Lithosphere- coasts

Question 1

Factors influencing costal landscapes

Answer 1

• Rock type and structure
• Tides- high tides mean more erosion as water is further up the coast
• Sea depth- steep sea beds create higher and steeper waves with more energy
• Prevailing winds- determine path of a wave and properties (determines fetch- distance of open water which a wave has travelled, greater fetch= greater energy)
• Wind speed- Higher wind speed= more erosional power
• People- removal of protective materials from beaches can lead to greater erosion, reduce or divert erosion with sea defences

Question 2

Destructive waves and constructive waves

Answer 2

Destructive:

• High energy
• Erosional
• Short wavelength, high height
• High frequency (10-12 waves per min)
• Circular orbit
• Low period
• Backwash greater than smash (drags more material, little deposited)
• Steep Gradient

Question 3

Hydraulic action

Answer 3

Waves break against the rock face. Any air trapped in the cracks, faults or joints is compressed and put under pressure. When the wave retreats the air expands again, weakening fissures and loosening/ breaking off rock.

Question 4

Abrasion/ corrasion

Answer 4

Rocks and other sediment are propelled against cliff faces by waves, this wears away the rock overtime. Repetitive and long term corrasion at the foot of a cliff can erode a wave-cut notch which may result in the collapse of the rock above.

Question 5

Attrition

Answer 5

The eroded material is itself worn down through attrition. Wave action causes items of rock debris to bump into each other, scrape and break off/ wear away. The reduction in size makes it easier for waves to transport the debris so waves have more access to the cliff, increasing erosion.

Question 6

Solution/ corrosion

Answer 6

The breaking down of costal rock following a reaction to chemicals in the sea water.

Question 7

Wave pounding

Answer 7

The brute strength of the waves against the rock face, it can smash pieces of rock. Compared to the action of a sledgehammer.

Question 8

Freeze thaw weathering

Answer 8

Jointed rock is forced apart by the expansion of water as it freezes in fractures. It occurs in cold climates where temperatures are often around freezing and fluctuate above and below 0°C.

Question 9

Stumps

Answer 9

• Disconcordant coastline- headland formed
• Sea refracts around headland, joint exploited by waves
• Cracks enlarged, cave forms
• Two caves erodes into arch
• Roof of arch collapses, sea stack left
• Wave-cut notches from erosion cause stump