Coastal Landforms Flashcards
What do the different types of coastlines mean?
They are the way the layers of rock are laid down in relation to the coastline, hugely influences the erosional landforms likely to be found there
What is a concordant coastline?
Rocks running parallel to the sea (present at south perbeck)
What is a discordant coastline?
Rocks on these coastlines run perpendicular to the sea (present in east perbeck)
How does a wave cut platform develop?
When waves break at the foot of a cliff producing a wave cut notch. This undercutting is the result of erosion by waves (e.g. abrasion and hydraulic action). As the cliff is undercut, the rock above collapses and so the cliff gradually retreats. Wave cut platform is formed, and gets covered by high tide
How does the formation of wave cut platforms have a negative feedback on the rate of cliff erosion?
Material that has collapsed will prevent waves eroding the coastline as they act as a barrier. Waves have to get through wave cut platform first, meaning they will loose energy and break much before they get to the back of the beach, slowing rate of erosion
How is cave, arch, stack and stumps formed?
The headland is attacked by waves via erosion (hydraulic action and wave quarrying), along lines of weakness, forming a cave. Weakness runs through headland, 2 caves form back to back, eventually breaking through and creating an arch. Waves attack base of the arch, and weathering at the top of the arch, when this collapses it leaves a stack. This is further attacked until it collapses leaving just the base, eventually leading to a stump
What is a cliff profile and what is it responsible for?
Gradient of the cliff face… responsible for whether a cliff is gentle or steep in gradient
What are steep cliffs often associated with?
Slow L eroded resistant rocks e.g. granite
What are sedimentary rocks… how are they formed?
Sedimentary rocks form as layers of deposited sediment, either on the beds of ancient oceans or rivers.
What are bedding planes?
They are layers of sediment that represent surfaces of exposure that occcured between depositional events.
What happens when the bedding planes are horizontal?
Then the cliff profile will be stable with a steep cliff face. However, due to tectonic movement, rock is uplifted and folded. This can change the alignment of strata in cliff profiles
Give an example of a wave cut platform:
Along the coast of Dorset, particularly at lulworth cove
Give an example of a stack:
Old Harry, Dorset
Give an example of a stump:
British isles coast, UK
Give an example of a cliff:
El Capitan summit, California