thinking about archaeology

View from the Heelstone

* Please note the images in this post, as explained below, were changed and the text slightly adjusted at 8.50pm on December 1.

Let’s have a dispassionate look at the latest Stonehenge news. The Stonehenge Hidden Landscape Project (University of Birmingham and the Ludwig Boltzmann Institute for Archaeological Prospection) continues its geophysical survey. So what’s new?

The press release is titled “Discoveries provide evidence of a celestial procession at Stonehenge”, which is pretty much what all the journalists who reported it said (often just copying the release). It includes a “podflash” interview with Vince Gaffney, and there is a video visualisation of the theory here.

The Independent really went to town, using words like “extraordinary” and “massive”, suggesting the discoveries might “turn the accepted chronology of the Stonehenge landscape on its head”, and that “Stonehenge site’s sacred status is at least 500 years older than previously thought”. The project as a whole is going to “transform scholars’ understanding of the famous monument’s origins, history and meaning”. Golly.

I couldn’t see where all this came from, so I contacted the Birmingham University press office, who very kindly gave me some geophysics plots. As no other news media anywhere as far as I can see had used them, I thought it would be helpful to post them here, which I did. The press office later asked me to replace them with the lower resolution images below, which show pretty much the same thing, though the actual anomalies that are interpreted as prehistoric pits are harder to pick out.

I mostly leave it to others to look at these plots and comment on the interpretations (please do). What I will do here is describe what the Birmingham team found, and add a bit of context.

They pick on two geophysical anomalies, just south of the northern line of the Cursus. Here is the survey on its own:

And this is their interpretation, a triangle connecting the two pits revealed by the survey (at the top), and the Heelstone at Stonehenge (at the bottom):

Seen from the Heelstone, they say, the eastern anomaly is on an alignment towards midsummer sunrise, and the western is on an alignment towards midsummer sunset. (Assuming there are no obstructions, the eastern site is visible from Stonehenge; but the western site, as Gaffney says, cannot be seen, explaining their choice of a burning post in the video representation.)

These anomalies have not been excavated or cored, so we do not know what they are, or how old they are.

Antler from the west end of the Cursus has been dated to 3630–3370BC (1). The earliest known phase at Stonehenge is some five centuries later, at 3015–2935BC. The erection of the Heelstone is undated, but is generally assumed to have taken place at an early stage in the site’s history, perhaps as early as 3000BC – though as my excavation there in 1979 showed, at that date (we’re guessing these dates) the stone may have been standing a little bit north-west of its present site (2).

The press release gives this comment on the two anomalies from Vince Gaffney (project leader from the IBM Visual and Spatial Technology Centre at the University of Birmingham):

“This is the first time we have seen anything quite like this at Stonehenge and it provides a more sophisticated insight into how rituals may have taken place within the Cursus and the wider landscape. These exciting finds indicate that even though Stonehenge was ultimately the most important monument in the landscape, it may at times not have been the only, or most important, ritual focus and the area of Stonehenge may have become significant as a sacred site at a much earlier date.”

The release also notes “a new horseshoe arrangement of large pits north-east of Stonehenge which may have also contained posts”. No indication is given of which features this refers to.

A “previously unknown gap in the middle of the northern side of the Cursus”, also noted in the press release, sounds like the gap that the English Heritage landscape survey (see below) found in 2010.

There are several other survey projects in the Stonehenge world heritage site, most still in progress.

Stonehenge landscape relationships geophysics survey

In June 2011 this project conducted a geomagnetic survey covering two square kilometres north of the A344, between King Barrow Ridge and Fargo Plantation (largely equivalent to the Birmingham survey area, without the block south of the road). The work was directed by Timothy Darvill (Bournemouth University), and Friedrich Lüth and Andreas Fischer (Römisch-Germanische Kommission, Deutsches Archäologisches Institut, Frankfurt) with support from Sensys GmbH. Details have not been published.

