THE BOOK
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....
To order, click
HERE

Tuesday, 17 September 2013

The 2013 Rhosyfelin Dig



Many thanks to Chris for allowing this link to his new Rhosyfelin album.  Some stunning pics in there:

http://chrisjohnsonnl.smugmug.com/Rhosyfelin-2013-dig

Chris has had a long chat on the site with MPP -- and all will be revealed at the lecture in Moylgrove tomorrow evening.  It's obvious that the plan this year is to keep going down in what is considered to be the key part of the site -- beneath the big "orthostat" and towards the outer edge of the spur where last year the diggers claimed to have come across a stone hole or post pit and a possible Iron Age hearth and camping site.

From the two of Chris's photos reproduced above, it looks as if the diggers are now down into fluvio-glacial deposits or till, for there are lots of stones with rounded edges on them, and that means transport either in ice or in water.  The soil doesn't look particularly gravelly, so till might be the preferred option......  I wonder if there are any striae on the rounded and sub-rounded stones?  Note also the big quartz boulders lying about in the mixture.  We can hazard a guess that the rounded stones will all be interpreted as hammer stones or mauls, but I hope to goodness that they have had a qualified geomorphologist or two on the dig this year, so that some professional judgments can be made on what is natural and what is not. 

Clearly the intention is to find something beneath the "orthostat" (organic materials or maybe some artefact or other) which would "prove" that the big chunk of rock was not there 10,000 years ago and was put there as a result of Neolithic quarrying activity.   On the other hand, rockfalls have been going on here for a very long time, intermittently,  and even if a Neolithic skeleton is found beneath the big stone we cannot say that the removal of the stone from the rockface was a result of human intervention -- we might simply be looking at the result of an unfortunate accident........

Rumour has it that the exposed ground surface shown in the photos is dated to 3100BC -- apparently on the basis of a C14 date from last year.   I will be really interested to learn what dates have been obtained, and exactly where the organic samples have come from.

Finally, there are rumours of bits of Neolithic pottery being found somewhere on the site.  Again, hard evidence awaited.........

If necessary I'll eat my hat, but for now I have to say that everything in my photos, and all the other photos I've seen suggests that we are looking at a long-continued set of natural processes without any human intervention at all.


30 comments:

Constantinos Ragazas said...

Brian,

“Rumour has it that the exposed ground surface shown in the photos is dated to 3100BC -- apparently on the basis of a C14 date from last year.”

The question cannot be settled by just one C14 date. What about the many other dates that have not been reported?

If two samples from the same soil date one old and one more recent, which would be the more significant date? In my view the most recent. As the older samples could have gotten there by other means, like river deposits. Same is true for the C14 dates for samples from under the “orthostat”; most important would be the youngest such dates not the oldest.

Kostas

BRIAN JOHN said...

Kostas -- we need to see the full details before we start speculating.

Phil Morgan said...

Brian says
"From the two of Chris's photos reproduced above, it looks as if the diggers are now down into fluvio-glacial deposits or till, for there are lots of stones with rounded edges on them, and that means transport either in ice or in water. The soil doesn't look particularly gravelly, so till might be the preferred option...... I wonder if there are any striae on the rounded and sub-rounded stones? Note also the big quartz boulders lying about in the mixture. We can hazard a guess that the rounded stones will all be interpreted as hammer stones or mauls, but I hope to goodness that they have had a qualified geomorphologist or two on the dig this year, so that some professional judgments can be made on what is natural and what is not."

The ground surface below the large recumbent rock may well be of fluvio-glacial origin, or till, as perhaps indicated by some rounded boulders.
However, I feel it is of far greater importance that the recumbent rock, together with the other bulky rocks and associated debris displaced from the rock face, show sharp angular edges.

I would have thought this indicates that the mass of large rocks, at the foot of the rock face, has come to rest on a pre-existing fluvio-glacial/till surface, thus making the existence of stria on the rounded/sub-rounded stones, and the possible presence of quartzitic rock, of no consequence.

Nice photos Chris.

Phil M.

BRIAN JOHN said...

Not all of the local rhyolite slabs and boulders have sharp edges. If you look carefully at Chris's photos you will see that many have rounded or eroded edges. Those have got yo be explained. Did our intrepid quarrymen go around with the intent to round them off with some locally manufactured abrasives? Also, if there are striations on some of the rounded and sub-rounded boulders that at least gives us a guide to the age of the deposits beneath (and I think around the edges of) the famous orthostat. I agree that this does not help us to date the emplacement of the big stone and the rest of the superficial debris. Neither does it help us to know HOW the material fell from the rock face and the crags.

rob ixer said...

