Devils Marbles Conservation Reserve
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The Devils Marbles Conservation Reserve is located south of Tennant Creek area of Northern Territory in Australia.
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[edit] Location
The area is located near Wauchope, 114km south of Tennant Creek, in the Northern Territory. It contains formations of naturally rounded and oval boulders called Karlu Karlu by the local Aborigines. The boulders are located in a traditional Aboriginal sacred site and are important to the local Aboriginal people. The Kaytetye people believe that the boulders are the eggs of the rainbow serpent. Over time, the ceremonies and stories related to the Devils Marbles have largely been lost, but the site is still very important to the tribe and may be considered to be among the oldest religious sites in the world. The Reserve is accessible (by short pathways) all year round and has a network of pathways with information boards and a basic camping area.
There is sometimes some confusion about the correct spelling. In Australia, no apostrophes are used when referring to geographical names. However, when referring to the rocks themselves, and not to the reserve, an apostrophe should be used. Therefore: the Devil's Marbles are located in the Devils Marbles Conservation Reserve.
[edit] Formation
The Devil's Marbles are made of granite, which surfaces like a little geological island in the desert, surrounded by incredible amounts of sandstone. The granite is thought to be formed about 1.7 billion years ago as a result of the hardening of magma within the earth's crust. Thick layers of sandstone on top of it put a lot of pressure on this granite. After the folding of the earth's crust, which lead to the lifting of the granite, and the erosion of the sandstone the granite came to surface. The pressure was gone which caused the granite to be able to expand; cracks formed, and it fell apart in big, square blocks.
The second phase of the formation of the Marbles started when these blocks got exposed to water. The surface of the blocks began to decay under the influence of the water, and a layer of loose material surrounded the individual blocks. When they came to the surface completely, this layer was flushed away by water and blown away by wind. The next phase of decay had started now.
The roundening of the granite blocks is a result of both chemical and mechanical weathering. Firstly, exfoliation plays a part. Chemical processes cause the surface of the blocks to expand and/or shrink. Thin layers of rock come off the boulder. This rounds the granite block, because the chemical processes have more effect on areas with edges. These processes cause the rock to look like it is made of layers like an onion. In effect, only the outer few centimeters are affected by chemical weathering. This process is called spheroidal weathering. Secondly, the boulders are suffering from solarisation. Because the temperature differences between day and night are so great, the rocks expand and shrink a little bit every 24 hours. This causes some rocks to crack, sometimes even splitting them in half.
[edit] Controversy
One of the marbles was removed from a formation in 1953 and taken to Alice Springs to form a permanent memorial to John Flynn, the founder of the Royal Flying Doctor Service in Australia. At the time, this was seen as a way of remembering his link to the outback, but in later decades it was a source of great controversy because the rock was removed from a sacred site without the direct permission of the tribal elders. In the late 1990s, a boulder swap was arranged, and the missing marble was removed from the grave, cleaned, and returned to its original place. The grave is now marked with a similar boulder donated by the local Arrernte people. [1]
[edit] References
[edit] External links
- "Controversy about removing a "marble"", Alice Springs News, 1999-09-08.
- Devils Marbles Conservation Reserve.
- More about Devil's Marbles.
