Stand looking west and imagine the stormy sea, lashing against cliffs. The sea gradually erodes the cliffs, the relentless waves find lines of weakness to exploit. Blowholes may form where the waves are forced upwards through the cliffs, and sea caves where they cut into the cliff. Over time the sea cave may extend right through a headland into an arch, which may then collapse forming a stack. This stack is eventually eroded by wind and water down to a stump. At the base of these features is a wave cut platform - a flat area at the foot of sea cliffs formed by wave erosion.
Except..... the scene as you look out to see does not have any stacks, arches or cliffs...
... or does it? ....
Turn to look south-east, across the A77 towards the area in front of the low hills. You are standing on a wave-cut platform and there are some features in the field that would usually be associated with cliff erosion.
This is a raised beach, a wave cut platform that is now higher than the present shoreline. It was formed at sea level, but is now above the tide line, indicating that the sea level has dropped in this area. Raised beaches are common in southern Scotland where the landscape is rebounding after being covered in glaciers during the Ice Ages. Glaciers are very heavy and their weight pushed the landmass down, causing it to sink and the relative sea level to rise. Once the temperatures rise and the ice melts, the land gradually rises back up and the relative sea level sinks again. This is known as isostatic readjustment. By scientific dating or identification of marine fossils found in the raised beach, geologists can establish sea levels at known points in the past, and calculate the rate at which the land is rising.
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Estimations should be made from the coordinates, there is no need to enter the field opposite.
- Which coastal erosion features are found in the field behind the A77?
- Estimate the height of the nearest such feature
- Estimate the height of the former cliff behind it
- Find the height of the raised beach by estimating the height you are above the high water mark - shown by seaweed on the beach.
- The most recent glacial event was around 12,000 years ago. What is the average annual fall in sea level here over this period?