THE BOOK
Some of the ideas discussed in this blog are published in my new book called "The Stonehenge Bluestones" -- available by post and through good bookshops everywhere. Bad bookshops might not have it....
To order, click
HERE

Tuesday, 27 November 2018

Waun Mawn - clutching at straws



The so-called slight mound on which the eastern recumbent tone is supposed to rest.  There are undulations -- up and down by around 10 cm -- but this degree of surface roughness is no greater than that seen right across the site.  The "slight mound" mentioned by Dyfed Archaeology was not beneath this stone at all, but beneath the western recumbent stone which we see in the distance. 



Below I have copied in -- without any editing at all -- a commentary on MPP's talk to the National Park Archaeology Day on 17th Nov, written by a member of the audience.  I'm very grateful to him.

--------------------------------------

MPP led us through a rapid list of works in North Pembrokeshire: the Roman villa, Banc Ddu, and Dryslwyn  (should that be Pensarn?), before ending with Waun Mawn in a thrilling performance.

The Waun Mawn segment started with a reference from the RCAHMW published in 1925, from a visit to the site on 18 June 1914. Within this is the sentence “ the surface of the common is much broken up by turf cutting, which has evidently obliterated traces of further stones of the circle, though it is probable that a further examination would reveal their positions.” It is curious that there is no apparent evidence of peat extraction over this area to be seen today. MPP didn’t dwell on this subject at the time, but drew attention to HH Thomas’s discoveries in the years afterwards and how we were lucky that they had not drawn the obvious conclusion that we have with this site.

The significance of the digging on the moor did not become apparent until the end, when there was a question about this disappearance of the peat across the site. MPP said this was due to the digging mentioned in the Royal commission. I not sure there is any evidence of peat digging on the ridge, it could be possible down in the col to the south. As a reader of this blog, any digging at Waun Mawn immediately calls to mind the quarrying to south and northwest of the site. I suspect any peat here would have been extremely thin. MPP pointed out that the name means ‘peat moor’. The site is however close to the summit of the ridge, Cnwc y Hydd, or the Stag’s Knoll. How much of a tradition of peat or turf cutting was there on Preseli?

Evidence for the stone circle is not strong. MPP marked up seven (I think) stone holes excavated. Two images of holes were shown, which were very convincing, although possibly small – it is difficult to tell in the lecture. We were shown a hole for the easternmost recumbent stone, which looked very dubious, but was obviously suffering from the effect of the weather. There may well be better evidence for this. I think this was the area of ground repaired by DAT in 2007.

One interesting facet is that all the material in the holes has been sieved to retain any stone chips to be examined for petrological evidence. We may have the start of a Waun Mawn debitage thesis to match the one from Stonehenge.

A range of large stone circles were outlined – Long Meg, Ring of Brodgar, Avebury, etc. Waun Mawn may be the third largest stone circle in the British Isles. While looking at these plans it was pointed out that some of them have gaps where stones should be, so why couldn’t Waun Mawn have equivalent gaps? I have gaps in my teeth, does that make me related to a certain film actress with gaps in her teeth?

A disclosure during the talk is that the easternmost recumbent stone sits on a small mound, possibly make it more distinctive. The final slide shown had Waun Mawn superimposed on a drawing of Stonehenge phase 1. This gave the tantalising suggestion that from the centre of the supposed circle to this mound is an alignment to the Midsummer sunrise as happens at Stonehenge. The conclusion was that more digging was needed next year.

There was no mention of where the stones went, or of other such similar matters. The audience were not looking for this aspect of the story. The site location slides happened to show Rhosyfelin, Carn Goedog and curiously, Cerrig y Marchogion along with the other sites, but they were only mentioned in passing, if at all. The synchronicity of events in radiocarbon years after 3000 BC was pointed out several times. There does seem to be a lot of activity around this time. It would be interesting to look at an analysis of radiocarbon dates of the region now that there are starting to be large numbers of them.

Top marks for an interesting, well presented talk that ran through all the various sites and episodes in North Pembrokeshire. it will be very interesting to look at the detail in the specialist studies as they come out.

----------------------------------------------

So yet another bravura performance from our old friend MPP, in front of an audience not particularly inclined to question anything.  One has to admire him for sheer brass.......... and so the hoax rolls on, getting ever more elaborate.

Just a few points:

1.  The comment from RCAHMW about peat cutting is, I think, nonsensical.  For a start, there are no traces of peat cutting here, because this is not a blanket bog area.  As NRW and the National Park have noted, this is an area of dry heath, and the soil horizon here is just the same as the soil horizon in many other parts of Preseli where the slope is quite steep and where there is good surface drainage.  I have published some images showing what it is like.  Secondly, if there had been peat cutting here (in other words, if the surface had been lowered), it would not have obliterated traces of any ancient stone circle -- it would have made them more obvious.  (There are some signs of peat cuttings on Preseli, especially near Foelcwmcerwyn -- and they are pretty obvious to anybody who walks over them.)  It may be that some of the quarrying traces on Waun Mawn and Cnwc yr Hydd were mistaken for peat cuttings, by people who did not examine them properly.

2.  Agree that the evidence of stone sockets is not very strong.  In fact, it's downright lousy.

3.  I imagine that as we speak, Rob Ixer will be ploughing through a bag of fragments collected from the site.  He will be searching desperately for fragments of foliated rhyolite and spotted dolerite -- both of which seemed to me -- on the basis of a superficial examination -- to be missing.

4.  The significance of gaps in a stone circle?  What is the point MPP is trying to make here?  Again, we see the complete commitment to the idea that there was a circle here -- but if truth be told, there is no evidence and he's just joking......

5.  Eastern recumbent stone on a small mound?  MPP has got this all wrong.  The recumbent stone recorded by Dyfed Archaeology as being on a slight mound was the western recumbent stone, not the eastern one. See this document:

https://archwilio.org.uk/arch/query/page.php?watprn=DAT1567

Groom,P , 2006 , Erosion Control Works at Waun Maun Standing Stones SAM Pe124

That mound is in any case too small to be noticed by anybody who does not have the eye of faith.    There is no discernible mound at the position of the eastern recumbent stone.

6.  Does the imaginary mound at Waun Mawn lie in exactly the compass position, from the proposed circle centre-point,  of the Midsummer sunrise on the Stonehenge horizon?  As we all know, the precise position of the midsummer sunrise (and any other sunrise, for that matter) varies from place to place, depending on the nature of the far horizon -- hills or plain, near or far........  To suggest that the builders of any stone circle at Waun Mawn knew the precise compass direction of the Stonehenge midsummer sunrise and then replicated it here by making a nice mound (which happens to be invisible today) strays so far into Robin Heath territory that I think we might be wise to forget about it.  The superimposing of one carefully drawn map on another carefully drawn map is as old as the hills, an old conjuring trick designed to cause gasps of delight in a gullible audience........

