Archaeology The Cairns

The Cairns 2016 Season

IMG_0704It has been a hugely successful season at The Cairns. The site is now largely cleared showing the broch outline in totality, finds have shed more light on the social and economic life of the site and of course it would appear that we may have found the remains of an actual inhabitant.

Martin Carruthers, Site Director, continues…….

The site is firmly put to bed now and it’s time to take stock, a little, of what the season has been like.

Well, lots of people who have visited the site this year have commented very positively on our progress, noting how different the site looks to previous visits! But how did we really do set against the original aims for the field season this year?

Inside the broch

The bronze pin found inside the broch today.

It was our aim to remove the last chunk of rubble infill from the broch interior – covering about a fifth of the interior space – and get into a position where we could begin to excavate the floor layers and occupation deposits across the whole of the broch.

After waiting for some time for the pied wagtail chicks to fledge, and leave the rubble that they were nesting in, we did, in the end, manage to remove all of the remaining rubble infill from the broch and open up the entire interior.

It looks splendid! We can now really appreciate what a monumental building it really was.

A big surprise that emerged from this process was the discovery of an impressively complete –  still fully roofed – and pristine wall chamber and its well-preserved doorway, opening off of the western wall face of the broch interior.

In the end we were able to excavate the rubble down to the uppermost occupation activity inside the western zone of the broch.

Some of the contents of just one bag of charcoal from one of the hundreds of broch-floor samples. The tiny oval pieces are barley grains.

Across the rest of the base of the broch, we continued to excavate the occupation deposits in the south-eastern and southern rooms of the interior.We resolved how people had accessed these rooms via a corridor space and we found occupation deposits across the whole of this sector. The floors were seen to be every bit as rich as those seen in the north-eastern room in the previous season.

Importantly, we could see that the same cycle of floor creation seems to be at work – where, essentially, a clean clay floor was laid down, then occupation detritus built up on it and then, after a time, this was covered up by another clean clay floor.And so on for a, currently, unknown number of times.

This is great news as it confirms that we will have a depth of floor deposits here with which to assess what was happening inside the broch over a long period of time – hopefully from its very beginning to its end. Students have been sieving and sorting the materials from the floor deposits this year, we can begin to see what kind of material is present. The occupation deposits have yielded vast quantities of charred plant material, especially cereal grains and other charred straw, chaff, and sundry other plants.

There is burnt bone, small stone and bone tools (such as the immaculate needle that came out of the broch entrance passage); the tiny bones of microfauna, such as mice and voles; there’s bird bone and fishbone and there are pottery fragments.Of course, we had a tiny glass bead from the sieving of these deposits a few months ago. We have even got rather a lot of coprolites, i.e. fossilised poo!

The prodigious quantities of cereal grain matches what has previously been found at well-excavated broch sites such as the Howe, in West Mainland, and Scalloway in Shetland, and emphasises that one of the likely roles of brochs was as major collection points for agricultural produce. The volume of charred grain from any archaeological context is always a tiny fraction of that which was lost through complete combustion and this, therefore, tells us that there was at one time a vast quantity of grain likely being stored inside the broch at The Cairns.

This is an important clue as to the role of the broch, which will be followed up and amplified in future work. As well as all the environmental material, the floors also yielded a very nice range of artefacts this year, including pottery, lots of stone tools, a beautiful bronze pin and two tiny bronze rings or chain-links!

The souterrain

The souterrain passage.

For the souterrain, our aims were to reveal the main roof lintels and then remove these and excavate floor deposits inside the underground passageway.

After spending an unexpectedly considerable time revealing no fewer than three layers of superimposed roof slabs, and the soily deposits between them, as well as working out the relationships between these deposits and everything else nearby, we did indeed manage to remove the big lower lintels. Not much time was left to fully excavate the floor deposits, but a selective investigation of the floor appears to confirm that we have likely got two main phases to the souterrain, as it was extended in length at one stage.

A final nice surprise was the discovery of a fragment of a tiny amber bead from the deposit inside the souterrain passage!

Trench M

Trench M - the metalworking area.

Trench M is the metalworking area to the north of the broch.

We had set ourselves the general aim of simply learning more about the nature of the production under way during the Iron Age.

We fully excavated the remains of the clay furnace and found that rather than representing a copper-smelting furnace, as we had previously thought, this feature looks very much like it was for iron smelting.

The slag and other residues indicated that there was heavy processing of iron ores under way.

There were distinctive and diagnostic features uncovered indicating where the tuyere, or nozzle betwixt the base of the furnace and blow-pipes, or bellows, would have sat, assisting in the supercharging of the heat inside the furnace.

Just a small part of the team left at the very end of this season's excavation.

It’s fascinating that we therefore seem to have bronze-working – as evidenced by the large assemblage of pin and brooch moulds, crucibles and copper alloy waste previously encountered here –  as well as iron-working going on at the same time and place.

