CLEVELAND WAY EARTHCACHE 2: THE WAINSTONES EarthCache
CLEVELAND WAY EARTHCACHE 2: THE WAINSTONES
-
Difficulty:
-
-
Terrain:
-
Size: 
(not chosen)
Please note Use of geocaching.com services is subject to the terms and conditions
in our disclaimer.
One of a series of Earthcaches that can be completed by Geocachers walking The Cleveland Way - the long distance footpath which encloses the largest continuous area of moorland in England.
With one exception all the rocks forming the North York Moors are sedimentary, having been deposited is seas or river deltas during the Jurassic period. They started to form 213 million years ago and the youngest sediments are 150 million years old. Then 58 million years ago a stream of molten larva was injected into the rocks & today this forms the Cleveland Dyke or Whinstone Ridge.
The sedimentary rocks can be divided into 4 groups:-
The oldest are the Lias rocks – grey shales and impure limestones sandwiching sandstones and ironstones in the middle. The Lias was originally deposited as fine silt and mud on the bed of a deep sea and so contain lots of fossilised sea creatures. The Lias rocks have a maximum thickness of 440 metres (1400 feet) and are mostly seen as almost horizontal layers which are easily eroded.
Above these are the Ravenscar Group of rocks which were laid down in a great river delta which formed as the seas shallowed. The sand and mud deposited at this time were compressed and now form the massive sandstones and shales of the high moorlands, which outcrop particularly in the northern part of the National Park. On three occasions during its existence, the delta was invaded by the sea and dark grey limestones were deposited.
Above the 250 metre (820 feet) thick Ravenscar rocks are over 200 metres (650 plus feet) of Oolitic Group rocks were deposited. A 4th marine invasion flooded the delta and alternating layers of clays, sandstones and limestones were deposited in warm shallow seas. The layers derive their name from the limestones, most of which consists of tiny rounded grains, each about the size of a pin head. Each grain, or oolith, has a sand grain or piece of shell at the centre around which a layer of limehas been deposited. These ooliths become cemented together to form a limestone which is said to be oolithic.
The youngest Jurassic layers are the Kimmeridge Clay group – a series of fossil-rich clays up to 225 metres (740 feet) thick. These are thought to have been laid down when the seas increased in depth and they form the low ground in the Vale of Pickering.
At the end of the Jurassic the area rose above the sea and there was a break in deposition. Later it subsided and was again covered by seas in which layers of chalk was deposited. This chalk has been completely eroded from the North York Moors but still forms the Yorkshire Wolds to the south.
At the listing co-ordinates you are at The Wainstones – the most spectacular rock outcrop on the west and north escarpments of the moors. These escarpments rise nearly 300 metres (1000 feet) from the fertile Vale of York and there are many old alum quarries towards the top, the working marked by discarded pink, burnt shale. You might also have noticed lines of small depressions running along the contour about 2/3rds of the way up the slope. These are old jet workings.
The Wainstones belong to the lower part of the Ravenscar Group and the unusual shapes are the result of centuries of erosion by ice, rain and wind. You should have walked past several information panels erected by the North York Moors National Park Authority which will give you some of the information needed to log this Earthcache.
To log the earthcache you need to send me an e mail the answers to the following questions along with your email address and (optionally) post a photograph of yourself at the site.
You can log your visit as a "find" for your straight away and I will contact you asap to let you know any errors if there are any.
1) What sort of rock appears to make up the Wainstones ?
2) What percentage of the world’s remaining moorland is thought to be in Britain ?
3) What is Jet Rock the fossilised remains of ?
Additional Hints
(Decrypt)
Farpx Lngr & Juvgol zvtug uryc jvgu gur nafjref
Treasures
You'll collect a digital Treasure from one of these collections when you find and log this geocache:
Loading Treasures