7.  More digging needed next year?  OMG -- will this nonsense never stop?

8.  Synchroneity of radiocarbon dates around 3,000 BC?  The coincidence of some dates around this time is completely meaningless without secure archaeological contexts, and these are completely lacking.  Also, we  have no control sites to work with -- so the density of dates at Rhosyfelin and Carn Goedog, and their distribution through time, may be no different from the situation pertaining at innumerable other sites in a landscape that was occupied in Neolithic and Bronze Age times.

---------------

So there we are then.  We are not an inch further forward, except that the story has become ever more elaborate and has strayed even further into the world of fantasy.  As our intrepid reporter says, we look forward to the specialist studies more in hope than expectation.


Monday, 26 November 2018

Fluvioglacial gravels exposed at Picton Point

About a year ago I did a post on the glacial deposits around Picton Point, at the junction between the two Cleddau Rivers.  I was intrigued then and am even more intrigued now, having been there for another visit a couple of days ago.

https://brian-mountainman.blogspot.com/2017/11/picton-point-old-glacial-deposits.html

What was particularly interesting in 2017 was the high concentration of rounded and sub-rounded pebbles and cobbles on the foreshore to the west of the headland.  I assumed that there were fluvioglacial gravels in the neighbourhood, and this was confirmed by the geological map, as seen in the BGS online Geology Viewer.

The junction of the two Cleddau Rivers at Picton Point.  Key to the sediments:  blue = till; pink = fluvioglacial gravels; yellow = silt and clay on the modern intertidal mudflats.


Recently there has been a small landslip on the drift cliff about 50m west of the headland.  The cliff is about 15m high, and is much overgrown, but there is a new exposure that shows at least 2m of fluvioglacial gravels overlying brecciated or broken bedrock of shales and mudstones.  The lower metre or so of the gravels are iron-stained, but above that they appear fresh and uncemented.

 The lower part of the exposure.  At the base, unstained brecciated bedrock debris.  Above that, c 40 cm of iron-stained slope breccia grading up into c 1m of iron-stained fluvioglacial cobbles, 
sands and gravels.

The upper 1m of fluvioglacial materials, loose and unstained, incorporating a wide range of erratics.  Some of the cobbles are up to skull size.


From a cursory examination, the erratics incorporate a wide range of dolerites, rhyolites and volcanic rocks similar to those found on Ramsey Island  and the western end of the Dewisland Peninsula.  This matches observations made on the foreshore last year.

The deposits here may even be thicker than 2m -- the uppermost 5m of the cliff face has a gentle slope and is covered with thick vegetation.  The gravels are exposed at the surface in the fields inland of the cliff -- so the thickness may be c 7m.  Apart from the iron-staining at the base, these deposits look fresher and less weathered (one might even say less rotten) than the gravels at Llangolman:


I have on many occasions discussed the spreads of till and fluvioglacial materials here and there on the south Pembrokeshire land surface, well to the south of the putative Devensian ice limit.  Here they look remarkably fresh, and because they are uncemented in an environment in which there is much free iron and manganese in the groundwater, I am tempted to say that they are Devensian in age.  But since the gravels are in a sheet extending up to 25m above the river level, that would mean that glacier ice must have been present across the whole of the landscape hereabouts. That in turn means that the ice extended at least 10 km inland from the shores of St Bride's Bay.  And that in turn suggests that the other glacial and fluvioglacial deposits in South Pembrokeshire might also be Devensian rather than Anglian or Wolstonian in age.  Very confusing.........

One idea that has been discussed in the past is that the till deposits of South Pembrokeshire are of Anglian age, but that some of the fluvioglacial deposits were emplaced by heavily-charged meltwater rivers flowing southwards from the Devensian ice edge when ice wastage set in -- maybe after 20,000 years ago.  As noted elsewhere on this blog, it is reasonably proposed that  much of the water carried in the Gwaun-Jordanston  meltwater channel system was carried westwards and then southwards, flowing through the Trefgarn Gorge and then along the Western Cleddau valley past Haverfordwest and into the inner reaches of the Daugleddau.   There are large expanses of gravels in the valley, including some that look like gravel terraces which were partly removed as the river level dropped.  There is one such gravel terrace remnant at Cherry Grove in Haverfordwest, less than 100m from where I grew up.  

But could the Picton Point gravels belong to this same system of Devensian gravel terraces?  I doubt that very much.  For a start, there do not seem to be long strips of gravels parallel with the course of the present river.  Second, the gravels here seem to be at too high an altitude.  And thirdly, there are far too many large -- skull-sized -- cobbles and boulders in the gravels, had they originated up to 20 km away in the western foothills of Preseli.  Contained clasts of this size must indicate an origin not far away -- and that means ice in the neighbourhood, within a km or two.

I am very puzzled indeed.......










Thursday, 22 November 2018

Holgar and the bluestone voyage

The 14-man crew at work (12 paddlers) on their epic voyage......

The other evening I gave a talk at Verwig and was happy to meet Nick Newland, who was heavily involved in the building of the Holgar and in the voyage filmed in August 2012 by the Discovery TV Channel.  We had a chat about it, and Nick promised to send me the only material ever written about the boat and the voyage -- it was published in a boatbuilding magazine but has never, apparently, been put online.

I wrote a previous report here:
https://brian-mountainman.blogspot.com/2012/10/latest-discovery-channel-spectacular.html

Much of the article is on the technical aspects of building Holgar, modelled quite closely on the Ferriby Bronze Age boat -- which must have been built at least a thousand years later than any boats that might have carried bluestones from Pembrokeshire to the other side of the Bristol Channel.

Although the boatbuilders tried to be as authentic as possible in the boatbuilding methods used for this "lashed planking" vessel, there were all sorts of ways in which modern methods were substituted for ancient ones.  For a start, the planks were smooth and the cuts were as accurate as modern methods would allow -- within a millimetre or so.  The main planks running the full length of the boat (42 feet long)  were not made with rough oak or yew, but with three laminations of Douglas fir glued with epoxy resin.  Laminated strips were also cut on jigs and then glued up and used for the main frames.  Plywood formers were used, and modern fixes had to be used to achieve the bow and stern curves.  The overlapping joints between touching planks were cut with modern saws.   All of the holes for the lashings that held the planks together were made with modern drills.  The lashings were made from artificial fibres.   Screws were used to hold things together while glueing was in process, and then removed when the glue had set. Caulking was done with a natural moss, but it was inserted with a modern "caulking iron."  Many other technical details are given in the article, but the conclusion is inescapable that Holgar was vastly more sophisticated and more seaworthy than anything that could have been made in the Bronze Age, let alone the Neolithic.........  And if anybody tries to tell you that the Holgar project demonstrated that a boat like this could have carried one bluestone or lots of them, it did nothing of the sort.  It simply showed that this particular "imitation" boat, built with the use of a wide range of modern materials and methods, was capable of carrying a single bluestone monolith weighing about a tonne.



