Some of the ideas discussed in this blog are published in my book called "The Bluestone Enigma" -- available by post and through good bookshops everywhere. Bad bookshops might not have it....
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Tuesday, 30 November 2010

Where was the Anglian shoreline?

This is the conventional picture of the distribution of land, sea and glacier ice during the Anglian Glaciation, around 450,000 years ago.  This is in my view the best "candidate" for ice reaching Salisbury Plain.  Two things to bear in mind. 

First, the ice edge is shown following the Bristol Channel coasts of Somerset, Devon and Cornwall.  this cannot be right, because we know of glacial deposits well inland, around the Mendips and beneath the peaty sediments of the Somerset Levels.

Second, the assumption of dry land everywhere in the English Channel takes no account of isostatic loading.  If the ice limit is pushed maybe 30 - 40 km southwards (which would be more in tune with the geomorphological evidence) then we have a mechanism for considerable depression of the SW Peninsula and for sea water to flood into the English Channel to more or less the position of the present coastline.  Only in this way can we explain the giant erratics and other anomalous features of the English Channel coastlands.

Isostatic depression in Somerset and Wiltshire

Back in June, I put up a number of posts relating to isostatic and eustatic interactions in the SW of England, with particular reference to the "giant erratics" that have exercised geologists and geomorphologists for so long.  Here is one of the posts:
Please have a look at the others too, for the period 6-10 June.  This is a fairly comprehensive statement of my position......

My current theory is that much of SW England was covered by glacier ice in the Anglian Glaciation, around 450,000 years ago.  At the peak of that glacial episode, global sea-level was around 140m lower than it is today.  If the giant erratics were emplaced at that time, either by sea ice or through the direct effects of glacial deposition, the land surface must have been depressed by more or less the same amount.  To achieve that amount of depression, we need about 420m of ice on the land surface.  Can we achieve that scale of loading from what we currently know about ice limits etc?

The top illustration is from a computer model created by Dr Alun Hubbard and colleagues at Aberystwyth University -- it should apply to any of the extensive UK glaciations.  It is predicted that the ice was about 500m thick along the north coasts of Cornwall and Devon and up to 800m thick in the Bristol Channel.  The ice would have been over 400m thick over the Somerset Levels and around the fringes of the Mendips, and 100 - 200m thick over the western fringes of Salisbury Plain.

So we have perfectly adequate ice thicknesses (if this model is correct) for the scale of isostatic depression that we need if we are to "explain" the giant erratics.  There are still lots of questions.  How sensitive was (and is) the crust in this area?  Would deep isostatic depression along the coasts of the Bristol Channel have been sufficient to push down the English Channel coasts as well by almost the same amount?  I suspect so, since the distances are not great -- some of those south coastal areas are less than 50 km away.  Was there a bulge beyond the area of deep isostatic depression, and if so, where was it?  So far as I know, there has been no attempt thus far to fix the position of a hinge line in Southern England separating depressed areas from uplifted areas.

The bottom photo (from the edge of the Greenland ice sheet) shows what the ice edge might have looked like in Southern England -- in the vicinity of the Mendips and the Chalk scarp -- at the time of maximum glaciation.  What did the glacier profile look like at the time?  Was it a classic equilibrium profile as established by Nye, Robin and all the other great glaciologists -- with the ice surface gradient steepest at the snout or ice edge, and gradually diminishing up-glacier?  Or was it something quite different, with a much flatter profile induced by sub-glacial ground conditions, terrain irregularities,  and the thermal characteristics of the glacier itself?

It would be great to get some input on this debate from geophysicists and glaciologists......

Monday, 29 November 2010

Darvill dumps Neolithic hospital idea?

Been having another look at Dennis Price's excellent Eternal Idol site, and I homed in on this bit in the report of the Devizes seminar back in May -- I had read through it before without taking full note of it.

It looks very much as if Tim Darvill has abandoned his Neolithic Hospital idea in the wake of the almost unanimous howl of derision that has come from the archaeological world.  He still talks about the Neolithic significance of the "bluestone source area" and about a Neolithic culture there -- without mentioning sacred springs or healing powers.  He can't resist talking about the similarity of the dolerite outcrops in the natural state to "built monuments" --  but I think that's fanciful.  Maybe any rocky outcrop or tor in the mountains can be likened to a built monument -- OK, if you want it enough.  But I maintain that there is no SPECIAL association between Neolithic structures in the Preseli Hills area and bluestones.  If bluestones were handy, they used them, just as they used whatever stones were handy.

But I do like his suggestions that the stones at Stonehenge have been rearranged over and again, many times, and that some of them have been broken up.  And it's interesting that he even suggests that the bluestones at Stonehenge might have been used as convenient sources for stone implements.  That idea was put forward by me in THE BLUESTONE ENIGMA -- and it has also received some attention from Olwen Williams-Thorpe and her colleagues.  And I also like the suggestion that the "doing" at Stonehenge was more important than the objective -- as if the builders were experimenting or even playing around with building techniques.  Ah, that fellow Darvill is a man after my own heart!!

The statements at the end of the report are very enigmatic -- and even mischievous.  Signs of a convergence of ideas here?

"Tim Darvill’s talk on “Beyond Stonehenge” considered the bluestones, unsurprisingly given his recent excavations on the site. But there was little or no mention of healing powers – instead, he gave a very different view of the site to the conventional one that we’re familiar with. He started with the Preseli source sites, where the natural outcroppings are very similar to built monuments, and where there is already a Neolithic culture associated with the source stones. He believes that the bluestones are the first stone structures within the henge, but that they’ve been subject to constant rearrangement through prehistory to Roman times. Some of the remains are no longer found today as orthostats, suggesting that the stones have been constantly recycled into different configurations, and broken up.

Importantly, Darvill claims that we should regard Stonehenge “as a Roman temple”. Certainly the bluestone sequence seems to be much longer than conventional chronologies, with the major pit in Darvill’s excavation dating to the 4th century AD. This long sequence of changes, he suggests, is because the “doing” was more important than the result; perhaps in a similar way to Silbury, where the scope of the monument seems to have been extended many times. (Puzzlingly, Darvill suggests this chain of bluestone activities appears to have included breaking them up for stone implements.) He concluded that there are “many reasons why Stonehenge is Stonehenge …” with all sorts of connections and associations. Was Stonehenge at the centre of the different communities through history, or at the edge? Probably both, at different times."

From:  Stonehenge and Avebury seminar at Devizes – a report,  by Dennis on May 27, 2010 (seminar report written by Alex Down)

Lots of hits

Just checked the counter for this blog, and realized that it has gone over 11,000 page views and 6,000 hits on the site.  That's reassuring -- so somebody out there is reading my ramblings.  None of it matters, of course, alongside things like homelessness, poverty and war, but on the basis that we all need to think of frivolous things now and then, I hope that the posts which I have put up over the past months will at least have stimulated some thought........ and maybe tilted a few edifices that were built on sinking sands.

