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Devonian Reef EarthCache

Hidden : 1/14/2013
Difficulty:
2.5 out of 5
Terrain:
1.5 out of 5

Size: Size:   not chosen (not chosen)

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Geocache Description:

This earthcache will enable you to find out more about the remarkable Devonian age reef exposed in the Kimberley.  This geological structure is unique in its size and grandure and with the cultural history it is assocaited with at this particular location.  The site can usually only be accessed during the dry season (May to September) .

The old Lillimooloola Police Station provides a quiet, off the road, locality from which to enjoy the spectacle of the Devonian Reef, appreciate the unique geology and learn a little about the fascinating local history that this landscape was so much a part of.  In order to log this earthcache as "found it" you wil need to email us answers to the questions below which you can find from notice boards at this site, Tunnel Creek, Geikie Gorge, Windjana Gorge and/or the web - but first some geological information about this site.
 
The Devonian Period is known as the age of the fish.  Fossil fish can be found at several sites in the Kimberley but you have to know where to look.  The rock formation known as the Devonian Reef is a large coral reef that once extended around the Kimberley coast. Remnants of this reef are now exposed in two main areas of the Kimberley one of which includes the area that you are now standing and the other is near Wyndham.  This remnant reef forms a spectacular set of ranges that rise up abruptly out of the plains amd includes the sites of Tunnel Creek, Geikie Gorge and Windjana Gorge.  Once buried beneath the sea, the reef is now exposed and has undergone physical and chemical weathering leading to features such as underground rivers, caves and gorges.  The reef is comprised of limestone.  This rock easily dissolves with rainfall but then its minerals re-precipitate forming huge stalactites and stalactites (and other structures) within the range itself.  Some of these features can be seen inTunnel Creek.
 
Jandamarra was an aboriginal freedom fighter that made great use of the cave system as a hideout against the local police.  His story is fascinating and a must read to understand how the original inhabitants of Australia reacted to the influx of European settlers - a pattern that has corollaries with modern history today. 
 
1. Do stalactites grow up or down?
2. What was the approximate length of the original reef system?
3. How did Jandamarra escape from Tunnel Creek when the front and back entrances were being guarded by police?
4. When was the Devonian period in millions of years?
5. Estimate how high the reef is at the Lillimooloola location?
6. Limestone is a rock made up of which minerals?

Additional Hints (No hints available.)