Dr Jo McKenzie has kindly volunteered to write the blog today………….Hello from the beginning of the end – the last week of the Cairns 2018 field season! (and sadly, my last day on site).
Time seems to have gone very quickly, and it doesn’t seem a year since I was last at Cairns sampling the amazing sequence of floor deposits preserved within, especially, the north-eastern quadrant of the broch.
You’ll have seen some of the images of these floors in several of Martin’s posts – beautiful, intricate lenses of material, each tiny layer representing a different episode of activity and deposition by those who were the last before us to spend their days ‘doing stuff’ in the Cairns broch.
I use a technique called soil micromorphology to take small ‘block’ samples which are then used to make microscope slides, allowing us to analyse complex deposit sequences like the broch floors in enormous detail – as outlined in my blog from last year (LINK). Here’s a shot of one of those samples being taken. This tin is just 5×7 cm, but that’s plenty big enough to give us a fantastic sample through the many deposits in this small section through lenses of probable charcoal, burnt peat, burnt stone, bone and much more.
We now have a great sequence of samples through these complex deposits, traversing the north-east quadrant and nicely aligned within our 50cm grid (affectionately known as Terence for no good reason, except I suppose that it helps to be able to make a personal apology when you’ve kicked yet another of Terence’s nails out for the umpteenth time that day – as fellow north-east quadrant-ers Ole, Ross and Mike can testify!)
We’ve also been lucky enough to get enough depth of deposit to take a sample close to the large hearth setting in the north-west area of the broch, which is really good news as the closely-packed layers of paving in this area make getting good samples a challenge. Here’s today’s sample extracted, and turned carefully over for the excess material to be carefully shaved off the back of the tin so that the sample can be sealed. A lovely sample of dark, dense carbonised material representing activity around the cracked hearth surface.
It’s intriguing to spot tiny features within the tin samples which I know will be so interesting to examine in detail under the microscope – fine laminations of material, or inclusions such as charcoal or bone. Here’s an example of what must be pretty much the tiniest bones we find on site – a fish vertebrae, seen adjacent to the tin taken next to the north-west hearth setting, seen here magnified under my small geological viewer.
It’s also been great to see the site making such amazing progress – so many new structures being uncovered outside of the broch with Bobby’s team, and spending these last few days working right alongside the fantastic discoveries still being made inside the well. Above all, it’s been brilliant to get the chance once again to work with the great Cairns team – students, volunteers and old hands alike. I think today must have been the busiest I’ve ever seen the broch interior – and needless to say, there was plenty of archaeology for every pair of hands to tackle!
Roll on next year.