This is reminiscent of the Iron Age workshop excavated at Minehowe, in Tankerness, and it may be that the complex pyrotechnical processes and skills required for both types of metal production were complementary, and mutually served in a shared facility.

Another important thing learned this year from Trench M was that this rich episode of metalworking was not the only one to have occurred in the area. As we nudged into deposits further into the depth of the building in the trench we found lots of iron slag, bog ore and cakes of iron furnace bases, indicating that metalworking had been a hallmark of the northern part of the site for a longer time.

Indeed, a surprise discovery was the emergence of what appears to be another, possibly better-preserved, iron-working furnace to the south of the original one! We’ll learn more about this next season.

The new extension trench

In Trench Q, the walls of the village buildings surrounding the broch begin to emerge.

Trench Q was our extension trench this year. We removed a big spoil heap and broke new ground in order to link through the metalworking area of Trench M to the broch and in so doing hoped also to reveal a sector of the putative extramural village surrounding the broch.

This went well and although its early days for this trench, we nevertheless were able to reveal substantial wall-heads and faces, which were obviously double-faced and therefore free-standing walls of substantial buildings rather than the single-skinned, revetted walls (walls that are dug down into, and against deposits that predate them), that are usually the hallmark of later Iron Age buildings.

We were able to add to these architectural observations aspects of the artefacts, as the pottery from both above, and against, these walls appeared to be of the Middle Iron Age type (the period of the broch) which have “everted” (splaying-out) rims and nice rounded, globular bodies.

Indeed, in one place, up against one of the walls, we found the greater part of a whole vessel that had likely fallen apart when in use, as five heat-affected rocks (“pot-boilers”) and a pot lid were found inside the remains of the vessel as though it had accidentally split apart due to the thermal shock.

Trench Q, therefore, has demonstrated that we do appear to have a substantial village surviving surrounding the broch and in future seasons we will be able to learn a great deal more about it. Many important questions will hopefully then be able to be addressed.

Is the village absolutely contemporary with the construction of the broch? Did its inhabitants have the same lifestyle as whoever was resident inside the broch? What was the precise social and political relationship between villagers and broch occupants?

Middens and houses

One way we hope to address the question of different social status among the different houses and households of the settlement is through analysing their middens. They do say that you are what you eat after all! Our aim is to be able to match specific buildings to their waste products, discarded midden, and the like, so that we gain a window into their cycles of production, consumption and waste.

We hope that will represent a better, more detailed, and thorough index of the status of these buildings than simply plotting the status of the artefacts from within the buildings. We hope this will form the basis for comparison of each house against the others.

The very good news is, therefore, that this season we think we may have begun to uncover some of the midden that goes with the broch itself. Just outside the front door of the broch, and snug against the outer wall face, we have uncovered a thick, rich, organic soil, full of shell midden, animal bone and charcoal, that is a likely contender for having come from inside the broch itself.

The further exploration of this deposit in future years will hopefully mean we gain a direct access to the waste product of the broch household, which, taken in tandem with the occupation deposits from inside the broch, will be incredibly informative about the role and status of the broch.

The human remains

The whalebone vessel that contained the human jawbone, with the red deer antlers snug against it.

Finally, one thing that was not a part of our original research agenda and aims for the site this season was possibly the most surprising discovery of all!

This was the human remains – a jawbone and some other fragments that had been placed inside the upper fill of the whalebone vertebra vessel, with two deer antlers and a saddle quern snug against the whalebone.This is a remarkable set-piece depositional event! There will be far more post-ex work required to elucidate the details of what this may mean, but already there are some very interesting issues to contemplate.

First of all, this deposit or cache of items have been placed on the top of the broch midden that I have just described. Immediately after their placement, they were buried in substantial rubble that appears to mark the end of the broch as a free-standing building in the same manner and at the same time as the rubble fill in the interior of the broch.

So we may be looking at an act of closure and abandonment or decommissioning of the broch, which was given a heightened significance or drama through the use of human remains. Many questions therefore stem from this.

How old were the human remains at the point when they were placed in the whalebone vessel and buried? Do they date to the time of the deposition or are they much older remains, possibly held over, curated, as an heirloom or a relic? Maybe even perceived as relating to the ancestral generation who founded the broch several centuries earlier?

Are the remains, in fact, even older than this?

They might even be fragments of human skeleton, found during the Iron Age, within the low mound just to the north of the main trench, which we know is a Neolithic site!

Well, before we get too carried away with the many possibilities, I should simply reflect on the fact that we will hopefully begin to answer at least some of these questions in the next few months as we undertake post-excavation analysis.

I look forward to sharing the results with you.

Thanks to Sigurd Towrie and Orkneyjar