Gosh but we have come a long way from the recognition that the rhyolite with planar fabric/rhyolite with good jointing and half a dozen other rhyolites recognised from the Stonehenge debitage in 2008, their precise matching to Craig Rhosyfelin in 2010 and final recognition that the long outcrop face matched debitage EXACTLY both macroscopically and macroscopically. If only some of Chris' photos had been available a couple of years ago. All the macroscopically 'different' rhyolites (a to d) can be seen. Matching would have been easy and routine (but less exciting).
The photos do suggest that the proto-orthostat has an odd/unique orientation with respect to the outcrop/quarry face.
We're I a betting man (I am not and believe it to be a grave sin) my money would have to go with far sighted man rather than blind nature at least for the rhyolite groups a-d.
M.

BRIAN JOHN said...

Thanks Rob, for those comments. Nice pictures do not indicate precise provenance! Even if all four recognized types of foliated rhyolite are present along this rock face and in the debris beneath it, you do not have 100% sampling cover of the Rhosyfelin - Pontsaeson area, and you do not have 100% knowledge of the Rhyolitic debitage at Stonehenge. You are always limited by sampling locations and the density of sampling points. So although you can SUGGEST that some of the rock fragments at Stonehenge (or quite a lot of them from the places where excavations have taken place) are matched pretty well with the fabric of the rocks exposed on the Rhosyfelin rock face, you do NOT know how many other locations there may be in the neighbourhood from which similar rocks might have come.

That's why I have said over and again on this blog that it has not been conclusively demonstrated that anything at Stonehenge has actually come from the rock face about which there is so much excitement. Any good peer reviewer in a geological journal would make exactly this point.

The supposed "orthostat" didn't look so unusual or unique in 2011 when it was first exposed. Remember that its "uniquenness" in Chris's pictures arises largely from the fact that everything around it has been carted away, leaving it in glorious isolation!!

BRIAN JOHN said...

Rob -- to help the average punter, can you put some labels onto Chris's photos so that we can be better informed as to what these 4 types of folitaed rhyolite actually look like in the flesh, as it were?

Phil Morgan said...

Brian says :--
"So although you can SUGGEST that some of the rock fragments at Stonehenge (or quite a lot of them from the places where excavations have taken place) are matched pretty well with the fabric of the rocks exposed on the Rhosyfelin rock face, you do NOT know how many other locations there may be in the neighbourhood from which similar rocks might have come."

Surely this argument can be applied to the successful provenance of any stone at Stonehenge, or at any prehistoric structure?

The logical answer to any good peer reviewer would be, "Go forth and invest the research, the sampling effort/time, and the cost of analysis, to prove otherwise?"

Regarding the following observation :--
"The supposed "orthostat" didn't look so unusual or unique in 2011 when it was first exposed. Remember that its "uniqueness" in Chris's pictures arises largely from the fact that everything around it has been carted away, leaving it in glorious isolation!!"

However, if the uniqueness arises from the surrounding material being carted away, then it begs the question "why wasn't the large stone also removed at the same time, and by the same transport process?"

I suggest that the 'uniqueness' comes from the fact that it has not only come to rest parallel to the rock face, as opposed to the remaining large stones which are predominantly at right angles to major axis of the outcrop, but it rests beyond what can be judged as a 'reasonable' natural sliding distance, from that rock face.

Looking forward to Rob's annotation.

Constantinos Ragazas said...

Matching rhyolite fragments from the Stonehenge debitage to the Rhosyfelin outcrop does not answer the question how these fragments got to Stonehenge; if these fragments do not match any of the stones at Stonehenge.

I presume we will not stretch sensible reason on this to argue prehistoric people carried these stone fragments to Stonehenge in bucketfuls!

And what is so strange about the position of that 'proto-orthostat' lying at the bottom of the rock face? Can't massive sliding stones pivot as they slide over other lying stones?

Kostas

BRIAN JOHN said...

Phil

A good peer reviewer would simply ask "Is your conclusion supported by the evidence you have presented?" If the evidence is defective, or if the conclusion is too outrageous with respect to the hard facts, then he/she would say "Rewrite, or get more evidence, or modify your conclusions." Been there, done that many times.......

Material being carted away -- I meant carted away by the archaeologists!

The angle of the stone with respect to the rock face is not important -- a stone of this shape, if it comes from high on the crag, could roll or slide. And if there is a snowbank at the time, friction would be reduced and the stone could end up well away from the rock face.

Dave Maynard said...

