
When a change in the system causes other changes that have a similar effect
How does the global carbon system have an impact on the coastal system?
More carbon dioxide being emitted into the atmosphere -> contributes to global warming -> resulting in a global temperature rise -> sea temp rise