Coastal geomorphological processes Flashcards
What drives the processes?
Driven by an input of energy, comes from waves or wind
Can be marine or sub-aerial
What do these processes do?
Change characteristics of components of a coastal landscape - shape of beach or cliff, sand dunes
What is a marine process?
Operate on a coastline
What is a sub-aerial process?
Operate on land
What are examples of sub-aerial processes?
Weathering
Run off
Mass movement
What are examples of marine processes?
Waves
Tides
Longshore drift
What are some processes of marine erosion?
Hydraulic action Wave quarrying Abrasion Attrition Solution
What is hydraulic action?
It is the force of the water on rocks weakening the surface
What is wave quarrying?
A breaking wave moving towards cliff face traps air as its hits cliff face in the cracks of the rock. When water pulls back en explosive effect happens as air is released from where it was trapped, can degrade rock
What is abrasion?
Material carried by water wears aware cliff face
What is attrition?
When material hits against each other it breaks it down
What is solution?
Relates to the dissolving of calcium based rock
What effects the rate of coastal erosion?
Wave steepness and breaking point
Fetch
Sea depth
How does wave steepness and breaking point affect coastal erosion?
Waves that are steeper have a greater erosive power on the rocks
Waves the break as the foot of the cliff has greats amount of energy of the bottom of the cliff
How does the fetch affect coastal erosion?
Longer a wave has travelled the more energy it will have generated - greater erosive power
How does the sea depth affect costal erosion?
Where there is a steep sea bed, this creates higher and steeper waves
Shallow sea bed means waves can loose energy further away from the coastline because of the increased fricton
How does costal configuration affect coastal erosion?
Where there are headlands, it is subjected to greater erosion, the headland will refract the wave energy weakening the waves for the beach further on
How do the presence of beaches affect coastal erosion?
Beaches absorb wave energy, they provide protection against marine erosion, they are accumulations of sand and shingle. Beaches ensure that waves loose energy and have to deposit material. Sand creates flat beaches, shingle creates steep beaches
How does human activity affect coastal erosion?
Humans can protect coastal environments through sea defences which reduces erosion but can increase erosion elsewhere
They can negatively affect environment through removing protective material like sand and shingle causing increased beach erosion
How does the lithology affect coastal erosion?
Relates to characteristics of rock
Resistance to erosion, if rocks are aligned in certain positions makes them more susceptible to erosion or not
Permeability of rock
Clay - less resistant
Granit - more resistant
Jointed rocks - less resistant to erosion
Differential rate of erosion
What is a concordant coastline?
Bands of different rock run parallel to the coastline
What is a discordant coastline?
Bands of different rock run perpendicular to the coastline
What commonly forms on a discordant coastline?
Headlands and bays
What is an example of a discordant coastline?
Durlston Head
What is an example of a concordant coastline?
Lulworth cove