The loading of the bluestone onto the boat was done quite smartly, involving a strange ramp-like structure made of logs lashed together and positioned between the tide marks at Gwbert in the Teifi Estuary.  The idea was that the stone would be put into position on a cradle on the beach at low water, lifted up with the aid of a "rolling log" on top of the structure, and then let down onto the bottom of the Holgar when it was manoevred into position on a rising tide.  Then the  ropes would all be released, and the boat with the stone on board would be allowed to float free.  In reality, on the day when the stone was supposed to be loaded, there was a Force 6 gale blowing, and a certain degree of technical interference was needed before the stone was properly positioned on the boat. The author of the article does not go into detail on that, but let's assume that the use of a JCB might have been deemed unsporting........



Then we come to the voyage, which was flagged up at the time as demonstrating that a bluestone could be carried by a Neolithic boat all the way from the North Pembrokeshire coast to Stonehenge.    In reality, the Pembrokeshire coast was not tackled at all.  The boat with its bluestone on board was taken by road to Loughor  and then paddled most of the way from there to Burry Port -- with safety boats in attendance and with a tow being provided when the 12 paddlers found that they could make no headway against the tide.  Then the boat went back onto the lorry again for the journey to Barry, where it restarted its voyage to Cardiff Bay.  There was a further weather delay, and the boat was lifted out of the water for assorted repairs and for the replacement of caulking. The voyage was then resumed, and the crossing was made to Portishead on the other side of the Severn Estuary. Once again there was a tow, across the central part of the channel, so as to avoid any interference with commercial shipping..........  The paddlers then took the boat to Avonmouth and up the river on a flood tide to the Clifton Suspension Bridge and on into Bristol Harbour.  The final leg of the journey took the boat upriver, struggling against a powerful river in flood, as far as Keynsham.  There the journey was abandoned, and the Holgar let the river carry it back to Bristol Harbour.

All in all, this was an interesting piece of experimental archaeology.  But there were so many modern technical fixes in the boatbuilding, and interventions (relating to weather and tides) during the "bluestone voyage" itself, that in my mind, just as in the "Millennium Stone" fiasco, the conclusion has to be that sea transport of large bluestones, even in the Bronze Age, would have been well nigh impossible.


Postscript

Here is a description of the building of the other "Ferriby replica" -- called "Morgawr" and built by a large team in Falmouth.  Here the methods used were more authentic, but not totally so -- and there were episodes during which the temptation to use modern technology proved too much............

This boat was rather leaky and cumbersome, by the sound of it.   I think the conclusion must be that the Ferriby boats were probably used for sculling about in shallow coastal waters and maybe on rivers and lakes and in marshy areas, where the boats could be grounded quite easily for baling out and for repairs.

https://onlinelibrary.wiley.com/doi/full/10.1111/1095-9270.12058

Video

https://www.youtube.com/watch?v=22chM3wYrk0








Monday, 19 November 2018

Waun Mawn is a Scheduled Ancient Monument




Photos from 2006 (DAT/ Cadw) and from 2018 showing the recumbent stone supposedly associated with a "slight earth mound."

Thanks to Dave for drawing this to my attention.

https://archwilio.org.uk/arch/query/page.php?watprn=DAT1567

Groom, P.  2006  Erosion Control Works at Waun Maun Standing Stones SAM Pe124

I had assumed that Waun Mawn was not a Scheduled Ancient Monument, but it appears that it is!  The number is SAM Pe124.  That means that Cadw must have had some involvement in the consent and monitoring process for the digs on the site in 2017 and 2018.  I shall try to find out what the consent process was (and is) and ask them what they thought of the state of the site when the diggers departed.......

I am also intrigued that some remedial works were undertaken by Cadw in conjunction with the National Park back in 2006 -- involving the laying down of black fabric in "erosion hollows" and infilling with stones and soil and turf taken from a little distance away.  The details of the work are given in the PDF mentioned above.  

Its clear from the Cadw documentation that  Dyfed Archaeological Trust was not very attracted by the idea that there are the remains of a stone circle here.  The only point of potential archaeological interest is the mention of  "a slight mound" in conjunction with their stone 3 (which I have labelled as "stone 1" in my earlier posts).

I have walked across this site many times without seeing any mound at all, and all we can see on close examination is a slight rise in the turf surface on one flank of the stone.  The surface is maybe 10 cm higher than the surface a couple of metres away, and this scale of variation or undulation is insignificant in an area where the ground surface undulates everywhere.  Where there are big erratics lying on the ground surface (or even fallen standing stones) the ground is protected to some degree from ongoing erosion, so I think this is not a matter worth commenting further on.  Neither Cadw nor Dyfed Archaeological Trust personnel thought the matter worth commenting on either.

Sunday, 18 November 2018

Ceibwr and Witches Cauldron -- unconsolidated clifftop till

Dessicated Irish Sea till on the clifftop near Ceibwr.  This is a massive till with a clay-rich matrix -- presumably made from dredged sea floor deposits from Cardigan Bay.   Here the till is at least 2m thick.  

On the clifftops between Ceibwr and Witches Cauldron, on the coast between Newport and St Dogmaels, there are many exposures of till, sometimes with a gravelly matrix and sometimes clay-rich as in the classic Irish Sea till found at Gwbert and Newport.  These exposures are found at an altitude of 75m; further to the SW they occur on clifftops that are 150m high -- so we can be sure that the ice that came in from the north and north-west during the last glacial episode surmounted these cliffs along the whole of the North Pembrokeshire coastline.    We knew that already, but confirmations are always good........

https://brian-mountainman.blogspot.com/search?q=+Ceibwr

https://brian-mountainman.blogspot.com/2015/12/ceibwr-three-meltwater-channel.html

Another exposure of matrix-supported till -- the matrix is mostly silt and sand, maybe derived from older sandloess and other coastal deposits.  The reddish iron-staining  may be post-depositional, or maybe inherited from the colour of the over-ridden deposits.    Above the till is a slope deposit  which is organic-rich and with occasional signs of stratification; some layers contain small fragments of shale breccia, and oitheres appear to be made of colluvium.

Stony till (lower 50 cms) made for the most part of brecciated bedrock fragments, overlain by c 50 cms of brecciated slope deposits made of local shales and sandstones.

Another patch of coarse till adjacent to the coast path.  Beneath the till there are slope deposits that appear to have been churned in a permafrost environment.

A patch of stony till packed with erratics, in an inaccessible clifftop location near Witches Cauldron.  Here the till is c 1m thick.

The stratigraphic relationships between the till and other deposits are exactly the same as in other North Pembrokeshire exposures.  There are brecciated slope deposits (head) beneath the till in places, where the coastal slope is adequate for the downslope mobilisation of weathered and frost-shattered bedrock.  There are thin brecciated materials above the till as well, grading upwards in colluvium, sandloess and modern soil.

There is no reason to doubt that all of these deposits date from the Devensian glacial episode and from the Holocene.

However, there are also older materials to be found hereabouts, as I shall explain in another post.







Monday, 12 November 2018

The bluestone quarries -- the best hoax since Piltdown Man?

Rhosyfelin.  Does anybody else see a loading platform and a revetment here?  No?  Neither do I.