The Seductive Charms of Fred Flintstone

It's interesting that in various forums (fora?) on Stonehenge my ideas (which are of course not unique, having also been articulated by many others over the years) have come in for a lot of stick from people who claim that it is tantamount to sacrilege to deny that Neolithic tribesmen were in possession of some Ancient Wisdom, not to mention technical abilities (navigation over sea and land, stone-handling, boat building) which were far ahead of their time.  Some people clearly WANT to believe in the technical wizardry and even spiritual sophistication of our ancient ancestors, even if there is remarkably little evidence in support of their ideas.  We could call this the Fred Flintstone syndrome -- on the basis that Fred, Wilma, Barney and the rest of them made us feel good because we saw many of our modern foibles and obsessions (and our handy gadgets) placed in a prehistoric setting -- and we were able to enter a hilarious fantasy world which was somehow totally different from ours but at the same time reassuringly similar.  So Fred and the rest of them could drive a car, take photographs, play records and even fly........

The other widespread belief is that this Ancient Wisdom has been LOST.  It was there once, and it was truly wonderful, but we cannot see any signs of it today (except in monuments like Stonehenge) because mankind has been foolish enough, in making progress on certain fronts, to lose sight of the ancient instincts and esoteric knowledge of our ancestors.  So man has maybe advanced technically while regressing spiritually.  The fact that we have no real records of this Ancient Wisdom is all down to the foolishness of modern man -- but it was there nonetheless, and we have to show it due reverence.  Hmmm.......

When I'm wearing another hat I write historical fiction, and the key piece of advice I have to bear in mind all the time is this:  "Beware of populating your story with modern people dressed in fancy dress."  It's very hard to recreate another era in which patterns of speech were different, public and private morals were different, technology was different, and belief systems were different.  In my novels I frequently have to remind myself that in the early 1800s there was (at least among the bulk of the UK population) a fundamental belief in the "truth" of everything in the Bible, and no inkling at all of the ideas that Darwin was later to introduce to the scientists of the world.

So back to the Ancient Wisdom enshrined in Stonehenge ........  in short, poppycock.  Generations of archaeologists have maybe not subscribed to some of the more extreme forms of Ancient Wisdom Worship, but they have not helped with books like "Stonehenge Complete", "Stonehenge Decoded" and "Solving Stonehenge" which have all promoted the idea of the immaculate Stonehenge, designed and constructed with wondrous precision by technically sophisticated men who deserve not only our admiration but also our unswerving loyalty.  

I much prefer a view of life which has space in it for grand aspirations, inspired leadership and technical innovation alongside material shortages, incompetence, flagging enthusiasm, and assorted cock-ups.  That matches much more precisely what we see on the ground at Stonehenge -- a ruinous monument from which at least 70 stones are missing, in which the straight lines are not quite straight, the stone spacing is anything but regular, the stones themselves are a strange assortment of all shapes and sizes and rock-types, and the circles are not quite circular.  Exactly the sort of thing that could have been built -- or at least dreamed of -- by those incompetent clowns Fred and Barney.

Sunday, 28 November 2010

Main spotted dolerite source area

Been up to the top of Carningli in the snow today -- quite delightful.  The visibility was excellent -- and I got this pic of the eastern end of Preseli.  Click to enlarge the photo.  The rocky outcrops on the mountain ridge include Carn Meini (immediately to the left of the TV mast), Carn Breseb, Carn Gyfrwy, and Carn Ddafad-las.  These are all possible source areas for the spotted dolerites at Stonehenge -- but the consensus at the moment is that the majority probably came from Carn Goedog, which is the massive tor on the north-facing hillslope, immediately below the TV mast in the photo.

There are some rhyolites in this area too, but the rhyolites at Stonehenge seem to be very variable -- and some fragments seem to have come from the lower land in the foreground of this photo.

Friday, 26 November 2010

The small sarsens

 Five of the lintels still in position on top of the big sarsens.  BUT did these lintels once stand, and did some of the smaller standing stones once lie?

When we talk of Stonehenge we normally refer to the "big" sarsens and the "small" bluestones, often forgetting that there is another category of monoliths on the site -- namely the sarsen lintels.  Most archaeologists assume that there were originally 35 of these, 30 making up a "ring of interlocking lintels) on the outer circle, and then another five capping the big standing stones in the trilithon horseshoe.  Today there are only 9 left in position, meaning that (if they were there in the first place) 26 have fallen.  There appear to be four on the ground, and the assumption is that 22 have disappeared completely, as a result of stone collecting or "quarrying" activities on the site.

Anthony Johnson goes to great lengths to show how closely similar the 6 lintels left on the circle sarsens are, around a metre wide, 75 cm deep, and around 3.4m long, with a curved long profile and tongue and groove joints where they butt together, and mortise and tenon joints to hold them in position on top of the sarsens.  They are estimated to weigh about 6 tonnes each.

The discussions are all coloured by the assumption of the "immaculate" Stonehenge  -- but I think it perfectly reasonable that the small sarsens and the bluestones should be lumped together as an assemblage of smallish stones.  For some strange reason it is never admitted that the sarsen lintels ever were standing stones, or indeed that the bluestones ever were lintels (although the shaping of some of them is interesting to say the least).  What about all those Q and R holes that are assumed to have held stones at one time?   There is no logic at all, as far as I can see, in assuming that the stones in those holes were bluestones rather than small sarsens.  By the same token, might not some of those pits discovered all over the place -- for example in the 2008 Darvill / Wainwright dig -- have held small sarsens which were later rejected or re-used as lintels on the final stone setting?

Also, if there really was at one time a ring of standing stones at Bluehenge or Bluestonehenge,  it now looks increasingly unlikely that these were bluestones, since there are no bluestone chips or fragments on the site.  So they must have been small sarsens.  Whether these were taken to Stonehenge is another question.........

My suggestion is that the builders of Stonehenge first of all brought as many smallish stones (3 - 6 tonnes in weight) onto the site from wherever they could find them, not worrying whether they were blue or not!  Sarsens and erratics were all mixed up in a single assemblage.  They never had enough of these small stones to complete what they were trying to do.  Later, they decided to use big stones as well, and hauled as many big sarsens onto the site as they could manage.  When they started playing around with lintels, they discovered that sarsen was easier to shape than dolerite or the rest of the grotty collection of bluestones they had at their disposal, and they completed part of their grand design, putting a few lintels into position --  but then they ran out of stones and ran out of energy, and the monument was abandoned as a partly-finished shambles.

Does anybody have any EVIDENCE to show that I'm wrong about all of this?

Wednesday, 24 November 2010

Dead stone and living wood?

Building on my last post, I paste below a comment from an article by John Barrett and Kathryn Fewster.   I haven't followed the full debate on this topic of domains of the living (associated with wood) and domains of the dead (associated with stone) -- but clearly I am not the only one who thinks that MPP and R have been pushing the Madagascan example rather too forcefully!

It is of course commonly suggested that Bronze Age standing stones might be memorial stones, and indeed in West Wales some of them do have burial traditions associated with them  -- for example Bedd Morris and Hangstone Davy standing stones.  Much later, in the Early Christian era, the Celtic Crosses and pillars found on sacred sites were also memorials or commemorative features.  But so far as I can see those stones were always local -- picked up and erected more or less at the site on which they were found.  As I have said many times before, there is no sign in West Wales that spotted dolerite was particularly revered, or preferred over other stone types.  And is it not also the case that memorial features are just as often made with wood as with stone?  What about the old wooden cross, the archetypal symbol of Christianity......?  And the totem poles of NW North America, many of which are clearly associated with ancestors, death rituals and burials?  There are also wooden totem poles in New Zealand too, that are clearly associated with ancestors and death.

