Caves, arches, stacks and stumps

Question 1

Where do caves, arches, stacks and stumps occur?

Answer 1

Across headlands. Lines of weakness in a headland. The area of weakness may originally have been a wave-cut notch. If the cave is formed in a headland, it may eventually break through to the other side forming an arch.

Question 2

Explain the process of cracks forming into stumps.

Answer 2

• Caves occur when waves force their way into the cracks in the cliff face. The water contains sand and other sediment that grind away at the rock until the cracks become a cave. Hydraulic action is the predominant process.
• If the cave is formed in a headland it may eventually break through to the other side, forming an arch. The arch will gradually become bigger until it can’t support the top of the arch. When the arch collapses, it leaves a stack on one side.
• The stack will be attacked at the base until eventually collapses.

Question 3

Give one example of this.

Answer 3

Old Harry’s Rocks