Sunday 31 December 2023

The Ups and Downs of Ice Flow

 I am told there is some confusion being spread about glaciers and ice sheets flowing uphill. Contrary to the impression some people have got they obey the simple law of gravity, they flow downhill.

But when they are constrained in a passageway either by mountains or other large amounts of ice of course the flow can rise up and over obstacles because of the pressure from the weight of the ice above. The total mass is flowing downhill even if parts of it are going up.

A simple experiment will show it how works, find a short flexible but reasonably stiff string of beads. Provided the are constrained in tube or valley they can easily be pushed over obstacles and will happily bump over ridges on their way downhill.

The key is that their lateral movement is controlled. Now consider the broad dry Bristol Channel during the last ice age, there are no mountains and, as it is at the edge of the ice sheet, no deep layers of ice to constrain any flowing ice. It will follow the downward slope. Try pushing your beads across an incline with a lip at the far edge. Down the slippery slope they will go, not deep into Somerset.


Thursday 28 December 2023

Recent Ice Dropped Boulders

Icebergs which may have dropped debris, including boulders, sailed to our latitudes in the last little ice age, it wasn't just Frost Fairs on the Thames. 


Iceberg at the western harbour head of Delfshaven on January 2, 1565 during the cold wave in the Little Ice Age - Cornelis Jacobsz van Culemborch 1565 - (The grounded iceberg was measured at more than 6 meters high and almost 70 meters long). https://museumrotterdam.nl/collectie/item/11113
 

So maybe some of those ice dropped boulders on our coasts haven't been there that long.  

As Bing imagines it.

Bristol Channel Boulders - No Ice Required

On 30 January 1607, around noon, the coasts of the Bristol Channel suffered from unexpectedly high floodings that broke the coastal defences in several places. Low-lying places in Devon, Somerset, Gloucestershire, and South Wales were flooded. The devastation was particularly severe on the Welsh side, extending from Laugharne in Carmarthenshire to above Chepstow in Monmouthshire. Cardiff was the most badly affected town, with the foundations of St Mary's Church destroyed. It is estimated that 2,000 or more people were drowned, houses and villages were swept away, an estimated 200 square miles (51,800 ha) of farmland inundated, and livestock destroyed,wrecking the local economy along the coasts of the Bristol Channel and Severn Estuary. https://en.wikipedia.org/wiki/1607_Bristol_Channel_floods


But there was another legacy of the flooding, thought to be a tsunami caused by an underwater earthquake, it moved boulders on the edges of the Bristol Channel.


A very detailed paper which explains the positioning of many Bristol Channel boulders as tsunami relics. Calling them all glacial erratics may be simply wrong.



Glacial Gradients and Gravity

There is a suggestion that the glacial gradient from South Wales to Stonehenge was sufficient for ice to flow along it:

From https://brian-mountainman.blogspot.com/

Just a reminder that during the last ice age the Bristol Channel was above sea level and was a deep wide valley. Glaciers flow downhill so rather than the ice floating up the channel and landing on the Somerset coast from south Pembrokeshire it would have followed the gradient. 



Figure based on: "Location and bathymetry of the Bristol Channel. Contours are depths in metres relative to mean sea level" from "Impact of Tidal Energy Converter (TEC) Array Operation on Sediment Dynamics" - Scientific Figure on ResearchGate. Available from: https://www.researchgate.net/figure/Location-and-bathymetry-of-the-Bristol-Channel-Contours-are-depths-in-metres-relative-to_fig4_260052339

Unpredictable weather not unprecedented again.

 A year ago The National Trust warned of the dangers of the new norm of "tumultuous weather" - https://www.nationaltrust.org.uk/services/media/weather-and-wildlife-2022 This year the National Trust is: "sounding the alarm for UK wildlife as the loss of predictable weather patterns and traditional seasonal shifts causes chaos for nature." https://www.nationaltrust.org.uk/services/media/weather-and-wildlife-2023

As a worrier myself, and as this endangers ancient sites, I was intrigued enough to quickly look to at the historical records to see if the unpredictability was unprecedented. 

My approach was to graph the difference between one year's temperature, or rainfall, record and the previous year's. 


So for instance 2022's mean temperature was 10 deg C and 2021's 10.3 so I record that as a drop of 0.3 for 2022. Obviously the larger the gains and drops the more "unpredictable" the weather is. 

Last year's post is here: https://www.sarsen.org/2022/12/is-this-years-tumultuous-weather-set-to.html and has links to data sources and results.