Quote from Barrett and Fewster:

"PP&R attempt to demonstrate the 'correctness' of their analogy by firstly, bringing in anthropological data additional to their own case-study in Madagascar which leads them to the conclusion that the ancestor cult is universal in small scale societies which base their organization on kinship affiliation (PP&R 1998: 310). Secondly, a relational analogy (which PP&R term an analogy of materiality) is used to suggest that the structuring principle, that has been identified in Madagascar and that links wood to the living and stone to the ancestors, is universal (PP&R 1998: 309). We shall take each in turn and show that neither is universal".

Article: Stonehenge: is the medium the message? (response to Michael Parker Pearson and colleague, Antiquity, vol. 72, p. 308, 1998)

Article from:Antiquity -- Article date:December 1, 1998 Author: Barrett, John C.; Fewster, Kathryn J.

Sacred Stones and Madagascar


Last night I had an interesting conversation with a good friend who was for a time a missionary in Madagascar.  We got to talking about sacred stones, and he told me about the "ancestor stones" of the tribal community in which he spent ten years.  He also described the "domain of the dead" which was inhabited by the spirits of the ancestors who were left there, not cremated but slowly rotting away.  He described how the ancestors were occasionally carried back to the village from the "domain of the dead" and given food to sustain them.  Then they were taken back to the domain again, by a complicated and tortuous route designed to make them lose their sense of direction.  This was so that they would remain in their domain and not be tempted to come back to the village -- thus allowing the living to get on with their lives.  Each family had standing stones in or near the village which were greatly revered, since they "held" the spirits of the ancestors.

Clearly it is incredibly difficult to transpose or import a belief system from Madagascar into a UK-based neolithic community, but this appears to be what Mike Parker Pearson has done, in conjunction with Ramilisonina.  Over the last couple of years this theory has been expounded in a number of articles, and on the telly -- but not by any means to universal acclaim.  As many others have pointed out, the traditions and beliefs of the Madagascar tribes are not actually more than a few centuries old, and to claim that there is some sort of universality to the belief system involving "ancestor stones" would be a grave mistake.  Most of the tribal groups of the world do NOT have this belief.  It seems to me that MPP has invented the Stonehenge "domain of the dead" as an explanation for what he has found (or imagined) at Bluestonehenge, and as a counterbalance he has then imagined that there must have been another area (around Woodhenge) which must have been the domain of the living.

An anthropological leap too far?  Is MPP looking for a reason to label the bluestones as sacred or special,  and then by extension to justify the imagined stone-collecting expeditions to West Wales? I think so.

There is also a problem over designating the burial area as "the domain of the dead" -- maybe that is to put a "western" construction on it.  My friend told me last night that the belief in his village was that the ancestors simply passed on, and were really still alive but in a different world of their own.  So they were still present, and could be communicated with.  So you had to revere and respect the ancestor stones -- to do otherwise might well bring bad things down upon your family.  In that village they did not practice cremation, since maybe they felt that that would somehow destroy the spirits of the ancestors.  It all goes to show how hard it is for us to see inside the heads and the hearts of people living in totally different traditions and in other lands.

Anyway, for what it is worth, here is an interview I came across with Ramilisonina.

This is from the Archaeological Institute of America web site:
Exploring the connection between Stonehenge and Madagascar's modern-day megaliths

One of Madagascar's first native-born archaeologists, Ramilisonina's ethnological research on modern Malagasy traditions informs his study of ancient sites on the island. Together with Mike Parker Pearson of the Stonehenge Riverside Project, he also developed a new interpretation of the ritual landscape around Stonehenge and the nearby timber-post site known as Woodhenge. He spoke with journalist Richard Covington about the recent discovery of "Bluestonehenge", a site near Woodhenge and Stonehenge, and the similarities between Madagascar's living traditions and the burial rituals of Neolithic England.
What exactly did the team find at "Bluestonehenge"?
We discovered a circular ditch, inside of which were fragments of bluestones, large megaliths brought from Wales. Artifacts from the site date to around 2500 to 3000 B.C., the same era as Stonehenge.
How does Bluestonehenge relate to Stonehenge?
Bluestonehenge was a stone circle on the Avon River, and burial ceremonies could have begun there. The bodies might have been cremated at the site and then taken to Stonehenge for burial. We see the same sort of practice today in Madagascar.
What do you think was the purpose of Stonehenge?
It was a sacred place where people came to make contact with the creator gods and the spirits of their ancestors.
What similarities do you see between Stonehenge and megaliths in Madagascar?
In Madagascar, stone belongs to the world of the ancestors and is used to construct tombs and monuments. So stone in Madagascar is really for sacred purposes, for the dead. Wood is for the living. Houses here are made of wood or earth.
Never stone?
Before the 18th century, no one in Madagascar built a house in stone. Stone was reserved for the dead or to commemorate an important event. Stonehenge also seems to have been a monument to the dead.
Is ancestor worship still practiced in Madagascar?
Yes, there's still ancestor worship. In the capital, Antananarivo, you can say that people are civilized, Christianized. But it's here where you still find the greatest number of ancestor shrines.
Why is that?
In spite of Christianity, we still honor our ancestors. For example, on sacred hills with tombs, where people come regularly to pray to their ancestors, there is often a church just nearby. So, the Malagasy in Antananarivo go to church on Sunday and to the tombs of their ancestors on Monday.
How did you come to see a connection between the modern monuments in Madagascar and the ancient megaliths of Stonehenge?
Mike and I have worked together in Madagascar since 1991. We had many discussions about standing stones, and he invited me to come see Stonehenge. Even though the stones in Madagascar are smaller, I could see there was still a similar element of magic at Stonehenge.
Do you also see parallels with Woodhenge?
Yes. In Madagascar, people also create shrines in wood circles. The wooden monuments are placed in the middle of villages or alongside fields. Memorial stones for the dead are placed beside paths or roads.
Are there other ritual elements to the surrounding landscape?
There are sacred forests. But deforestation is a serious problem. I just returned from my village in the Bezanozano region and there were fires everywhere. My brothers were dejected because fires had burned down many trees. Archaeologists fight very hard for the protection of forests, which have very concrete evidence of our ancient culture.
Do people still erect stones in Bezanozano?
There are standing stones all over Madagascar, not just in Bezanozano. The way they are erected varies, but they are always connected to the dead, our ancestors, and invisible spirits, just as at Stonehenge.
Have you ever erected one?
Oh yes. After my father died 10 years ago, we erected a commemorative stone on the side of a road. We visit it to say our prayers and ask his help.

Sunday, 21 November 2010

A Load of old Balls

Been looking up those Scottish ball bearings.  The process has made me rather cynical about the ball bearing theory.  See the link above --and also have a look here:

and here:

and here: 

It appears that the majority of those that appear to date from the Neolithic (over 400?) are carved, with knobs and grooves and shapes that can and have been classified by researchers.  They are mostly about the size of tennis balls.  They might have been used as weapons, or as ceremonial or prestige items -- or items used in sporting contests -- and some are incredibly elaborate and beautiful.   Were they equivalent to the Welsh love spoons, made by farm-hands and sailors on dark winter nights or long voyages, as symbols of love, in which the skill of the maker could be admired by the lady recipient?

They cannot have been used as ball bearings, since they would not have rolled properly either in a groove or on a flat surface.  From what I can gather, the only REALLY round and unornamented stones to be found in Scotland are associated with the Iron Age -- far too late to have been of much use for the building of Stonehenge.

