This cache requires you to climb a hill and scramble up a 20m rock with reasonable easy foot spaces on to the top of an outcrop. Once climbed the outcrop is flat.
CHILDREN MUST BE SUPERVISED
An EarthCache which requires you to visit the location given, make some observations and answer some questions.
Please feel free to message or email the answers to me at the same time as logging your find.
There are other caches close-by, making the walk worthwhile but be warned, this is quite a way from the nearest parking.
Getting to this cache is a significant undertaking since it is several hundred feet above the nearest parking. Please come prepared for a muddy and uneven hike and be ready for changes in the weather.
Grit stone is a type of sedimentary stone created by rivers which wash down small particles of rock, usually in fast flowing erosive rivers. As the particles carried in the water moves to slower flowing areas the particles sink to the river or delta bed and build up. Over millennia these deposits build up, are compressed by the weight above and form hard durable stone .
The gritstones were deposited from vast braided river systems, including estuaries and deltas during the Carboniferous (Namurian- Westphalian) 320-310 million years ago and consist of quartz grains.
Millstone grit is very durable and resistant to erosion; there are prominent escarpments from Derbyshire all the way up the Pennines and Northern England. The grits are "millet seed" quartz grains meaning the size of the gains are about the same as a grain of millet or rice.
On occasion, as the rock is forming the quartz can seep into cracking either vertical or horizontal and form small seams of more concentrated quartz within the rock, it precipitates out in small cracks in many rocks causing what appear to be quartz like veins. There veins are much harder than the rock around them which means that when the rock is eroded they can be left behind. The quartz infill a fault then rock erodes quicker than quartz
The lines you see are occasionally cross-cutting, which is a common feature of quartz veins in rocks. They protrude out of the rock, which tells you that it's very resistant material, relative to the host rock. This is an extremely common phenomenon.
Erosion
Weathering
Weathering is the breakdown of rocks at the Earth’s surface, by the action of rainwater, extremes of temperature, and biological activity. It does not involve the removal of rock material. Weathering can leave sharp breaks in the rock surfaces caused by heat or ice breaking the rocks apart.
How is erosion different to weathering?
Erosion is the process by which soil and rock particles are worn away and moved elsewhere by wind, water or ice. Weathering involves no moving agent of transport. Erosion will move the small particles that the wind or water can carry away to different location, leaving behind rounded rock surfaces. Erosion will move the easiest particles first.
At this location the rock has suffered erosion and this can be seen because the rocks are rounded with the veins of harder rock being left behind. As the wind and rain has battered these rocks it has broken off small particles of the slightly softer rock and left behind the harder veins of quartz. The quartz being harder means the lines on the rock show where the quartz has precipitated through the rock as it formed. It’s not a lot harder so the veins are only slightly raised above the smoother rock face.
Hopefully you now know what you are looking for and understand why these lines runs cross the rock face.
So to some questions
You will need to climb onto the top of the largest outcrop to get your answers, hence the terrain rating.
- Please describe the rocks around the location, concentrate on the top surface of the largest one and you can limit your description to the surface of the outcrop including texture and any imperfections in the smoothness of the rock face.
- Please tell me why this rock is crossed with lines looking like roots or veins standing up from the surface, giving reasons for your answer.
- Please tell me the length of the longest raised line and what is the average width of them.
If you feel willing and able you are welcome to include a photo of your experience here.
Please send your answers either by email or message and you are invited to claim your find and send your answers together.
Thanks for visiting the area and attempting this cache.
Enjoy the area
treboR