I have updated the data and there is no change in the pattern, the amount of unpredictability by my definition seems to be same. There doesn't seem to be any evidence that the amount of unpredictability is unprecedented or unusual so far. Against a background of rising temperatures this is good news and long may it continue.





If anyone is interested in the Data or more graphs please get in touch.

 

Sunday 24 December 2023

Debunking Pigs From Scotland

 Last year I did a round-up of the Isotope evidence for "neolithic pigs from Scotland"  - https://www.sarsen.org/2022/10/strontium-values-reappraisal-south-west.html . 

I missed another paper that came out a fortnight later:

Dr Gordon Barclay kindly pointed this out to me and so I should update the record:

The paper is open access, so please read it. The key passage is:


Key to this study is our ability to distinguish between northern and southern British Pb sources and this can be achieved because of differences in the underlying geology between these two parts of Great Britain. The Pb isotope composition of rocks and minerals tends to be dominated by major geological tectonic events such as mountain building, which is accompanied by metamorphism and the intrusion of granites, the heat from which drives the re-mobilisation of Pb to create ore deposits.

The junction between these two tectonic plates is called the Iapetus Suture and it runs on a NE–SW line from Berwick-upon-Tweed to the Solway Firth and projects into Ireland.The underlying geology to the north and south of this suture is fundamentally different; the Laurentian basement, to the north, is geologically much older (> 3000Ma–c. 1750Ma) and is depleted in uranium (U) whereas the Avalonia basement in the south is geologically much younger (c. 700Ma), and this means the Pb isotope compositions, related to the basements of the two areas, are different. As this geological boundary essentially defines the modern political border of Scotland with England, it provides a potential method of discriminating between Scotland and the rest of Great Britain.

The conclusion is quite clear, in their opinion: 

"We have tested this application using a sample of Neolithic pig enamel from sites in southern England, some of which, because of Sr isotope composition, could not be excluded from an origin in northern Britain. Pb isotope data from the teeth excludes Scotland as a source but the diverse range of Pb isotope results, combined with other isotope proxies, are consistent with the animals being raised on a variety of lithologies of diverse age and from variable environments."

So is this end of the idea of neolithic links between Scotland and Stonehenge, I wouldn't bet on it.


Thursday 21 December 2023

Laying out the Sarsen horseshoe using triangles.

From William Stukeley onwards the geometry underlying the arrangement of the stones of Stonehenge has lead to many different diagrams, usually with arcs and sometimes with triangles and hexagons.

Quick doodles based on the triangle I deduced from Tim Darvill's work: https://www.sarsen.org/2023/05/ding-dong-over-stonehenge-timekeeping.html has lead me to simple diagram which matches the geometry of the flat faces of the trilithons in the inner horseshoe. It seems different to the historical other diagrams I have seen but I would be surprised if it is new. If you know of a prior example please tell me.

Please excuse a rough diagram:


But you say; "Tim,  you endlessly witter on about the middle trilithon and the Altar Stone being at 80 degrees, rather than 90, to the central axis of the monument".

Behold, I respond, if you turn the triangle one gap rather than two it gives a 12 degree twist which is close enough for government work.

  



 

Wednesday 8 November 2023

Led Zeppelin’s missing photograph has been found.

 

The original of the iconic photograph on the cover of Led Zeppelin IV was recently discovered and will soon be on display at the Wiltshire Museum.

Visitors will for the first time be able to clearly see the face that has stared out from millions of albums across the world.


After conservation work an exhibition ‘The Wiltshire Thatcher: A Photographic Journey through Victorian Wessex’ is scheduled to open on Saturday 6th April 2024 and run through until Sunday 1st September 2024

The photograph was spotted in a Victorian album at a public auction by Brian Edwards, a Visiting Research Fellow with The Regional History Centre, UWE Bristol.

The mystery of who the figure was been solved after half a century.

He was a thatcher from Wiltshire, Lot Long (1823 -1893) from Mere.

Led Zeppelin IV

The untitled album, usually known as IV, was released on November 8, 1971, and has sold more than 37 million copies worldwide.

The album was Classic Rock’s Greatest Album of All Time - https://www.rocklistmusic.co.uk/steveparker/classicrock.htm and remains Led Zeppelin’s ‘most streamed album today.’ https://musicdatablog.com.ar/en/ranked-albums/led-zeppelin-discography-streaming/

The album’s cover artwork was radically absent of any indication of the musicians or a title but featured the iconic framed image, often been referred to as a painting, which was discovered by Robert Plant in an antique shop near Jimmy Page’s house in Pangbourne, Berkshire.