Wait for it -- The Great Mesolithic Inundation

Here comes the latest earth-shattering tome about Stonehenge -- "The Stonehenge Enigma" by Robert J Langdon, £14.99 from ABC Publishing Group (or £7.99 paperback).  There is some high-profile promotion going on, with a full web site with text and graphics, and even some videos on YouTube.

I'm always happy to help with promotion work for other struggling authors, so above I have pasted a copy of the cover.

The central thesis is that in the Mesolithic, after the end of the last glacial episode, Southern Britain was inundated by the sea to such a depth that it was possible to transport the bluestones and the sarsens by sea, all the way from their places of origin to the site of the monument.  As suggested by the book cover, RJL claims that the shoreline of this great inundated landscape was literally at the edge of the monument site.  The author cites isostatic depression in support of his theory, and claims that the geological evidence backs up his arguments in a manner that is incontrovertible.

Sadly, he does not appear to understand isostasy, eustasy, geomorphology or glaciology -- and as a result I suspect that NOBODY is going to take this book seriously.  On looking at the text extract on the website, it appears that the author thinks that peat is an indicator of a submerged landscape.  It patently is not.  He appears quite unconcerned that there are no shorelines or marine sediments in the areas which he wishes to have been submerged.  He appears to forget entirely that because ice sheets build their mass through extracting moisture from the oceans, global sea levels at times of extensive global glaciations are LOWER than they are today, and that even very dramatic isostatic depression in Southern England could not have created the inundation that he describes so graphically.  Finally, there is one piece of evidence that he appears oblivious about -- the submerged forests that surround the coasts of Wales and SW England.  All of these show that during the Mesolithic there were extensive woodlands beyond the current coastline, demonstrating that sea level was LOWER than it is today.  These woodlands, peat beds etc were gradually inundated by the sea during the Holocene sea-level rise to the position of the present shoreline.

There are hundreds if not thousands of radiocarbon dates which show what happened, as well as a multitude of studies in the fields of stratigraphy, geomorphology, botany and zoology.

Can I suggest, RJL, that you have a look at some of my previous posts on this blog, and follow up some of the literature?  At the moment this looks like a ruling hypothesis in search of some evidence......

More about the Scottish ball bearings

The ball bearings in their grooves on a temporary "railway track" -- in the background the stone slabs resting on their platform, which in turn rests on the ball bearings.

This is all very jolly -- another experiment conducted on relatively flat and dry ground.  The tracks are impressively long and straight, as delivered from the timber merchant.  How might this all have worked in the REAL world, I wonder?  Note how hype has taken over again -- the University of Exeter shows that it is no slouch when it comes to TV deals and the use of phrases like "Secrets of Stonehenge" -- anything Darvill, Wainwright and Parker Pearson and their tribes can do, the Exeter tribe can do too.
From the Univ of Exeter web site :  Press release

Discovering the secrets of Stonehenge

A revolutionary new idea on the movement of big monument stones like those at Stonehenge has been put forward by an archaeology student at the University of Exeter.
Whilst an undergraduate, Andrew Young saw a correlation between standing stone circles in Aberdeenshire, Scotland and a concentration of carved stone balls, which may have been used to help transport the big stones by functioning like ball bearings.
Young discovered that many of the late Neolithic stone balls had a diameter within a millimetre of each other, which he felt indicated they would have been used together in some way rather than individually.  By plotting on a map where the carved balls were found, he realised they were all within the vicinity of Neolithic monuments known as recumbent stone circles.   These stone circle monuments in Aberdeenshire share an equivalent form to Stonehenge, yet with some much larger stones.
To test his theory Young built a model using small wooden balls which were placed in a grooved pieces of wood moulding, similar to a railway track but with a groove rather than a rail.  The balls were spread apart and a mirror image of the track was placed on top supporting a wood platform. He then placed concrete slabs on the tracks, to replicate a heavy weight.
Young said, “I then sat on top of the slabs to add extra weight.  The true test was when a colleague used his index finger to move me forward, a mere push and the slabs and I shot forward with great ease.  This proved the balls could move large heavy objects and could be a viable explanation of how giant stones were moved, especially in relation to where the stone balls were originally found.”
A further experiment on a much larger scale was arranged with the financial assistance of Gemini Productions and WGBH, Boston for NOVA, an American documentary TV programme.  They were focusing on Stonehenge and wanted to see if a team of archaeology students directed by Professor Bruce Bradley, a lead archaeologist at the University of Exeter could build and test a life size model using wood that might reflect how massive stones could have been moved across the landscape.  Previous experiments, which others have carried out to move large stones had not been particularly effective.  The building of a hardened surface to roll logs on and the trench experiments only moved the stone with great effort and if they had been moved in this way the hardened surface or trench would show up in the archaeological record, however these have not been found.
In the large scale experiment, green wood was used for cost purposes. Neolithic people would have had access to much better materials, such as cured oak, which is extremely tough and was in abundance due to the great forests at the time. They also had the technical ability to cut long timber planks, known through archaeological evidence of planks used as a way of creating tracks for people to walk on through bogs.  The experiment used hand shaped granite spheres as well as wooden spheres.
Professor Bradley said, ‘Our experiment had to go for the much cheaper option of green wood, which is relatively soft, however, we successfully moved extremely heavy weights at a pace.  The demonstration indicated that big stones could have been moved using this ball bearing system with roughly ten oxen and may have been able to transport stones up to ten miles per day.  This method also has no lasting impact on the landscape, as the tracks with the ball bearings are moved along leap froging each other as the tracks get moved up the line.”
He added, “It demonstrates that the concept works. It does not prove that Neolithic people used this method, but it was and is possible.  This is a radical new departure, because previous ideas were not particularly effective in transporting large stones and left unanswered questions about the archaeological record they would have left behind.”
The next stage in the project is to collaborate with the engineering experts at the University who can calculate the loads which could be transported using various combinations of variables such as hard wood and U-shaped grooves.  This will provide the mathematical evidence to see how much force would be needed to get the stone moving and to keep it moving. This will enable the project team to gain an even greater understanding of how stones may have been transported across huge distances and even up hills.  The ultimate goal is for a full scale experiment in Aberdeenshire using more authentic materials, stone balls and a team of Oxen.

Date: 18 November 2010

Saturday, 20 November 2010

Ballbearing spectacular on the way

 Here comes the latest wondrous theory relating the the movement of Stonehenge stones over long distances.  A number of papers carried this story in the past week.  Here's the version that appeared in "This is Wiltshire" -- I assume it is the press release, reproduced more or less word for word. 

As usual, this "spectacular reinterpretation" which throws amazing new light on Stonehenge, which will cause us to reinterpret everything and revise all our theories etc etc etc ....... is being funded by an American TV documentary maker.  The latest in a long line of Stonehenge fantasy epics.  Wait for it with bated breath.

Anybody for boule?  I reckon this is another Scottish conspiracy, like the one that tries to convince us that golf was invented in Scotland.