The Stonehenge Riverside Project geophysics survey

This multi-university field project, responsible for most of the recent excavation in the world heritage site, has a geophysics project directed by Bournemouth University’s Kate Welham. They have surveyed over 5.5 hectares since 2004. Details have not been published.

Stonehenge landscape survey (English Heritage)

This is the first modern detailed survey of the earthworks and other standing remains within the world heritage site – the barrows, field systems and linear ditches, tracks, ponds, recent military remains and so on.

Stonehenge mapping project (English Heritage, part of the National Mapping Programme)

This created a map-based record of everything of archaeological and historic interest that is known about the world heritage site from aerial photos. It added 539 sites to the 2,062 recorded at the start, and continues to be updated.

Stonehenge lidar surveys

Lidar creates a very detailed 3D image of the ground surface using airborne laser imagery, and has revealed subtle new details to known earthworks such as field boundaries. The English Heritage survey is described here and in Antiquity 2005 (3). Wessex Archaeology has an impressive 3D animation using lidar data here, and a zoomable lidar image of the whole world heritage site here.

Stonehenge laser scanning (English Heritage)

This has created a high resolution 3D image of the surfaces of the megaliths, and was done on site in spring 2011.

References

1 “The date of the Greater Stonehenge Cursus”, by Julian Thomas, Peter Marshall, Mike Parker Pearson, Joshua Pollard, Colin Richards, Chris Tilley & Kate Welham, in Antiquity 83 (2009), 40–53

2 “On the Road to Stonehenge: report on the investigations beside the A344 in 1968, 1979 and 1980”, by M Pitts, Proceedings of the Prehistoric Society 48 (1982), 75–132

3 “New light on an ancient landscape: lidar survey in the Stonehenge World Heritage Site”, by RH Bewley, SP Crutchley & CA Shell, in Antiquity 79 (2005), 636–47

13 responses

  1. Thanks Mike and the Birmingham team for the data that really is helpful and clears things up. It was apparent that something was not working out from the text available on Saturday but without co-ordinates not so easy to say exactly where the mistake lay . Heritage Daily didn’t help by giving one of the pits sites as the same for last years “Henge “ .
    Assuming the pits are contemporaneous with the cursus i.e. 3630- 3670 BC then the declination for solstice rise and set and that time was 24.05 degrees and the azimuth for sun set at the Solstice as seen from the heel Stone would be 309.5 degres . Looking at the GE image the azimuth for the Heel Stone to western pit alignment is 312.6 degrees (a convenient mark is the south western edge of the field that contains the “Cursus Barrows “ ) which is three degrees further north than the sun ever actually gets to . The alignment towards the solstice sun rise is accurate and the resulting distance between the two points is within a couple of metres of exactly 2 Km . the mid way point is thus within a metre over 1 Km ,this point when extended due south as suggested for the final leg of the procession does not lead to the centre of Stonehenge but a point 210 metres east of the centre of the monument .
    I have stuck to falsifiable data but problems with the conjecture about alignments involving non intervisibility and painfully slow processions all based on two pits that are undated ,unexcavated and too big to have held timber posts or megaliths might take up too much room .
    George

    November 29, 2011 at 6:16 pm

  2. Susan Greaney

    Thanks Mike. Why none of the media thought to ask for the plots is beyond me!

    As George says it is very difficult to judge the theories based on two undated and unexcavated anomalies. It would be interesting to compare these plots with previous geophysical surveys conducted in 2006 and 2007 by the EH team, plus of course the Stonehenge landscape relationships survey…

    November 29, 2011 at 11:05 pm

  3. There appears, at first sight, to be an additional problem with the plot diagrams:

    I took the layout that mike kindly provided above and inserted it into a CAD program so that I could get a trace diagram of the proposed alignments. On taking that line trace and imposing it onto areal satellite mapping, there seems to be a one degree rotation: That is to say that the Birmingham plot appears to be rotated by one degree anti-clockwise from North relative to Google Earth (and also relative to the Microsoft mapping service).

