We have a plague on both our houses (ours and my mother-in-law’s next door). Everyone has a chest infection, we are all coughing like old sheep and the kitchen is vanishing under the piles of the useful dosing syringes you get with Capol: even the two year old sounds like a pensioner asking for twenty Berkley Menthol Kingsize in the corner shop.
It has been a productive week on the project nevertheless. I went to Lancaster on Tuesday to meet up with Mairead and Denise from Oxford Archaeology. They are going to do the specialist analysis on the environmental samples, this is the work we got funding for last month. The point of the meeting was to prioritise which samples they would look at first. This initial assessment phase will allow us to focus most of our energies on those samples where we have good preservation. One of the things we are also looking for is for Denise to identify the charcoal small finds.
Charred plant remains like this can tell you lots of different things about the site and the environment. However, the first priority with our charcoals is to identify the species of the plants. I hope to use some of this charcoal as dating evidence. Good radiocarbon dating needs several things. First of all, you need to be able to prove that your sample is the same age as the archaeology.
For example, this is one of the postholes in the timber circle showing in cross section during 2013. The dark layer at the top is a topsoil which is still developing, anything in here could be very recent. Beneath that, we have the hill-wash which lies over the prehistoric archaeology. There would be no point in dating charcoal from either of these two contexts. Charcoal from the layer beneath might be more interesting. This is the layer that was formed when the posts of the timber circle were removed so, in theory at least, a date from here could tell you when the circle went out of use. This would be even more valuable if you could combine it with a date from the layer at the base of the posthole. Some of this has not been disturbed since the posts were first erected and therefore you could possibly get evidence to tell you when the circle was built and how long it was in use for.
All this is only half the battle: some trees live a very long time. If we try to date the posthole using part of some 400 year old oak we are going to get a date which is too early by 400 years. This is where Denise’s work comes in. She will be looking for charcoal from twiggy new growth on short-lived species for us to date. These species identifications should mean that we can confidently say that whichever samples we chose to date would only have been a few years old and therefore give us a representative date.