This is a simple EarthCache but in a challenging location.
Please be aware you will need sturdy footwear and may need to clamber over rocks , there is a footpath to the location.
All you have to do is visit the location, read the description and use your new knowledge and observational skills to answer so questions.
When you have your answers either message or email them to me and feel free to log your find at the same time.
At this location you will find yourself surrounded by huge blocks of stone which has fallen off the rock face to your south.
The rock type is mill stone grit, here is some information about the formation of mill stone grit.
Millstone Grit, is made from sand, grit and rounded pebbles of quartz and some feldspar. It is known as ‘Millstone’ Grit because it was used to make millstones for watermills, however it has also been used for building stone, paving slabs and various other applications It’s coarseness gives it a very rough surface which is great for climbers
The Millstone Grit was deposited as part of a vast river delta system, formed where a river met an ancient sea. The sand and grit material was washed down from a range of ancient mountains formed between 430 to 380 million years ago, during the Devonian period, when the modern day North America collided with Europe. The sediments were later eroded and deposited some 60 million years after during the Namurian stage (326-313 million years ago) of the Carboniferous period.
The sediments were deposited as multiple, overlapping and evolving sandbanks within the river delta. As the water flow varied different layers were formed and if you look carefully you will see some fine lines, these are called bedding planes and can cause weaknesses in the overall rock structure.
Water and weathering can use these weaknesses ingress into the rock, washing away and breaking the rock along these planes. This is why blocks of rock have fallen from above, rain, ice and plant life have worked into these cracks and eventually the weight of the rock has brought it down.
At the location given you will find a large block that has come to rest with the bedding plane in a vertical orientation. Here water and ice has worked its way into many of the vertical weaknesses and caused some wide cracks.
So to some questions
Please look at the block with the vertical orientation of the bedding planes
- Please describe the texture, bedding planes in the rock and grain size(s) of the rock. Can you conclude if it is millstone grit or not? Please explain your reasoning.
- Please tell me if it is in situ or from elsewhere, then conclude as to why its at this location? You can use the shape of the block, the link to the cliff and please explain your reasoning.
- Please describe the orientation of the vertical bedding planes (i,e. the direction of the bedding planes, N-S, E-W etc)
- Please tell me the height of the block and the width of the largest crack.
If you feel you are able and willing include a photo of your experience.
Thanks for attempting this EarthCache and I hope you enjoyed the location)