Key Coastal Processes Flashcards
What is littoral zone made up of
Offshore Nearshore - breaker zone/surfer zone Foreshore- smash zone Backshore Land
The littoral zone creates a dynamic equilibrium. What natural processes can affect this?
Inputs of sediment from the sea and currents from rivers
Weathering and mass movement (backshore)
Constructive and destructive waves causes deposition and erosion
Tidal range determines where the action takes place
Offshore currents and longshoremen drift determines the movement of sediment
The littoral is one of dynamic equilibrium. What are the human activities which affect this?
Dredging of rivers to make way for shipping- reduces the sediment that gets backshore
Dredging of backshore
Coastal defences against flood and erosion
Valentin’s classification of coasts
Advancing Coast Emergence = emerging coastline Deposition = outbuilding Coast Retreating Coast Submergence = submerging coast Erosion= eroding Coast
What are the two types of coasts
High energy and low energy
Characteristics of a low energy coastline
Spits, bars, salt marshes Constructive waves Short fetched More deposition and transport Sheltered from large waves Lowland coasts Coastal plain landscape
Characteristics of a high energy coastline
Destructive waves Erosion and transport Weathering Steep cliffs, wave cut platforms, arches, stacks Large waves Rock6 landscape
Characteristics of a concordant coastline
Arrangement of rock types parallel to the coast
Alternate hard and soft rock
Characteristics of a discordant coastline
Arrangement of rock types perpendicular to Coast
Headlands and bays
More land forms
Geological structure on coastal morphology
Rock formation- the rate of cooling may mean rock has more cracks and faults so it’s more susceptible to erosion
Different types of rocks - sedimentary, igneous or metamorphic
Bedding planes due to the different layers of deposition
Dip of land - seaward vs landward
Exposure of bedding planes
Anticlines and synclines
What factors influence coastal recession
Lithology hard vs soft rock
Differential erosion- how permeable rocks are eroded, how impermeable rocks are eroded, water can increase saturation of make them more susceptible to erosional processes and subaerial weathering
Chemical weathering due to minerals that make up rock (limestone)
What is the role of vegetation on a coastline
Stabilising soft sediment
Plant succession occurs - pioneer plant
As the conditions change, the plants adapt
Keeps happening until there is a balance
The role of salt marshes
Haloseres , plants that can survive in salty conditions
Found in estuaries
Tide brings in sea water
Flocculation occurs which allows particles to stick together
Pioneer plants survive - conditions change
Colonisation of plants
The order of grasses in salt marshes
Eel grass Mudflat Cordgrass Marsh grass Pickle weed Salt grass Least to most tolerant of sea water
The role of sand dunes
To protect the coastline
Not fully vegetated
Subject to large ration via the winds
Depends on the tide to what vegetation grows there
