The name of this EC comes from the day we checked into the caravan park and the lovely manageress used that name to describe the Rock, Mt Augustus.
Take a walk to GZ from the parking waypoint, but make sure you follow the meandering path so you wander through the huge old grove of white trunked River Red Gums, they are purely stunning.
Mount Augustus is an “inselberg” meaning ‘island mountain, which rises 715 metres out of the surrounding alluvial plain. Arid shrub-land and dominated by wattles, cassias and eremphilas cover the inselberg and the surrounding plain.
Geology:
Mount Augustus is an asymmetrical anticline (rock layers that have been folded into an arch-like structure), which is steeper on the NE side than on the SW side.
The rock consisted of sand and gravel deposited by an ancient, south-easterly flowing river system that drained the region about 1600 million years ago. This river flowed over a faulted and eroded surface of 1800-1620 million year old granite and metamorphic rocks. The river deposits consolidated to form sandstone and conglomerate, and were then buried beneath younger marine sediments, which were laid down when shallow seas covered the region between 1600-1070 million years ago.
The rocks were buckled into their present-day structure about 900 million years ago when movement along faults in the underlying granite and metamorphic rocks caused localised, strong, north-east directed compression. The marine sedimentary rocks that overlay the sandstone and conglomerate have since eroded from Mt Augustus, but now forms the hills around the two local stations of Mt Augustus and Cobra, homesteads. Erosion has also removed sandstone and conglomerate from the north-western end of Mt Augustus to expose the underlying granite rocks at The Pound and other sites around the rock.
To claim you smiley please answer the following questions and email, or send via the Geocaching Messenger App, the following.
- At GZ look SSE and gauge the angle of the prominent fault lines, and compare with what you see when you turn westward towards the higher part of the gorge.
- On your walk to GZ describe in your own words the types of rocks you pass along with the colours.
- Not compulsory but post a photo of yourself or your GPS at GZ, or in between one of the magnificent River Red Gums.
Congratulations to m4yb for FTF