Welcome to Ilkley Moor! This cache is one of a series of caches that will take you on a tour of some of the many geological features that you can find at this scenic location.
Ilkley Moor
Ilkley Moor is an area of upland moorland, covering 676 hectares. Internationally, this type of moorland is rare, despite being relatively common in the North of England, and as a result has significant nature conservation interest. Mosaics of heather moorland, blanket bog, acid grassland and flowing streams make up the character of Ilkley Moor. Mixed with these are small stands of pine woodland, scattered trees, tarns and exposed rock faces.
Ilkley Moor is underlain by a succession of shale and course grained sandstones including the Addingham Edge Grit that forms the Cow and Calf rocks. The sand that forms these rocks was originally laid down on shifting sandbanks in a great river about 320 million years ago during the Carboniferous Period.
Deep burial caused the sand to harden into rock and subsequent earth movements and erosion brought the rock back to the surface again. By the end of the Ice Age, about 13,000 years ago, ice had scoured the moor and deposited the long low ridge of Lanshaw Delves, a glacial moraine. Since then peat has accumulated in sphagnum bogs.
Sandstone Depositation
Ilkley Moor is underlain by a succession of alternating coarse-grained sandstones and shales. The edge is formed by the Addingham Edge Grit, a hard, coarse-grained sandstone, commonly called gritstone.
The sand that forms this resistant rock was originally laid down on shifting sandbanks in a great river about 320 million years ago during the Carboniferous Period. Subsequently, the sand was buried by later overlying sediments perhaps to a depth of about 5 kilometers where it was subjected to great overburden pressure and stress from the collision of tectonic plates turning it slowly into hard sandstone.
Logging your Find
In order to log your find, please send a message to my profile answering the below questions. The answers can be found by visiting the location, reading the above description, and taking observations in the field.
Look at the Gritstone edge facing the East.
- Observe and describe the rock (grain size, colour, etc).
- Describe the layers. How thick are they?
- Does the thickness of the layers vary?
- Explain how you think the layers were formed.
As Ilkley Moor is a stunning part of the world, you may optionally want to upload photos of your visit, of course I would love to see them! You can log your find immediately, but please send the answers within 24 hours. I will respond to your message as soon as I can. Logs where incomplete answers have been given, or where an email has not been received, may be deleted.