Human-environment interactions in the Hadrian's Wall Landscape

You wait a whole year for a blog post, then two come along at once etc. Following the existential musings of the previous post, I figured I'd better post some fun geoarchaeological stuff. I have been working with a number of colleagues on various projects for the past couple of years, that are loosely related, and fall under the general banner of Human-environment interactions in the Hadrian's Wall Landscape. Regular blog readers will remember in 2021 I talked about the new excavations at Birdoswald. These have been progressing nicely, and we have uncovered all sorts of amazing finds and environmental material.

I have also been working with Dr Eline Van Asperen, and Masters student Damian Rudge, looking at long term changes in the environment, and whether these relate to Roman or earlier activities such as lead mining. In 2022 we were awarded a small grant from the Royal Archaeological Institute to collect some peat cores with the aid of local volunteer groups. Eline analysed these for pollen, and Damian analysed them using pXRF (supported by ICP analysis with Dr Simon Chenery at the BGS). The pollen analysis is used to understand how vegetation has changed over time, and the pXRF and ICP provide information on the geochemical signals in the peat, which can relate to environmental change and human activity. Togther the team has produced some very interesting results on the nature and timing of landscape change, though we need a bit more data to assess the extent of these changes, and for it to be ready for publication. 

At Birdoswald, we have been working over the past two years with wood charcoal specialist Dr Dana Challinor, who has been looking at the extensive charcoal deposits we have recovered from the site. Again, some exciting preliminary results, with a very interesting range of species being exploited for fuel. Some of the same species can be seen in the thin section micromorphology samples, which I have been working on. Most exciting, is that in thin section we can see not only the excellent preservation of wood charcoal, but some thick ashy deposits which are full of phytoliths!

Phytolith researchers will know that phytoliths have not been extensively studied in British contexts. There are lots of challenges, largely that the types of deposits which produce good phytolith assemblages are not often present, but also there is a lack of good reference collections. The deposits at Birdoswald are therefore very important, not just for telling us aobut plant use at the site, but for showing that phytoliths do preserve in large quantities on British sites, and it is worth sampling for these.

On the basis of these pilot studies, we have just been awarded a further small grant from the British Academy/Leverhulme, to enable us to a) complete the analysis of the Birdoswald charcoal assemblages, and b) carry out further coring work to get a better idea of the variability of landscape change, and for further radiocarbon dating so we can construct a more detailed chronology. Watch this space!

A. shows a fragment of wood charcoal, B,C,D show various phyotliths embedded in an ashy phosphatic matrix