4. UK Evolving Physical Landscape: Coastal Weathering and Erosion

Question 1

How can rock be broken down?

Answer 1

Mechanical

Chemical

Biological

…. Weathering.

Question 2

What is Mechanical Weathering?

Answer 2

Breakdown of rock - without changing chemical composition - main mechanical weathering - salt weathering

Seawater gets in cracks in rock - water evaporates and forms crystals - expand and put pressure on rock - repetition of process causes rock to break up

Question 3

What is Chemical Weathering?

Answer 3

Break down of rock by changing chemical composition - carbonation weathering happens in warm and wet conditions

Seawater and rainwater have carbon dioxide dissolved in them - makes them weak carbonic acids - carbonic acid react with rock containing calcium carbonate - rocks dissolve by rainwater

Question 4

What is Biological Weathering?

Answer 4

Break down of rock by living things e.g. plant roots growing into rock cracks - pushing them apart

Question 5

What is Mass Movement?

Answer 5

The shifting of rocks and loose material down a slope - cause coasts to retreat rapidly - more likely happen when material full of water - acts as lubricant - makes material heavier - three types of mass movements

Slides - material shifts in a straight line
Slumps - material shifts with a rotation
Rockfalls - material breaks up and falls down slope

Question 6

What are the 3 Processes of Erosion as a result of Waves?

Answer 6

Hydraulic power - wave crashes against rock - compressed air inside the joints - pressure on rock - repeated compression widens joints and bits of rock fall off

Abrasion - eroded particles in water scarpe and rub against rock - removing small pieces

Attrition - eroded particles in water smash into each other - smaller fragments - edges get rounded off as they rub together