Coastal Landscape Flashcards
What shapes the coastline
Different physical processes of weathering,mass movement and erosion
What are 3 types of weathering
- Chemical
- Biological
- Mechanical
What is mass movement
The downhill movement of material under the influence of gravity
Types of mass movement vary according to…
- Material involved
- Amount of water in the material
- Type of movement, e.g. sliding, slumping
Define Abrasion
Breaking waves throw sand, pebbles and boulders against the coast during storms
Define Hydraulic Action
The sheer weight and impact of water against the coastline, particularly during a storm ,erodes the coast. Also waves compress air in joints in rocks, forcing them apart
Define Attrition
Rocks and pebbles carried by waves rub together and break into smaller pieces
Define Solution
The chemical action of seawater dissolves some rocks
When does sliding happen
When loosened rocks and soil suddenly slide down the slope. Blocks of material may all slide at once
What is Longshore Drift
The process by which beach sediment can be transported along the coast by waves.
Define Traction
Large boulders are rolled along the seabed by waves
Define saltation
Smaller stones are bounced along the seabed
Define suspension
Sand and small particles are carried along in the flow
Define sloution
Some minerals are dissolved in seawater and carried along in the flow
The load carried by _ is deposited by _ waves
Waves
Constructive
What factors influence depositaton
- Sheltered spots (e.g. bays)
- Calm conditions
- Gentle gradient offshore causing friction. All reduce the wave’s energy
What type of rock is eiser to erode
Soft such as clay
What type of rocks makes it so that the cliff will be less rugged and less steep
Soft such as clay
What type of rocks makes up bays
Soft such as clay
What type of erosion are hard rocks resistant to
All types
What type of rock causes cliffs to be high, steep and rugged
Hard rocks such as granite
What type of rock makes up wave-cut platforms
Hard rocks such as granite
What is a concordinate coast
A coast made up of the same rock type
What is a discordiant coast
A coast where the rock type alernates, forming headlands and bays
What is a joint and a fault
Smaller cracks; faults are larger
Are joints and faults prone to erosion
Yes
What is a destructive wave
A wave where the swash is weak and the backwash is strong. Material is dragged into the sea, eroding the coast. Destructive waves have high energy, and occur in stormy conditions
What is a constructive wave
A wave where material is deposited, building up the coast. Constructive waves have lower energy and occur in calm conditions
How do different seasons impact coastal erosion in the UK.
Cold temperatures in winter lead to freeze-thaw weathering in cliffs
Coasts are often subjected to strong winds, _ the eroding power of the _, and heavy _ contributes to mass movement
Increasing
Waves
Rainfall
Frequent storms can damage coastal landforms like…
Spits
Beach _ can be removed from a section of _
Sediment
Coastline
How can sand dunes be removed
By storms
Where are prevailing winds from in the UK and what is the impact of this
South-west
This brings warm,moist air from the Atlantic anf requnet rainfall
Coastal erosion definition
The breaking down and removal of material along the coast
Coastal retreat definition
when coastl erosion causes the coastline to move further inland
How are cliffs shaped
Through weathering and erosion
When is a cave formed
When the waves erode a weakness in the rock such as a joint or a fault
When is an arch formed
When two caves erode back from either side of a headland and meet in the middle
When is a stack formed
When an arch collapses
How are wave-cut platforms formed
The erosion of cliffs can create wave-cut platforms- areas of flat rock at thte of the cliff
What is a spit
Narrow beaches of sand or shingle that are attached to the land at one end. They extend across a bay or estuary or where the coastline changes direction. They are formed by longshore drift powered by a strong prevailing wind
What is an adantage of having of a sea wall
Protects cliffs and buildings
What is a disadvantage of a sea wall
Expensive-£5000-£10 000/m
What are advantages of groynes
Prevent sea removing sand
Cheaper-£200/m of timber
What are disadvantages of groynes
Exposes other coastal areas
What are advantages of rip rap
- Rocks absorb wave energy
- Cheaper-£1000-£3000/m
What are advantages of beach replenishmnet
- Sand reduces wave energy
- Maintains tourism
- Cheaper- £2000/m
What are advantages of offshore reef
Waves break on reeft and lose power
What are disadvantages of offshore reef
- May interfere with fishing
- More expensive-£5000/m
What are groynes
Wooden or rock structures built along the beach at right angles
What is beach nourishment (recharge)
Sand or shingle is added to a beach to make it higher or wider
What is sand dune regeneration
Grasses, bushes and trees are planted to stabilise dunes
What is a sea wall
Concrete walls, about 3-5 meters high, built at the foot of cliffs or the top of a beach; sometimes curved to reflect the waves back out to sea
What is rip rap (rock armour)
Large boulder puled out at the foot of the cliff or the top of a beach
Define Fetch
This is the distance of open water which the wind has been blowing the longer the fetch, the more powerful the wave