The framed colour image of an elderly man carrying a large bundle of hazel sticks on his back will be recognised worldwide. 

Closer inspection reveals this framed image was a coloured photograph, the whereabouts of which is now unknown.

The original, which is now in Wiltshire Museum, has tantalising fingerprints from it being copied using coloured inks. 



The discovery

The Victorian photograph was discovered by Brian in an auction catalogue of sale in Dorchester, an album titled ‘Reminiscences of a visit to Shaftesbury. Whitsuntide 1892. A present to Auntie from Ernest.’  Tim Daw was able to attend the auction, verified it was the genuine photo and bought it on behalf of the Museum.

 



Featuring exceptional photographs from Wiltshire, Dorset and Somerset, the Victorian photograph album contained over 100 architectural views and street scenes together with a few portraits of rural workers. Most of the photographs are titled and beneath the photograph made famous by Led Zeppelin the photographer has written ‘A Wiltshire Thatcher.

Brian Edwards said: “Led Zeppelin created the soundtrack that has accompanied me since my teenage years, so I really hope the discovery of this Victorian photograph pleases and entertains Robert, Jimmy, and John Paul.” 

A photographer named Ernest

There was no further clue to the photographer’s identity and either side of the turn of the century there were over 300 photographers named Ernest. 

The search was on for a largely unknown Victorian photographer of great talent and skill, probably with extensive training in chemistry.  

A part of a signature matching with writing in the album, suggests the needle in this haystack is Ernest Howard Farmer (1856-1944), the first head of the School of Photography at the then newly renamed Polytechnic Regent Street. Now part of the University of Westminster, Farmer had worked in the same building as the instructor of photography since 1882, when it was then known as the Polytechnic Young Men’s Christian Institute. 

The Wiltshire thatcher

About 50 thatchers were identified through trade directories and the census. In the Southwest of Wiltshire, where the other album photos were taken, only one was of a similar age to the figure in the photograph. 

This was Lot Long (sometimes Longyear), who was born in Mere in 1823 and died in 1893. At the time the photograph was taken, Lot was a widower living in a small cottage on the Shaftesbury Road in Mere. Whilst certain corroboration has not yet been found, family resemblances and circumstantial evidence support this identification.

Note on the exhibition 

David Dawson, Director of Wiltshire Museum, said: “This exhibition will be a celebration of the work of Ernest Farmer, who today is little-known but was a leading figure in the development of photography as an art form. Through the exhibition, we will show how Farmer captured the spirit of people, villages and landscapes of Wiltshire and Dorset that were so much of a contrast to his life in London. It is fascinating to see how this theme of rural and urban contrasts was developed by Led Zeppelin and became the focus for this iconic album cover 70 years later.”

Thursday 2 November 2023

The Stone Circles - A Field Guide - Coming April 2024


 

The Stone Circles

A Field Guide

Colin Richards and Vicki Cummings

Imprint: Yale University Press

The definitive guide to the stone circles of Britain and Ireland

From Stonehenge and the Ring of Brogdar to the Rollright Stones and Avebury, the British and Irish Isles are scattered with the stone circles of our prehistoric ancestors. Although there have been many theories to explain them, to this day there is no consensus about their purpose.

Colin Richards and Vicki Cummings provide a clear and illuminating field guide to 424 key stone circle sites in Britain and Ireland. Organised by region, this handy volume sets out the features of these megalithic monuments, including their landscape position, construction, and physical properties. The authors take stock of cutting-edge research and recent excavations stone circles that were previously lost to time. They present new insights on the chronology, composition, and roles of different circles to transform our understanding the sites.

Beautifully illustrated with photographs, maps, and plans, this is an essential guide to Britain and Ireland’s most mysterious prehistoric monuments.


Hardcover

9780300235982

Published: 23 April 2024

£19.99

Friday 27 October 2023

Mynydd Preseli Lidar

Click Picture to Embiggen 

The drover tracks leading up over the saddle are particularly obvious. 

