This is an EarthCache and has special requirements for logging it. You cannot log a Found It without responding to the logging requirements set out below.
Only one find claim per Message. Each Geocacher claiming a find must submit an individual response. One team can not lodge a response on behalf of a group of people.
Please note: Mount Alfred is not a physical mountain - it is the name of a nearby property. This area and this road take the name from the Station.
You are standing at the base of a very interesting geological formation. I happen to think the rocks here are quite fascinating and beautiful, rugged and noteworthy.
How did they get here?
During the early Cretaceous period (135-100 Ma), a large marine transgression flooded much of Western Queensland, commencing from near Cape York, and then extending south and west to cover the western half of the State, as well as significant areas of New South Wales, South Australia and the Northern Territory.
Large quantities (over 1500m) of fine to medium grained sediments (predominantly sandstones, siltstones and shales) were deposited. Although some of the sandstones deposited during this period were quartz sandstones, the majority were lithic, i.e. composed of sand-size grains which consisted of fragments of then pre-existing rocks. Generally, these source rocks were volcanics. These rocks cap the more porous, water-bearing rock of the Great Artesian Basin. Towards the end of the Cretaceous period the inland sea began to recede and the sedimentary deposits became exposed and subject to the next part of the rock cycle - weathering.
What is happening now?
Rocks are naturally fractured at several levels. Mineral grains have boundaries, which can be areas of weakness in the rock. Sedimentary rocks often are layered and the layers sometimes are not bound together well. More massive rocks can have joints which will open as the rocks are exposed due to erosion. Physical weathering acts to widen these rock fractures.
As rocks are alternately heated and cooled (cycles of hot/cold), they expand and contract; minerals expand and contract different amounts, and this differential expansion and contraction may stress rocks and crack them. Fires (and even lightening!) can crack rocks too! These hot/cold cycles can occur in a matter of moments (say, as the sun suddenly passes behind a cloud) or in a matter of hours (daily temperature change) or in the matter of days (air mass behind the passage of a warm/cold front). This is part of what is called Physical or mechanical weathering
In addition, living things can also cause weathering - that is, Biological weathering. Tree roots grow into cracks and widen them, which helps physical weathering. Some bacteria and other organisms secrete acidic solutions, which helps chemical weathering.
A geological symbiotic relationship perhaps?
It is really difficult to separate physical from chemical or biological weathering, because all three proceed at the same time (though not necessarily at the same rates).
Physical weathering helps chemical weathering by breaking rocks up into smaller chunks, thus exposing more surface area. With more surface area exposed, chemical reactions happen faster.
Also, if slopes are flattened by physical weathering, water and soil can build up and thus speed chemical weathering.
Chemical weathering helps physical weathering by weakening the mineral grains which make up rocks. This makes the rocks easier to break up by mechanical means.
Biological weathering helps both, as described above. Trees fracture rock with their roots, which makes them easier to break up physically and exposes more surface area for chemical weathering. Bacteria which secrete acid solutions speed chemical weathering. (Acknowledgement)
To claim this smiley 😀 you MUST provide answers to the two questions below.
If you do not submit answers within a reasonable time, your log is likely to be deleted.
1. Explain in simple terms what has happened to this area.
2. What examples of weathering can you see at this site?
AND, importantly,
3. Take a photo of yourself or part of yourself in front of any part of this area. Include it in your message, but please do not post it in your log, it might give too much away.
When you have your response to the above questions, please, if possible, Message us, using the link at the top of the page underneath the name of the Cache. We prefer the Message method, as apparently, we don't respond to emails very well, but messages we do. We will contact you by Message once your Message has been received.
But please log your Found It 😀 in the meantime, and just say that you have Messaged your answers to the CO. We do reply to all logs within a reasonable time, and if there is a problem with your answers, we will ask you for further clarification.
Happy Earthcaching!