CARPENTER ROCKS effects of Coastal Erosion EarthCache
CARPENTER ROCKS effects of Coastal Erosion
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The coastline around Carpenter Rocks is characterised by gentle undulating Calcarenite dunes that are of relatively low elevation. Marine outcrops are visible along the coast here. The ridges run parallel to the current coastline this resulted from fluctuating sea levels during the Pleistocene period (1.8 million to 10,000 years ago). This causes the propagation of the coastline.
Coastal erosion involves the breaking down and removal of material along a coastline by movement of wind and water. It leads to many land forms, and combined with deposition play an important role in shaping the coastline. The coastal area experiences storm surges and very high wave energy as a result of the south and south-westerly aspect and subsequent Southern Ocean swell.
METHODS OF EROSION
Hydraulic Action:
When a wave impacts on a cliff face, air is forced into cracks under high pressure widening them. Over long periods of time, the growing cracks destabilise the cliff and fragments of rock break of it
Corrosion/Abrasion:
The repeated action of waves breaking on a cliff is enough to remove material from it over time
If sand and shingle are present in the water, it will act like sandpaper and erosion will take place faster
Attrition:
Beach material is knocked together in water reducing their size and increasing their roundness and smoothness
Corrosion:
Carbon Dioxide in the atmosphere is dissolved into water turning it into a weak carbonic acid. Several rocks, e.g. limestone are vulnerable to this acidic water and will dissolve into it. The rate of dissolution is affected by the concentration of carbonates and other materials in the water. As it increases, dissolution becomes slower.
FACTORS AFFECTING RATE OF EROSION
1- The biggest factor - Strengthening of waves
2- Certain landforms further reduce the waves power, i.e. the distance waves have to travel before reaching the coastline cliffs may reduce its energy. Headlands refract waves around them reducing their erosive power at one location but increasing it at another.
3- Weathering creates weakness in rocks that are exploited by the process of erosion .(freeze/thaw) weathering creates cracks in rocks, increasing the rocks susceptibility to hydraulic action.
4- Humans also have an impact, e.g. dredging (for better shipping access)but this reduces the amount of energy dissipated from incoming waves and so increases erosion. Also removal of vegetation as was done along the coast here.
Access to the above co-ordinates is along a dirt track accessed by 2wd if dry conditions otherwise 4wd.
At the end of the first track you can walk up another to get you closer to ground zero.
A short stroll along the ridge will bring you to where you need to be.
Spectacular views will greet you. You may even spot a cray fishing boat or two.
Please be aware of your environment you are walking in and stay away from the cliff edge.
Some of the rocks may be sharp. We would not recommend this earthcache to be done by small children unless you keep a very close eye on them.
At the listed co ordinates you will be standing close to hole in the rocks surface.
(There is no need to get too close to it)
Please take note of your surroundings.
You must send answers to the listed questions. You may log the cache before you send the answers but you must send the answers. Logs without answers will be deleted.
Q1
At ground zero how do you think this hole was formed?
What is the approx. size of the hole?
Q2
Facing the water at ground zero ,Hole in front of you,Victoria coast on left and South Australia to the right and looking slightly to your right South Australian side is a larger rock formation.
The formation looks a little like the Pinnacles
How do you think this came about?
What type of rock is it?
Q3
How do the rocks differ at ground zero compared to the larger rock formation?
Q4
Describe what effects erosion has had here as you look about. What is the biggest effect?
We hope you enjoy visiting the area and remember take care of the environment you are in
CONGRATULATIONS on FTF 3LG and your milestone
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