The suburb and streets of Giralang are known for its very astronomical naming conventions and green corridors, but did you know there is also some interesting geological features hidden away, including quite a few minor fault lines with obvious Iron and Quartz deposits…?Hopefully the local residents don't suddenly have a mining company interested and have purchased earthquake insurance !!!**
Giralang and surrounds are wedged between a mesh of geological boundaries. This includes the early and late Silurian shallow marine sediments of the Canberra Block and the Proximal quartz turbidite of the Cullarin block. These seem to dance around each other, cut by fault lines containing iron and quartzs deposits running perpendicular to the ridge line and the Barton HW.
So now the G in Giralang can definitely also stand for Geology !
To be able to log this Earthcache
At the posted coordinates, answer the following as best you can...
- Describe the predominant rocks at your feet, colour, texture, and any other notable features. If you can find a loose piece of this material, pick it up and compare its density to other different (lighter coloured) rocks in the area (make sure you return the rock). To also prove you visited the site, and also for our enjoyment : ) , please send us any private attached photo of your feet and\or area showing the ground you are standing on at GZ, be creative if you like (GPR or Smartphone included)
- Walk in an easterly direction along the fire trail, appropriately how many metres away does the colour start to change in the rocks along the trail. At what point along the ridge line, relative to the initial outcrop does this start to occur?
- Name (or describe) the type of geological feature that you might be standing on, what “meaning” it had for Cornish miners, what type of valuable material is it - if you are stuck there is a hint below?
- Explain the process that creates these types of outcrops (bonus points for a diagram or the layers and basic chemical equations), what does it tend to indicate?
- Optional, send or post a photo of your favorite view from along the ridge line in your log, yourself or team can be in it or not. Please don’t spoil the cache for others, so don’t include photos of the geological features in your public log.
And send us the answers (email or message) to be given the permission to log the cache.
** Don’t worry they are very minor faults