I seem to have spent most of this week in pursuit of either money or favours. Not for myself, you understand, but purely for the greater good of the project. A research funding opportunity has come up within the university to allow us to bid for more support and so I have spent a lot of the last two weeks writing an application for that. I could try to claim that this was why there was no post last week. However, if I am honest that had more to do with half term and spending time eating ice cream and chips in Blackpool.
If we get it, I have decided to use this money to get some of the analysis done on preserved plant remains of various kinds. There are different kinds of these samples. Bulk soil samples, like the ones being collected in this picture by Katie and Jack, should hopefully pick up 5 litres-worth of all the preserved macroscopic plant remains in that layer. Once you have your tub of soil you pump water through it to make the plant remains (which are generally lighter than soil) float out so you can catch them in sieves. We have already done this with most of the samples, which leaves us with a small collection of tiny bits of charcoal from each layer we sampled.
Of course, we also have lots of bigger chunks of charcoal which we identified on site and picked up with the other small finds. A big part of the bid I have just submitted is to get the money to pay and archaeobotanist to identify all the plant species in this charcoal. As we already understand (we hope) the archaeological relationships between all the layers then this should allow us to see how the charcoals on site change over time. This should include both the wood that people are collecting and deliberately burning on site as well as other local planty bits which happen to have got into fires and got burnt.
All of this will tell us quite a bit about the landscape and environment around the caves and enclosures we work on but, as it relies on things getting charred to preserve them, it will inevitably be only a partial picture. Our third possible source of plant remains is fossil pollen. You sample for pollen in a different way, digging a continuous block of soil out of a section, like this one at the back of Fairy Holes Cave. If you are lucky, then the soil conditions have been damp enough to preserve a representative sample of all the pollen which was drifting around on the breeze at the time the layer formed. If you sample at enough points down the column it should be possible to look at how the local vegetation changed through time.
The other bonus to all this analysis of plants is that, once we know what kind of charcoal we have, then we will know if we can apply for money from the Natural Environment Research Council to have it radiocarbon dated. Radiocarbon labs are understandably reluctant to date charcoal unless they know exactly what it came from. Trees live a long time, so for a charcoal date to tell you anything meaningful about the date of a pit then you want to be dating a little twig that sprouted the year it was buried, rather than a chunk of the middle of an oak that was already 150 years old when it went in the ground.