The Bluestones Erratic Train

Over the years we have discussed erratic trains and trails on many occasions, and I have just prepared a new map showing the main ice streams affecting the Bristol Channel area in the Anglian Glaciation.  (Or maybe it was the Wolstonian?  Nothing is certain in this life......)

I'm fairly happy with the ice stream arrows for both the Irish Sea Glacier and the Welsh outlet glaciers affecting South Wales.  The red arrow is based on the paper I did with Lionel Jackson in 2009 in "Earth" magazine, suggesting a contact zone along which the two ice masses ran side by side at more or less the same speed, without much mingling.  (Ice acts in some ways like a fluid, but we must not carry that analogy too far.....)

Along the red line we might expect to find a train of bluestone erratics, but only if there was a continuous process of erosion and entrainment at the Presell end of the line, in the source area. As I have explained, I think the entrainment of Preseli erratics (spotted and unspotted dolerites, rhyolites, dacites, volcanic ashes and sandstones) might only have occurred on a substantial scale at the beginning of the glaciation concerned, with the supply cut off as the ice thickened.  So the route might be approximately OK, but the "erratic train" might just be a pipe dream.

There would also have been wobbles in the route, and in reality the "red route" would have had a lot of kinks in it, in response to waxing and waning ice pressure both from the southern flank and the northern one.

Then there comes the last complication -- the wastage of the Irish Sea Glacier, which would probably have been catastrophic and very rapid.  It appears to be normal towards the end of a glacial episode for "pulses" or readvances to occur around the fringes of smaller ice masses such as the Welsh ice cap -- and advances of the South Wales glaciers could well have pushed the debris associated with the Irish Sea Glacier (including quantities of erratics) southwards, beyond the present coast line and into the area now submerged beneath the sea.  There are signs of just such terminal and lateral moraines both in Swansea Bay and in Cardigan Bay, associated with Devonian glacier advances following Irish sea ice wastage.

More to be discovered -- of that I have no doubt.

Altar Stone, Thin Section 277, and the Senni Beds

Thin section of sample 277 -- courtesy Rob Ixer

Don't get me wrong. I just love the idea that the Altar Stone at Stonehenge has come from the ORS Senni Beds -- but since this is a scientific blog, every now and then we need to ask some inconvenient questions.

The current orthodoxy is that the Altar Stone is from the Senni Beds -- and not from the Cosheston Beds on the shore of Milford Haven. The foundation of all of that is the paper by Ixer and Turner-- much cited -- dating from 2006. That's quite a while ago, in geological terms.

Reference:  Ixer, R.A. and Turner, P. 2006. A detailed re-examination of the petrography of the Altar Stone and other non-sarsen sandstones form Stonehenge as a guide to their provenance. Wiltshire Archaeological & Natural History Magazine 99, 1–9.

Access: 

https://s3.amazonaws.com/academia.edu.documents/34467863/New_Altar_Stone4.pdf?AWSAccessKeyId=AKIAIWOWYYGZ2Y53UL3A&Expires=1508843254&Signature=Wrg997%2FpwxUA93JX5tToNb4VsUk%3D&response-content-disposition=inline%3B%20filename%3DA_detailed_re-examination_of_the_petrogr.pdf

I have been looking at the paper again, and am forcefully reminded that there is actually a huge amount of doubt surrounding this identification. The centrepiece of the work by Ixer and Turner was a thin section from the Salisbury Museum collection, labelled "277 Altar Stone Stonehenge."  Who took the sample, and when?   Is sample 277 one of the Cunnington samples?  Quote: "Cunnington (1884) identified five fragments of the Altar Stone, that he assumed resulted from dressing of the stone, amongst his loose finds, although they are now missing."

Quote: "Therefore, the thin section labelled ‘277 Altar Stone Stonehenge’ in the Salisbury Museum Collection is likely to remain, for the foreseeable future, the only piece of the monolith available for investigation. It is imperative then that it should be described as fully as possible and that this description becomes widely available."

In Discussion (Quote):

This, paper represents the first detailed description of the Altar Stone for over eighty years and is in broad agreement with H.H. Thomas other than his identification of abundant garnet and glauconite. Glauconite is a green, chlorite-like mineral and so, if present, has been subsumed under chlorite in the present description. The disparity over the amount of garnet is more significant and puzzling. Thomas noted significant amounts of garnet in his ‘heavy residues’ (Thomas, 1923, 244) but did not report garnet in his thin section description of the Altar Stone. Although trace amounts of garnet can be overlooked/underestimated in thin section the present study could not confirm significant amounts of garnet microscopically. The presence and amount of garnet is important as Thomas was struck by the coincidence between the garnet-rich nature of his Altar Stone ‘heavy residues’ and the unusually garnetiferous nature of the Cosheston Beds and it was the presence of these unusual amounts of garnet in both, that led him to suggest the Cosheston Group might have been the origin of the Altar Stone. Without further sampling (this would require many grammes of Altar Stone to crush before separating the heavy minerals) the garnet problem must remain unresolved.