 Link to explore below. (20-22 DSM works best) 

Thursday 12 October 2023

The Stonehenge Altar Stone was probably not sourced from the Old Red Sandstone of the Anglo-Welsh Basin


The Stonehenge Altar Stone was probably not sourced from the Old Red Sandstone of the Anglo-Welsh Basin: Time to broaden our geographic and stratigraphic horizons?,

Richard E. Bevins, Nick J.G. Pearce, Rob A. Ixer, Duncan Pirrie, Sergio Andò, Stephen Hillier, Peter Turner, Matthew Power,

Journal of Archaeological Science: Reports, Volume 51, 2023, 104215,

ISSN 2352-409X,

https://doi.org/10.1016/j.jasrep.2023.104215.

(https://www.sciencedirect.com/science/article/pii/S2352409X23003905)

Abstract: Stone 80, the recumbent Altar Stone, is the largest of the Stonehenge foreign “bluestones”, mainly igneous rocks forming the inner Stonehenge circle. The Altar Stone’s anomalous lithology, a sandstone of continental origin, led to the previous suggestion of a provenance from the Old Red Sandstone (ORS) of west Wales, close to where the majority of the bluestones have been sourced (viz. the Mynydd Preseli area in west Wales) some 225 km west of Stonehenge. Building upon earlier investigations we have examined new samples from the Old Red Sandstone (ORS) within the Anglo-Welsh Basin (covering south Wales, the Welsh Borderland, the West Midlands and Somerset) using traditional optical petrography but additionally portable XRF, automated SEM-EDS and Raman Spectroscopic techniques. One of the key characteristics of the Altar Stone is its unusually high Ba content (all except one of 106 analyses have Ba > 1025 ppm), reflecting high modal baryte. Of the 58 ORS samples analysed to date from the Anglo-Welsh Basin, only four show analyses where Ba exceeds 1000 ppm, similar to the lower range of the Altar Stone composition. However, because of their contrasting mineralogies, combined with data collected from new automated SEM-EDS and Raman Spectroscopic analyses these four samples must be discounted as being from the source of the Altar Stone. It now seems ever more likely that the Altar Stone was not derived from the ORS of the Anglo-Welsh Basin, and therefore it is time to broaden our horizons, both geographically and stratigraphically into northern Britain and also to consider continental sandstones of a younger age. There is no doubt that considering the Altar Stone as a ‘bluestone’ has influenced thinking regarding the long-held view to a source in Wales. We therefore propose that the Altar Stone should be ‘de-classified’ as a bluestone, breaking a link to the essentially Mynydd Preseli-derived bluestones.

Keywords: Neolithic; Stonehenge; Altar Stone; Sandstone analysis; Provenancing

Under a Creative Commons license

Monday 25 September 2023

The Altar Stone in close up

Full size photo - https://photos.app.goo.gl/fgJgkqLgdkMhzvyj9


Thought experiment: What if the Altar Stone is a later, say, Roman addition to the monument? Is there anything that proves it isn't? If it was what would we expect it to be like? How could we tell? Where might they have brought it from?

The answer is probably where would we expect to find debitage from it and it seems it was found deeper than we we would expect from such a late introduction to the site.


Saturday 23 September 2023

The Altar Stone - Not welsh, so where is it from?

An important paper on the Stonehenge Altar Stone has just been released:

It probably didn't come from South Wales and surrounding areas.

Its petrographic fingerprint which includes a diagnostic high Barium (Ba) content mostly doesn't match the Old Red Sandstones (ORS) of the area, and the ORS rocks there that also have a high Ba don't match other characteristics. 

The hunt for the source is on.  Suitable areas that also have neolithic sites are the top suspects.


AlexD, CC BY-SA 3.0, via Wikimedia Commons - Old Red Sandstone is coloured Brown 



The paper: - Open Access.

The Stonehenge Altar Stone was probably not sourced from the Old Red Sandstone of the Anglo-Welsh Basin: Time to broaden our geographic and stratigraphic horizons?

