At the given co-ordinates you will have a good view of a disused quarry where you will be able to see a cross-section of the underlying geological structure of the surrounding area. Toowoomba is a plateau that has been formed by a large layer of volcanic rock that was deposited on the lower layer of Early Jurassic Mesozoic [Marburg Formation] of predominantly sandstones, siltstones and shales. The volcanic deposit is known as the Main Range Volcanics comprising predominantly basalts, agglomerates, shales and dolomites.
Panoramic view looking SE from the Toowoomba Plateau
Over the years [millions of them] the overlaying volcanic rocks have steadily been eroded away and the plateau that you are now standing on is what has remained. To the west of Toowoomba the plateau extends as far as Dalby and Cecil Plains. To the north it extends as far a Tingora and the Queensland New South Wales boundary in the south.
In order to log the EarthCache you will need to answer the following questions via an e-mail to the developer, cincolcc(at)gmail.com
1. At the given co-ordinates you will need to examine the cross-section of the quarry before you. Describe the predominant colours that the visible rocks are comprised and how they differ from each other.
2. Look at the rock that makes up the bulk of the quarry wall. What rock do you think this is and why?
3. What is the colour of the top layer that is visible? Based on what you can see, describe what the texture might be.
4. Describe what you see when you look EAST from any point along the escarpment.
PLEASE DO NOT POST ANY PHOTOGRAPHS OF THE QUARRY WALL!
FTF goes to = Stickybears
{Information in this description was retrieved mainly from the Geological Survey of Queensland Map – 1 : 500,000 [Moreton Geology] by R.J. Allan, Chief Government Geologist.}
