erosion and transportation Flashcards
hydraulic action
when a wave crashes, air can be trapped and compressed, either in joints in the rock or between the wave and the cliff. when the wave retreats, the compressed air expands, this continuous process can weaken joints and cracks, causing pieces of rock to fall off.
cavitation
bubbles formed in the water may implode under the high pressure, which generates tiny jets of water which over time will erode the rock
wave quarrying
actions of waves breaking against unconsolidated material such as sand and gravel. waves scoop out the loose material.
corrasion
when waves advance they pick up sediment. the transported material is hurled at the cliff. example of energy flow in action. size shape and energy of sediment determines rate of erosion.
abrasion
sediment is dragged up or down or across the cliff face in a sort of sandpapering effect. important for wave cut platforms.
solution/corrosion
weak acids in sea water can dissolve alkaline rock such as chalk and limestone
attrition
gradual wearing down of rock particles by impact and abrasion, making rocks smoother and rounder.
factors affecting coastal erosion
- waves- destructive/constructive more in winter when destructive is more prevalent
- rock type (lithology) its physical strength and chemistry. e.g granite erodes slower.
- geological structure- cracks joints bedding planes
- presence or absence of a beach
- subaerial processes- weathering and mass movement
- coastal management
traction
rolling of course sediment along the sea bed which is too heavy to be picked up by the sea.
saltation
sediment bounced along thee sea bed, light enough to be picked up or dislodged but too heavy to remain in the flow of the water.
suspension
smaller lighter sediment picked up and carried with in the flow of the water
solution
chemicals dissolved in the water, transported and precipitated elsewhere.
factors affecting type of transportation
-velocity
-particle size
in high energy coastlines, heavy material able to be carried.