Abstract

Stone 80, the recumbent Altar Stone, is the largest of the Stonehenge foreign “bluestones”, mainly igneous rocks forming the inner Stonehenge circle. The Altar Stone’s anomalous lithology, a sandstone of continental origin, led to the previous suggestion of a provenance from the Old Red Sandstone (ORS) of west Wales, close to where the majority of the bluestones have been sourced (viz. the Mynydd Preseli area in west Wales) some 225 km west of Stonehenge. Building upon earlier investigations we have examined new samples from the Old Red Sandstone (ORS) within the Anglo-Welsh Basin (covering south Wales, the Welsh Borderland, the West Midlands and Somerset) using traditional optical petrography but additionally portable XRF, automated SEM-EDS and Raman Spectroscopic techniques. One of the key characteristics of the Altar Stone is its unusually high Ba content (all except one of 106 analyses have Ba > 1025 ppm), reflecting high modal baryte. Of the 58 ORS samples analysed to date from the Anglo-Welsh Basin, only four show analyses where Ba exceeds 1000 ppm, similar to the lower range of the Altar Stone composition. However, because of their contrasting mineralogies, combined with data collected from new automated SEM-EDS and Raman Spectroscopic analyses these four samples must be discounted as being from the source of the Altar Stone. It now seems ever more likely that the Altar Stone was not derived from the ORS of the Anglo-Welsh Basin, and therefore it is time to broaden our horizons, both geographically and stratigraphically into northern Britain and also to consider continental sandstones of a younger age. There is no doubt that considering the Altar Stone as a ‘bluestone’ has influenced thinking regarding the long-held view to a source in Wales. We therefore propose that the Altar Stone should be ‘de-classified’ as a bluestone, breaking a link to the essentially Mynydd Preseli-derived bluestones.

Richard E. Bevins, Nick J.G. Pearce, Rob A. Ixer, Duncan Pirrie, Sergio Andò, Stephen Hillier, Peter Turner, Matthew Power,

Journal of Archaeological Science: Reports, Volume 51, 2023, 104215,ISSN 2352-409X,

https://doi.org/10.1016/j.jasrep.2023.104215

(https://www.sciencedirect.com/science/article/pii/S2352409X23003905)

Friday 22 September 2023

Ground Penetrating Bayonet

Before modern gizmos were invented the usual way to locate buried stones was to prod the ground with a bayonet, Alexander Thom amongst others was a keen proponent of the method into the 1960s.

So it is fascinating to spot a bayonet in among the tools of Atkinson's 1958 excavations at Stonehenge.


 It appears to be an Enfield Socket Bayonet fitted with a handle - or something similar.

I note English Heritage sell replica bayonets - https://www.english-heritageshop.org.uk/british-enfield-rifle-bayonet - "This type of bayonet was manufactured in England from 1853 to around 1870 and saw service until about 1875. It was designed to fit the Enfield 1853 Pattern Musket (also known as the P53 Enfield). It saw service in the Crimean War, American Civil War, New Zealand Land Wars and the Indian Mutiny. It is a typically British design in that it has a blade “shoulder” and is shallow fullered."

Though I doubt they would approve of their use at Stonehenge now.

 


From: https://historicengland.org.uk/images-books/photos/item/P50851 
Excavations between fallen Trilithon upright stone 55 which broke into two pieces. 1958. 

Thursday 21 September 2023

The underside of stone 55B - 1958

The underside of stone 55B as it is lifted from its fallen position. An unreported stone lift.

Wednesday 20 September 2023

1958 Excavation Of Altar Stone, Stone 80

https://historicengland.org.uk/images-books/photos/item/P51908 Photographer: Atkinson, R J

Craig Rhos-y-felin Bullet Stones

The rhyolite boulder collected by R. S. Newall in 1924 from an excavation at Stonehenge which has been discussed before at length - https://www.sarsen.org/2023/07/the-erratic-that-came-in-from-cold.html - has an appealing "bullet" shape.

The pillars at Craig Rhos-y-felin, where the boulder has been petrographically matched to, tend to have these rounded tips and the excavations there revealed many such bullet shaped tips that have broken off. These boulders still at the quarry obviously haven't been transported anywhere and so the bullet shape of the boulder "is a tale... signifying nothing.” 


Photo by Adam Stanford - annotated by me


Photo by Mike Parker-Pearson with "Newall's Boulder" floated in by me. 

Photos of quarry from, and more information available at :

Craig Rhos-y-felin: a Welsh bluestone megalith quarry for Stonehenge 

Published online by Cambridge University Press: 07 December 2015 

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

Craig Rhos-y-felin 2014 - 2023

Click  any photo to embiggen A few photos from my periodic visits - the vegetation recovery from 2014, the excavation years to 2023 is great to see.  The bottom photo looking down on it is from 2016 - Please feel free to copy and use the photos if they are useful

Thursday 7 September 2023

Strange lines in the landscape

Two parallel soil marks behind what was the car park, not seen them before.  

I can't see any evidence on the 1943 photo;


UPDATE - a slightly different shot to the first one shows dust (I think)billowing up from the end of the further line. I think they may be marks left by a cultivator. But no sign of a tractor.

