Tafoni EarthCache
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Welcome to my world .... the back ends of parks and reserves seldom visited! This earthcache is located in the northern section of the Rocky Gully Forestry Reserve. The co-ordinates will take you to a small field of granite boulders .... many of which contain the Geomorphological* feature known as Tafoni.
* Geomorphology is the study of landforms.
Tafoni are cavernous cavities found on the undersides of granite boulders in arid and semi-arid regions. Excellent examples exist along South Australia's south coast and on Kangaroo Island although the most noteworthy are found on the Inselbergs (island mountains) in central Eyre Peninsula near the towns of Wudinna and Minnipa.
It is believed that moisture at or near the earth's surface attacks the rocks from underneath making the rock friable (flakey) and more easily weathered. It may seem strange that one of the most significant weathering agents in arid areas is in fact water! Ancient Egyptian columns that have laid in the sands for thousands of years do show some surface weathering from wind driven sand but in fact it is the undersides of these columns that show how relatively quickly subsurface moisture can weaken even rocks as hard as granite.
The surface of these boulders often develop a coating of lichen which can act as a protective layer for the outer layer of the boulder.
At the listed co-ordinates you will find an example of a small tafoni. More can be seen roughly 65m. away at S35 06.077 E139 12.213 and S35 06.085 E139 12.225. At this last set of co-ordinates there are also small examples of other granite features.... a small "Wave rock" and a granite pool known as a gnamma.
To claim this Earthcache as a find you need to email me the answers to the following questions. .....
1. Approximately how many GPS receivers could fit in the cavern at the
listed co-ords?
2. From the listed co-ords estimate the size of the largest boulder visible
on this boulder field.
3. Offer a possible explanation (geomorphological or creative) for
the "Wave Rock" feature mentioned above.
While now optional for earthcaches please feel free to include a photo of yourself on top of your favourite boulder!!!!
Any log entry that has not been accompanied by an email of the correct answers will be deleted.
For best access to this cache park at the listed car park co-ords and follow the Lavender Federation Trail back towards Murray Bridge for approximately a kilometre. You will then see a railway bridge on your left. Go under the bridge and into the northern part of the park. tracks will lead you to this Earthcache and the other hides in this series.
Additional Hints
(No hints available.)
Treasures
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