Coasts Flashcards
What type of system is a coast?
Considered a open system as it receives inputs from outside the system and transfers outputs away from the coast
What is a sediment cell and what type of system is it?
A section of the coast and usually a closed system
11 in England and Wales
What is dynamic equilibrium in a sediment cell?
Where inputs and outputs of sediment are in a constant state of change but remain in balance
What are sources?
Where sediment originates from
What are through flows?
The movement of sediment along the shore - Long shore drift
What are sinks?
Locations where deposition of sediment dominates
What are feedback loops?
Mechanisms which enhance changes within a system, taking it away from dynamic equilibrium (positive feedback) or mechanisms which balances changes, taking the system back towards equilibrium (negative feedback)
What is a negative feedback loop?
Lessens any change which has occurred within the system
What is a positive feedback loop?
Exaggerates the change making the system more unstable and taking it away from dynamic equilibrium
What is the littoral zone?
The area of coast where land is subject to wave actions
Why is the littoral zone constantly changing?
Short-term factors: Tides and storm surges
Long-term factors: Changes in sea level and climate change
What are the subzones within the littoral zone?
Backshore - area above hide tide level and only affected by exceptionally hide tided
Foreshore - Land where most wave processes occur
Offshore - The open sea
What does Valentines classification describe?
The range of coastline that can occur
Why might there be an advancing coastline?
Due to the land emerging or deposition being the prominent process
Why might there be a retreating coastline?
Due to the land submerging or erosion being the prominent process
What is erosion?
A collaborative process which involves the removal of sediment from a coastline
What are the main types of erosion?
Abrasion - Sediment is moved along the coastline, causing it to be worn down overtime
Attrition - Wave action causes rocks to hit against each other
Hydraulic Action - Air forced into cracks from waves
Solution - Mildly acidic seawater causes rock to be eroded
When are erosion rates at their highest?
When waves have a long fetch
High tide
Heavy rainfall
In winter
What will determine a rocks vulnerability to erosion?
The resistance of the rock (lithology - type)
What are examples of erosional landforms?
Caves
Arches
Stacks
Stumps
Wave-cut notch and platform
What are the main types of transportation?
Traction - Large, heavy sediment rolls along the sea bed
Saltation - Smaller sediment bounces along the sea bed
Suspension - Small sediment is carrier with the water column
Solution - Dissolved material is carried within the water
When does deposition occur?
When a wave loses energy meaning the sediment becomes to heavy to carry - it is a gradual process
What is flocculation?
When clay particles clump together due to chemical attraction and then sink due to their high density
What is a spit?
A long narrow strip of land which is formed due to deposition
What is a bar?
A spit which, over time, crosses a bay and links up 2 sections of the coast