What has Northumberlandia got to do with geology? Well quite a lot actually. It all started way back in the Carboniferous Period about 359.2 to 299 million years ago, when the earth was covered with huge swampy forests, where plants, giant ferns, reeds and mosses, grew. When dead plant debris falls into the swamp, the standing water therein protects it from decay due to the deficiency of oxygen. This lack of oxygen allows the debris to persist whilst also preventing, insects and other organisms that might consume it from flourishing.
To form the thick layer of plant debris required to produce a coal seam, the rate of accumulation must be greater than the rate of decay. Once a thick layer is formed, it must be buried by sediments such as mud or sand. These are typically washed into the swamp by a flooding river. The weight of these materials compact the plant debris and aids in its transformation into coal, but this is a very slow process.
The fifty feet of plant debris needed to make a five-foot thick coal seam would require thousands of years to accumulate. During that time the water level of the swamp must remain stable. If the water becomes too deep the plants of the swamp will drown and if the water cover is not maintained the plant debris will decay. The formation of a coal requires the coincidence of highly improbable events. Peat is formed initially but as it continues to compress it becomes coal. There are three main types of coal; Lignite, Bituminous and the highest quality of them all, Anthracite. Coal is a combustible rock and along with oil and natural gas it is one of the three most important fossil fuels. It has a wide range of uses; the most important of which is for the generation of electricity.
Surface mining is a method used when coal is found near the surface, and this is the case at Shotton. The coal seams are interspersed with fire clay which makes it especially useful for mining as this fire clay is suitable for brick making and is supplied to local and national brickworks. Also mined is dimension stone, used in the restoration of historic monuments. Shotton surface mine at Blagdon, north of Newcastle is currently the largest opencast site in the UK, and the company mining it, in conjunction with the landowners, recognised that whilst recovering much needed coal for UK energy generation and providing local employment, there was also a unique opportunity to create a spectacular art form that would provide a legacy for future generations.
The project is known as restoration first; taking an extra piece of land donated by the landowner adjacent to the mine and providing a new landscape for the community to enjoy while the mine is still operational. Internationally renowned artist artist Charles Jencks designed Northumberlandia and gained inspiration for the landform from the distant Cheviot Hills, which are pulled into the foreground by the curves and shapes of the female form used for Northumberlandia. She is 34 metres high and 400 metres long and is claimed to be the largest female form in the world. If you walked all of the pathways you'd cover over 5 kilometres!
To claim this Earthcache you will have to go to the highest point of Northumberlandia. The views from up there will make it all worthwhile and you will get a great view of the open cast mine, the materials from which Northumberlandia was constructed. So you'll need to email me with the answers to the following questions. Any logs that are not backed up with emailed answers WILL BE DELETED!
1/ As you walk from the car park past the woods towards Northumberlandia there are two large boulders with plaques on them. This material is what is used for the dimension stone. But what do they look and feel like and what type of rock do you suppose they are?
2/ At the top you'll find a much smaller sculpture by the aforementioned Charles Jencks. What material do you think the pointer is made of, and why do you suppose they didn't use something from the mine in keeping with the rest of the feature? (If the path to the top is closed for maintenance please say so in your email and I'll accept just the other two answers.)
3/ Looking out over the mine you can clearly see one of the coal seams. Which direction is it sloping and at approximately what angle?
Please do NOT put any of these answers in your log or it WILL be deleted
4/ Optional Task : As the mine should have completely disappeared in a few years time and the land returned to farmland it would be very interesting to see these changes occur. So can you add a photograph overlooking the mine (west) and include the date taken in the description.
My image dated June 2015, even shows the coal seam in the background should you not be able to see one when you visit.
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The site is managed by the Northumberland Wildlife Trust and The Land Trust and it is they who have kindly given permission for this Earthcache.
Congratulations!
This was tundra70's 5000th cache & bikeit's 5500th!