Neagles Rock is a prominent outcrop that has long been a favourite picnic spot in the Clare Valley.
It is an example of a silicified structure adjacent to the Clare-Spalding Fault. Silicified structures are ones in which organic matter becomes saturated with silica - essentially a fossilization process. Silicification most often occurs in two types of environments - either the specimen is buried in sediments of deltas and floodplains or organisms are buried in volcanic ash. This very major structure is the most significant structural discontinuity in the Clare Valley.
Silicification adjacent to major faults is common in the Skillogalee valley and in many parts of the Mid-North region, and often the silicified zones are extensively brecciated (composed of angular fragments of older rocks melded together) and may be recemented (bound together) with more silica and iron oxides.
To claim this earthcache you will need to visit the listed coordinates, and make the short hike up to the lookout itself.
Email answers to the following questions to claim the earthcache:
1. What group does the dolomite at Neagles Rock Belong to?
2. Is this silicification due to sedimentation or organisms being covered in volcanic ash? What evidence supports your answer?
3. Describe the colour of the rocks at the lookout. Identify the mineral that you think is responsible for this colour.
4. Examine the largest rocks at the outcrop. You can see harder, paler layers of silica. What angle are these layers at? Why do you think they are presently at that angle?
You are welcome to log the cache after you have submitted your answers. We will only contact you if there is an issue with your answers.