3.1.3.3 Coastal landscape And Development Flashcards
What are the inputs in the formation of a landform?
Coastal geology
Climate
Nature of the waves
What are the process of formation of a landform?
Erosion Weathering Deposition Wave refraction Sea level change
What are the outputs in the formation of a landform?
Sediment
Landform
On which type of coastline do headlands and bays form?
Discordant
Why is wave energy focused on headlands?
Wave refraction
Why are bays subject to deposition?
Due to the lower energy waves they recieve
What are the main landforms o erosion?
Headlands and bays
Cliffs and wave cut platforms
Caves arches and stacks
Where does a wave cut notch form?
Where destructive waves between the high and low tide lines at the foot of the cliff concentrate energy. So this rock faces more erosion and over time the cliff becomes undercut
What are characteristics of a wave cut platform?
Smooth and flat (5 degrees)
Why, over time, does the platform eventually cease to grow?
- the waves break further and further out
- wave energy is dissipated over a further distance
- rate of erosion decreases
What is usually the maximum width of a wave cut platform?
500m
Why is the formation of wave cut platforms a negative feedback loop?
Because over time the effects become less destructive due to the growth of the platform
Wat are cliff profile features?
Caves, arches and stacks
Where do caves, arches and stacks tend to form and why?
On headlands because wave refraction focuses wave energy of eroding the headlands
What is a geo?
A narrow, steep sided inlet opened up by hydraulic action
How is a cave formed?
Where the cracks or joints in a cliff becomes undercut by hydraulic action and abrasion
What is a blowhole?
When force from the waves hit the back of a cave with full force and enlarge joints in the cave roof. If overlying rocks are sufficiently weakened, they collapse
Why do caves often form in headlands?
because erosion is the strongest there
How is an arch formed?
When a cave breaks through the headland and opens through
What is a stack?
A tall rock formed when the roo of an arch collapses
Stands a lone from the headland
What is a stump?
The remainder of when the top of a stack is weathered and eventually collapses in stages
What are examples of cliff profile features?
Old Harry’s Rocks in Dorset
Twelve Apostles in Victoria, Australia
What is a beach?
A temporary accumulation of sediment (store) within a sediment cell
LArgely formed of sand or shingle
Formed from material of offshore sand bars, longshore drift, wind loan sa from up coast ad ass movement
Where do beaches form?
Between the highest point reached by storm waves and lowest spring tides
Why do sand beaches typically have a gentle slope of around 5 degrees?
Because the grains are small and easily compacted therefor little water can percolate through so th majority of th water moving up the beach wil return throughbackwash which smooths and flattens the beach
Why are shingle beaches usually steep at 10-20 degrees?
Because the large sediment size means they are less compacted. Therefore water can percolate better and the back wash does not pick up a lot of material from the beach back into the sea. This creates a beach which is unlikely to be eroded
What is a swash aligned beach?
Generally parallel to oncoming wave crests
Experience minimal longshore drift
Found on irregular coastlines where longshore drift is impeded, waves hit sections of the coast head on
What is a drift aligned beach?
Oriented parallel to direction of longshore drift
Have considerable amounts of sediment transported long distances a long them
Develop where a coastline is fairly regular
Can extend out from the coast line if there is a sudden change in the direction of the coastline e.g. an estuary
What is a spit?
An elongated, narrow ridge of land that has one end joined to the mainland and projects out into the sea or across an estuary
On which sort of beach does a spit usually form?
Drift aligned
What is a simple spit?
- straight or recurved
- do no he minor sits, or recurved ridges, along their landward edge
What is an example of a simple spit?
Spurn Head - East Yorkshire
What is a compound spit?
- Have a series of minor spits or recurred ridges along their landward side
What is an example of a compound spit?
Hearst Casle Spit, Hampshire
What makes a spit more permanent?
When sediment is deposited above the HWM
What is a tombolo?
Whe a spit connects to an island from th main land
What is an example of a tombolo?
St Ninians in Shetland
What does the formation of a tombolo create?/
More sheltered conditions on the lee-side of it which may lead to deposition and salt marsh formation
What is a barrier beach?
When a spit extends across a bay or joins two headlands together
They can only form if there is no current lowing off the land