Grumble, grumble... I wanted to go to MPP's talk tonight, but didn't see the additional comments about booking until I checked to see the time this afternoon. Alan Wills replied very promptly with the extra information that MPP will be talking at the Dyfed Archaeological Trust Pembrokeshire day on the 23rd of November, have to wait until then.

Good for Moylegrove to have a big turnout though, even if they are all MPP diggers.

Is there a way of reversing the order of comments so the youngest is at the top?

Dave

BRIAN JOHN said...

Dave -- I shall investigate that.....

Yes, the booking thing was not well advertised. In the event, I had 2 tickets, and if you had asked you could have had one of them! You could probably have got in anyway -- there was standing room only, but they let everybody in.

Just got back. MPP didn't stop to chat afterwards -- shot off to have a shower! Will report as fully as I can on the proceedings.

Phil Morgan said...

Hello Brian,

Without trying to be argumentative, I have some questions regarding 'Peer Review', and some observations in connection with the 'Big Stone'.

1). Peer Review.

Unfortunately, or perhaps fortunately, all my peers are now dead or in prison, but as a well meaning amateur in the world of archaeology and its associated disciplines, I find it difficult to see how peer review can be effectively applied to the problem of locating the source of stones that form prehistoric monuments.

Let us take the Stonehenge Altar Stone as an example. I understand that it has been said by those who know, that this stone probably originated in the Senni Beds of the Devonian Old Red Sandstone.

However, the Senni Beds stretch from Kidwelly in the west of Wales, to the Abergavenny area in the east, a straight line distance of some 80 kilometres; additionally, the subtle composition of the beds can change within a matter of metres, let alone over a distance of tens of kilometres.

My question ----- Is there a criteria established, for the minimum number of samples to be taken, from a minimum area of land surface, before the sampling exercise can be accepted as being representative?

Otherwise a lifetime of sampling, by a team of samplers, would effectively amount to a zero result.

2). The Big Stone.

Brian says ---

a). "The angle of the stone with respect to the rock face is not important -- a stone of this shape, if it comes from high on the crag, could roll or slide."

b). "And if there is a snowbank at the time, friction would be reduced and the stone could end up well away from the rock face."

In reverse order,

b).I agree that snow/ice would reduce the frictional resistance considerably, but are you suggesting it only snowed when the big stone moved, if not, then why didn't the other, quite large, stones slide for a similar distance?

a).Unfortunately Chris's great photos don't show the area of the crag in question, but an examination of my own, and other people's photos, show that the big rock is equal in height to the rock face alongside it, therefore, for it to have fallen from a great height to give it sufficient momentum to roll and slide, it would have to have been perched on the top of the crag like a church spire, which I feel is a stretch of the imagination.

The only other way it could have rotated during a fall from a great height, would be if it had lived on the top of the crag further up the valley where the outcrop is considerably higher. This would then involve some means of transport to its present location, whilst leaving other large rocks in-situ.

I have a photo taken during the 2013 dig, which clarifies the above problem. However, during an on-site discussion with Professor Parker Pearson, I promised that my photos would not be published on the internet. Perhaps, the embargo will be raised following the Moylgrove presentation.

Phil M.

Myris of Alexandria Alexandria Alexandria said...

Kostas unless the Rhos rhyolites are background glacial debris nobody thinks they were moved to Stonehenge as small bits in plastic buckets. Much of the debris is flaked (hence I and B's use of the term debitage). The Rhos rhyolites moved to Stonehenge as large blocks.
You must read the primary literature carefully. The Rhos debitage does not match any standing or ABOVE ground orthostat but may match one or perhaps a couple of buried orthostats that have been 'flaked'
I can only urge you to take a stiff drink (but only in moderation) and read the primary literature. Many of the papers are now FREE on line on Ixer's site - name escapes me but the academic huge site where you can download papers. Go visit and feast.
Brian .....we have been here too often I am certain were I and B and colleagues to be shown to be incorrect they will admit it. I think it unlikely as they are capable and careful of their reputations.
M

BRIAN JOHN said...

Myris -- you are being unkind to Kostas. He is perfectly justified in asking whether the rhyolite debris or debitage came to Stonehenge in leather bags or baskets as small fragments, shards or flakes, maybe because they were tradeable items on account of their colour or status or usefulness as cutting tools. You say: "The Rhos rhyolites moved to Stonehenge as large blocks." Kindly justify that statement.

Myris of Alexandria said...

