What landforms are created by erosion?
Cliffs/Wave cut notches/platforms
Headlands and Bays
Caves, Blowholes, Arches, Stacks and Stumps
What causes a wave cut notch to form?
When the waves undercut the cliff
How does a wave-cut become a wave-cut platform?
A wave-cut notch develops into a cave, the overhanging cliff is no longer supported casuing the cliff to collapse. This happens repeatedly and the layer of flat rock left is the wave cut platform.
Angle of a wave-cut platform?
Less than 4 degrees.
Wave-cut platform:increase/decrease erosion?
The wave-cut platform decreases the rate of erosion, as the waves have further to travel to the base of the cliff. The wave energy also disserpates over the platform, reducing the amount of erosion occuring.
What is a discordant coastline?
A discordant coastline occurs where bands of different rock type run perpendicular to the coast.
What is a concordant coastline?
A concordant coastline occurs where beds, or layers, of differing rock types are folded into ridges that run parallel to the coast.
Most common coastline-headlands and bays?
At what type of coastline was Lulworth Cove formed
What is wave refraction?
As waves approach a coast they are refracted so that their energy is concentrated around headlands but reduced around bays. Waves then tend to approach coastline parallel to it, and their energy decreases as water depth decreases.
Name the 4 types of erosion.
How does geology affect headlands & bays?
When the waves erode the cliff, the softer rock gets eroded faster as it is less resistant. This means that the hard rock sticks out to sea - this is called a headland. The sheltered area between the headland is called a bay- this is where a beach is formed.
How are caves formed?
When waves erode the cliff it causes cracks. Due to the erosional processes, such as hydraulic action, air trapped in the cracks gets compressed by the force of the waves against the cliff causing more erosion to take place. As the crack crumbles and erodes further into the rock it forms a cave.
How are arches formed?
An arch is formed when a cave gets eroded through to the other side of the cliff.
How is a blow-hole formed?
Occasionally,wave action and weathering erodes joints in the cave roof to form a blow hole. Where the cave erodes through the headland an arch is formed.
How is a stack formed?
A stack is formed when the roof of an arch collapses.
What is a stump?
A stump is a collapsed stack.
What is differential erosion?
Alternatiting rate of erosion of hard and soft rock
At what type of coastline is Old Harry located?
What is cliff retreat?
Repeated process of cliff collapsing after a cliff can no longer support the overhand of cliff because of the formation of a wave-cut notch.
What is the order of sand dune succession?
What type of transportation carries sand?
What type of vegetation grows at the embryo dune?
Lyme grass, marram grass and sand couch
At what stage is the dune most acidic?
Why is an obstacle needed for a sand dune to form?
To catch and trap the sand, so it build up to become a sand dune.
What is humus?
- the organic component of soil, formed by the decomposition of leaves and other plant material by soil microorganisms.
How much sand is exposed at the yellow dune?
How are spits formed?
Spits are formed where the coast suddenly changes direction e.g. across a river mouth. Longshore drift continues to deposit material across the mouth of a river which results in the formation of a long bank of sand and shingle forming.
What is longshore drift?
The sediment is carried out to sea in the backwash in the direction of the prevailing wind. The sediment is then brought back into shore at 90 degrees in the swash.
What is a bar?
When a spit joins two headlands
What forms behind a bar?
What is a tombola?
A spit that joins with an island
What forms behind a spit?
What type of plant can survive in a saltmarsh?
Halophytes - Pioneer plants
How do landforms of deposition occur?
Landforms of deposition occur where accumulation of sand and shingle is greater than it is removed.
Type of wave- Strong swash?
What type of is created by distant storms?
What is a cusp?
Cusps are crescent-shaped indentations that form on beaches of mixed sand and shingle.
Where are cusps formed?
They are formed where there is a junction between sand and shingle
What is a berm?
There are often a series of smaller ridges formed beneath the storm ridge known as berms.
What are ridges and runnels?
Ridges and runnels form parallel to the shore line in the foreshore zone. Ridges are areas of the foreshore that are raised above the adjacent shore which dips into a Runnel.