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Monday 19 September 2011

Where is the GBG limit in SW England?

As my faithful fellow-bloggers know, I have spent a lot of time on this blog trying to work out where the GBG limit may be in SW England.  (Are we talking here about one big glaciation?  Or maybe we are talking about several glacial episodes, spread over hundreds of thousands of years, and reaching different parts of the Bristol Channel coastline at different times?)

This has all come into focus again because my dear friend MPP has repeated what my other dear friend GW has said several times on the record -- namely that glacier ice has never affected the coasts of Devon, Cornwall, Somerset and the SW generally.

Interestingly enough, academic geomorphologists, whom we would expect to know about these things, have chosen by and large to stay well clear of the discussion, for reasons that I find hard to understand.  (Are they actually SCARED of Profs GW and MPP?  That would surprise me, since they both seem to me to be perfect gentlemen.)  But if you press them, of course they know that the ice DID reach these coasts on the shores of the Bristol Channel.  It's just that they don't want to say so, for fear of being knee-capped or something. 

In exchanging messages with various colleagues whom I respect, I got this reply from one of them.  He says there are "..........very clear signs of glaciation further north at Kenn in what was Avon and in the Bristol-Bath area.  There are some amazing landforms such as the Court Hill col-gully, infilled with fluvioglacials, including enormous boulders until they put the M5 through.  Some of the infill deposits are still visible in the wood beside the motorway.  At Kenn, till-like material, which includes striated boulders weighing several tons, is overlaid by marine and non-marine interglacial deposits. Amongst the erratics recovered were a piece of Ulster White Limestone, which contained the usual characteristic foraminiferal fauna of this unit. See the many papers of Dave Gilbertson's work in the area, and his PhD thesis, summarised and updated in the GCR volume.   Aminostratigraphy suggests several ages for the interglacial deposits - some are as old as OIS 15 (although there should be a considerable health warning on all these very old aminostratigraphic 'dates', as Kirsty Penkman has demonstrated!)  I spent some time working on the issue of glaciation in this area, with follow-up investigation in the Kenn area, in Gordano and in the Bath/Bristol Avon valley.  There is no doubt in my mind about a glacial incursion in that area, as far upstream as Bathampton, but no further. There are plenty of erratics recycled in the river gravels at Bathampton and elsewhere through the valley, mostly derived from the Bristol District and/or the S Wales coalfield, but I never saw any bluestone fragments, in any of my pebble counts."

I won't mention his name, for fear that medics in white coats or heavies in dark coats will come calling on him, but that sounds pretty unequivocal to me.   He also says:  "My work with erratic palynomorphs suggests that the ice sheet that was responsible for the deposition of the Fremington Clays was coming pretty well southeastwards and the ice coming onshore at Fremington would probably have 'missed' Pembrokeshire".

I think I'm right in saying that everybody who knows anything about glacial deposits accepts that we have a true glacial till at Fremington, and more till on Lundy Island, and more till on the north coasts of the Scilly Isles.  There is a lot of debate about other deposits, like the Trebetherick Boulder Bed, but that's enough evidence to be going on with, and if we have a number of sites where glacial deposits are widely accepted (Kenn, Court Hill, Nightingale valley, Bathampton, Lundy, Fremington, and the Scillies, to name just some) then only an idiot would say that the ice did not cross the Bristol Channel.

But the idiots keep on saying it, and those who should put them right just keep on saying nothing.  This is a very strange and even bizarre sociological and psychological phenomenon, and even a hoary old ex-academic like me (having seen most things in my time) finds that very strange.  This is actually nothing to do with academic etiquette.  That requires the experts in a particular field to assess the evidence and speak out, and the non-experts to keep quiet or to defer to the experts.  But here we have the non-experts pontificating and the experts shrinking away into the undergrowth on the grounds that they "don't know enough about the subject."  Oh my God.....  whatever happened to academic integrity?

12 comments:

Tony H said...

Perhaps the introverted geeky geomorphology experts are so absorbed in their specialist studies that they literally DON'T NOTICE the flamboyant trendy extrovert non-experts making outlandish statements? [You mentioned a very strange and even bizarre psychological and sociological phenomenon in your last paragraph, so I am following your line of thought]. There's nowt so queer as folk.

Tony H said...

I visit the Portishead area (now in North Somerset) fairly often and the landscape certainly looks, to a very rusty Geography graduate's eyes, to have glacial features. I also have visited the Fremington Quay in North Devon (it is now a Country Park) where there is a glacial deposit. I bet the geologists working on the construction of the M5 Motorway in N. Somerset acknowledged the presence of erratics, glacial deposits etc, as you mention them. The Somerset County Council presumably possesses, or possessed at the time, a Minerals Officer working for the Planning Dept.(as in Wiltshire). That person should have knowledge of glacial deposits along the coastland, etc,as clay is a valuable mineral resource.

