✅COASTS 3.1.3.3 - Coastal Landscape Development Flashcards
How is a wave cut platform formed?
Waves breaking at foot of cliff form wave cut notch
Undercutting is result of erosion by waves
As undercutting continues, rock above collapses and cliff gradually retreats
A sloping rocky platform is left behind, the wave cut platform, covered at high tide
What effect do wave cut platforms have on the rate of erosion?
They affect the wave’s ability to erode the cliff because they have further to travel in shallow water
They break earlier and dissipate their energy, reducing rates of erosion
What type of process is soil creep?
Creep/flow
What type of process is mudflow?
Flow
What type of process is run off?
Flow
What type of process is landslide/slump?
Slide
What type of process is rockfall?
Fall
How does soil creep occur?
Slow form of movement of individual soil particles moving down a hill or slope, slow
How does mudflow occur?
Earth and mud flowing down a slope or hill
How does run off occur?
A type of flow from one store (rockface) to another (beach or sea)
How does landslide/slump occur?
Where material slides on a curved surface over weak and unconsolidated rock
How does rockfall occur?
Sudden form of collapse or breaking away of rocks from a cliff face
Where are two examples of wave cut platforms outside the UK?
Collaroy Beach, NSW, Australia
Fisherman’s Rock, NZ
Where are two examples of cliffs located outside the UK?
Ketubjorg Cliffs, Iceland
Dryholaey, Iceland
Wher are two examples of caves located outside the UK?
Punta de Arucas, Spain
Waiahuakua Cave, Hawaii
Where are two examples of arches located outside the UK?
Es Pontas Arch, Mallorca, Spain
The Azure Window, Malta
Where are two examples of stacks located inside and outside the U.K.?
Old Harry’s Rocks, Dorset
12 Apostles in Australia
Twelve Apostles Stacks, Victoria, Australia
Where are two examples of stumps located outside the UK?
Faro, off the coast of Sweden
Bay of Naples, Italy
How is a stack formed?
Headland is attacked by waves along lines of weakness
The erosion exploits a weakness, forming a cave
If the weakness runs through the headland, two caves may form back to back
Eventually an arch is formed
Wave attack continues at the base of the arch until it collapses, leaving a stack
How is a stump formed?
When a stack is continually eroded until it collapses
In what conditions do slash aligned beaches form?
When waves break parallel to the coast
In what conditions do drift aligned beached form?
When longshore drift moves material don the coast, producing a range of partially detached features
Example of a Drift aligned beach
The Orford Ness Spit, Suffolk
In what conditions do sand dunes form?
When dry material from flat, open beaches is blown inland
Large tidal rain can cause sand to be dried out, meaning it can be blown into dune
In what conditions do mudflats and slat marshes form?
When finer material stacks together in the shallow water of estuaries
When do beach cusps occur?
Where the coarser material at the top of the beach absorbs wave swash
Where do bay head beaches build up?
In sheltered, low energy environments of coves. Wave refraction focuses erosion on the surrounding headands, encouraging deposition in the bay
How are coves formed
Concordant coast
Hard rock erodes, soft rock erodes fast behind it, creates circle
E.g Lulworth Cove
Where do bay bars form?
Across estuaries, blocking off rivers
Where do barrier beaches form?
Where waves recycle offshore material
How do drift aligned beaches develop?
Where waves approach the coastline at an angle, the swash moves material up the beach in that direction, and the backwash returns at right angles - LONGSHORE DRIFT
How do swash aligned beaches develop?
When waves break parallel with the coast, the movement of water and material is largely up and down the beach. Little LSD.
Example of a swash-aligned beach?
Chesil Beach, Dorset
What features arise from swash aligned beaches?
Bay head beaches
Bay bars
Barrier beaches
What features develop from drift aligned beaches?
Spits
Recurved spits
Tombolos
Cuspate forelands
What can form behind a spit?
Brackish lagoon, due to trapping water. E.g, Slapton Leg, Dorset
What are tombolos?
When spits extend from the coasts to an island- e,g., Isle of Portland in UK
What are cuspate forelands?
Triangular shaped features which may have resulted from changes in the growth and direction of spits.
When does deposition occur?
When there is insufficient energy to move sediments further in low energy environments
Where do runnels form?
Close to low water marks, separating pools of standing water at low tide
Where do ripples form?
Small marks that appear where the slop of the beach increases and where the tide moves over the beach
How does pebble size change up the beach?
Bigger, heavier pebbles are found further up the beach because more energy is required to transport them. Smaller lighter ones are further up to the backshore.
What are the features of swash aligned beaches?
Beaches can be large, especially if facing into prevailing wind
Landforms are created by offshore sediment
Found right at the back of bays due to wave refraction
What are the features of drift aligned beaches?
Pebbles and sand drift along because in wind direction
Landforms created by material moved along beach by LSD
What is a spit?
A long, narrow feature that extends from the mainland at the end of a drift aligned beach
Why does a recurved end occur?
Wave refraction and a second dominant wind force material to move in a different direction
What are examples of tombolos?
Isle of Purbeck, UK
Angel Road, Shodo Island
In what conditions do tombolos form?
Island close to mainland Area of shallow water Preferential supply of sediment (cliff erosion) Small, low energy waves Sheltered area Consistent prevailing wind