Tuesday 29 August 2023

The Little Britain Stonehenge

Kenny Brophy - "...recently visited Stonehenge, curious to see how this icon of Britishness is presented to visitors and tourists. ...It is very clear that the Stonehenge experience – the real Stonehenge – is a long way removed from the idealised Stonehenge we keep getting told about. If this monument is a jewel in the crown, it’s a fake.

The reality is sadly many miles removed from the glossy airport adverts – make no mistake, visiting Stonehenge in the summer these days is a tawdry, tacky experience...

...The very existence of Stonehenge is political, created in many phases of activity that were designed to empower and boost certain individuals and interest groups. Medieval stories about the stones were political too, origin myths to support claims of power and the status quo. These stones have been and continue to be used to peddle myths about the past while conserving power and control today – academic power, political power, power over access, an essential celebrity and politician photo opportunity, a place that one has to be associated with...


Thanks Kenny, it's a great gift to be able to see, what we might think of as ours, as other see it. It should free us from many blunders and foolish notions. If only the fanciful wrappings and devotions might be stripped from it and reveal the real Stonehenge. 

One of the many reasons I preferred the old visitor centre was its honesty of purpose and architecture.   

Thursday 24 August 2023

An Erratic Train of Thought

As we continue to wait for the analysis of the Mumbles erratic, which was claimed to be the "smoking gun" of the Stonehenge Bluestone Glacial Transport idea, it is worth reconsidering the pantheon of coastal erratics in the southwest of Britain. Conventional glacial theory says they shouldn't be there, but they are, so the theory needs refining. That they were entombed or carried on icebergs seems to be the most probable answer.


Quaternary of South-West England edited by S. Campbell, C.O. Hunt, James D. Scourse, D.H. Keen, N. Stephens

The good Dr John, however, seeks inadvertently to confuse:  "Whatever its erratic history may be, the boulder demonstrates that the Irish Sea Glacier impinged upon the Gower coast, carrying erratics from the west and displacing local Welsh ice on at least one occasion."

The source of the erratic is important, if it was entrained in a glacier and dropped by the glacier then the source and destination must be connected by a plausible path. But if it sailed free in or on an iceberg then the source could be unconnected, and its position doesn't demonstrate the extent of the glacier at all.

Wednesday 16 August 2023

The Ice Rafted Giant's Rock at Porthleven, Cornwall (probably).

Photo thanks to Rob Ixer



"...many authors have favoured ice-rafting as the most likely mechanism for emplacement of the Giant's Rock and similar large erratics in the South-West. Indeed, Tricart (1956) also favoured this mechanism to explain the presence of large erratics on the French Channel coast. However, if floating ice carried the erratics to the south coast, then problems arise regarding contemporary Pleistocene sea levels. Mitchell (1972) sidestepped the problem of low sea levels during glacial stages by arguing that these erratics were rafted into position at the beginning of the Saalian Stage when the level of the sea might still have been relatively high after the preceding, warm, Hoxnian Stage. Similarly, Stephens (1966b) argued that the large erratics could have been emplaced by pack-ice and icebergs during the waning of an early pre-Saalian (Anglian?) glacial period when world sea level would have been high enough to allow the erratics to be `floated' into position (Fairbridge, 1961). As an alternative hypothesis, Stephens suggested that towards the end of the Saalian ice-sheet glaciation, isostatic depression of the land had allowed the sea to move icebergs against these coasts despite a generally low eustatic sea level. Such a mechanism is similar to recently proposed models of Late Devensian glaciomarine sedimentation in the Irish Sea Basin (e.g. Eyles and McCabe, 1989, 1991). Bowen (1994b) recently suggested that the Giant's Rock could have originated in Greenland and then been transported to the South-West on ice-floes from a disintegrating, Early Pleistocene, Laurentide ice sheet. In support of the ice-rafting hypothesis, the most convincing evidence is that the erratics are very largely confined to a narrow coastal zone, invariably below 9 m OD, and within the reach of storm waves today..."

"Conclusion"

"The Giant's Rock is the most impressive and intriguing of the large erratics found around the south and west coasts of Britain. Despite having attracted scientific interest for nearly a century, its exact origin and mode of emplacement are still unknown and it remains the subject of much controversy. Although some workers have maintained that the 50-ton erratic was emplaced directly by glacier ice, most believe that it was delivered to its present location on floating ice..."

