Iron Age Post-excavation The Cairns

Radiocarbon dates shed light on life and death in the Iron Age

Analysis of the human jawbone deposited outside The Cairns broch has given new insights into the formal closure of the monumental structure at the end of its life.

Analysis of the human jawbone deposited outside The Cairns broch has given new insights into the formal closure of the monumental structure at the end of its life.

In July, the excavation team found the jawbone, which had been placed in the upper fill of a large vessel, carved from the vertebra of a whale.  It also contained the semi-articulated remains of three newborn lambs, and other animal bones.

The whalebone container had been deposited against the outer wall of the broch, near its entrance.

Propped against the side of the vessel were two red deer antlers placed upright, on-end.  The shed antlers were both right-sided and therefore from two different animals. On the opposite side, a very substantial saddle-quern had been placed snug against the base of the whalebone vessel.

Previously it has been suggested that the jawbone – which belonged to an elderly woman – might be much older than the deposit it had been placed in. This is because Iron Age communities may have been curating fragments of their ancestors, using them to add drama and significance to rituals performed at important times in the life of the community.

The new radiocarbon dates, however, make this unlikely and it seems the woman died shortly before her jaw was deposited outside the broch.

Time of death

The location of the whalebone vessel against the outer wall of the broch.

The woman died between AD120 and AD240, in the latter part of what is conventionally termed the Scottish Atlantic Middle Iron Age.  One of the lambs returned a radiocarbon date of AD89 to AD214.

The semi-articulated nature of the lamb remains means that this date is the time the deposit was placed outside the broch and is, therefore, an independent verification of the date for the human bone.  The dates largely overlap, meaning the jawbone is unlikely to represent a curated item.

Instead, the date of the woman’s death is in the last occupation period of the broch, before it was partly demolished and infilled with rubble (AD84-210).

It seems likely that deposit was part of the measures taken to formally decommission the broch at the end of its life. 

The life (and unusual diet) of the individual

Because we only have a mandible, it’s not possible to produce a full biography of the woman.

A preliminary assessment, however, is providing useful insights into her lifestyle.  It suggests the jaw belonged to a woman aged between 50 and 70 – a considerable age for the period.

She seems to have led an active working life judging by the condition of the teeth – only two were left! The jawbone had grown over most of the missing teeth sockets, showing they had fallen out during her life. This may have been brought about partly through using the mouth to tightly clamp materials, such as grasses and straw, while working on them with her hands, perhaps making plant-fibre items such as bags and containers.

The teeth that remained were substantially worn, possible from a combination of the above and the abrasive grit accidentally included in products made with flour produced on quernstones.

Isotopic analysis showed she had consumed a surprisingly high quantity of marine-derived protein (probably largely fish).  Most isotopic studies of human remains from the Middle Iron Age tend to show very low or imperceptible levels of fish proteins in the human diet. 

This might seem surprising considering the island nature of Iron Age Orkney, but this lack of fish is also notable in Iron Age period middens. These heaps of food waste very rarely contain much in the way of fish at all. 

The fact we have evidence of substantial fish consumption is intriguing and perhaps marked her as special.  We are, after all, very often reminded that we are what we eat!

Looking across the interior of The Cairns broch.

The new data makes events at the end of the broch all the more interesting. 

A curious aspect of the late occupation deposits inside the broch is that, unlike the majority of Middle Iron Age buildings, there was fairly substantial amounts of fishbone strewn across one of the uppermost floor horizons. This has been interpreted as large quantities of small fish being smoked inside the broch in a final episode of activity.

Is there some connection between the woman, whith her unusually high marine protein diet, and the fishbones inside the broch late in its occupation?  Further work will be required to figure out if the marine contribution to her diet occurred throughout her life, or only at a certain point, or episodically, but the coincidence is intriguing, and also, perhaps, supports the suggestion that he is very much someone who was strongly associated with the broch.

It seems likely that the woman lived in the last half century, or so, of the monumental phase of the broch, before it went out of use.  When she was a young woman, the towering broch, and its surrounding settlement, would still have been the paramount place in the landscape and was, most likely, a potent symbol of authority and order. 

Indeed, it is very tempting to think that the woman was a member of the broch household, and that by the time of her death, she was considered to be an important member of the community, perhaps an elder. 

It may not be pushing this line of consideration too far to suggest that it was her death that occasioned the final abandonment and decommissioning of the broch.  There examples in the ethnographic literature, from different cultures around the world, where the death of an important person – who had a significant association with a particular house – resulted in the end of that entire house as well. 

Perhaps the woman’s death was the final impetus required to end the broch in a period when perhaps its use and integrity had already been in decline for a time.  More analyses in the near future should add even more detail and fascinating new elements to this developing story of life and death during the Iron Age.

Martin Carruthers would like to thank Orkney Archaeology Society for funding the new radiocarbon dates.