Ball bearings used to build Stonehenge says exper 18th November 2010

Neolithic engineers may have used ball bearings in the construction of Stonehenge, it was claimed today.
The same technique that allows vehicles and machinery to run smoothly today could have been used to transport the monument's massive standing stones more than 4,000 years ago, according to a new theory.
Scientists showed how balls placed in grooved wooden tracks would have allowed the easy movement of stones weighing many tons.
No-one has yet successfully explained how the heavy slabs used to build Stonehenge were shifted from their quarries to Salisbury Plain.
Some, the bluestones, weighed four tons each and were brought a distance of 150 miles from Pembrokeshire, Wales.
Attempts to re-enact transporting the blocks on wooden rollers or floating them on the sea have not proved convincing.
The hard surfaces and trenches needed when using rollers would also have left their mark on the landscape, but are missing.
Experts hit on the new idea after examining mysterious stone balls found near Stonehenge-like monuments in Aberdeenshire, Scotland.
About the size of a cricket ball, they are precisely fashioned to be within a millimetre of the same size.
This suggests they were meant to be used together in some way rather than individually.
The Scottish stone circles are similar in form to Stonehenge, but contain some much larger stones.
To test the theory, researchers from the University of Exeter constructed a model in which wooden balls were inserted into grooves dug out of timber planks.
When heavy concrete slabs were placed on a platform above the balls, held in position by more grooved tracks, they could be moved with ease.
Archaeologist Andrew Young described the experiment in which he sat on top of the slabs to provide extra weight. He said: "The true test was when a colleague used his index finger to move me forward - a mere push and the slabs and I shot forward. "This proved the balls could move large heavy objects and could be a viable explanation of how giant stones were moved."
The team went on to carry out a life-size test funded by an American TV documentary maker.To reduce costs, the scientists used relatively soft green wood rather than the hard oak that would have been plentiful in Neolithic times, when Britain was covered in forest.
This time, the researchers used hand-shaped granite spheres as well as wooden balls.
The results proved the technique would have made it possible to move very heavy weights long distances.
Professor Bruce Bradley, director of experimental archaeology at the University of Exeter, said: "The demonstration indicated that big stones could have been moved using this ball bearing system with roughly 10 oxen and may have been able to transport stones up to 10 miles per day.
"This method also has no lasting impact on the landscape, as the tracks with the ball bearings are moved along leap-frogging each other as the tracks get moved up the line."
Neolithic people were known to cut long timber planks, which they used as walkways across bogs, Prof Bradley pointed out.
Although the tests do not prove for certain that the ball bearing method was used, they show "the concept works", he said.
He added: "This is a radical new departure, because previous ideas were not particularly effective in transporting large stones and left unanswered questions about the archaeological record they would have left behind."
The next stage in the project is to provide mathematical evidence of how much force would be needed to keep a stone moving.
Ultimately, the scientists hope to conduct a full-scale experiment in Aberdeenshire using more authentic materials, stone balls and a team of oxen.

Bluestone debris and the matter of Stonehenge quarrying

My thanks to Pete G for drawing this (from 1933) to my attention.  Newall obviously thought that the lump of bluestone had come from Stonehenge -- and the same assumption has been made about all of the other bits of bluestone scattered about.  Recently I heard about a mantelpiece in Amesbury that was made of bluestone (presumably spotted dolerite?), and there has also been mention of bluestone lumps in many of the house foundations in Amesbury.  The conventional wisdom is that because these stones exist, that proves that Stonehenge has been used as a "bluestone quarry" in recent centuries.  However, it is just as likely that this is wishful thinking, and that the stones have come from a genuine "bluestone" erratic litter in the Stonehenge - Shrewton - Amesbury area.

As far as I know, there is no inventory of these stones -- the closest thing I have seen to a "list" was in the big 1991 report from the OU team including Richard Thorpe and Olwen Williams-Thorpe.  There are "anomalous" stones all over the place on Salisbury Plain -- the best known of which is of course the big bluestone boulder that came from the long barrow known as Boles Barrow, near Heytesbury.  For years archaeologists and others have been striving to prove that the spotted dolerite boulder now in Salisbury Museum wasn't actually from that Neolithic structure at all.  We know why -- if it really was incorporated in that monument it must have been present on Salisbury plain around 5,500 years ago -- far too early to fit into the thesis of long-distance stone haulage associated with Stonehenge.

Bluehenge fantasy

This rather exotic reconstruction of Bluehenge or Bluestonehenge comes to us courtesy of a Canadian (?) TV programme called Nova.  Not having seen the programme, I'm not sure what the "exciting findings" are, but I suspect that there aren't any -- just the usual dose of fantasy.  Quote:

"Archeologists have ..... hypothesized that stones may have been removed from Bluehenge around 2500 BC and used to shore up Stonehenge itself, which is known to have undergone major restoration around that time. One theory holds that Bluehenge was a place of life, where the living gathered, and Stonehenge was the “domain of the dead,” and ancient Britain’s first known cemetery".

Splendid stuff -- and all based on  a few supposed sockets and two small fragments of "bluestone."  In my view it's much more likely that the stone sockets held small sarsens.   Have a look at my previous post:

Monday, 15 November 2010

The Chalk Escarpment

 Above -- the chalk scarp at Beacon Hill, near Devizes.  Below: the chalk scarp near the Westbury White Horse.

I'm increasingly convinced that the chalk scarp holds the key to the origins and the transport of the bluestones.  The edge of the chalk downlands of Wiltshire is generally marked by a very steep scarp which is seldom straight, but broken up into a multitude of rounded spurs separated by indentations in the form of steep sided dry valleys or coombes.  There are a few gaps in the escarpment where larger rivers have cut back into the downland,  but the map on the last post shows how prominent this chalkland edge really is.

It is and was a formidable barrier -- it may have been a barrier to the ingress of glacier ice from the west during the Greatest British Glaciation (c 450,000 years ago?) and it must also have been a major barrier which effectively set a western limit on the stone collecting expeditions of the Stonehenge builders.  Did the ice edge coincide with the escarpment?  Further research is needed on this.

Sunday, 14 November 2010

The Stonehenge Neolithic stone collectors

OK -- so the people who collected the Stonehenge stones (both sarsens and bluestones) had to range across the countryside in order to collect everything that was available to them.  So -- assuming that the climate was favourable and that terrain conditions were also suitable -- how far did they go?

The two maps above are helpful.  Both the maps are courtesy Wiltshire County Council.  The one shows the terrain to the W and NW of Stonehenge / Amesbury, and the other shows the geology, with two circles superimposed.  The inner circle has a radius of 20 km and the other 30 km.  I'm increasingly coming to the view that the stone collectors first collected their stones from quite close to the monument, and pushed further and further afield -- maybe up to 30 km away in some instances.  The key factor was the smooth and undulating grassy surface of the chalk downland.  So what stopped them in the end?  I've suggested many times that maybe they ran out of stones, ran out of energy, and ran out of motivation -- or that priorities simply moved on.  But maybe one key factor also was the chalk scarp.  It's a pretty impressive barrier, full of indentations but generally facing west.  Hauling stones up that scarp, or even up the valleys that broke into it, would have been very daunting indeed.

So sarsens and bluestones that were above the scarp were maybe quite easy to collect, whereas anything below the scarp was not.  Worth thinking about.......