    I may be being a bit picky, but this changes their angles: Rather than being an identical angle from the Heelstone to the ‘evening’ and then ‘morning’ sunrise pits, there appears to be a two degree difference.

    Imposed screen-print of CAD trace diagram using satellite image from Mike Pitt’s site:

    Trace diagram imposed on Google Earth and rotated clockwise by one degree:

    Is there any way to get more precise geographic positions for these pits?

    December 1, 2011 at 12:59 pm

  4. Jon , accurate co-ordinates or grid refs would be useful but there is enough info from the image for us to plot the sites of the pits accurately enough to see the problems . The red line is reminiscent of a ley liners pencil width but even if the image is distorted it is unlikely to have been the basis for any calculation and merely a guidline .

    George

    December 1, 2011 at 5:31 pm

  5. George

    Aye, but if that’s the case and even the ‘solstice’ alignments were just guideline ideas not based on any real fact, is there anything left in the recent announcements that merits any attention?

    Jon

    December 1, 2011 at 8:01 pm

  6. I may have misunderstood you George: Using the plots Mke provides above, the red lines do appear to be accurately drawn (give or take ten or twenty metres). However, a mirror line about North Axis appears to put one (or other) pit some 60 or so metres away from its apparent mirror line counterpart.

    Seems a big discrepancy to me unless the plot has some severe local distortions in its lateral axis (or maybe using Google earth to compare isn’t a good enough method of checking)

    December 1, 2011 at 8:28 pm

  7. Not sure wht you mean by mirror line Jon . GE like GIS is relatively accurate but should be supported with large scale maps and geodesic progs .As long as we know where the the points are accurately enough we can calculate their various relationships ,distortion only affects their relationships on that image . However we have no evidence that level of accuracy would ever have been achieved in the period .

    December 1, 2011 at 8:50 pm

  8. Data required for a proper analysis:

    1) Accurate grid refs of the supposed pits (georeferencing a doubtful GE overlay, though fun, isn’t adequate)

    2) Horizon altitudes in each of the postulated alignment directions as viewed from the Heelstone

    December 1, 2011 at 11:49 pm

  9. Sorry George, didn’t explain well: A mirror line is just an engineering term used for an object ‘mirrored’ about an axis: So the mirror of a line pointing east (about the north) would be a line pointing west: If you can see a true horizon, the bearing of your morning sunrise at solstice will be an identical mirror of the evening sunrise (about solar North).

    But if one was interested in the bearing of the summer solstice from a point such as the Heelstone, it doesn’t seem logical to choose a location for one’s primary marker where the hills beyond (particularly the Durrington/Larkhill ridge to the North East) are at an elevation which will obscure your view of the horizon sunrise event.

    December 2, 2011 at 10:01 am

  10. Overlays are not useful but the site of the pits on the earlier images ,now removed , provided accurate enough info for accuracy up to 0.2 of a degree .Similarly the height OD of all three sites and also the horizon from the Heel Stone are available on the various large scale maps maps and surveys and subsequent altitudes can be calcualted from these .Clearly the horizon altitudes for both “alignments ” are not the pits they are merely under the “line” of the “alignment” .

    December 2, 2011 at 10:10 am

  11. Just for fun, here’s a picture of sunset on Dec 24th taken from the location of the pit at the east end of the Cursus:

    December 24, 2011 at 9:16 pm

  12. Does anyone know if Birmingham University are likely to share the coordinate data of where the pits are located?

    March 28, 2012 at 8:27 am

  13. Scroll down to find the article .
    http://www.prehistoricsociety.org/publications/publication/past_71_july_2012/

    It now seems that the snail paced “procession “ and the mistaken calculation of the midway point being aligned on the Heelstone at the solstice has been quietly forgotten . The unexcavated ,undated , and in one case unsighted pits , inaccurately calculated to be aligned on the solstices now only “appear “ to be aligned . A further eight months might see that put to bed too .

    George

    August 22, 2012 at 11:22 am

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