Monday 9 November 2020

MPP at Waun Mawn - Diwrnod Archaeoleg 2020 Archaeology Day


Waun Mawn: a former stone circle near the bluestone quarries for Stonehenge by Prof. Mike Parker Pearson. 

In 2017 and 2018 the Stones of Stonehenge Project, led by researchers from University College London and the universities of Southampton, Bournemouth and the Highlands & Islands, carried out excavations at Waun Mawn in North Pembrokeshire to discover if the four monoliths there are all that is left of a prehistoric stone circle. These four monoliths – three of them recumbent and one still standing – form an arc which previous archaeologists have suspected may be remains of a circle. Our excavations discovered a further six empty sockets around the perimeter, revealing that this stone circle was originally 110m in diameter. This makes it one of the largest stone circles in Britain and the same diameter as the ditch around Stonehenge. The team have also been able to establish its age by radiocarbon dating and optically stimulated luminescence (OSL) profiling and dating.

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Waun Mawn: safle cerrig cylch blaenorol ger y chwareli cerrig glas ar gyfer Côr y Cewri gan Yr Athro Mike Parker Pearson (yn yr iaith Saesneg) 

Rhwng 2017 a 2018 ddaru brosiect Cerrig o Gôr y Cewri, wedi ei arwain gan ymchwilwyr o Brifysgolion Coleg Llundain, Southampton, Bournemouth ag yr Highlands & Islands, cloddio Waun Mawn yn ogledd Sir Benfro. Pwrpas y cloddio oedd darganfod os dim ond y pedwar monolithiau ar y safle oedd ar ôl o’r cylch cerrig cynhanes. Mae tair o’r monolithiau yn orweddol, tra bod un dal yn sefyll, gyda’u gilydd yn ffurfio arc mae archaeolegwyr yn y gorffennol wedi dynodi i fod yn olion o gylch flaenorol. Mae’r cloddio diweddar wedi darganfod chwech socedi cerrig ychwanegol o gwmpas y perimedr, sydd yn dadlennu fod y cylch crwn ar y safle wedi bod yn 110m o ddiamedr yn wreiddiol. Mae hyn yn gwneud y cylch crwn yma yn un o’r rhai mwyaf yn Prydain a’r un diamedr a’r ffos o gwmpas Côr y Cewri. Mae’r tîm hefyd wedi sicrhau oed y safle yn defnyddio dyddio carbonradio ag methodoleg dyddio a phroffilio ymoleuedd cyffroi optegol. 

Tuesday 6 October 2020



Landscape and Monuments 

Mike Parker Pearson, Joshua Pollard, Colin Richards, Julian Thomas, Chris Tilley & Kate Welham 

ISBN: 9789088907029

More details and read for free at:

For many centuries, scholars and enthusiasts have been fascinated by Stonehenge, the world’s most famous stone circle. In 2003 a team of archaeologists commenced a long-term fieldwork project there for the first time in decades. The Stonehenge Riverside Project (2003-2009) aimed to investigate the purpose of this unique prehistoric monument by considering it within its wider archaeological context.

This is the first of four volumes which present the results of that campaign. It includes investigations of the monuments and landscape that pre-dated Stonehenge on Salisbury Plain as well as excavation at Stonehenge itself. The main discovery at Stonehenge was of cremated human remains from many individuals, allowing their demography, health and dating to be established. With a revised radiocarbon-dated chronology for Stonehenge’s five stages of construction, these burials can now be considered within the context of the monument’s development. The different types of stone from which Stonehenge is formed – bluestones from Wales and sarsen silcretes from more local sources – are investigated both at Stonehenge and in its surroundings. These surrounding monuments include single standing stones, the Cuckoo Stone and the Tor Stone, as well as the newly discovered circle of Bluestonehenge at West Amesbury beside the River Avon. The ceremonial Stonehenge Avenue, linking Stonehenge to Bluestonehenge, is also included, with a series of excavations along its length.

The working hypothesis behind the Stonehenge Riverside Project links Stonehenge with a complex of timber monuments upstream at the great henge of Durrington Walls and neighbouring Woodhenge. Whilst these other sites are covered in a later volume (Volume 3), this volume explores the role of the River Avon and its topographic and environmental evidence.