Carn Goedog.  Does anybody else see a stone-filled ditch, a platform and a pillar extraction point when they look closely?  No?  Neither do I.

Rhosyfelin.  Does anybody else see the "exact extraction point" from which a bluestone monolith pillar has been extracted?  No?  Neither do I.

Carn Goedog.  Does anybody else see evidence of a Neolithic quarry from which bluestone monoliths have been extracted?  No?  Neither do I.


Rhosyfelin.  Does anybody else see a quarrying forecourt and working surface here?  
No?  Neither do I.

((I have another 20 or 30 photos showing natural features interpreted as having "engineering significance"  -- you'll find them in other posts on this blog.   I have resisted the temptation to put them all in here, since you would simply get bored..........))

The Art of the Scientific Hoax

I have done various posts on hoaxes before, including the following:

https://brian-mountainman.blogspot.com/2018/04/the-bluestone-quarries-great.html

Anyway, having observed the antics of various archaeologists (and geologists) over the last eight years, I am now completely convinced that the claimed “discovery” of Neolithic bluestone quarries in Wales is the most imaginative and professional hoax since Charles Dawson “discovered” Piltdown Man in 1912. (1)  What is possibly most impressive about it is that it has been built up systematically now over a period of eight years without any of the conspirators spilling the beans.........

Charles Dawson (sitting) at the site of his "earth-shattering" discovery........


It's a pity that scientific hoaxes have gone out of fashion, since they cause much embarrassment to the experts who are fooled by them and much innocent amusement for everybody else. Mind you, they don't do much for the reputations of the perpetrators -- although, if you are lucky, like Charles Dawson, you might be dead before you get rumbled.

As followers of this blog will know, year after year I have conducted — in all seriousness — a forensic examination of all of the evidence placed into the public domain by the archaeologists who claim that there are bluestone monolith quarries at Rhosyfelin and Carn Goedog in the Preseli uplands of Pembrokeshire; and time and again I find that the evidence just does not withstand even superficial scrutiny (2). So I'm sure that the archaeologists, led by Professor Mike Parker Pearson of University College London, have pulled a fast one and have joyfully fooled the media, the public and a large part of the archaeological establishment.

For a scientific hoax to be successful, it requires three preconditions:

1. A gullible public predisposed to believe in “new discoveries” — in this case, stories about the great skills of our prehistoric ancestors and the meaning of Stonehenge.

2. A colourful and swashbuckling lead character who has a respectable past and a strong media presence.

3. A body of “evidence” cited in support of the hoax which cannot be checked or replicated by anybody else.

All three preconditions are amply fulfilled in this case. In these days of alternative facts and false news, almost anything will grab the attention of the public.  The mere use of the word "Stonehenge" in a press release guarantees wide media coverage.  MPP is a popular figure who has been called the “Indiana Jones” of British archaeology, with a reputation for an endless stream of controversial theories. As far as I am aware, there was no independent scrutiny or peer review of the dig sites at Rhosyfelin and Carn Goedog while MPP and his team were at work between 2011 and 2016.   And the excavations have now been filled in, so that nobody can go back to them to check the cited “evidence”.  Wonderful!  That's a perfect scenario for a successful hoax……….

There has been extensive media coverage of the “bluestone quarries” since 2011, and this has ensured a considerable flow of research funding to finance eight digging seasons at the “quarrying” sites and elsewhere, as the archaeologists claim to be hunting for “proto-Stonehenge” in the North Pembrokeshire landscape.  Interestingly enough, the breathless and uncritical coverage has come not just in the tabloid press but also in popular archaeological and historical magazines.  Even science journals which -- presumably -- have some respect for the scientific method, have been swept along in the torrent of fake news coming from the digging team and their university press offices.

https://www.manchester.ac.uk/discover/news/stonehenge-bluestone-quarries-confirmed-140-miles-away-in-wales/
https://www.telegraph.co.uk/science/2016/06/05/original-stonehenge-was-dismantled-in-wales-and-moved-to-wiltshi/
https://www.dailymail.co.uk/sciencetech/article-6018799/Ancient-WELSHMEN-helped-build-Stonehenge-5-000-years-ago-using-vast-bluestones.html
https://www.archaeology.org/issues/208-1603/trenches/4162-trenches-wales-stonehenge-bluestones
https://www.pourlascience.fr/sd/archeologie/lorigine-de-certaines-pierres-de-stonehenge-identifiee-au-pays-de-galle-12225.php

But clues as to what was going on were picked up at an early stage. The archaeologists who started digging at Rhosyfelin in 2011 announced before they broke the turf that they were investigating a quarry — which raised a few eyebrows. (Scientists do not normally announce their results before their research has started…..) At all stages of the dig, when I examined the open excavations in the company of other geologists and geomorphologists, we became more and more certain that all of the claimed “quarrying” or engineering features were entirely natural. Three of us published two peer-reviewed papers in 2015 containing our findings, but the archaeologists refused to acknowledge the existence of the papers, and even now, three years later, they will not admit that there is a dispute going on (3).  This is not just bad manners; it is scientific malpractice.

It gets worse.  After eight years of digging, not a single field report has been published. There have only been two reviewed journal articles, the first described by a senior academic as “one of the worst papers I have ever read” and the second one equally suspect (4).  The radiocarbon dating evidence from the two excavation sites does nothing to support the idea of quarrying, and has indeed been claimed to comprehensively falsify the quarrying hypothesis (5). No earth scientists have been systematically involved on-site in the annual excavations, which means that no serious questions have been asked when features have been interpreted as man-made. There have been no “control digs” at similar sites which migh demonstrate that the “quarrying" features are distinct or unique. And finally, not one of the many sites examined thus far for traces of “proto-Stonehenge” has proved to have anything to do with the iconic monument on Salisbury Plain (6). At every setback, the archaeologists have refused to back off,  have simply made their story more elaborate, and announced their next anticipated big discovery………..

So do the archaeologists still have any credibility? No.  Has the hoax finally run out of steam? Yes.

Here is a suggestion to the six senior members of the “bluestone quarries” project.  You've been rumbled.  Come clean, and admit that you have been enjoying a jolly prank with a serious intent in the background — namely to demonstrate how easy it is to promote a hypothesis that is underpinned by zero evidence.  Job done.  You should now, with smiles on your faces,  remind the public and the media that they should not necessarily believe things simply because they are repeated over and again, with apparent conviction, by senior academics.

POSTSCRIPT

Having thought more about this, I'll add a fourth precondition needed for a successful scientific hoax:

4. The ability to suppress or "drown out" anything inconvenient that might show up the hoax for what it is.

This can be achieved by doing deals with big business or grant-giving bodies which see that there would be large negative impacts for them should the hoax be exposed.  They will help you to promote the hoax and to suppress independent scientific research and conclusions.  You can also "drown out" inconvenient expressions of concern by using your contacts to repeat the hoax in print as often as possible and to develop it bit by bit in a way that can be represented as "hypothesis confirmation."   And of course you can vilify your opponents behind the scenes and use your establishment contacts to ensure that anything they write has little chance of being published.   This is all very jolly as long as you are not concerned about scientific ethics.