May the Heavens forfend that I be cruel to Kostas.
We of the Pan-Hellenic League shall stick together against the Barbarians (however long we are waiting for them.
But.....only I have seen vast amounts of debitage, most is small, less than 15 grms in weight,(the volcanics with sub-planar texture are almost all smaller than that) and rounded slivers.
Unless the stones have an especial special meaning, or you want to pebble dash something, are you going to carry gravel to Stonehenge.
I agree there is no proof that the debitage was moved as large blocks (bet! it were though).
Google/Yahoo (wha'efer)Robert Ixer. Academia.edu and it will take you to the primary papers plus a little bonus-gem on Mons Claudianus-just up the Nile and other ramblings.
M

BRIAN JOHN said...

Sound points, Myris. So -- much of the debitage that you have examined is very small -- little bits and slivers the size of gravel fragments and up to about an inch across? So you think most of it is the destruction material that comes from chipping bits off something large -- such as a stone or a boulder or an orthostat -- with a maul or a hammerstone? Now how would you tell whether the bigger thing that was being destroyed -- or shaped -- was the size of a skull, or the size of a standing stone? Difficult, I should have thought -- so we are in the realms of speculation. Lots of options -- were some broken or snapped-off orthostats simply destroyed because they were a nuisance? Were some small erratics (too small or the wrong shape to be used in stone settings) destroyed because they were of no value and were maybe in the way? Or are we talking about small stones brought in as trading objects from Rhosyfelin (by men with blue plastic buckets) on the basis that they were good for cutting things, or simply because they were things of beauty? (The Rhosyfelin rhyolite is indeed very beautiful when fresh, as Chris's photos attest.)

Constantinos Ragazas said...

Myris,

Would reading the 'primary literature' answer the question “how the Rhosyfelin fragments got to Stonehenge”? And if you are an author to such 'primary literature' wont answering the question here be as good as reading the 'primary literature' there?

Shouldn't we expect sensible answers to this question? I agree “carried by bucketfuls” is not sensible! Never meant to be. But only meant to highlite this crucial question.

The issue CAN be resolved. By diverting some of the effort and expense from digging deeper and under the “orthostat” at Rhosyfelin to making a surgical incision to sample the suspected stones buried at Stonehenge.

And if these don't source the foliated rhyolite fragments in the Stonehenge debitage, would you then be willing to accept the only sensible explanation is these Rhosyfelin fragments got to Stonehenge by either glaciers or meltwater. As Brian (in the first instance) argues and as I (in the second instance) argue.

Its been over a year waiting for those Rhosyfelin carbon dates to be released by MPP. Is he still waiting for clearance from National Geographic as he previously claimed?

Kostas

Myris of Aexandria. said...

Kostas
Both can be done and indeed discussions about re-excavating Atkinson's trenches may be in progress. EH is a very careful body and SH its Achilles Heel.

I worry about the ability of glacial action making axe-heads and bifurcate flakes.
But if the debitage does not match any ortostat present or lost (oh weasel words) then mother nature is in with a chance.
The proto-orthostat is also an elephant in the room.

C14 dates we are all awaiting those.

No the correct and only proper place to present data is the literature.

We are but fleeting shades the literature in not just for Christmass(sic).
Read the literature do not hide behind weak excuses. Read it.

M

BRIAN JOHN said...

Kostas -- don't blame the geologists or the archaeologists about EH's paranoia about "protecting the stones." I'm sure they have been asked over and again to allow samples to be taken, but if they keep on saying "no" where do you go next? Maybe they just don't want controversies to be resolved? More beneficial in keeping interest alive is to keep the arguments going, with periodical wacky fantasies published as "groundbreaking" or "earth shattering" discoveries in the pop press......

BRIAN JOHN said...

Myris -- nobody ever said that glacial action can make axes or bifurcate flakes. All people have ever said is that glacial action can provide the raw material for human beings to play about with.

You say: "But if the debitage does not match any ortostat present or lost (oh weasel words) then mother nature is in with a chance.
The proto-orthostat is also an elephant in the room." Don't follow your logic here. You don't need to have a match between an orthostat and a pile of debitage to ague either for glacial or human transport. The match is immaterial. The debitage -- or part of it -- could well have come from a smaller rhyolite boulder that was never embedded in the ground and might indeed have been viewed as a nuisance.

With all due respect, Mother Nature is in with a chance whether or not there is an orthostat-debitage precise match. We should not be so preoccupied with bluestone orthostats. There is a lot of other foreign material at Stonehenge too, which I am not prepared to simply forget about. That stuff (in mauls, packing stones etc or simply in fragments found in the debitage or the regolith) is highly relevant.