Tuesday 15 August 2023

Debating Visual Truth at Stonehenge in the Seventeenth Century


Inigo Jones, perspective of Stonehenge, from Stone-heng Restored (London: Printed by James Flesher for Daniel Pakeman, 1655), plate 42

Abstract

Over the course of the seventeenth century, two representations of Stonehenge—one published in William Camden’s Britannia (1600) and the other in Inigo Jones’s Stone-heng Restored (1655)—were invoked repeatedly in an intensifying debate over the monument’s origins. This debate engaged both the virtuosi community of the Royal Society and members of the closely related, fledgling world of English architectural discourse, and the two representations became the common ground for both conversation and contestation. This paper traces the entangled afterlives of these two images, and argues that their reproduction and reinterpretation by members of natural history, antiquarian, and architectural communities created both discord and new, collective knowledge. Drawing on recent work exploring how images produced for divergent purposes and audiences were integrated into natural philosophical study, I explore how, through their reproduction, alteration, and recontextualization, these images functioned as tools of both division and mediation, and created space for debate and new investigation.


Kaemmer, H. (2023). Description or Design: Debating Visual Truth at Stonehenge in the Seventeenth Century. Nuncius, 38(2), 278-310. https://doi.org/10.1163/18253911-bja10064





William Rogers, perspective of Stonehenge from William Camden’s Britannia (London: Printed for George Bishop, 1600), 252


Inigo Jones, inscribed plan of Stonehenge, from Stone-heng Restored (London: Printed by James Flesher for Daniel Pakeman, 1655), plate 38 Citation: Nuncius 38, 2 (2023) ; 
10.1163/18253911-bja10064  Courtesy of the Getty Research Institute

Monday 14 August 2023

Erratic Castaway

Just a reminder that any Glacial erratic found on the edge of a body of water is probably a boulder that hitched a ride on an iceberg rather than evidence of actual glaciers. 

"An iceberg carries a rock though Jökulsárlón, Iceland's glacial lagoon." https://pin.it/3xNpM9M


Norway, Svalbard, Spitsbergen. Nordvest-Spitsbergen National Park, Liefdefjorden, Monacobreen aka Monaco Glacier. Large boulder floating on iceberg in front of glacier.  https://www.alamy.com/norway-svalbard-spitsbergen-nordvest-spitsbergen-national-park-liefdefjorden-image156487112.html


It seems that the erratic found on the Mumbles seashore - https://www.megalithic.co.uk/article.php?sid=56283  - is just another fascinating example of this phenomenon, having probably enjoyed a cruise around St David's Head rather than the proof of anything else, despite the lurid headlines and press release:

Stonehenge mystery solved: 'Smoking gun' discovery provides 'missing piece' of puzzle


Across the water in North Devon there are about twenty examples of these probable dropstones, Baggy Point is one https://www.geographysouthwest.co.uk/wp-content/uploads/2021/10/PTV-Baggy-Point-Erratic.pdf explains more.

A fuller explanation of them, and the debate about how they arrived is at: https://data.jncc.gov.uk/data/965f9190-c00b-4a6b-aa9f-8e3855492404/gcr-v14-quaternary-of-south-west-england-c7.pdf


And at   https://data.jncc.gov.uk/data/965f9190-c00b-4a6b-aa9f-8e3855492404/gcr-v14-quaternary-of-south-west-england-c2.pdf



Thursday 10 August 2023

Current terminology of the Stonehenge bluestones lithologies.


From: Bevins, R., Ixer, R., Pearce, N., Scourse, J., & Daw, T. (2023). Lithological description and provenancing of a collection of bluestones from excavations at Stonehenge by William Hawley in 1924 with implications for the human versus ice transport debate of the monument's bluestone megaliths. Geoarchaeology, 1–15. https://doi.org/10.1002/gea.21971  



Sunday 6 August 2023

Moving Poetry from Google's Bard


遠い地より運び
古の人の手に託され
今も聳える石

(Trans)
From a distant land carried
By the hands of ancient people
Stones still stand tall

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

Bluestones from afar,
Carried by ancient hands,
Standing strong today.

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

Old men recount a fantastic tale,
That the ancient 'henge stones are glacial.
But their theory lacks,
Any supporting facts,
So the myth is complete cock and bull.

