mixed questions Flashcards
What is attrition?
materials carried by waves, bump/collide with each other and so are smoothed and broken down in to smaller particles.
What is longshore drift?
longshore drift is the movement of particles along a coast moving in an eastwardly direction, moving up the coast at a 45 degree angle and coming back in to the ocean at a 180 degree angle.
what is swash?
swash is when the wave goes from A to B. Swash is the particles coming on to the coast
what is backwash?
backwash is the particles coming back in to the ocean.
what is abrasion/corrasion?
this is when the coast is worn down by material carried by the waves. waves throw particles against the rock at high speed, and erode rock rather like a sandpapering action.
what is corrosion?
this is the chemical action of the sea water, the acids in the seawater slowly disolve the mineral particles in the rock.For example carbonic acid in sea water dissolves calcium carbonate in limestone.
What is hydraulic action?
this involves a force of water against the coast, the waves enter cracks (faults) in the coastline and compress the air with in a crack, when the wave retreats the air in the crack expands quickly causing a minor explosion this is repeated continuesly.
what are sea walls?
sea walls are a concrete rock barrier placed at the foot of a cliff it has a curved face to reflect the waves back in to the sea they cost up to 6 million pounds per kilometre.
What are groynes?
timber or rock structure built from out to sea they trap sedament being moved by longshore drift, they are spaced 200 metres away from each other and cost 10 thousand pounds each.
What is rock armour?
piles of large boulders dumped at the foot of a cliff, the rocks force the waves to break absorbing their energy, they cost up to 1000-4000 pounds per metre.
`What is beach nourishment?
The addition of sand and shingle to an existing beach they cost 3000 pounds per metre.
What is marsh creation?
Allowing low lieing coastal areas to be flooded by the sea to become salt marshes they cost between 5000 to 10000 pounds per hector.
