Dr Kimberley Davies
University College Cork
Venue Ricmond JSB

“Messy, muddled and murky: using off-site environmental archaeology to investigate wetland settlements in Scotland and Ireland”

Kim Davies, on behalf of the Celtic Crannogs team

Maarten van Hardenbroek, Nicki Whitehouse, Helen Mackay, Pete Langdon, Andrew C. G. Henderson, Katie Head, Thierry Fonville, Phil Barratt, Tony Brown

Humans have always been attracted to lakes as resource hotspots. In the Iron Age to Medieval Period in Ireland and Scotland, this attraction is reflected in lakeside settlements and in the construction of artificial islands called crannogs, in thousands of small and largely lowland lakes. Due to the nature of these archaeological sites, excavations of these wetland structures can be logistically and financially challenging, meaning our ideas concerning prehistoric wetland societies are based on a limited number of sites. Sedimentary records from very close to archaeological sites offer the opportunity of retrieving information from a range of proxies around lakeside settlement usage and environmental impact that would otherwise be difficult to obtain without excavation.

We can detect activities with both high-temporal and high analytical resolution that appear to have had profound effects on and within small lake environments that were typically sensitive to environmental change. These methods also allow us to place these records within a wider environmental context that can aid our understanding of local and regional conditions across the time period in question. Our research on crannogs and lakeside settlements characterises the prehistoric human-environment interactions associated with crannogs by analysing geochemical (sedaDNA & biomarkers) and biological signals (diatoms, biogenic silica, invertebrates) preserved within both the crannog and wetland/lake sediments.

The sedaDNA provides detailed information about the plants and mammals that lived, died, or were kept on the sites in different periods of site use. This information is compared with a range of traditional palaeolimnological proxies that allow us to differentiate between (i) changes that happened regionally in the lake catchment (based on pollen, x-ray fluorescence scanning, stable carbon and nitrogen isotopes, n-alkanes), (ii) changes that happened in the lake ecosystem (based on loss-on-ignition, diatoms, biogenic silica, invertebrates, C:N ratios), and (iii) changes that occurred very locally at the sites (based on pollen and spores, invertebrates, sterols, PAHs, and sedaDNA).

Our sedaDNA and biomarker results complement data from both archaeological excavation and traditional palaeoenvironmental proxies to provide a more detailed and robust image of the environment in which our ancestors were operating. We also show that different proxies in the same sediment core provide insights in past environments at different spatial scales.

Location

University of Bradford