The big issue here is the amount of garnet among the heavy minerals in the rock.  Herbert Thomas and Richard Thomas have both stated that there are substantial amounts of garnet in the Altar Stone itself -- but garnet is missing from thin section 277.  There are also substantial amounts of garnet in the Cosheston Beds.  So was HH Thomas right all along?  And have Ixer and Turner simply assumed that thin Section 277 was correctly labelled, when it might have just come from a piece of debitage  assumed -- unreliably -- to have come from the Altar Stone?

A simple matter of a sample being mislabelled?  The mystery deepens.........

MPP: I have discovered a speculation!

I just came across this. I thought it worth sharing, especially since it came from an academic web site that prides itself on its academic rigour........

Mike Parker Pearson: "I led the team of researchers that discovered that Stonehenge was most likely to have been originally built in Pembrokeshire, Wales, before it was taken apart and transported some 180 miles to Wiltshire, England." 

Stonehenge isn’t the only prehistoric monument that’s been moved – but it’s still unique

http://theconversation.com/stonehenge-isnt-the-only-prehistoric-monument-thats-been-moved-but-its-still-unique-51962

(This was in the “science and technology” section of The Conversation…..Dec 11th, 2015. It prides itself on "Academic rigour, journalistic flair”………….)

Green Bridge of Wales -- the beginning of the end?

Pics from Doug Reubens and Gareth Davies

 This has nothing to do with Stonehenge, bluestones or glaciers -- but since we enjoy talking of the forces of nature on this blog, this might be of interest.  Storm Ophelia has been causing some severe cliff falls in Pembrokeshire -- and one of the most spectacular rockfalls has been on the tip of the Green Bridge of Wales (one of the most famous arches in the British Isles).  These photos show the damage.

The outer "block" (which will become a stack when the arch goes) is now much reduced in size, and the state of near-equilibrium that existed there is gone.  Not sure how this will affect the stresses in the arch itself.  Depends how riddled with fractures it is.  Ironically, the compression on the arch may now be greater than it was before, so it may become stronger.......... we shall see........

As I write, Storm Brian is battering the coast, and lots of people are rushing down to the limestone cliffs and the Stack Rocks area with their cameras.........

I'm more interested in the submerged forest, and wonder if it will be exposed after this storm surge coinciding with spring tides.

 Pic: Beth McColl.  After the fall.........

Another photo, taken 22 Oct by Guy Candler.  It shows the fracture face in much more detail.  

POSTSCRIPT

We now know that the large fracture scar high up on the pillar is the result of the Storm Ophelia storm (16 October), and the lower (smaller) scar is the result of a second rockfall during Storm Brian on 21st October

Lambert Glacier -- a thing of beauty

There are few things on this planet more impressive than a big glacier in full flow.  This is the Lambert Glacier in Antarctica.  It flows into the Amery Ice Shelf.  Click to see the image enlarged.

At the base of this NASA image, it is about 30 km wide, but at the big confluence with Fisher Glacier it is about 60 km wide.  Across most of the area shown in the image, the glacier velocity is between 500 m and 800 m per year, but the velocity speeds up as the ice gets towards the ice shelf, with a flow rate of c 1 km per year.    Surging glaciers sometimes move faster than that, but this is assumed to be the fastest-flowing big outlet glacier on the planet.

The streamlines or flowlines are shown here in extraordinary detail.

 Here is another image -- this time from Google earth.  You can see many of the same features.

Parker Pearson et al under scrutiny -- more scientific misconduct?

On looking back at the literature over the past couple of years, I have been reassessing the following:

Parker Pearson, M., Pollard, J., Richards, C., Schlee, D., and Welham, K. (2016).  "In search of the Stonehenge Quarries,"  British Archaeology,  Jan/Feb 2016, pp 16-23.

Parker Pearson, M. (2016).  "Secondhand Stonehenge?  Welsh Origins of a Wiltshire monument."  Current Archaeology 311 (2016), pp 18-22.

Both of these articles were published in the spring of 2016, about three months after the publication of the QN article by Dyfed Elis-Gruffydd, John Downes and me.  That article, peer-reviewed and revised on the advice of referees and editor, described the landforms and stratigraphy at Rhosyfelin and made the point that there was no trace of a Neolithic bluestone quarry at the site, no matter what the geological affinities with Stonehenge might be.  Parker Pearson, Pollard, Richards, Schlee and Welham (all senior archaeologists) must have known about the paper, and they must all have read it.  They must also have been fully aware of the "media storm" that followed in December 2015 when their big Antiquity paper was published within a few days of our second paper in Archaeology in Wales.  There were literally hundreds of write-ups in the press and in magazines, and on digital media as well. The great majority talked about the dispute.  Assorted academics made comments on the record, flagging up the fundamental disagreement between one group of specialists and the other.