BRIAN JOHN said...

Are the geomorphologists actually unaware of what the archaeologists are saying? That's quite possible -- I have been in touch with one of two of them, and when I say that GW and MPP have both, in my hearing, said that glacier ice never crossed the Bristol Channel, their defensive instinct is to assume that I might have misheard or misreported things. So they won't go into battle on the basis of hearsay. In one respect, that's fair enough. But I wish they would have a bit more respect for my integrity. (And of course, GW and MPP are too smart ever to put this statement in writing -- it's one of the throw-away lines they put in when talking to gullible audiences!)

BRIAN JOHN said...

Re the glacial deposits, yes, they are well known and accepted by everybody. What interests me in the statement I cited is the presence of erratics weighing several tonnes in these deposits, including a piece of white limestone from Ulster. Now how did that get from Ulster to the Kenn - Court Hill area? Not over the highlands of Mid-Wales, that's for sure. It must have been carried by an ice stream that crossed Pembrokeshire.

Tony H said...

I believe MPP, at least, has a reputation for 'throwaway lines', and it's something I've witnessed for myself at his talks!
Have you thought of at least writing to your local daily newspaper, the Western Telegraph, with a suitably toned-down report on your take on what MPP, Joshua Pollard AND Colin Richards said at the Newport public talk a few days ago? In particular, questioning their understanding that glacial ice did NOT reach the coasts on the shores to the south of the Bristol Channel. A calmly - worded statement might be picked up by the wider media and win you a few more converts, if not the acknowledgement you might ideally be looking for from these archaeology academics. I am sure there are lots of Pembrokeshire folk who like to hear both sides of any debate. There is a fair chance this would quickly be picked up by the South Wales press in general.

Tony H said...

I see your Post of 15th February 2011, "A Glaciological Dilemma", includes a message from Chris Hunt, mentioning Dave Gilbertson finding the Ulster White Limestone at Kenn [near Clevedon].

BRIAN JOHN said...

Thanks Tony -- you are right -- I must try not to over-teact, and maintain a calm and dignified approach -- and in course of course the world will eventually claim that they knew this nonsense aboiut human transport was nonsense all along. (But I have to admit to getting a bit stirred up by people who tell lies, quite knowingly, and then continue to tell lies regardless of the fact that people have asked them to be more truthful.....)

Eventually the truth will win out ....

BRIAN JOHN said...

Ulster white limestone at Kenn -- yes, very interesting. Will do a post on this.

Tony H said...

Brian, re your Post of 15.23 22/09/11:-

I believe the expression we could use is "Softly softly catchee monkey"!!
I agree there are a number of very naughty monkeys involved presently, most of whom enjoy looking at themselves in the mirrors others have given them, but in my present analogy the 'monkey' involves a far more
significant aspiration, nothing less than your central thesis that Man did NOT transport the bluestones all the way from Pembrokeshire to Stonehenge. Incidentally, at least MPP has just stated in your presence that he no longer believes that the bluestones were transported by sea: so that is one battle won, is it not? Considering how absorbed/ obsessed our Newport Hall archaeologist-trio appear to be with worldwide ethnographic evidence (or non-evidence) of primitive peoples moving megaliths some distances, MPP appears to have made something of a concession. He said it direct to me in the last year or so also.
No doubt there will soon be press releases, starting first in British Archaeology and Current Archaeology, as regards this summer's excavations etc in Pembrokeshire and plans for next year.

BRIAN JOHN said...

I haven't tracked MPP's thought processes, but I got the impression that he suddenly switched from "maritime transport" mode to "land transport" mode when it became apparent that the Altar Stone had not come from Milford Haven but from the Brecon Beacons -- so a trip for the bluestones along the route of the A40 road suddenly became an attractive proposition.....

Anonymous said...

Yes, and of course MPP could find himself very poular with the Wales tourist industry in the process; similarly, GW, who, I understand, is, or has been, a Director of Bluestone National Park Resort (www.bluestonewales.com/christmas) near Narberth.

BRIAN JOHN said...

Ah -- didn't know about GW directorships......but I suppose famous people get invited onto these things. I didn't get invited -- I opposed the Bluestone Village application!

But of course Tourism Wales, Tourism Pembs, the National Park, and Uncle Tom Cobbley and all just LOVE the fantastic tales that the archaeo boys tell them and tell the world. It's all good stuff for raising the profile of Pembs and bringing in a few more tourists. They are not the slightest bit bothered about whether they are getting the TRUTH or not... and I can understand where they are coming from.