Neolithic climate change

Continuing on the theme of what might have been optimal environmental conditions for stone-pulling on Salisbury Plain, it's difficult to sort out from the pollen and other records what short-term oscillations were truly climate-related, and which one were related to human activities like forest clearance, increased agricultural activity etc.  However, it does appear that in the Neolithic the climate was cooler than it was in the Mesolithic -- the relatively warm period dated to 8,000 - 5,000 BP is often called the Holocene Climatic Optimum.  The climax vegetation seems to have shifted from a southern type of deciduous forest to one with a more "northerly" aspect, with more conifers.  Was it also drier?  It's difficult to say, from the current evidence.  But later on, during the Bronze Age, there is much evidence (from the Somerset levels and elsewhere) to suggest that it did get significantly colder still, and also wetter, with raised water levels and more boggy conditions. 

So could it be that during the Late Neolithic, with cool and moderately dry conditions, and a relatively well-cleared and open landscape, the Salisbury Plain grasslands (with a well-drained chalk substrate) presented ideal stone-pulling conditions?  And could it also be that before a few centuries had passed, the weather turned nasty again, and that that might have limited the range over which the stone-collectors could operate?  If all the stones had already been gathered up over a radius of maybe 30 km, maybe the "cost" expressed in terms of manpower and human effort simply became too high for the Stonehenge project to continue?  And there does seem to be evidence that during the Bronze Age society was changing anyway, with a greatly reduced interest in doing spectacular things with heavy stones.  These are intriguing possibilities......

Danish Neolithic stone pulling

 This video is great fun, even if you don't understand Danish!  It's a good reconstruction of the methods by which goodness knows how many Neolithic burial chambers / long barrows / cromlechs were built all over Europe.  So these techniques were clearly available to the builders of Stonehenge, as were the techniques of tipping up extremely large monoliths (like those on Brittany) and placing them vertically in the ground.

So those techniques are not in question.  The really interesting question is this:  what are the conditions required for this activity to take place?  You need four things (at least):
1.  Motivation
2.  Technical ability and manpower
3.  A ready source of stones of the right sort
4.  Favourable physical conditions

That's what we really need to concentrate upon.  I have noticed that the successful stone hauling experiments have been done on flat or undulating terrain in dry conditions.  Obviously if your sledge or rollers are sinking into a bog forward movement of the stone will become impossible; and there also comes a point, on a slope of a certain gradient, where haulage upslope will become impossible even with vast numbers of men who have an unhindered route and a clear pulling trail. 

To me that suggests that Salisbury Plain (dry undulating chalkland) was good stone-pulling territory, whereas West Wales (with thin acid soils, frequent bogs, deep wooded river valleys with rushing streams, and more or less continuous Neolithic jungle covering the land surface) was not.

Around 4,500 years ago, when the "stone phase" of Stonehenge was under construction, what was the climate like?  According to Michael Allen, in the Early and Middle Neolithic there was still a lot of primeval forest left on Salisbury Plain, with thick deciduous woodland in the valleys and coombes, and with quite large areas of secondary woodland on the plain itself.  The area of grazed grassland was expanding all the time.  By the time of the "stone phase" (Late Neolithic) the clearance of primary forest is almost complete, and there is an almost continuous expanse of open grassland on the plain.  This cannot be coincidence.  Suddenly we have a large settled community based on farming, and a well developed social organization as well, allowing large-scale engineering projects to be initiated, if not actually completed.

And the haulage of stones was suddenly possible over an open landscape.  The crucial question is this:  how far afield were the stone collectors able to roam, given the technical and manpower resources that they had available?  Some thought needed on this.....

Pulling big stones

Came across a couple of interesting videos on YouTube -- the one below is of some strange stone-hauling ceremony in Northern India.  Not sure why they are going to all this effort!  From what I can find out, a number of tribes in Nagaland have these ceremonies, pulling large elongated stones which are then erected during  festivals -- it's suggested that they are phallic symbols, since the festivals seem to be associated with fertility.  It shows that big stones CAN be pulled across rough terrain, given a large enough group of pullers and a strong enough motivation.  I'll put up another link to an experiment in Denmark, where they  made a reconstruction of how a large capstone was pulled up onto the top of a burial chamber, by a large group of volunteers using a sledge, rollers, ropes, levers and wedges. 

I have never had any doubt about any of that, since it is evident that even if the Stonehenge stones were all fairly local to the monument, they must have been pulled in to the site.  How big was the radius of the collecting circle?  One mile?  Twenty miles?  That's something we still have to work on.......... but note that in this video the ground is dry and the weather warm.  That may be a point of some significance.

Tuesday, 9 November 2010

More than 30 different bluestone sources

 "Oh dear -- this gets REALLY confusing.  Why don't we just fill the bloody hole in again and forget about those blasted stumps?"  By the way, they are stumps 32d (spotted dolerite, in the foreground) and 32e (rhyolite, to the left) ......

I have been convinced for some time that there are well over 30 different sources for the bluestones in the Stonehenge area.  Been looking through the records, and here is a starting list. It's a difficult list to compile, because many identifications are from visual examinations only, while others are from detailed petrography and geochemistry (methods used by the OU team in the late 1980's), and yet more through detailed analysis by Dr Rob Ixer, Dr Richard Bevins and others, using the latest methods, in the last few years.   Geological names also change over time, and (for example) what used to be called rhyolite now has many different names.  Some provenances are known (where stone numbers are given) but there are literally thousands of smaller stones and fragments in the various collections -- and it is not impossible that some of these samples have been given different names and maybe different numbers, leading to duplication. Even the numbering of stones is not consistent.

Here is a list for starters -- thanks are due to Dr Rob Ixer for keeping me informed of progress on the geology of the Stonehenge finds.  I have listed some of his publications on previous posts.  I'll welcome corrections, since there are bound to be mistakes.  But I wouldn't mind betting that when this list is corrected it will get even longer, since stones currently grouped together (for example the white spotted dolerites and the pink spotted dolerites) may well prove to incorporate stones from different provenances.

On the other hand there is considerable geological variation on the rocky outcrops of Preseli and along the exposures of Fishguard Volcanics -- so for example a dolerite and a rhyolite may occur right next to one another on a single tor.

Note -- not all of the Stonehenge monoliths are listed below -- many stones have not been examined and still have to be categorized, especially those from within the spotted dolerite and unspotted dolerite groups.

Stonehenge Bluestone Types

1.  Unspotted dolerite ---- monoliths  45 and 62.  Carn Ddafad-las?

2,  Spotted dolerite -- densely spotted.  Monolith 42  -- Carnbreseb? 43?

3.  Boles Barrow dolerite -- spotted?  But similar to stones 44 and 45? From Carnmeini / Carngyfrwy area?

4.  Rhyolite  -- stones 38, 40, ignimbrite character.  Ash-flow tuffs (dacitic). Not Carnalw ? May be from different sources?

