Dig Diary – Friday, August 12, 2016

Day Thirty

Our team of supermodels - Jim, Anne, Ben and Jo - take to the catwalk in the latest line of matching Helly Hanson waterproofs.

Our team of supermodels – Jim, Anne, Ben and Jo – take to the catwalk in the latest line of matching Helly Hansen waterproofs.

The Ness is alive, with the sound of ‘chambered’ . . .

Trench T, on a rather less-than-clement day. But is it, or is it not, a chambered tomb?

Trench T, on a rather less-than-clement day. But is it, or is it not, a chambered tomb?

The Ness of Brodgar is suffused with a rosy glow today and it has nothing, absolutely nothing, to do with what passes for summer weather.

It is the amazing archaeology which has warmed us all and which explains the smile on site director Nick’s face.

He may have been proved right (probably/possibly!) and is carrying his vindication with considerable dignity.

It all centres around Trench T, at the bottom of which an extraordinary structure is now emerging.

It poked its nose above the surface of the enveloping midden last year, but it is this season’s excavations, under the guidance of Ben, which has thrown some clarity on matters.

Not that Nick and Ben agreed on what they had.

Mai uncovering the remains of the wall of the putative chambered cairn in Trench T.

Mai uncovering the remains of the wall of the putative chambered cairn in Trench T.

Nick, who has excavated chambered tombs before, had a sneaking suspicion that we were dealing with a chambered tomb, perhaps one along the lines of his own excavation at the Bookan chambered tomb, a kilometre or so to the north of the Ness of Brodgar dig site.

Ben, however, was more circumspect, and with some justification, as the mysterious structure has been comprehensively robbed-out in antiquity.

This year the evidence has accumulated more quickly and on Wednesday we told you of the newly-emerged orthostat which grew, and grew and grew.

Spot the post holes in Trench X.

Spot the post holes in Trench X.

Today, and for the first time, Ben was heard to mutter the “chambered” word and we may now be heading towards agreement.

There are various strands of evidence to ponder.

Today, Mai was cleaning back some material and found a large, stone block parallel to what is probably the outer wall face.

If there is a relationship between these two elements the structure is absolutely massive.

Further evidence lies in the composition of remnants of the robbing of the putative walls of the structure. It is composed of redeposited natural and shaley, shillety stone.

This is quite different from the wall composition of the other structures on site in which midden is often used in their construction as wall core.

The importance of this lies in the strong suggestion from this and other sites that midden appears to be associated with “life”, and in the Neolithic period may have been considered unsuitable material for “death” or use in chambered tombs.

Martin's anvil stone, which plugged one of the post holes in Trench X. Look closely to see the finely incised lattice decoration.

Martin’s anvil stone, which plugged one of the post holes in Trench X. It’s not clear on the photograph, but if you look at the stone closely you can see the finely incised lattice decoration.

There is also the matter of the way the orthostats have been utilised in our mysterious structure.

It is strongly reminiscent of the orthostats at Bookan and Nick is considering the possibility that we have here a Bookan-type chambered tomb, but on a truly monumental scale.

More excitement came from Trench X, this morning, where a series of stone-lined post holes have emerged, with perhaps four of them in a line and hints of a parallel line.

In one of the post holes, in what may be a secondary use, Martin has uncovered a large anvil stone which has been used to plug the hole.

Closer examination shows that it also has finely incised decoration, representing a fascinating find in a most unusual location.

The fossilised sea urchin.

The fossilised sea urchin.

The most beautiful find today came from the midden being excavated from above Structure Twenty-Six.

At first glance, it is a smooth, roundish piece of flint, but closer examination shows it to be a beautiful, fossilised sea urchin, probably from the Jurassic period and almost certainly deriving from North Sea chalk deposits.

In the Neolithic period someone found it, valued it for its beauty and unusual nature and used it as a tool, for under the microscope Ben discovered that it is covered with fine striations indicating polishing.

What it was polishing will remain a mystery until we find a stronger microscope, but it is a lovely thing and a fitting conclusion to a trying week.

We will see you all on Monday.

Until then . . .

From the trenches

Sam Harris hard at work sampling one of the hearths in Structure Eight.

Sam Harris hard at work sampling one of the hearths in Structure Eight.

Okay, so as you might have heard the archaeomagnetist is back on site! Though to a number of people I seem to be “Sample Sam”.

If you do happen to visit the site you will most likely find me contorted into some strange shape over or even in one of the amazing hearths.

This week has brought both clear blue skies and torrential rain –  ahh the Orkney weather – but all the more fun for the site director’s Border Collie, Bryn, to run around and role in the dry, or wet, grass. Apart from helping the odd camper van or two out of the quagmire of a visitor’s carpark (remember folks, not suitable for large vehicles) I have managed to do the odd bit of sampling here and there.

I started off last week in Structure Eight and all its magnificent collection of hearths!

I returned to one of the hearths I excavated last year, towards the southern end of the structure, and took the 26th set of archaeomagnetic samples. I’m sure it won’t be long before the Ness of Brodgar can claim to be the most archaeomagnetically sampled excavation in the British Isles!

Following this, I moved into Structure Eleven and the unexcavated hearth on offer there. Alas, upon half sectioning, no suitable material was found for archaeomagnetic studies. Though in a way this is still interesting as there were plenty of macrofossil remains which could prove useful for radiocarbon dating.

A beautiful, polished hammerstone, found today close to the sea urchin.

A beautiful, polished hammerstone, found today close to the sea urchin.

By the time you avid readers will be perusing this I will have just completed the western hearth in Structure Fourteen (from magnetic susceptibility to complete section monoliths – see pictures for the challenge this was).

The amazing multi-layered hearth contains seven layers of in situ burnt material. This offers the perfect opportunity to study the changes in the geomagnetic field during the lifetime of this hearth.

“Great, but what use is that to the archaeologist!” I hear you all say.

If we can define these changes in the geomagnetic field, then it can be utilised to date future hearths such as these. This allows us to date the last time the hearth cooled and as such fell out of use by our ancient ancestors.

For those of you that are interested, please visit my website,  where you will find the ongoing results of my research presented in the “research blog”.  A poster showing the results of the multi-layered hearth in Structure Fourteen is also available to view.

My work is never finished it seems because there appears to be another layer of burning stratigraphically below these hearths relating to another earlier hearth! This is mirrored by other hearths across the site representing the amazing continued presence at this iconic archaeological site.

As I mentioned above feel free to contact me with any queries or questions, as I am looking to visit other archaeological sites:

W: www.neolithicarchaeomagnetism.weebly.com

T: @Archaeomagnetism

E: s.harri11@student.bradford.ac.uk

Sam Harris