C:2 Physical landscape Of UK 1

Question 1

Explain the erosion of a wave cut platform

Answer 1

1- Waves hit lower part of cliff and and erode it (hydraulic action, abrasion).
2- The notch increases constantly in size until eventually it gets too deep and the upper part of the cliff can no longer support its weight
3- The cliff collapses and therefore retreats, forming a wave cut platfrom

Question 2

Explain the formation of a stump

Answer 2

1- A crack on the side of the headland is formed
2- As a result of hydraulic action and abrasion the crack grows into a cave
3- As the cave grows it eventually breaks through the headland forming a natural arch
4- Due to chemical and biological weathering processes the roof of the arch erodes, also as the size of the arch increases, the arch collapses.
5- Only a tall rock is left behind called a stack
6- The stack is eroded forming a stump which is only visible on low tides

Question 3

What is deposition and when does it occur

Answer 3

Deposition is when the sea loses energy and drops material, it occurs when the swash is stronger than the backwash
It is likely to occur when:
- Waves enter an area of shallow water
- Waves enter a sheltered area e.g. cave or bay
- There is little wind
- There is a good supply of material

Question 4

Describe the formation of a spit

Answer 4

1- Longshore drift moves sediment along the coastline
2- As a result of a sudden change in coastline e.g. a Bay behind a Headland which receives lower energy waves, deposition occurs
3- At first only the heaviest and Longest material is dropped by the headland, gradually as a spit develops it will receive smaller sediment
4- A secondary wind direction or change in the prevailing wind may shift the direction of the LSD deposition
5- Waves do not reach past spit making the waters behind it calmer
6- The spit may not reach the other end of the bay due to either deep waters or river currents

Question 5

Explain how an oxbow lake is formed

Answer 5

1- Erosion through hydraulic action and abrasion causes the outside bends of the river to bend out further and get closer together, forming a meander
2- This happens until only a small bit of land is left behind between the meander (known as a neck)
3- Because a river travels down the shortest course, it breaks through the neck and flows straight again
4- River Deposition cuts of the meander leaving behind an oxbow lake

Question 6

Explain how a waterfall is formed

Answer 6

1- Less resistant rocks erode more easily via hydraulic action and abrasion, undercutting the hard rock
2- The hard rock is left overhanging and eventually collapses as it isn’t supported
3- The fallen rocks crash into the plunge pool where they swirl around causing more erosion via attrition
4- This process is repeated and over time the waterfall moves upstream
5- A steep sided gorge is formed as the waterfall retreats