Coastal landforms Flashcards
What causes headlands and bays to form?
Headlands and bays are found in areas of alternating bands of harder and softer rock perpendicular to the waves
As the softer rock erodes quicker it creates a bay leaving the more resistant rock protruding into the sea as a headland
How does a cove form?
A cove forms where the coastline has bands of resistant and less resistant rock running parallel to the oncoming waves
There is usually a band of resistant rock facing the oncoming waves, with a band of softer rock behind
wave action will erode the softer rock quickly, which will leave behind a circular cove with a narrow entrance to the sea
Wave refraction within the cove spreads out the erosion in all directions, creating
the typical horseshoe shape - Lulworth Cove in Dorset, UK, is a good example of a cove
How are wave cut platforms formed?
When the sea erodes the base of a cliff a wave cut notch is formed
This notch is then extended further into the cliff until the cliff collapses leaving behind the wave cut platform
Describe what is happening during the sequence: cave, arch, stack and stump
First cracks in a headland begin to widen due to erosion and eventually forms a cave
This cave is then continuously eroded until it breaks through the other side creating an arch
The base of the arch will continuously get smaller and eventually the top of the arch will collapse leaving a stack
The stack will be undercut at the base by wave action and will collapse to form a stump
How is a beach formed?
Form in sheltered areas such as bays
Deposition occurs through constructive wave movement, where the swash is stronger than the backwash
Beach formation usually occurs in the summer months when the weather is calmer
What is a spit?
An extended stretch of sand or shingle that extends out to sea from the shore
Spits occur when there is a change in the shape of the coastline
Or the mouth of a river, which prevents a spit forming across the estuary
A spit may or may not have a ‘hooked’ end, depending on opposing winds and currents
How is a spit formed?
Sediment is transported by longshore drift
Where the coastline changes direction, a shallow, sheltered area allows for deposition of sediment
Due to increased friction, more deposition occurs
Eventually, a spit slowly builds up to sea level and extends in length
If the wind changes direction, then the wave pattern alters and results in a hooked end
The area behind the spit becomes sheltered
Silts are deposited here to form salt marshes or mud flats
What is a lagoon?
A lagoon is a small body of water which is cut off from the sea
It could have been left behind by a bar or tombolo
What is a tombolo?
A tombolo is formed when a spit joins the mainland to an island
Chesil Beach in Dorset is a tombolo, as the mainland is joined to the Isle of Portland
