Two locations at Ceibwr where TWO tills are exposed together -- a cemented till below, with cemented gravels above, and then a fresh uncemented Irish Sea till above, close to the ground surface. Are we looking at evidence here of two widely separated glacial episodes?
With the renewed interest in the Wolstonian, I have been wondering whether Ceibwr should be investigated by researchers who are far more expert than I with a view to assessing the ages of the two tills exposed. Previously I have assumed that the older glacial deposits here must be of Anglian age -- but now I'm not so sure. Could they date from an Early Devensian glacial episode? Well, that is something which is being investigated elsewhere -- but on balance that would make the two deposits very close in age, with only 20,000 years between them. Intuitively, I feel that the lower till is very old and the upper one very young -- with hundreds of thousands of years separating them.
I have done many posts on Ceibwr over the years, but I am pretty certain of the Quaternary stratigraphy, which is as follows:Modern soil -- c 20 cms. Uncemented
Sandloess and colluvium -- c 50 cms. Uncemented. Holocene?
Clay-rich Irish Sea Till -- up to 2 m thick. Uncemented. Devensian?
Brecciated slope deposits -- up to 50 cms thick. Uncemented
Clay-rich colluvium -- c 20 cms thick. Uncemented but stained / gleyed. Ipswichian interglacial?
Glaciofluvial gravels -- c 1.5m thick. Stained and cemented. Anglian?
Stony till -- up to 1m thick. Stained and cemented. Anglian?
Brecciated slope deposits -- up to 1 m thick
How does the sequence here relate to that at Black Mixen, Lydstep? There you can't see the two tills in the same section, but I suspect that the age relationship is the same.
https://brian-mountainman.blogspot.com/2018/05/lydstep-ancient-till-site-confirmed.html
I think we need these deposits to be dated. Watch this space......
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