NOTES

(1)
 Charles Dawson’s “Piltdown Man” hoax, perpetrated in 1912, is one of the most famous scientific hoaxes of all time. Dawson (with the aid of other persons unknown) fabricated bits of two human skulls and claimed that he had discovered, near the village of Piltdown, the “missing link” between apes and human beings. There were concerns about his “discoveries” but the hoax was not proven until 1953, many years after Dawson’s death in 1916.

(2)
https://www.academia.edu/19788792/Quaternary_Events_at_Craig_Rhosyfelin_Pembrokeshire

https://www.academia.edu/19788912/Observations_on_the_supposed_Neolithic_Bluestone_Quarry_at_Craig_Rhosyfelin_Pembrokeshire

“The Stonehenge Bluestones”, 2018, Greencroft Books, 256 pp. ISBN: 978-0905559-94-0
http://www.brianjohn.co.uk/the-new-book.html

(3)
Parker Pearson, M., Pollard, J., Richards, C. and Welham, K., 2017. The origins of Stonehenge: on the track of the bluestones. Archaeology International, 20, pp.52–57. DOI: http://doi.org/10.5334/ai.353
(4)
 Mike Parker Pearson, Richard Bevins, Rob Ixer, Joshua Pollard, Colin Richards, Kate Welham, Ben Chan, Kevan Edinborough, Derek Hamilton, Richard Macphail, Duncan Schlee, Jean-Luc Schwenninger, Ellen Simmons and Martin Smith (2015). Craig Rhos-y-felin: a Welsh bluestone megalith quarry for Stonehenge. Antiquity, 89 (348) (Dec 2015), pp 1331-1352.

"Craig Rhos-y-felin: a Welsh bluestone megalith quarry for Stonehenge", by Mike Parker Pearson, Richard Bevins, Rob Ixer, Joshua Pollard, Colin Richards, Kate Welham, Ben Chan, Kevan Edinborough, Derek Hamilton, Richard Macphail, Duncan Schlee, Jean-Luc Schwenninger, Ellen Simmons, Martin Smith
Antiquity, Volume 89, Issue 348, December 2015
https://eprints.soton.ac.uk/421631/1/Megalith_quarries_Antiquity_REVISED.pdf

(5)

(6)





Friday, 9 November 2018

CA continues its quaint quarrying promotion campaign

The so-called bluestone quarries "in focus",  according to Current Archaeology.  I thought that magnifying glasses were supposed to be used for close scrutiny, and for bringing clarity?  Instead, what we get is sychophantic and shallow journalism, no scrutiny, and most definitely no enlightenment......


Thanks to Tony and David for drawing my attention to this one:

"Moving Monoliths: new revelations from the Preseli bluestone quarries". Current Archaeology, No 345, Dec 2018, pp 52 -- 55.

New?  This is all very surprising, since there has been no new work at either Carn Goedog or Rhosyfelin, and the last publication to mention the sites was almost a year ago:

Parker Pearson, M., Pollard, J., Richards, C. and Welham, K., 2017. The origins of Stonehenge: on the track of the bluestones. Archaeology International, 20, pp.52–57. DOI: http://doi.org/10.5334/ai.353
https://brian-mountainman.blogspot.co.uk/2016/01/parker-pearson-et-al-on-carn-goedog.html

It is a sad state of affairs when a journal insists on flagging up "new revelations" when there is really nothing of any interest out there. Having now had a chance of looking at the article, it's clear that whoever wrote it has been conned.  He or she simply regurgitates material that is at least three years old, which has no more substance to it now than it did in 2015.  The author refers to all sorts of things that are supposedly "remarkable", including the "remarkable precision" of the Bevins / Ixer provenancing of individual stones to "specific rock faces."   That is wrong, as the author must know if he/she had bothered to read the literature properly. Then there is reference to "clear traces of Neolithic quarrying" -- with no mention of the fact that this is hotly disputed, with others (including myself) seeing no such traces.  The radiocarbon dating evidence, which by any independent analysis falsifies the quarrying hypothesis at Rhosyfelin, is portrayed as giving precise dates for quarrying activity.  "New revelations about how the stones were extracted and transported from the quarry sites are still emerging....."  Sorry, but there are no new revelations.  False news and sloppy journalism.

On and on it goes, with the author faithfully repeating whatever he / she has been told by MPP and his team.  It's all here -- the usual stuff about platforms, loading bays, trackways, dry stone walls and so forth........  As I have said before on this blog, this sort of stuff is typical of MPP and his team; we --  the gullible readers -- have no opportunity to see measured sections or site descriptions or to scrutinise this old-fashioned thing called  EVIDENCE.  What we get instead is a string of unsupported assertions and fantasies.  As I have said before, when I examined both of these sites I could see no evidence in support of any of these features, and had to conclude that they were all products of a desperate hunt for something of significance.  We don't even get to see the stratigraphic context of a "new" radiocarbon dated sample.  We are just expected to accept that it is important.

What is most entertaining in this article is the use of several photographs from the two digs at Rhosyfelin and Carn Goedog, purporting to demonstrate the existence of the "engineering features" which are lovingly referred to in the captions.  That was not a smart idea.  I defy any reader of the magazine to say, with hand on heart, that they can see anything in the images other than a jumble of rocks and sediments, arranged by nature without any human intervention at all.

Much is made of the discovery of something that might be a Neolithic end-scraper --  but the supposition that this might have had something to do with quarrying is nonsensical.  The reference to "a large, level platform" at Carn Goedog is frankly ridiculous -- on the photos it is neither large nor level, and when I examined in it reality, when the excavation pit was still open, I simply saw a jumble of large rocks with many different sloping surfaces which could never have facilitated the sliding and removal of pillars or anything else.

The latter part of the article consists of a string of yet more speculations and fantasies, bringing in proto-Stonehenge and Bluestonehenge for good measure.  Those are best forgotten about -- the evidence -- such as it is -- is years out of date.  On the final page of the article, there is a summary of what MPP et al wrote in the 2017 article:

Just beyond the edge of the platform we found an 11 m-long, 3 m-wide ditch. Dug to a depth of 0.4 m, its upcast was deposited on the side away from the outcrop and the ditch was then filled with large stones, creating a permanent barrier across which no monolith could be transported. The latest radiocarbon date on charcoal from this ditch indicates that it was filled-in around or after 3020–2880 BC. ..................      In summary, Carn Goedog’s main period of monolith extraction was slightly later than at Craig Rhos-y-felin, in the two or three centuries before 3000 BC. The same method was used of lowering monoliths onto a level platform, in this case built largely of large flat slabs with sediment in between them, sitting on top of the Neolithic ground surface. Unlike Craig Rhos-y-felin, no hollow way was formed by the hauling-away of monoliths, presumably because the hard ground and tough grass cover on this elevated hillside were not eroded by moving stones over the surface. The construction of a stone-filled ditch (the date of which coincides with Stage 1 at Stonehenge) as a barrier to cut off access to bluestone pillars from the outcrop, is intriguing. It may have served to prevent removal of any more of these important stones.


