Coastal Erosional Landforms

Question 1

Explain what two processes form cliffs and how whether it is soft rock or hard rock being eroded influences the appearance of the newly-formed cliff.

Answer 1

Cliffs are shaped through a combination of erosion and weathering. Soft rock like sand or clay erodes easily to create gently-sloping cliffs. Hard rock like chalk is more resistant and erodes slowly to create steep cliffs.

Question 2

Explain the formation of caves, and hence cliffs, in detail, and how this leads to the formation of a wave cut platform. (5)

Answer 2

1. As destructive waves attack a rocky headland, hydraulic action and abrasion erode a wave cut notch.
2. Over time, the notch enlarges to form a cave.
3. The unsupported rock above it is undercut and eventually collapses into the sea, forming a cliff.
4. Continued erosion and collapse causes the cliff line to retreat which leaves a level area of rock called a wave cut platform, only fully exposed at low tide.
5. Backwash also contributes to its formation by carrying rubble back out to the sea.

Question 3

Define weathering

Answer 3

Weathering is the breakdown of rocks caused by weather conditions

Question 3

Example of a wave cut platform

Answer 3

At Portstewart, near the Strand.

Question 4

Explain the formation of caves, giving extra detail, and stating the predominant processes in their formation. (4)

Answer 4

1. Caves are formed when waves are forced into cracks in the cliff face.
2. The water contains sand and other materials, which grind the rock until the cracks become a cave.
3. The waves also force air into the cracks, which increases pressure, causing them to eventually break up, forming caves.
4. Corrasion and hydraulic pressure are the predominant processes.

Question 5

Caves can transform into which other two coastal features? Put them in order, to include caves to begin with.

Answer 5

Caves –> Arches –> Stacks

Question 6

Explain the formation of an arch

Answer 6

If a cave is formed in a headland, it may eventually break through to the other side by the process of erosion, forming an arch.

Question 7

State simply what a stack is.

Answer 7

A tall column of rock.

Question 8

Explain how a stack is formed and eventually, a stump. [4]

Answer 8

1. The arch will gradually become bigger as a result of erosion by waves and weathering, until it can no longer support the top.
2. When the arch collapses, it leaves the headland on one side and a stack on the other.
3. The stack will continue to be eroded at the base, which weakens it. 4. It will eventually collapse to form a stump.

Question 9

Name one example of a stack.

Answer 9

Old Harry Rocks, Isle of Purbeck