Cullen Raised Beach EarthCache
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The flat grassy area which today is Cullen Golf course, is infact a “raised beach”, or “marine terrace”, which was formed by a drop in sea levels during the last inter-glacial highstand (a period of raised sea levels caused by melting of the ice sheets) – previously the sea would have been much higher, at the level where the raised beach is visible today
This is called Isostatic sea level change and is the result of an increase or decrease in the height of the land. When the height of the land increases, the sea level falls and when the height of the land decreases the sea level rises. Isostatic change is a local sea level change whereas eustatic change is a global sea level change.
During an ice age, isostatic change is caused by the build up of ice on the land. As water is stored on the land in glaciers, the weight of the land increases and the land sinks slightly, causing the sea level to rise slightly. This is referred to as compression. When the ice melts at the end of an ice age, the land begins to rise up again and the sea level falls. This is referred to decompression or isostatic rebound. Isostatic rebound takes place incredibly slowly and to this day, isostatic rebounding is still taking place from the last ice age.
Among the coastal features along here, Bow Fiddle Rock is a classic example of a sea stack with a dramatic natural arch (GCEZ2) this is found roughly a kilometer from here around the rocky headland to the west. At the end of the beach there is a tunnel into a cave known locally as the "weasel's hole".
And toward this far end of the golf course, itself a ‘raised beach’, we find some coastal erosion features similar to those called locally, the " 3 Kings"( which you can see at the start of the course near the car park) . Raised beaches are wave-cut platforms, and take the form of an elevated area of sloping ground, sitting above the present tide line. In the past, the area of the platform would have been at sea level, and evidence of this can often be found in the form of beach shingle at the inland edge of the platform.
Raised beaches are therefore clear evidence that sea level has changed
In order to claim this earthcache, email us via our profile ( please do not post in your online log or use the message feature ) the answers to the following tasks :
1 ~ What are the coastal erosion features toward the far end of the golf course and how are they evidence that they were once at sea level ?
2 ~ Estimate the height of the former cliffs behind the golf course, about where the main road and hotel are now.
3 ~ Find the height of the raised beach by estimating the height you are above the high water mark
4 ~ At the inland side,near the base of the cliffs, describe the soil/ground here, is there evidence here that this was once a beach?
Optional task to post a photo of yourself and/or GPS somewhere on the beach here .
You must carry out these educational tasks as required by the Earthcaching organisation as a condition of logging the cache. Logs that do not adhere to these guidelines will be deleted without notification. See www.earthcache.org
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