It's saddening to see that yet again CA is allowing itself to be a free promotional vehicle for something that just does not make any sense.  Just think about it for a moment -- why on earth would the  Carn Goedog quarrymen (just for fun, let's assume they actually existed) want to dig an 11m long ditch and fill it with big stones, just to stop people taking any more monoliths away from Carn Goedog?  When I looked, I saw no ditch, no spoil heap and no "fill" of large stones.  We are just told that they existed, and are expected to believe.  There is no evidence that the spotted dolerite from here (or anywhere else) was revered or special in any way, and if anybody had wanted to collect spotted dolerite monoliths they could have taken them from anywhere on other parts of the tor, or from the abundant assemblage of elongated erratic stones littering the local landscape.  This really is the storytelling obsession take to the extremes of absurdity.

I have seen a number of "junk science" articles in Current Archaeology before -- but I think this one really does take the biscuit.

========================

NOTE

Given the fact that Mike Parker Pearson announced, about a year ago, that it was his intention to discover a giant stone circle -- proto-Stonehenge -- at Waun Mawn in September 2018, I am 100% convinced that the editor of CA set aside space in the December 2018 issue of the mag for a huge "breaking news" article.  When it transpired in September that there was nothing of any great importance at Waun Mawn, the editor was forced to fill the vacuum with this hotch-potch of old news, dressed up as something new and exciting.  Others might agree with me that it is more exciting to sit in front of a blank wall, watching paint as it dries......

Confucius he say:  be careful what you wish for.

Was Stonehenge an art installation?




Following our discussion on whether Stonehenge was a folly -- and whether I was serious in suggesting that in a BBC interview -- here is another interesting twist.

There is due to be a conference next February between artists and archaeologists (I think it would be more useful if they were to have one between scientists and archaeologists, but that's another matter......)

Let's go back a bit:
https://brian-mountainman.blogspot.com/2010/09/more-on-stonehenge-folly.html

This is from another post in 2010:

Been engaging in a good debate on the Modern Antiquarian Forum, and thought I might share this post:
I have tried not to enter the discussion on WHAT STONEHENGE WAS FOR, but it's appealing to think of it as a puzzle, or an enigma, or a riddle, or even a folly. Maybe the builders themselves didn't know what it was for -- and there was just a powerful ruling clan who wanted to build something wacky as part of its attempt to establish its power base and to try out building techniques? Maybe they were VERY clever and knew that once it was built or partly built, for thousands of years thereafter people would expend vast amounts of energy and brain power trying to work out what the hell was going on...... and in the process invest the builders with spiritual, mathematical, astronomical and organizational skills that they never actually had. Brilliant!

Well, follies are generally built by eccentric people as a means of self-glorification. They have to have the cash and labour resources to do the job, and some handy land available, but otherwise (apart from the planning system) there's nothing much to prevent them from giving expression to their fantasies. Another feature about follies is that they are often not finished, because cash runs out, or the locals get upset about all this self-aggrandizement, and refuse to cooperate by withdrawing their labour or in other forms of sabotage. Stonehenge fits the bill precisely!

Anyway, some people have problems with the idea that Stonehenge might not have had either a practical or a ritual purpose.  There is some quite suggestive evidence to support the idea that Stonehenge was a folly, built by a power-mad cheiftain for self-glorification or else for the purpose of confusing future generations........

To repeat -- more or less -- what I said the other day:

1. Nobody can agree what Stonehenge is actually FOR. So it's an enigma -- and the whole point of creating a folly is that it should be enigmatic. Whoever had the cunning plan to build it, it obviously worked.

2. The signs are that it was never properly designed.  All that messing around with stone settings etc. Things that tend not to get finished are generally more frivolous than things that have a very serious intent -- like palaces and cathedrals etc.

3.  I read into the structure that the resources were never there to finish it -- either manpower resources or stone availability -- and that there was no clear economic imperative.

4. There was nothing like it before or after. That means it was an aberration, or a one-off. That signals folly to me.

5. All societies have their eccentrics and their peacocks who just want to show off.  It would be strange if Salisbury Plain had no prehistoric follies on it. 

In the context of the advance publicity for this artist/archaeologist symposium, Chris Catling has said
‘I think archaeologists are beginning to understand that the past cannot be interpreted solely in terms of practicalities: we will not fully enter the minds of our ancestors until we appreciate that the artistic impulse is evident in a Neolithic polished axe and an Iron Age hillfort, and that artists have in the past been the innovators, leading humans into new areas of experience’.

He is not exactly saying that "installations" like Stonehenge are not necessarily "functional" or utilitarian, and he is not exactly saying that the old enigmatic ruin might be a folly, but what he does seem to be suggesting is that our prehistoric ancestors had artistic instincts which were strong enough to influence the design of an Iron Age hill fort.  If a hill fort, why not a stone circle or a stone row, or even a cromlech?  

It's not very much of a leap from there to the suggestion that Stonehenge might itself be an art installation, designed to express something emotional, arising simply from the creative impulse......

We have of course already heard about the theory that Stonehenge was a "sounding box" or a place for giving musical performances -- if banging on big rocks with smaller bits of rock can be counted as music......

And how much distance is there creatively, between a work of art and a folly?

Southern Cardigan Bay coast -- Devensian stratigraphy

Exposure at the northern end of Whitesands Bay, with a lodgement Irish Sea till overlain by deposits suggestive of an ice wastage environment -- similar to the situation at Abermawr.


One of the more confusing sequences in Pembrokeshire -- from the Trwynhwrddyn Peninsula at the northern end of Whitesands Bay.  The two till layers were probably laid down in a single glacial episode very close to a wasting ice edge.

Parrog, Newport -- showing the classic sequence through the Devensian glacial cycle.

Gwbert, at the mouth of the Teifi estuary.  This was a classic exposure of Irish Sea till and interbedded sands and gravels -- but the exposure was completely destroyed during coastal defence works.


Llanina, near New Quay.  There is some debate in this area about tills derived from the Irish Sea Glaciet and from the Welsh Ice Cap.  This is one of the enigmatic coastal sections -- still not adequately studied.








Thursday, 8 November 2018

Cemented raised beaches in Pembrokeshire

The raised beach resting on its rock platform at Poppit in the Teifi estuary.  here the beach is stained with iron oxide and manganese oxide, and is partly cemented.


Another exposure of the raised beach at Poppit, showing a basal boulder bed and an overlying beach made of smaller cobbles.  Does this sequence represent a transgression? All the deposits are stained and partly cemented.

This Poppit section of the raised beach shows distinct layering of pebble beds and beds of sand and shingle.  Drapes of colluvium and sandrock above.  There are strong similarities here with some of the raised beach exposures on the Isles of Scilly.