5.  Rhyolite --  stones 46 and 48, rhyolitic ash-flow tuffs.  Carnalw area?  Same source?

6.  Rhyolite fragment from a different source from the above types

7.  Laminated calcareous ash -- stumps 40c, 33f,  41d

8.  Altered volcanic ash -- stump 32c, 33e?

9.  Rhyolite -- another type -- stump 32e.  Related to Pont Saeson samples?

10.  Micaceous sandstone -- stumps 42c, 40g (Palaeozoic -- South Wales origin?)

11.  Rhyolite -- lava -- stone 46

12.  Rhyolite -- flinty blue -- different lava?  stone 48

13.  Spotted dolerite with whitish spots --stones 33, 65, 68, stump 70a?, stump 71?, 72

14.  Spotted dolerite with few spots -- stone 31, 66?

15.  Spotted dolerite with pinkish spots -- stones 150, 32, 34, 35A, 35B (one stone), 39 (?), 47, 49, 64, 67, 69, 70

16. Spotted dolerite -- moderate spots -- stone 37, 61, 61a?

17.  Unspotted dolerite -- stone 44 -- different from stones 45 and 62

18.  Very fine-grained unspotted dolerite -- stone 62

19.  Silurian sandstone -- Cursus -- fragments

20.  Devonian sandstone -- Altar Stone -- Devonian Senni Beds -- Carmarthenshire or Powys

21.  Sarsen sandstones -- various types -- packing stones and mauls

22.  Jurassic oolitic ragstone -- Chilmark?

23.  Jurassic glauconitic sandstone -- Upper Greensand?

24.  Gritstone unspecified fragments (Maskelyne, Judd)

25.  Quartzite unspecified fragments (Maskelyne, Judd)

26.  Greywacke unspecified fragments (Maskelyne, Judd)

27.  Granidiorite -- Amesbury long barrow 39

28.  Quartz diorite -- ditto

29.  Hornblende diorite -- ditto

30  Flinty rhyolite -- fragments from Pont Saeson

31.  Rhyolite fragments -- with titanite-albite intergrowths (source unknown)

More on small glaciers

As part of my ongoing attempt to spread knowledge about glaciers, and how they behave, here are two fantastic images from Google Earth.  The one below shows an amazing and near-perfect cwm or cirque (or corrie, if you insist on English) on the north-facing edge of a basalt plateau neat Isafjordur, NW Iceland.  Click on it and you can even see the little moraine that shows the glacier terminus position -- probably during the Younger Dryas cold episode around 10,500 years ago.

The other photo is from North Norway, and it shows a small cirque glacier (aligned broadly NE) typical of many in the uplands -- if you click on it you can see the blue ice near the snout, and even the morainic debris within the glacier.  The small glacier that occupied the cwm near Foelcwncerwyn probably looked something like this.

Monday, 8 November 2010

The Preseli Ice Cap (2)

The Preseli Ice Cap might have looked something like this -- this is Drangajokull in NW Iceland.  Click to enlarge.  This ice cap is very thin and rather inactive today -- in many places you can see the bedrock coming through the ice surface.  With climate warming, it's wasting very rapidly, and may be gone within decades.  There is one major difference with the Preseli Ice Cap -- this one has had a number of quite substantial outlet glaciers which have been capable of dramatic glacial erosion -- in particular Kaldalon, which runs down towards the bottom left corner of the photo. Ah -- happy days -- I was there in 1960.  My first serious encounter with a glacial landscape.

The Preseli Ice Cap

 The only cwm on the Preseli uplands, eroded over many glacial episodes by a small cirque glacier.

Was there a Preseli Ice Cap during the Ice Age?  Almost certainly, yes -- on a number of occasions, at the beginning and end of each glacial episode.  This is exactly what we would expect in a location some way removed from the main ice centres but which would probably have had adequate precipitation to create a permanent thin ice cover while the big ice caps were waxing and waning over the Cambrian Mountains, over Ireland and in the Irish Sea area.  I got thinking about this from having a glimpse of the latest computer models of the Devensian glacial episode, from Aberystwyth University. 

The only trace of a moraine which can be termed "local" is in the cwm to the east of Foelcwmcerwyn, the highest summit on Preseli -- at 536 m.  There is a rather indistinct ridge made of till, down in the valley beneath the old slate quarry and dissected by stream action.  I have always thought that this feature dates from the last small glacier on Preseli -- tucked away on the shady lee side of the summit, where snow could accumulate and survive and be converted into ice.  The glacier will have been a small cirque glacier, capable of a modest amount of erosion.  When?  Probably Younger Dryas or Zone 3, when there were also small glaciers in many of the Welsh uplands.  But prior to that, the glacier will have existed in exactly this spot many times before, in earlier glaciations.

When the Preseli ridge was covered by its little ice cap, I don't think it was ever active enough to affect the landscape through the carving of erosional features, or through the transport of eroded debris downslope.  In other words, there may not have been sufficient ice thickness for the ice to FLOW (except in the cwm) -- it may have remained frozen to its bed, and may therefore have had a largely protective role.

The Stonehenge bluestone sources -- 24 and still counting?

Igneous outcrop at Pontsaeson near Brynberian, one of the recently identified bluestone sources

To continue:

After counting the 15 or so bluestones and fragments so far mentioned, we have abundant packing stones and mauls that are often conveniently forgotten about -- but there are massive quantities of them, some as large as 60 kg in weight.  There isn't much geology on these -- but we know that there are small sarsens, and also Jurassic oolitic limestones and glauconitic sandstone, probably from the fringes of Salisbury plain.

At least 18 rock types, and still counting.

Then we have the famous Altar Stone, probably from the Senni Beds of Carmarthenshire or Powys, and other fragments of volcanic ashes (two distinct types), Preselite (a term which is almost as vague as "bluestone")  and sandstones.

What we still don't know, until this is sorted out by the geologists, is how much repetition of rock types there is in the listing above.  The provenancing of finds from the Stonehenge Layer at Stonehenge and from the other sites near the Cursus and at "Bluestonehenge" may ADD to the list above, or some identifications may replace earlier crude identifications made without the benefit of modern techniques.  Rob Ixer, Richard Bevins and others are working on this right now, and their discovery of rocks from Pont Saeson and other sites north of the Preseli Hills is highly intriguing.

My guess is that we are now up to 24 different rock types, and still counting.  I wouldn't mind a small bet that the total number of sources will reach 30 before long.  There is no reason at all, in an assemblage of glacial erratics or in an ancient and degraded till deposit, to find even more rock types from the north and west.

Bluestone Rock Types -- 15 and counting

A short extract from "The Bluestone Enigma":

It was Herbert Thomas who speculated on a Preseli origin for the Stonehenge bluestones in 1908 and then went on to propose, in his famous 1921 lecture, that the bluestones were identical to rocks cropping out within one small area around Carn Meini. These bluestones, located within the bluestone circle and the bluestone horseshoe, comprise 43 stones, give or take a few.  The best estimate is that there are 27 spotted dolerites (including at least two that are broken in half), three unspotted dolerites, five altered volcanic ashes, five rhyolites (of which two are ignimbrites and two are lavas), two micaceous sandstones and a greenish sandstone called the Altar Stone.   The spotted dolerites are more variable than one might think;  some of them have obvious and large spots of whitish or pinkish feldspar, and others have spots that are almost too small to see with the naked eye.  The two micaceous sandstones and five volcanic ashes are just left as stumps, buried beneath the turf.

Most people believe that Herbert Thomas actually sampled the bluestones in the stone settings at Stonehenge.  He did not do that.  Instead, his work was based upon a visual examination of 34 in situ stones and an analysis of fragments and samples from assorted collections made by William Cunnington, Nevil Maskelyne and William Judd. His analytical method was called “standard transmitted light petrography” which involved a detailed examination of thin sections made from his samples.   He also looked at thin sections made from samples taken from the tors in the Preseli Hills, although it is unclear whether any of the samples were his own.  Again he seems to have depended largely upon samples collected by other geologists.   Some of the samples came from bluestone fragments found in the soil during excavations.  

