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Look at Diagram Q2 - Scottish Highers Geography - Question 2 - 2023
Question 2
Look at Diagram Q2. Explain the formation of a stack. You may wish to use an annotated diagram or diagrams in your answer.
Worked Solution & Example Answer:Look at Diagram Q2 - Scottish Highers Geography - Question 2 - 2023
Step 1
Formation of a stack: Describe the erosional processes
Answer
The formation of a stack begins with hydraulic action, where waves compress air trapped in the cracks of the rocks, leading to increased pressure and erosive force against the rock surfaces. As waves continue to break on the coast, they erode the base of the cliff, which is more susceptible to erosion due to the softer rock layers.
Over time, abrasion occurs as rock fragments and sediments being carried by the waves strike against the cliff face, further breaking down the rock.
This process often leads to the formation of a cave as the cliff continues to erode backward and deepens under the force of the waves.
Step 2
Formation of a stack: Explain how a stack is formed
Answer
As erosion continues, the cave may eventually erode through the headland, creating an arch. Eventually, the roof of the arch will become unstable and, due to ongoing erosion, it will collapse, leaving a pillar of rock isolated from the mainland. This isolated pillar of rock is known as a stack.
The stack continues to be shaped by the relentless forces of waves and erosion, further diminishing its height and eventually leading to its eventual disintegration if erosion persists.
Step 3
Formation of a stack: Conclude the explanation
Answer
In summary, the formation of a stack is a result of a complex interplay of erosional processes, primarily hydraulic action and abrasion, which work over time to sculpt coastal features from rock formations, ultimately resulting in the distinct geological feature known as a stack.