Dig Diary – Thursday, August 3, 2017
Day Twenty-Four
Great walls and long-distance links
Hugo points to the newly exposed outer face of the great wall in Trench J as its starts to curve towards the Loch of Harray — 4.35m wide.
Orkney, or at least the part on which the Ness of Brodgar is situated, made a very passable imitation of the Malaysian jungle this morning.
It was hot, wet and incredibly steamy.
This is the killer combination for archaeologists, as rain means waterproofs, but rain, heat and humidity together means sodden layers under the waterproofs.
To say it was uncomfortable is a gross understatement, but the Ness team pressed on regardless.
Over in Trench T, there is a feeling that this most puzzling of trenches may be beginning to make sense — perhaps.
Martha with the latest discovery of Lewessian Gneiss
Certain elements could be coming together and the many pits are now more clearly defined, if not wholly understood.
Supervisor Dave has probed along the line of another one of the recumbent orthostats that is partially still hidden, showing that it is a huge lump of stone at least four metres long.
Elsewhere in Trench T, Martha, our resident geologist, has identified two flakes of stone found there as being Lewissian Gneiss.
This rock is found, of course on the north-west coast of Scotland and the Western Isles and, as several of our more complete maceheads from past years are also Lewissian Gneiss, some of the long-distance links from and to the Ness are now even more evident.
The elements of Trench J are also becoming a little clearer.
Our UHI students, who were becoming a little weary of trowelling soil, struck upon a massive, and beautifully set, lump of stone and other courses that can now be seen as part of the outside wall face of the “Great Wall of Brodgar”.
Unfortunately, like many of the Ness structure walls, this huge affair has been extensively stone robbed in the past. The wonder is, looking at the size of the chunks of stone which constitute it, how they managed to move them, and from where?
The nicely laid inner wall face exposed by Woody in Structure Five.
The “Great Wall” respects Structure Five in the trench by gently curving round it, but it can be seen sit be set directly on the boulder clay, as is Structure Five.
This makes stratigraphic separation impossible, but raises the question of whether the wall is possibly very early in the history of the site.
Certainly, Structure Five now appears to have a slightly waisted form and orthostatic radials in common with early buildings, such as the Knap of Howar, Smerquoy (in St Ola) and the Braes of Ha’breck (in Wyre).
The pottery from the earlier excavation of Structure Five and the flint knife found in an entrance are also early, but there are strong hopes of more information when floor levels are reached.
That can only be done when some of the many peculiarities in the building, such as walls of good quality near walls of appalling quality, are resolved.
However, Woody’s sondage (deep, carefully planned excavation) is showing a wall of magnificent quality, so hopes remain high.
We wish to warmly thank a company called Replicade, who make wonderful drawer linings for the world’s top museums. These may sound mundane, but they are laser cut into layered, foam-like material, exactly following the contours of artefacts which are then snugly and securely held in the cut-out outlines.
Some of the Structure Eight team model their kneeling pads, courtesy of Replicade.
Alistair Carty, from Replicade, realised that their material would make excellent kneeling pads for diggers, so he made several from off-cuts and sent them to Nick.
Alistair, the knees of the Ness thank you.
It was delightful today to welcome Calum McKenzie, from Orkney’s Blide Trust, and several of his colleagues. They were shown around by Nick and will be welcome back anytime.
The Smart Fauna Collection – Jim Bright
Over the course of the season at the Ness of Brodgar, I have been tasked with recording layers of animal bone within the central midden area using the photogrammetry technique.
This way we can see how the bone deposits were placed within this section of the Ness.
Each time more of the midden is carefully removed, I make a 3D model so that experts in animal bone can later identify what they are and where they have come from.
Some of the numbered bone in the Smartfauna deposit awaits Jim’s 3D modelling.
During this process, I need to make sure I have enough photographs, not only of the midden area, but of each bone, taken at as many angles as possible.
As the bones are fragile I have to be careful I don’t lean on the deposits while taking the photographs to make the model, which can result in undertaking some interesting yoga moves got get the right shot!
The bone is also recorded using geo-referencing techniques, with the location of each bone stored in a coordinates system in order to ascertain how they are laying within the midden in 3D space.
Last find of the day — a bone point. One of the few pieces of worked bone from the Ness.
This results in lots of “zapping” in location data by the geomatics team here at the Ness — Mark Littlewood and Alette Bloom.
As with my other 3D models, I put coded targets around the area to be photographed, which can also be geo-referenced with the coordinates input into the photogrammetry software. This way we can have accurate scales for each 3D model.
Moreover, measurements between rocks and bones in the 3D model can be made within the photogrammetry software in real time, making life easier for those examining the deposits in virtual space.
The results of the Smart Fauna work so far can be seen in my “Smart-Fauna Collection” and it is interesting to see the bones in each model, as they were deposited hundreds of years ago.
My website, www.virtualpasts.com, has more information about what I do here at the Ness of Brodgar, and I will be posting more on the site in coming weeks.
