Flashcards in coastal landscapes Deck (49):
What is chemical weathering?
Rocks reacting with slightly acidic water e.g. limestone dissolved by carbonation.
What is biological weathering?
Action of plants and animals, causing rock to split apart.
What is mechanical weathering?
Water falls into cracks in rocks and freezes, causing it to expand over time the repeated thawing and freezing causes the rock to break apart.
How does mass movement work on the coast?
Mass movement is downhill movement of material under influence of gravity.
What are the types of mass movement vary according to?
Material involved, amount of water in material, type of movement e.g. sliding.
What is abrasion?
Breaking waves throw sand, pebbles and boulders against coast during storms.
What is hydraulic action?
Sheer weight and impact of water against coastline, particulary during storm, erodes coast. Also waves compress air in joints in rocks, forcing them apart.
What is solution?
Chemical action of seawater dissolves some rocks.
What is longshore drift?
Process by which beach sediment can be transpoted along coast by waves.(see revisin guide).
How does longshore dirft transport material along the coastline?
Directin of material movement determined by prevaling wind direction. Waves approach coastline at acute angle, bringing sediment onto beach in swash. sediment then dragged back to sea in backswash, under force of gravity at a right angle. Process continues in zigzag pattern, moving sediment along beach.
What is traction?
Latge boulders are rolled along seabed by waves.
What is saltation?
Smaller stones are bounced along seabed.
What is suspension?
Sand and small particles are carried along in the flow.
What is solution?
Some minerals are dissolved in seawater and carried along in the flow.
What is deposition?
Load carried by waves is deposited by constructive waves.
What are the different factors that influence dieposition?
Sheltered spots e.g. bays.
Gentle gradient offshore causing friction. All reduce wave's energy.
What is geological structure?
Geology affects how fast coastal erosion occurs. Soft rock is eroded much faster than hard rock. Particular landforms are created when soft rocks and hard rocks occur together.
How does soft rock influence a coastline?
Easily eroded by sea. Cliffs will be less rugged and less steep than hard rock coasts. Soft rock landscapes include bays.
How does hard rock affect the coastline?
Resistant to all types of erosion. Cliffs will be high, steep and rugged. Hard rock landscapes include wave-cut platforms and headlands where caves, arches and stacks are formed.
What are concordant and disconcordent coasts?
Concordant coasts are made up of same rock type. Disconcordent coasts, rock type alternates, forming headlands and bays.
What are joints and faults?
Joints are smaller cracks, faults are larger. Both make rock more prone to erosion. Rocks with more joints and faults are eroded more quickly.
What is a destructive wave?
Swash is weak and backswash strong. Material is dragged into sea, eroding coast. Destructive waves have high energy, and occur in stormy conditions.
What are constructive waves?
Material is deposited building coast. Constuctivewaves have lower energy and occur in calm conditions.
What is seasonality?
4 seasons have different impacts on coastal erosion. e.g. cold temperatures in winter lead to freeze-thaw weathering in cliffs.
What are the effects of story weather?
Coasts are often subject to strong winds, incerasing eroding power of waves, and heavy rainfall contributes to mass movement. Frequent storms can damage coastal landforms like spits. Spurn Head along Holderness coast is at risk of neing cut off mainland. Beach sediment can be removed from seaction of coastline. Sand dunes can be removed by storms.
What is a prevaling wind?
In UK come from south-west. Brings warm, moist air from Atlantic and frequent rainfall, contributes to weathering and mass movement on coast.
What is coastal erosion?
Breaking down and removal of material along coast.
What is coastal retreat?
When coastal erosion causes coastline to move further inland.
What are headlands and bays?
Develop on coastlines with mix of hard and soft rock. Often occur where cliffs have fault lines or joints. Hard rocks like chalk are often left jutting out in sea, forming headlands. Soft rocks e.g. sands are eroded, more quickly, forming bays.
What are cliffs?
Cliffs are common coastal features. Cliffs are shaped through weathering and erosions. Soft rock erodes easily to create gently slping cliffs. Hard rock erodes more slowly to create steep cliffs.
What are wave-cut platforms?
Erosion of cliffs can create wave-cut platforms-areas of flat rock at ase of cliff.
What are beaches?
Accumliations of sand and shingle formed by dfeposition and shaped by erosion, transportation and deposition.
What is a spit?
Narrow beaches of sand that are attached to land at 1 end. Extend across bay or estuary or where coastline changes direction. Formed by longshore drift powered by strong prevaling wind.
What are the positives and negitives of urbanisation on the coastline?
Weight of buildings makes cliffs more vunreble. Vahnges to drainage increases soil saturation. Raises intrest in protecting coastal landscapes.
What are the positives and negitives of agriculture on the coastline?
Increases soil erosion, increases sedimentation, creates wildlife habitats.
What are the positives and negitives of industry on the coastline?
Increases air, noise and visula pollution, can destroy habitates for birds, animals and sealife. Brings wealth and jobs to an area.
What are the effects of coastal recession and flooding?
Wildlife habitats destroyed, loss of people's homes, increased deposition further along coast, loss of businesses from disappearing cliffs, decreasing value of properties and diffulties in obtaining home insurance, disruption to communication networks-roads and railway lines-creating difficulties for commuters, cliffs became dangerous for walkers.
What is coastal recession another term for?
What are the advantages and disadvantages of sea walls?
Protect cliffs and buidingsm more expensive £5000-£10,000 per meter.
What aare the positives and negitives of groynes?
Prevent sea removing sand, exposes other coastal areas, cheaper-£2,000 per meter of timber.
What are teh positives and negitives of rip rap?
Rocks absorb wave energy, cheaper £1,000-£3,000 per meter.
What are the positives of beach replenishment?
Sand reduces wave energy, maintains tourism, cheaper £2,000 per metre.
What are the positives and negitives of offshore reef?
Waves break on reef and lose power, may interfere with fishing, more expensive £5,000 per metre.
What is the definition of hard engeneering?
Hard engineering options tend to be expensive, short-term options. They may also have a high impact on the landscape or environment and be unsustainable.
What is the definition of soft engeneering?
Use of ecological principles and practicies to reduce erosion and achieve stabilisatoin and saftey of shorelines and area surrounding rivers, while enchancing habitat, improving aesthetics, and saving money.
What is the significance of location for holderness coast?
Soft boulder clas easily eroded, susceptible to slumping after heavy rainfall; chalk is more resistant (Flamborough Head). Exposed to strong waves (fetch) from North Sea.
What physical processes are at work at the coast?
Coastal erosion: combination of strong waves and rock type ensure coast eroded rapidly.
Mass movement: clay frequently slumps from cliffs after rainfall.
Transport: strong waved move eroded material away from coastline; depostion happens further south.
What human processes affect the coastline?
Hard engineering on parts of coast have protected areas from erosion and cliff collapse. Hard engineering in some places has prevented transport making erosion worse in other places.