Poppit — parts of the raised beach are cemented with iron and manganese oxides — up to 1.7m thick. Much lateral variation — traceable along the coast for almost 1 km. Towards E extremity, the raised beach is associated with up to 2m of stratified sands and silts, although elsewhere it is overlain by blocky lower head. Above that, Irish Sea till and thinner upper head.

Here are some notes on other important localities:


North Pembrokeshire

A small exposure of cemented raised beach is plastered against wall of a cove to E of Ogof Golchfa — 75 cm of beach pebbles, overlain by 50 cm of shingle and then 45 cm of sand. All stained and cemented with iron oxide and manganese oxide.

The raised beach exposed at the main Ogof Golchfa exposure is NOT cemented. Leach described cemented raised beach deposits here, but they are no longer visible.

See: The Pleistocene Drift Succession at Porth-Clais, Pembrokeshire. Brian John. https://www.researchgate.net/publication/231973096_The_Pleistocene_Drift_Succession_at_Porth-Clais_Pembrokeshire

At Whitesands Bay (SM733 273), south of the stream, large igneous boulders are embedded in cemented raised beach shingle and are seen resting on a low RB platform. Above that there is main head (uncemented) and then a cemented sandrock.

Cemented and stained raised beach shingle also exposed sometimes at the base of the section in Druidston Haven.

Caerbwdy — fluvioglacial deposits are seen beneath c 3m of stony local till. No raised beach seen, but could well be present.

=========================

South Pembrokeshire

Broad Haven South — calcite cemented shelly raised beach is seen on the platform, overlain by cemented lower head. Sandrock in places over that, and then more cemented head. The sandrock may be a localised patch or lense. Then we see non-cemented fresh head on top of that, and finally up to 2 m of unconsolidated blown sands and sandloess and then soil.

West Angle — a stained raised beach (50 cm) is seldom seen, but is overlain by a sandy deposit with raised beach pebbles and mixed with head. Above that, the enigmatic silt and clay series…….

On the significance of cementation

The locations of cemented till exposures in Foxhole Cove, Gower.  Are they Later Devensian in age, or much older?  (Photo:  Prof Danny McCarroll /  QRA)

Occasionally on this blog I have mulled over the significance of cemented or concreted deposits -- which might also be referred to as duricrusts, hardpans, duripans or "indurated layers".  In Pleistocene deposits they involve the solution and mobilisation of minerals in groundwater and then their later precipitation because of oxidation, supersaturation or some change in chemical or physical circumstances -- including evaporation, temperature change or infiltration.  In the UK there are two main types of cement: (a) calcite, association with the mobilisation of calcium carbonate in limestone, chalk and related rocks; and (b) iron oxide and manganese oxide cement, sometimes associated with waterlogging and soil formation processes.  In the former case, the cement is normally coloured grey or white, and in the latter the colours range from orange to foxy red through to black.

Here are four of my earlier posts:

On the cemented water-lain deposits near Ceibwr and Witches Cauldron:
https://brian-mountainman.blogspot.com/2015/10/ceibwr-connected-pot-holes.html

On the cemented till and brecciated slope deposits at Black Mixen, Lydstep:
https://brian-mountainman.blogspot.com/2018/05/lydstep-ancient-till-site-confirmed.html

On the cemented raised beach and sandrock at Broad Haven South:
https://brian-mountainman.blogspot.com/2018/04/the-raised-beach-at-broad-haven-south.html

On the cemented till at Watch-house Bay and Foxhole Cove, Gower:
https://brian-mountainman.blogspot.com/2018/11/the-glaciations-of-gower.html

My interest in this issue was triggered by the fact that the editors and contributors to the QRA Gower Field Guide in 2015 attach no significance to the fact that some of the tills described in coastal sections around the Gower coast are cemented, and others are not.  We all know that hard-pan formation can occur in quite recent deposits in what appears to be more or less random circumstances;  I have described small-scale iron and manganese oxide concretions and staining in many sediment sequences, including the Pleistocene sediment sequences at Rhosyfelin, Abermawr,  Fopston, West Angle, Llangolman and elsewhere.   Sometimes these hardened and stained layers appear to be related to old water-table positions.  But the solid cementation of varied deposits several metres thick is another matter entirely, and almost always when such cemented deposits are described in the literature there is an assumption that the cemented deposits are OLD whereas the overlying uncemented deposits are YOUNG.  That is, of course, perfectly sensible........

In many locations across SW Britain the raised beach assumed to date from the Last Interglacial is solidly cemented:

Cemented raised beach at Carn Morval, Isles of Scilly

Cemented raised beach (Gower)

Cemented raised beach (Torquay)

Cemented raised beach, Broad Haven South (Pembs)

Associated with the assumed Ipswichian raised beaches (which are admittedly not always calcite-cemented!)  there are cemented head or slope breccia deposits, sandrock and some deposits that seem to be of fluvial origin. The specialist in this area is Ian West of Southampton University:

West, I.M. 1970. Carbonate Cementation of Some Raised Beaches and Blown Sands of Great Britain. Unpublished M.Sc. Thesis, Liverpool University, 257pp.

The sandrock deposits assumed to be linked in age and environmental contexts with the raised beaches have been heavily studied. One of the more interesting recent studies is this one:

Facies analysis and diagenesis of late Pleistocene shoreline sands, Saunton, North Devon
Sophie Young
The Plymouth Student Scientist, 2012, 5, (2), 486-543

http://bcur.org/journals/index.php/TPSS/article/viewFile/356/335

Stratified sandrock (now thought to be Ipswichian beach sands, for the most part) above the famous pink erratic at Saunton sands, Devon.

A photo from 1962 of the sandrock sequence at Bloody Basin, Saunton.  A classic unconformity!

There are abundant exposures of cemented limestone breccia (lower head) in Pembrokeshire, for example on Caldey Island and at Broad Haven South and Lydstep.  At the latter location, as described on this blog, the concreted limestone breccia (which has come from rockfalls and scree accumulations) is several metres thick, and covers an extensive area at Black Mixen, even roofing over a cave.  This material cannot be stratigraphically linked with either the raised beach platform or the cemented raised beach.  But it does overlie a cemented till:

Limestone bedrock, cemented till and overlying cemented limestone breccia at Black Mixen, Lydstep

One of the first things we learn in geology is that TIME is probably the most important factor in determining which sediments are consolidated and transformed into solid rock, and which ones are not. So it has to be true that the cementation processes referred to in my first paragraph need time, and that the most solidly cemented deposits are most likely (unless we can find other explanations) to be the oldest.

We know that the Lydstep cemented till is pre-Devensian, because it is capped by thick cemented brecciated deposits, and because very close by we can see a Devensian till in a Carboniferous Limestone context which is completely fresh and uncemented.  In this case there is no other explanation that withstands scrutiny.   But what about the cemented tills on Gower?  And what about the cemented deposits at Ceibwr and Witches Cauldron?  The jury is still out........ and we need cosmogenic dating.

I have done a lot of digging around to see what there is in the literature about RATES OF CEMENTATION -- but there seems to be remarkably little research on this topic, from anywhere in the world.   Maybe I have missed crucial articles -- in which case I will appreciate comments from others who are in the know!

