At the given co-ordinates you will find some information about the formation of coal and the layers beneath your feet, located on an adapted mine cap. Firstly, I'm going to share some of that information with you, as this area is a disused mining region.
About 280 million years ago the rocks under Bollington and the area where you are stood right now were being formed. The coal forest trees lived around 250 million years ago. Over time, these thick forests, the soil in which the forests grew, plus small sea creatures and plants within the soil all became fossilized. The gradual compacting process formed a seam of coal, and also fireclay. These can be burnt for energy, and therefore are known as fossil fuels.
The presence of this mine cap shows that you are standing above an area that in the past has been mined. Coal and fireclay have been extracted from the ground in this area for over two centuries. The earliest method of extraction was 'outcropping'. The miners would find coal in the hillside and follow the seams into the ground, digging tunnels often known as 'drift mines'. Deeper coal was reached by sinking shafts called 'bell pits'. 'Horse gins' increased production by utilising horsepower to wind up the miners and the coal. Finally deep shaft mines were sunk, the last being Moorside Mine which in 1906 was 360 feet deep.
For many years coal was a major source of fuel in this country. However, as steel making reduced and steam trains became modernised, coal was replaced by natural gas, oil and electricity. This had an impact on the coal mining industry which gradually declined. In 1963 the final shafts here, Moorside and Water Pits were filled and capped.
Now turn your attention to the fourth panel on this converted mine cap. It shows the model of a Bell Pit. You can see a little cage descending into the ground, but it gets interesting where they have modelled the layers of the earth the miners would have passed through right beneath your feet.
1) First, the cage would have descended through a thin layer of top soil,
2) Second, the cage would pass through a wider band of shale,
3) Third, the cage would have been lowered through a layer of sandstone,
4) Fourth, the cage would have passed through a layer of slate,
5) At the fifth level the miners would have arrived at the coal seam,
6) Finally, beneath the coal the miners would find a layer of fireclay.
So why Zircon? Zircon is just one example of accessory mineral found in sandstone. Commonly these minerals make up just a small percentage of the grains in sandstone. Many of these accessory grains are more dense than the silicates that make up the bulk of the rock. These heavy minerals are commonly resistant to weathering and can be used as an indicator of sandstone maturity. The natural colour of zircon varies between colourless, yellow-golden, red, brown, blue, and green. The name derives from the Persian zargun, meaning golden-coloured. This word is corrupted into "jargoon", a term applied to light-coloured zircons. The English word "zircon" is derived from "Zirkon," which is the German adaptation of this word. Red zircon is called "hyacinth", from the flower hyacinthus, whose name is of Ancient Greek origin. Zircon is ubiquitous in the crust of Earth, and is often found in sandstone, be it often in tiny grains.
This visual model makes everything sound simple and clean cut, but of course the layers of the earth are never that simple. You now need to walk over to the fence and walk a short way up the hillside until you get a clear view over the quarry that is below you.
Look down at the old quarry and what is fascinating is you can now look at some of the layers for yourself that you have just been shown on the model. Please study the layers you can see, and then contact me with the following information before you log your find. You do not need to wait for a response but if you do not send in your answers promptly I will delete your log.
Questions to be answered (to be sent to me, do not include in your log)
Firstly, there are two different quarry edges to be seen. One is lower down the hill beneath you, whilst one is higher up the hill to the side. Study them carefully. What layers can you identify, and do the two edges look the same or do they demonstrate different layers due to their differing heights on the hillside? List all the layers you can identify and at which of the two quarry edges you identified them.
Secondly, the model shows a layer of sandstone, however in this area of the Peak District there is commonly a more specific type of sandstone also to be found, and examples are lying about on the moor in front of you. What is this type of rock, and how is it different to the more conventional sandstone? Do you see a layer of traditional sandstone in the cliff face, or a layer of the local sandstone - or maybe you can see both at different levels? Describe what you can see and how you would tell the difference.
Finally, referring back to the cache title, can you do a little research and tell me what Zircon is used for?
A photograph of you or your GPS device at the mine cap would be good additional proof that you have been at GZ. This is not a logging requirement. Please avoid including photos of the quarry faces in your log.
Please enjoy your visit to the area.