Coasts Flashcards
Name a case study for a coastline that has a concordant side and a discordant side.
The Purbeck Coast.
Give an example of a Cove.
Lulworth Cove on the Purbeck coast.
Give an example of a Bay.
Worbarrow bay, Studland Bay or Swanage Bay on the Purbeck coast.
What are the four methods of material transportation by the sea?
Suspension, solution, saltation and traction.
Give an example of a blowhole.
Stair Hole in south Purbeck.
What is a tombolo?
A spit that extends from the mainland to an island.
When does deposition occur?
When there is insufficient energy to move sediment further.
State three significant factors in a low energy environment.
Wave and wind direction, the supply of sediment and the depth of the water.
How do swash-aligned beaches form?
When waves break parallel to the coast.
How do drift-aligned beaches form?
When longshore drift moves material down the coast producing a range of partly detached features.
State three landforms of swash-aligned beaches.
Bay beaches, bay bars and barrier beaches.
State three landforms of drift-aligned beaches.
Spits, bars and tombolos.
What type of system is the coastal system?
Open system
Where does most of the sediment in coasts come from?
Rivers
Describe a constructive wave.
Strong swash and weak backwash, flatter and smaller than destructive waves, causes material to ‘spill’ forward.
Describe a destructive wave.
Weak swash and strong backwash, taller and wider than constructive waves, causes material to be dragged back.
What is an input in a coastal system?
Sediment or energy brought into the system.
What is an output in a coastal system?
Sediment of energy washed out to sea or deposited further along the coast.
State four examples of flows/transfers.
Erosion, weathering, transportation and deposition.
Give three examples of stores/components.
Landforms such as beaches, dunes and spits.
What is negative feedback?
When a change in the system causes other changes that have the opposite effect.
What is positive feedback?
When a change in the system causes other changes that have a similar effect.
State six sources of energy in coastal systems.
Wind, waves, tides, currents, Sun and tectonics (tsunamis).
Describe a high energy coastline.
Receives high inputs of energy in the form of large, powerful waves caused by strong winds and long fetches. High energy coastlines tend to have sandy coves and rocky landforms such as cliffs, caves, stacks and arches. The rate of erosion is often higher than the rate of deposition.
Describe a low-energy coastline.
Receives low inputs of energy in the form of small, gentle waves caused by gentle winds (in sheltered areas) and short fetches. Low-energy coastlines often have saltmarshes and tidal mudflats. The rate of deposition is often higher than the rate of erosion.
Give a reason for a coast being of low-energy.
There is a reef or island offshore which protects the coasts from the full power of the waves.
How are waves formed?
By wind blowing over the surface of the sea. The friction between the wind and the water gives the water a circular motion.
What is wind created by?
Air moving from areas of high pressure to low pressure.
What are tides?
The periodic rise and fall of the ocean surface caused by the gravitational pull of the moon and sun.
What are currents?
General flow of water in one direction.
Other than wind, what can currents be caused by?
variations in water temperature and salinity.
When do beaches form?
When constructive waves deposit sediment on the shore.
What is the difference between sand and shingle beaches?
Shingle beaches are steep and narrow and made up of larger particles whereas sand beaches are wide and flat and formed from smaller particles.
Where are berms, ridges, runnels and grooves found on a beach?
Berms and ridges are found at high tide marks and runnels and grooves are found lower down the beach.