Tibooburra is the local Aboriginal word for “ heaps of rocks” named by the Wangkumara and Maljangapa people. These heaps are namely the Granites that are predominant around town. The Granites are only in the immediate area of Tibooburra.
Tibooburra owes its origin to the discovery of alluvial gold during the 1880s at the foot of the low ridges containing quartz reefs on the western side of town.
These ancient rocks are surrounded and overlain by much younger rocks. In geological terms an area of older rocks which appear from beneath younger strata is known as an inlier. The Tibobburra Dome or The Stony Downs system is inlier and comprises of Cambrian metamorphic rocks and Silurian granodioritic rocks. The Tibooburra Dome is a raised area of rocks in a dome formation. This was formed as a result of the slow upward rise of the relatively dense Cambrian rocks. These rocks have arched upward due to pressure from the large volumes of relatively light Silurian granodiorite bodies within them. This process is much like rising air bubbles in a thick liquid where the air attempts to move upward because of the large contrast in density. This is a common phenomenon in geology, with trapped bodies of low density rocks being forced towards the earth's surface by surrounding high density rocks. As the high density metamorphic rocks can't simply move apart to allow the deeply buried granodiorite body to migrate upward, the rocks arch and fracture. The Jump Up is a local term for silcrete capped mesas, cuestas (asymmetrical ridges) and ranges. They form a continuous bluff type landform and can be seen to the North and South east of Tibooburra and are very unique to the area. The Stony Downs slope away from the base of the Jump-Up. The higher rises are covered with the stony debris or gibber of the silcrete crusts. These gibbers are weathered pebbles of silcrete and quartz, mostly coated with a desert varnish which gives them a very polished appearance. The Granites which are the most obvious rock forms around the Tiboburra township are low hills of granite. They are the exposed centre of the Tibooburra dome, a granite batholith, and are the oldest rock formations in the area dating back to the Silurian age 450 million years.
There is a fantastic area of Granites at the Tibooburra caravan park if you are lucky enough to be staying there we encourage you to take a wander through this formation its truly amazing.
THE CACHE
This Cache will take you just out of town to Sunset Hill which is located on the Tibooburra Common.
Sunset Hill is part of the stony downs land system. It is strewn with ironstone, quartz, decomposed granite and slate. It is truly a magical place. You will notice a fantastic pair of binoculars that have been fully provided by the dedicated and proud people of Tibooburra.
To log this cache we require you to message us with the following answers to the best of your ability;
1 What colour is the local ironstone?
2 What colour is the quartz?
3 Tell us in your log what you find beautiful in the immediate area.
4 A photo of your team or part of your team at Sunset Hill to include with your log.
You are welcome to log your answers strait away but please message us with your answers. Cacher’s who do not fulfil the Earth Cache requirement will have their logs deleted.
We hope you enjoy Tibooburra as much as we did and we hope we taught you something about the basic geology of the area, this is our first Earth cache and we thoroughly enjoyed putting it together. At the time of placement there were no caches in Tibooburra and this was our way of leaving one that could be maintained. A BIG Thank you to biggles1024 who helped us with converting some coordinates for this cache. Cheers and Happy Caching TeamThommo.