It also occurs to me that cave science may have some valuable pointers to what happens out in the fresh air.  There are many places in caves in the limestone districts of the UK where roof falls and collapses have dumped brecciated limestone fragments in large caves and where cementation has then occurred as time has passed.  Are there any good examples which have dates attached?

Weren't the lads who were rescued from that cave in Thailand sitting on a pile of rubble from an old roof collapse?

All advice gratefully  received........

Cave collapse breccia -- apparently uncemented and therefore young?

==============================


POSTSCRIPT

It happens all the time -- one does a post and then discovers -- too late -- all sorts of interesting material in the literature.  In this case, two articles about the conditions in which calcite cement becomes abundant in the environment, leading to the cementation of previously unconsolidated sediments.  Both of the articles cited below make the point that sea-water conditions are important on west-facing coasts, leading to variable concentrations of minerals and in turn influencing the frequency of calcium carbonate trapped in marine organisms including sea shells. There is some relationship with the sea floor geology.  But to put it crudely, the higher the concentration of shelly material in beach sand and offshore sediments, the greater the likelihood of the cementation of sediments in the neighbourhood.  That all makes good sense.  But it does not mean that the importance of the "time factor" is reduced.  After all, on a coastline such as that of Pembrokeshire or Cornwall, conditions now will be broadly similar to the conditions that obtained during previous interglacials -- and the only significant variable (apart, maybe, from temperature and salinity oscillations) will be the position of the shoreline as glacial / interglacial shifts have occurred.   It is still the case, after perusing these articles, that the most solidly cemented sediments an any given locality will be the oldest.

https://www.researchgate.net/publication/261361303

Howie, F.M.P. and Ealey, P.J. 2010. An appraisal of Quaternary calcium carbonate deposits in Cornwall. Geoscience in South-West England, 12, 233-239.
Proceedings of the Ussher Society

ABSTRACT

Cornwall’s calcium carbonate-rich deposits consist predominantly of coastal Holocene beaches, beachrock, dunes, eolianites, tufa and speleothems, offshore coastal maërl beds and late Pleistocene littoral deposits. The majority of these calcareous deposits in Cornwall, with the exception of some tufas and speleothems, were clearly not derived from within Cornwall itself but are largely the product of a regional offshore north-east Atlantic CaCO3 budget controlled by cyclical marine transgressions and regressions coupled with local climate factors operating during the Quaternary.

DISCUSSION AND CONCLUSIONS

The Late Pleistocene to Holocene sands and gravels (Evans, 1990), covering the Devonian/Carboniferous bedrock in the 30 km coastal shelf around the Cornish coast are well-mixed with carbonate skeletal material with “a high preservation potential under present conditions, despite the evidence of bioerosion, disturbance by storm waves and transport of material by currents” (Stride et al., 1999) and are undoubtedly subject to entrainment in the strong tidal pulses prevalent around the south-west UK peninsula. Farrow and Fyfe (1988) considered that much of the north-west European shelf “represents a modern-day equivalent of the ‘calcareous shale’ facies common in the geological record” with the mud fraction of Holocene sediments on the shelf containing in the region of 10–20% CaCO3 rising to over 50% CaCO3 on supratidal mud-flats. The availability of calcium and carbon would therefore tend to sustain the production of shelly biota, the remnants of which are undoubtedly subsequently deposited and recycled on a large number of beaches around the Cornish coast as high- calcium carbonate skeletal shell sands. These sediments lie adjacent to a number of beaches, many of which are composed extensively of calcareous shell sand. These are, in turn, closely associated with carbonate dune fields, beachrock, tufa and, in coastal caves, speleothems. The available evidence indicates that these sediments and deposits have developed where there appears to be no association with limestone bedrock or calcareous head and therefore may be causally interrelated.

The possible effect of a north-east Atlantic influenced carbonate cycle in operation during the Pleistocene (Marine Isotope Stage 7 and/or 5e) is suggested by the occurrence of Quaternary calcum carbonate deposits around exposed headlands along the north and west Cornwall coast and north Devon coast (West, 1973; Gilbert, 1996) where mainland limestones do not occur. In contrast, the Quaternary calcareous raised beaches, cemented sands and tufas along the south Devon and south-west coasts of Wales are associated with limestone bedrocks and carbonate-rich head deposits which may have influenced their diagenesis (West 1970, 1973).

Fossil calcareous maërl accumulations are known from sediments of Miocene to Recent age on continental shelves and are used as stratigraphic markers and indicators of palaeoenvironmental conditions (Foster, 2001). The calcareous endoskeleton of the living algae forms annual growth bands similar to tree rings which make maërl a potential palaeoclimate proxy utilising, for example, Mg/Ca ratios in the individual growth bands. Maërl deposits from north France, Norway, Scotland and Ireland have produced useful on, for example Holocene climatic changes (Freiwald et al; 1991). The palaeoclimatological potential of maërl from Cornwall has not been studied in any detail.

=====================

Carbonate cementation of some Pleistocene temperate marine sediments

IAN M. WEST
First published: May 1973

Sedimentology, Volume 20, Issue2
Pages 229-249

https://doi.org/10.1111/j.1365-3091.1973.tb02047

ABSTRACT

Carbonate cementation of some carbonate and quartz sands in three raised beaches of temperate origins was investigated. The carbonate of the cements was found to have been derived from the dissolution of skeletal debris. The sandstones, so produced, now possess only low‐magnesium calcite, but the original sediments, like adjacent modern beach and blown sands, probably contained low‐magnesium calcite, aragonite and some high‐magnesium calcite, all of skeletal origin. In meteoric water the dissolution has occurred of all carbonate within minute, tubulelike, volumes of sand. Concurrent deposition in adjacent volumes of sand of low‐magnesium calcite formed cements that are irregularly nodular or uneven on a small scale. Aragonite within the minute nodules has been replaced paramorphically by low‐magnesium calcite. Additional local carbonate cements were formed at later dates, around and within solution pipes.




Tuesday, 6 November 2018

HHT's grand day out -- and the Stonehenge greystones



I came across this in the file of ancient reprints.  It's a translation of an article written by OT Jones in 1966 -- and it describes how the  bluestones - Stonehenge connection was initially made by the geologists.

It all started on a grand day out in the summer (one presumes) of 1908,  when Thomas, Cantrill, Strahan and Jones made a jolly train expedition to Rosebush railway station, walking from there to Crymych along the Mynydd Presely ridge before taking an evening train home from Crymych railway station on the "Cardi Bach."   They obviously looked at a lot of rocks on the way.   DC Evans was obviously their guide, and I have read elsewhere of his role in supplying material later on for HHT to look at.

Between that first trip and the serious work on the bluestones in 1918, ten years elapsed, and the First World War disrupted everything.  Maybe it was the end of the war that provided the impetus.

Note that Jones, in his Welsh-language article, calls the stones "Cerrig Llwydion"  -- not bluestones but GREY STONES.