Geology:
The area (Eromanga Basin) began to form in the early Paleogene (about 60 million years ago) when south-eastern South Australia started to sink and rivers began to deposit sediment into the large, shallow basin. The Eromanga basin is still gradually sinking, and still gradually accumulating sediment. About 20 million years ago, large shallow lakes formed, covering much of the area for about 10 million years. From that time on, as Australia drifted further north and the climate became gradually more arid, the lakes and floodplains started to dry. Only in the last 2.6 million years did the onset of the ice ages bring about the present climatic regime and the consequent fairly rapid aridification of the area.
Scientific definition:
Sandplain - varies from longitudinal dunefields, through reticulate dunes, to sandplain of aeolian reworked surficial sand Aeolian sand. Some inliers of Tertiary fluvial sediment with silcrete.
Cretaceous sediments of the Eromanga Basin, overlain by Cainozoic sediments. Common landforms are low silcrete-capped hills and claypans
The Earthcache:
Baldy Top is a earth mound with a rock cap, typically the cap is darker than the base and the horizontal separation is very clearly defined. This Butte is very typical in this area, but one of very few available to the public for easy access. It evidences the effect of erosion (Over time) on the rock cap and supportive mound. At one stage the (volcanic material) rock cap formed the area ground level, it was then flooded and erosion and time have shaped the hills as we see them now. the erosion is ongoing, as is the Eromanga basin settlement.
This is an easy Earth Cache to find and involves a walk up a track to the summit. The view at Sunset is very good and recommended. The track is well defined and can be walked safely by small children with adult supervision. Sturdy footwear and some drinking water are also recommended. If it is attempted at night, adequate lighting is advised. The EC would be expected to take about 20mins to complete. This is particularly relevent in the hotter months.
Parking is available at the EC origin. It is aproximatly 7 Km's from Quilpie.
To claim the EC please answer the following:
At WP 01:
What geological structure is evident at this location? What do you think it may have been used for?
What is the Elevation at this point?
At WP 02:
Is the horizontal separation of the "Cap" from the base visible here?
There is an identical peak about 300m from this point. What direction is it in from where you are standing?
Upload a photo from this point (Optional - no spoilers please)
Please submit your answers as soon as you can. It's ok to post prior, I will check your findings and respond if there are issues. Feel free to add a photo of yourself at the site if you want too. Group visits are encouraged. I hope you enjoy the experience, this is a very special area.