In order to claim this cache you will need to
- Visit the location
- Read the description below
- Email the answers to the questions below to me
This is placed between two of ‘the big walk’ caches and they make a superb route round these hills and gullies.
Thank you for looking and I hope you enjoy the location
Sedimentation
Sedimentation is the tendency for particles in suspension to settle out of the fluid in which they are entrained, and come to rest against a barrier. This is due to their motion through the fluid in response to the forces acting on them: these forces can be due to gravity, centrifugal acceleration or electromagnetism.
In geology sedimentation is often used as the polar opposite of erosion, meaning that sedimentation is the formation of rocks and strata, where erosion is the removal of material.
Settling is the falling of suspended particles through the liquid, whereas sedimentation is the termination of the settling process.
At this location you can see a rock face which shows evidence of sedimentation because the exposed face has several layers visible. These layers are created when a different material enters the sedimentation process.
So where you can see a layer of about 2 to 5cm there will have been a steady depositing of the same type of material for a prolonged period, probably at a river delta. It is impossible to accurately estimate the period of time a 2.5cm section of rock will have taken to form, but it is possible to say it would take more than a year and less than 50 years. During its formation, further up-stream a river will have been eroding rock strata with a constant flow of water and laying down material.
Where you can see a thin different layer, (less than 1cm) this would indicate a change in the river flow for a short period of time, probably an increase in the flow to make the river have access to different types of rock or material to transport down to the delta.
The number of this type of thin layers will give you some clues as to the frequency of these increases in water flow events.
So hopefully you will have enough information for Q2 so please message me the answers, you can log your find at the same time.
Questions
- Please describe the structure of the rock, what does it look and feel like?
- Please tell me why you think there are so many layers.
- How many layers can you see that are more than an inch thick(2,5cm)?
If you feel willing and able please include a photo in your log. (Do not include a photo of the whole rock face)
Thanks for visiting the site and I hope you enjoyed you walk up or down Naden Brook