In spite of all this furore, the two articles mentioned above blithely promote the bluestone quarrying hypothesis and make no mention of any inconvenient evidence or academic dispute. 

So there are two question here.  Did the authors of the two articles mentioned above have time to react to the publication of our two articles in November and December ?  And should they have changed their texts, even a proof stage, in order to inform their readers that their assumptions about bluestone quarrying were not universally accepted?  The answer to the first question is undoubtedly "Yes".  They had two months to make corrections and adjustments, and if they had requested relatively minor changes I am sure that the Editor would have agreed.  And the answer to the second question is also "Yes" -- since a responsibility is always placed upon authors to provide reliable information and to avoid the pretence of certainty in cases where there is doubt.  As mentioned in our earlier post
https://brian-mountainman.blogspot.co.uk/2017/10/another-geology-paper-and-case-of.html
a deliberate failure to cite "inconvenient" publications or data is tantamount to falsification, fabrication and the intentional distortion of the research situation.  That is rather a serious matter.

I haven't checked up on all the universities represented here, but MPP works at University College London, and all universities have Ethical Guidelines which staff and researchers are supposed to adhere to.  The internal guidelines generally insist on publication of research results in a responsible and timely manner, in a form accessible to other interested parties, with research results preserved for future reference in cases where replication might be needed.  It goes without saying that all academic authors must also adhere to COPE guidelines, which state:

Researchers should present their results honestly and without fabrication, falsification or inappropriate data manipulation. 

Reports of research should be complete. They should not omit inconvenient, inconsistent or inexplicable findings or results that do not support the authors’ or sponsors’ hypothesis or interpretation.

Authors should cooperate with editors in issuing corrections or retractions when required.

Authors should represent the work of others accurately in citations and quotations.

New findings should be presented in the context of previous research. The work of others should be fairly represented. Scholarly reviews and syntheses of existing research should be complete, balanced, and should include findings regardless of whether they support the hypothesis or interpretation being proposed.

From COPE website:  Wager E & Kleinert S (2011) Responsible research publication: international standards for authors. A position statement developed at the 2nd World Conference on Research Integrity, Singapore, July 22-24, 2010. Chapter 50 in: Mayer T & Steneck N (eds) Promoting Research Integrity in a Global Environment. Imperial College Press / World Scientific Publishing, Singapore (pp 309-16). (ISBN 978-981-4340-97-7)
https://publicationethics.org/node/11184

Well, I have grumbled before about the complete lack of research diaries or field reports representing seven seasons of excavations in the field.  Parker Pearson and his colleagues have behaved neither in a responsible nor a timely fashion.  Nor is there a single paper which presents in a satisfactory and scientific manner the findings in the digs at Rhosyfelin, Carn Goedog and a number of other sites. (The paper published in Antiquity in December 2015 is far adrift of the standard required, and does not withstand scrutiny.)

Mike Parker Pearson, Richard Bevins, Rob Ixer, Joshua Pollard, Colin Richards, Kate Welham, Ben Chan, Kevan Edinborough, Derek Hamilton, Richard Macphail, Duncan Schlee, Jean-Luc Schwenninger, Ellen Simmons and Martin Smith (2015). Craig Rhos-y-felin: a Welsh bluestone megalith quarry for Stonehenge.   Antiquity, 89 (348) (Dec 2015), pp 1331-1352. 

The published material in the British Archaeology and Current Archaeology articles is examined in these two blog posts: 
https://brian-mountainman.blogspot.co.uk/2016/01/the-emperor-marches-on.html
https://brian-mountainman.blogspot.co.uk/2016/01/parker-pearson-et-al-on-carn-goedog.html

It's pretty clear that the COPE guidelines have been broken in both of the articles cited at the head of this post --since they have wilfully ignored two relevant -- but seriously inconvenient -- papers that should have been cited and discussed.  This constitutes scientific misconduct.  The only extenuating circumstance is the limited amount of "revision time" available to MPP and his colleagues between our publication dates and theirs.

So let's be forgiving for the moment.  But if this pattern of behaviour (ie the wilful refusal to acknowledge the existence of "inconvenient" research) is repeated in future publications,  I might start getting upset.

Molesworth, and suffering in the cause of truth

My favourite book of all time is "Molesworth", written by one genius (Geoffrey Willans) and illustrated by another (Ronald Searle).  In one of the priceless episodes our hero Molesworth has a daydream in which he finds himself together with other "lusty skolars" in an Elizabethan college run by a psychopath called Doctor Kurdling.

Our hero argues with the evil doctor about the existence of America, and gets six of the best with the cane -- after which Kurdling says: "...that will teach you not to alter the ignorance of a lifetime!"

Here endeth the parable for today........