The proto-orthostat is the elephant in the room? Not at all. It's a big stone which may or may not be in its natural position. It may or may not have been intended for use as a local standing stone. To assume that it was "intended" for Stonehenge is to take fantasy to absurd lengths. Is every other "proto-orthostat" lying around in North Pembrokeshire (there must be thousands of them, mostly made of dolerite or spotted dolerite) an elephant in the room as well?

Phil M. said...

Phil Morgan politely asks for a response to his question and comments of the 18 September 2013 22:38, please.

BRIAN JOHN said...

Phil -- sorry about that. Accuracy of provenancing? Rob can answer that much better than I can -- but sure, where there are vast areas where the same rock type is exposed at the surface, your provenancing of a particular erratic of stone in an archaeological context is going to be pretty generalised. But as you say, the more detailed the field geology is, the more the geologists seem to discover about variations in time and space withing lithologies which were assumed to be the same only 20 years ago. Not sure what Rob thinks, but it seems to met that the type of detailed petrology / field mapping that sorts these issues out is not being done by many researchers these days -- too many geologists are lured by the prospect of great riches by going into mineral prospecting or the oil industry, leaving "uninteresting" things like the Devonian beds of South Wales unexamined.

Phil M. said...

Thanks for the advice which, I suppose, brings us back to my original suggestion, that having established a very close/identical correlation with a rock formation that is remote from the stone under investigation, then the burden should be on the peers to prove the findings wrong.

Somehow, I doubt if that will be the case though.


Constantinos Ragazas said...

Brian you write,

”The match is immaterial. The debitage -- or part of it -- could well have come from a smaller rhyolite boulder that was never embedded in the ground and might indeed have been viewed as a nuisance.”

I agree matching debitage to orthostats may be immaterial. Since such match is not conclusive for either human or natural transport. But if some stone fragments in the debitage (any stone fragments, I agree) do NOT match any of the Stonehenge stones (whether buried or exposed) then only natural transport can explain this. (Perhaps this explains why MPP shows no interest in doing the science here! Everything to lose and nothing to gain in promoting his narrative explanation.)

I don't agree stone fragments in the debitage could have resulted from the breakup of nuisance boulders. I know you made this argument before and I was never convinced of your reasoning then either. If there were such nuisance boulders that stood in the way, why not push them out of the way and down the hill rather than the more difficult task of breaking these up into small fragments? After all, if prehistoric people could haul megaliths up that hill, surely they could roll megaliths down that hill. Further, there are other nuisance boulders all over Stonehenge proper. Including the Heel Stone that clearly stood in the way of the purported procession.

But I understand why you would like to suggest breakup of boulders. Since otherwise, how do you explain the concentration of foliated rhyolite fragments (and other fragments) in the debitage? Targeted gracial till within circular confines? Meltwater basin bottom, anyone?

Kostas

Myris of Alexandria said...

Brian is correct few people do the detailed field work/petrography for ordinary rocks. Petrography is a dying art in any case and I often say Apres moi etc.
Geology has greater concerns than classical provenance studies.I can indulge as I am paid by the Constantine XI Palaeologos Research Fund.
No few people do it and with my
generation's death. Nobody will or probably could.
M

BRIAN JOHN said...

That's a bit depressing, Myris. No bright young men and women coming along who are motivated by pure research in the field, just for the joy of it?

TonyH said...

Brian/Phil/Myris/Kostas

Perhaps we should ask Stephen Fry and the creators of the often informative BBC Show, Q.I.[Quite Interesting facts] to do a programme feature on Stonehenge, In Particular the Provenance of the Bluestones.

Perhaps I'll contact their Editors/Researchers, t'would make for a most lively Edition, wouldst it not? - and Mr Fry is such a bright chap.

TonyH said...

The obvious solution to this lack of Bright Young Things, men or women coming forward into the sphere of Petrology is to get the subject of Petrology onto the World Stage, by virtue of a couple of gorgeous Actors.

Brian must first write a rugged Novel set in Northern Pembrokeshire on the on-going Search for Rocks, starring, say, Angelina Jolie as the pouting Geologist Petra, and Brad Pitt as Myris of Alexandria, the Poet - Petrologist, reincarnated Apollo who talks in riddles but comes up with the goods. There will, of course, have to be walk - on parts, non- speaking, for both Brian and Indiana Parker Pearson.

BRIAN JOHN said...

Good thinking, that man! And then of course a corpse has to be found face -down in the Neolithic hearth, with an archaeological trowel between the shoulder-blades. Who could it be? What dastardly motive might have driven the murderer to such lengths? I'm working on it......