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

I met a traveller from an antique land,
Who said, "Dost thou know
The bluestones are the work of a human hand ?
And do they not still stand, and still they show
That their sculptor well those passions read
Which yet survive, stamped on these lifeless things?"
For the hand that mocked them and the heart that fed:
The false words that icy fingers brought them here
The King of Kings, pure proven truth, has clearly said
To tell the charlatans to look and despair.
Of their theory nought remains. Round the decay
Of that colossal Wreck, boundless and bare
The lone and level grasses stretch far away.”
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(Image from Microsoft Bing Image Creator)

Wednesday 26 July 2023

Moving and raising megaliths in France

 

 A collection of informative videos put online by the “CPIE Val de Vilaine – Association Nature et Mégalithes”

Tuesday 25 July 2023

La construction du dolmen de Menga, Mantequera, Málaga


Dolmen de Menga (Official Site)

The Dolmen of Menga (Spanish: Dolmen de Menga) is a megalithic burial mound called a tumulus, a long barrow form of dolmen, dating from 3750–3650 BCE approximately. It is near Antequera, Málaga, Spain. It is one of the largest known ancient megalithic structures in Europe. It is 27.5 metres (90 ft) long, 6 metres (20 ft) wide and 3.5 metres (11 ft) high, and was built with thirty-two megaliths, the largest weighing about 180 tonnes (200 tons). Wikipedia - https://en.wikipedia.org/wiki/Dolmen_of_Menga
Text used under the Creative Commons Attribution-ShareAlike License 4.0

Human Transport of Megaliths - Experimental Evidence

The Bougon burial mounds are a group of five burial mounds constituting a Neolithic necropolis located in the commune of Bougon in the Deux-Sèvres department. The first monuments were built in the 5th millennium BC but the site was used until the middle of the 3rd millennium BC. A museum of prehistory, housing rich archaeological collections from excavations in the region, was built by the Departmental Council of Deux-Sèvres inside the archaeological park encompassing the site.

The archaeological park which integrates the necropolis also contains several educational spaces intended to evoke the construction of megaliths , through the experiments carried out between 1979 and 1998 in Exoudun-Bougon, and the large Neolithic collective habitat of the Fief Baudouin discovered in Airvault .

- The text and photos are translated from the French version of Wikipedia entry for the site and used under under CC BY-SA 4.0 - 

1979 experiments

These experiments were directed by Jean-Pierre Mohen. For details see Jean-Pierre Mohen and Chris Scarre (with the participation of F. Bouin, E. Cariou, P. Chambon), The tumulus of Bougon (Deux-Sèvres): Megalithic complex from the 5th to the 3rd millennium , Paris, Errance 2002 (ISBN 2-87772-240-6 and 978-2-87772-240-7 ) 

The first experiment concerned the extraction of a large megalithic slab of 3 m by 2.50m from a rocky outcrop located on the Chaumes plateau in Exoudun . The block was surrounded on three sides by large cracks. The fourth side was hollowed out by three people with chalk hammers . Wider notches were dug with these same hammers and antler picks, in the faults to drive wooden wedges into them. The wooden corners were wetted to make them swell in volume and the slab came off after an hour of work. It was then lifted with wooden levers to be able to slide wooden rolls of about 10 cm in diameter intended to move it .

The second experiment aimed to test a transport system for a monumental slab of the type found in tumulus F2. Faced with the impossibility of having a natural slab of this type, a concrete copy of the slab of tumulus F2 was made (identical weight and volume - a single slab 6 m long by 3.50 m wide and 1.30 m high whose weight is estimated at 32 tons). A removable transport path was built with unbarked wooden rollers 40 cm in diameter. The ropes were made from viburnum and ivy fibers by a craftsman according to a tradition still in force on local farms at the beginning of the 20th century . The block, covered with a braided rope net, rested on the wooden rollers arranged perpendicular to the two rails of the raceway. On July 28, 1979, 230 people pulling on ropes and 20 others pushing the block managed to move it 40 m away. Raising the block to 0.50m in height with three levers was then successfully tested.

Experimental archaeology: equipment used 





Liberliger, CC BY-SA 4.0, via Wikimedia Commons - Click to enlarge

1997 experiment

In 1997, F. Collin and B. Poisonnier experimented on site with a new “proto-wheel” type traction system with the 32-tonne test block. In this system, the principle of the removable path is retained but each roller is transformed into a hub after having fitted four recesses at each end. These recesses are intended to receive levers arranged radially to drive the movement of the roller. The experiment made it possible to move the block with only about thirty people while saving most of the ropes and the pullers. However, no mechanism of this kind is attested in the Neolithic period.

1998 experiment

In 1998, B. Poisonnier and R. Joussaume experimented with the construction of a trilith at a height of 1.50 m using levers and wooden wedges.

By Jochen Jahnke, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=12221012