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Thursday 14 December 2023

Gradually the ice front approaches Stonehenge.........




In a recent edition of Boreas journal, there is an interesting article about the sedimentological conditions that existed on the edge of the shelf in the Celtic Sea over the span of several glaciations.  Here are the details:

Fabian, S.G., Gallagher, S.J.& De Vleeschouwer, D. 2023 (October):  British–Irish Ice Sheet and polar front history of the Goban Spur, offshore southwest Ireland over the last 250 000 years. Boreas, Vol. 52, pp. 476–497.

https://doi.org/10.1111/bor.12631. ISSN 0300-9483.

As readers of this blog will know, for years I have been campaigning in my own quiet and unobtrusive way, for the Devensian and other ice edges to be placed where they make some sense according to the laws of physics, and at last I seem to be getting somewhere.  Fabian et al don't cite me in their list of references, but let's just assume that somebody, somewhere, takes the occasional look at some of my blog posts and other published material...........

Anyway, on the above map the authors now accept that 

(1) the LGM maximum ice edge was out on the shelf edge;

(2) the Isles of Scilly were affected by LGM ice more dramatically than admitted by James Scourse and others;

(3) the coasts of Devon and Cornwall were affected by LGM ice coming in from the NW;

(4) there was no ice-free enclave in Pembrokeshire, as I claimed in my last Quaternary Newsletter article;

(5) Late Devensian ice might have affected the coasts of Glamorgan and Somerset.

I'm not so sure about that last point.  I think the LGM ice affected the outer part of the Bristol Channel and its coasts, but not the inner part.........  the jury is still out on that one.

But note the ice limit shown for the Wolstonian.  The authors go with the latest theory that the Wolstonian glaciation (MIS6) was more extensive than the Anglian (MIS12) -- and on the map they show the Somerset Lowlands as being inundated by ice, and the ice edge pressing inland in the Bristol - Mendip area.  That's not too radical, and I am not the only one to have pressed that view -- the line here accords quite closely with that proposed by Gilbertson and Hawkins many years ago.

It is suggested on the map that the Anglian ice edge was overlapped by both the Wolstonian and the Devensian.

It's good to see that common sense is breaking out all over.....  next stop, Salisbury Plain.......



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