Osteological analysis: bone colour

So Emily, what is osteology? So osteology is the study of human remains, and we can apply this to an archaeological context where we identify the data, and then we can interpret that to reconstruct what life was like in the past. So how would you go about processing information like this? So essentially, what we need to do is systematically order the material in front of us. So I pour the material into a stack of mesh sieves that are different sizes, and that’s the easiest way to start off, really, is distinguish these fragments according to size.

So it would be sizes: 10 millimetre, 5 millimetre, and 2 millimetre. Take all the material out of the 10 millimetre sieve, go through each fragment, identify them as best as I can for what is remaining, separate them in terms of different aspects of the skeleton, and this includes the skull, the axial skeleton, which is the vertebrae, the appendicular skeleton, so legs and arms, and then any material that is unidentified.

Once I’ve separated all of the bone, I then go through and try and identify as much as I can from the small little features, including any sort of pathological lesions, what I could maybe ascertain from sex and age, maybe any animal bone inclusions as well, and also record the weight of the bone at each step. So before we go into looking at the individuals themselves, there’s a lot that you can tell from the bone about the actual pyre itself and how it was constructed. So what can you– I mean, visually, they already look quite different, so what can you tell? First and foremost, bone colour does change as a result of the firing involved.

Bone will transit through a spectrum of colour, from unburnt bone to fully burnt bone, and that goes from an ivory colour to fully white calcinated. And in between that spectrum, you will have greys and blues until, eventually, it does reach this full calcination, which is affiliated with intense burning. So what factors influence the variation of colour? So essentially, the colour is based on the quality of the firing. And the fire itself can be manipulated and influenced by a variety of environmental factors, for instance, the weather at the time, whether it’s particularly windy or whether it was raining as well.

It could be influenced by the quality of the firewood, how much firewood you actually had available at the time, how much oxidisation you had available, so if you did have a sufficient oxygen supply at the time, to keep it burning consistently. So when you’ve got cremation like that one, that looks like it’s got quite a variation of colour, how would that come about? So what we see here is an individual with a whole variety of coloration. We see, we’ve got some very dark blues, we’ve got some greys up until white calcination. So it’s covering the majority of the spectrum of bone colour.

This is a result of quite a varied burn, various factors that could potentially influence the firing at the time, maybe a shorter duration period, they might not have had enough fuel to keep the fire going. It’s also worth considering as well that the colour on the bone is influenced by the distribution of fat within the individual as well, because fat essentially acts as an ignition point for fuel. Knowing that individuals had to pay for their own pyres, and they had to pay professionals to construct them and, I guess, to maintain them, what kind of link can we make between the information that you’re gathering from the cremation and what that means about that person’s funeral and that individual?

You would expect that looking at the bone, for someone who’s had quite an expensive funeral where they’ve been able to employ someone to maintain their funeral pyre, you would expect a very high quality burn. So you would expect the bone to be mostly uniform in colour, very little deviation. But you’d be looking at the colour that’s towards the upper end of the spectrum, so mostly white or potentially grey or blue, but not very much variation from that. You would also expect the, potentially a higher fragmentation rate as well, where the individual has been, and the pyre has been well maintained, potentially the remains being mixed around and turned over to ensure that everything is being subject to sufficient firing.

For someone who is high status and who could employ a professional cremator, you’d almost expect the bone to demonstrate more interference, more manipulation of the material that was left over, and a more consistent burning colour, something that was a bit neater, a bit more uniform. So you talked a lot about colour, but is it only the colour that changes when the bone is exposed to the fire? No, not at all. So when bone is exposed to extreme heat, it also changes in its mechanical formation as well. So quite often, bone can warp, it can twist as well, it can fragment further, and this is all subject to the firing conditions at the time.

So this is the individual that we’re looking at in this course. So what can you tell from looking at these bones about the fragmentation and the colouring and everything you’ve just told us about? So what we can see from this individual here is relatively consistent coloration, OK, mostly white, very little deviation from this pigmentation. There’s also quite extensive fragmentation as well. We do have large fragments, but we also have these smaller fragments as well that are more 5 millimetres in size, if not, smaller. So we should be able to use that information to tell us something about the pyre that this person would have been burnt on, and then hopefully something else about them and their social status as well.

Yeah, absolutely.