So if we look at the main bluestones at Stonehenge (the standing stones or orthostats, and the stumps below ground) and ask how many localities they have come from, we immediately have problems.  This is partly to do with the variation in the dolerite and rhyolite groups -- we cannot assume that the spotted dolerites have all come from Carn Meini (it seems that Carn Goedog is a better bet if we want to look at a single locality) because there are many degrees of spottiness both within individual outcrops and within the Stonehenge bluestone assemblage.

The OU team that worked on the Stonehenge bluestones in the late 1980's concluded that out of the 39 samples they analysed, there were at least 3 distinct dolerite sources, and 7 different rhyolite sources.  Then there were also 2 micaceous sandstone sources and a number of volcanic ash sources.  That suggests about 15 sources in total -- and we are still counting.  Watch this space....... I'll put up another post shortly.

Saturday, 6 November 2010

Bothersome Bluestones

Time for a recap.  Below is a short article which I wrote for the Western Mail a few years ago.  Nothing has changed, except that the geologists have come up with a number of new sources or provenances for the "litter" of foreign stones in the Stonehenge district.  Some of the litter doesn't seem to have come from big stones at all, but from smaller fragments.  So glaciation looks more and more likely, and human transport less and less likely.

It strikes me as increasingly bizarre that the mere presence of foreign or erratic stones at Stonehenge is taken by most archaeologists as EVIDENCE of human transport and of some great purpose lying behind the use of the stones.  For me, as a geomorphologist, I take the physical presence of the stones as EVIDENCE (not PROOF -- that would be too strong a word) of glacial transport.  When people ask me where the hard evidence of glacial transport is, I say that it is right there, for them to look at -- in the assemblage of the things called "bluestones."  So then they say "No no, that's not evidence!  Find us some moraines and deposits of till, and erratics dotted all over the place!" 

Just be patient, you guys....... that's not how glaciers work.  I suspect we won't find loads of erratics or moraines, but we might well find very old till here and there, related to the ancient glacial deposits we already know about on the Somerset Levels and near Bath.

And the archaeologists, in their wild fantasies, conveniently forget that there is NO evidence of any kind in support of the human transport theory.  No quarries, no tracks, no rafts, no rollers, no boats, no lost stones.  Zilch.  Zero.  No precedents, no parallels or equivalents from anywhere else in Neolithic or Bronze Age history.  Just a blind faith in the supposedly powerful motivations and technical brilliance of our shadowy ancestors.  Oh dear oh dear.


Those Bothersome Bluestones......

The strange link between Mynydd Preseli and Stonehenge has been discussed enthusiastically by archaeologists for exactly one hundred years.  It was in 1908 that the Welsh geologist Herbert Thomas first suggested that the bluestones of Stonehenge might have originated in the uplands of Pembrokeshire, and by 1921 he had completed the research that confirmed his earlier speculation. 

One might have expected that Thomas, as a geologist, would have found a natural explanation for the transport of the stones.  It was already known that the great Irish Sea Glacier had crossed Pembrokeshire during the Ice Age, and that it had flowed up the Bristol Channel from west to east.  One or two geologists had already suggested that the bluestones were glacial erratics.  But Thomas blithely dismissed the glacial transport theory as “untenable” and went on to develop an extraordinary tale of Neolithic tribesmen collecting the stones from Preseli  and transporting them by land all the way to Salisbury Plain for incorporation into the Stonehenge monument.

In spite of the fact that Thomas’s theory had no evidence to support it, it was not questioned by other scientists, and to this day it has gone largely unchallenged.  On the contrary, it has been accepted by generations of archaeologists as fact, even though there is still not a shred of evidence to show that the great “stone collecting expedition” ever happened.  Within recent decades one or two geologists have had the temerity to argue in favour of the glacial theory, but they have been immediately vilified by the archaeology establishment.

Because the theory of human transport has never had to cope with facts (convenient or inconvenient) it has been embellished to a ludicrous degree, most recently by Professors Wainwright and Darvill, who have proposed that the bluestones were revered in Preseli for their supposed healing properties, and that this explains why they were collected and carried off to a sort of Neolithic hospital at Stonehenge.  This idea has no facts to support it either, and fellow archaeologists have accused the two learned professors of being “out with the fairies.” 

It’s time to bring this increasingly bizarre debate down to earth. Let’s look at a few facts.  The two professors have claimed that all of the bluestones have come from a small area around a spotted dolerite crag called Carn Menyn, where there was a bluestone quarry.  There is no quarry there, and the stones are now known (from work by an OU geology team) to have come from around 20 different sources scattered all over West and South Wales.  It’s claimed that the Altar Stone at Stonehenge came from Cosheston  on the shore of Milford Haven; but it’s now known that it came from  somewhere in Carmarthenshire or Powys. It’s claimed that the spotted dolerite of Preseli was revered for its magical properties;  in fact, it was never used preferentially in cromlechs or standing stone settings in Pembrokeshire or anywhere else.  The professors say that there were abundant healing springs in the area around Carn Menyn, used by local people until quite recent times;  in fact, there are no local traditions  which tell of any “special properties” in the local water supply.  We could go on and on..........

And while the archaeologists have been seeking -- with singular lack of success -- to portray their human transport fantasy as the truth, the geologists have quietly been getting on with their work.  It is now known that the Irish Sea Glacier did not simply flow up the Bristol Channel, but that it reached as far east as Street in Somerset, the Mendips and the city of Bath.  The 43 bluestones at Stonehenge can only be an assemblage of glacial erratics, left by the wasting ice somewhere to the west of Stonehenge.  New computer modelling of the Irish Sea Glacier by Dr Alun Hubbard and colleagues at Aberystwyth University shows that  at the time of its greatest extent, it probably flowed across Salisbury Plain.

Monday, 1 November 2010

Dewatering of warm-based ice

I've been looking at James Scourse's 1997 chapter in the big Stonehenge book, called "Transport of the Stonehenge Bluestones: testing the glacial hypothesis."  It's an interesting chapter designed to systematically demolish the theories of Kellaway and Thorpe et al about glaciual transport.  It's particularly interesting because the archaeological establishment has decided to accept it as THE glaciological and geomorphological assessment of the situation -- because of course it all sounds very learned, and because it suits them very well to be able to say "The best glaciological advice we have is that glacial transport of the bluestones to Stonehenge was impossible."    James Scourse himself, in the last sentence of the chapter, claims that he has "eliminated the impossible" from the debate about bluestone transport, thereby agreeing that the human transport of the stones -- however improbable -- actually happened.

As I have said before, scientists should not really use the word "impossible" because it may come back like a boomerang and hit them between the eyes.  I will return in due course to some to James's glaciology, which I think is pretty dodgy or selective (I think he puts up a number of Aunt Sallies just in order to knock them down), but for the moment I just want to think about the implications of ice close to an ice sheet margin flowing across highly permeable bedrock -- namely chalk.  I came across some discussions in the North American literature to the "dewatering" of warm-based ice when it is flowing across limestone or chalk.  This would presumably slow down or stop basal sliding and would then only permit movement by internal deformation, shearing etc.  What would the implications of this be for till emplacement and for the transport and dumping of erratics?

I'm of course aware that in Eastern England there is a lot of chalky till around, which implies that chalk was easily eroded by overriding ice and that the ice that did the eroding had plenty of basal lubrication ..........

Not sure who reads this blog, but if anybody has any thoughts on this, all comments gratefully received!