With contributions by: Umberto Albarella, Michael Allen, Olaf Bayer, Wayne Bennett, Richard Bevins, Christopher Bronk Ramsey, Chris Casswell, Andrew Chamberlain, Benjamin Chan, Rosamund Cleal, Gordon Cook, Glyn Davies, David Field, Charles French, Robert Ixer, Neil Linford, Peter Marshall, Louise Martin, Claudia Minniti, Doug Mitcham, Bob Nunn, Andy Payne, Mike Pitts, Rebecca Pullen, Julian Richards, David Robinson, Clive Ruggles, Jim Rylatt, Rob Scaife, Ellen Simmons, Charlene Steele, James Sugrue, Anne Teather, Sarah Viner, Tony Waldron, Katy Whitaker and Christie Willis

Saturday 29 August 2020

Macro Photos of Stones 53 and 54

 Steve Marshall has kindly provided some macro photos of the surface of Stones 53 (purple-grey) and 54 (orange) 

Stone 53

Stone 54


Friday 28 August 2020

Stones of Many Colours

Beside the road at Clatford Crossroads just to the North East of West Woods there is a lovely Sarsen enclosure, probably a Pound. Obviously crafted from local stones it displays the wide variety of the colours and crusts of the Sarsen stones. It would fascinating to see the results of a PXRF on them.

Tuesday 25 August 2020

The Colour of the Stones

 "The majority of the stones are grey, but Stones 54, 55, 101, and 156 exhibit an orange hue while Stones 53, 56, and 154 are purple-grey. " *

Out of interest I charted the PXRF data for Fe % for each stone from Nash et al 2020** 

PXF penetrates a little way into the stone so doesn't just measure the crust but it seems there is only a weak correlation between the perceived colours and the Fe concentration of the surface layers. Which is a bit mysterious.

Maybe the colouration is shallower than the PXRF sampling or it isn't an Iron colour that is being seen. Any thoughts?

The purple colour is thought to be from Manganese compounds so the same chart for Mn - no correlation at all!

It has been suggested that the colouration of Sarsens is by "Rock Varnish"  - see Steve Marshall - Geology of Avebury  - And for details and for more.  But if that is the case then elevated Mn would be expected on stones identified as "purple"

*David Field, Hugo Anderson-Whymark, Neil Linford, Martyn Barber, Mark Bowden, Paul Linford, Peter Topping, , Marcus Abbott, Paul Bryan, Deborah Cunliffe, Caroline Hardie, Louise Martin, Andy Payne, Trevor Pearson, Fiona Small, Nicky Smith, Sharon Soutar and Helen Winton (2015). Analytical Surveys of Stonehenge and its Environs, 2009–2013: Part 2 – the Stones. Proceedings of the Prehistoric Society, 81, pp 125-148 doi:10.1017/ppr.2015.2 


Sunday 23 August 2020

The Stonehenge sarsens -- did they come from Overton Down / West Woods? On this evidence, probably they did.

Discussing:  Origins of the sarsen megaliths at Stonehenge 


Geochemical evidence suggests the large sarsen stones at Stonehenge originate from the vicinity of West Woods, Wiltshire.  

The announcement about the Sarsen stone analysis pointing to West Woods as a probably source of the majority of the Stonehenge stones has mainly been well received but there has been some carping whether the samples from the Stonehenge Core actually match closely enough the samples taken in the field.

It is important of course to note that many more samples should, and I expect will, be taken to look at other areas and also to narrow down potential sources. It is also obvious that Sarsen is a difficult stone to fingerprint because of its formation from pure sandstones and that variations can happen in very small areas.

A secondary conclusion from the paper is about likely routes of the Stonehenge Sarsens. This blog was set up all those years ago to explore exactly that idea and so that the route that was first published here emerges as a favourite is pleasing.  See .

Displaying a West Wood Sarsen and my enthusiasm for it.

Especially because I want a result to be true means I try to check it by looking at it closely. Rather than replicate the paper's analysis I did a "Fruitcake Recipe" analysis. Are the ingredients similar enough in type and ratio to be the same recipe?

To check that the potential source and the core are similar enough the first pass through the data (from ) simply removes any sources that are markedly out of the range of the core for each element (chemical compound). One of the West Woods samples was removed in this process. How tight to constrain the range is open to argument and various methods could be used to determine a significant acceptable variation.

To create a chemical fingerprint I then removed the data of the compounds that convey little information to discriminate between the remaining sources. Again how tightly to draw that net is open to debate but I chose to leave more in than the paper did even though is makes the results less clear to read.

So I am pleased that my simplistic alternative analysis of the data centred on the core show that most of the closest matches come from the West Woods, Lockeridge, Piggledene and Clatford area. The other similar matches are from much further away and Occam's razor would suggest we should accept the source of the Stonehenge Sarsens is indeed from West Woods and adjacent areas.