'On-site' Isotopic Records of Human-Environment Interaction
In order to properly understand the nature of past human-environment interactions, it is essential to build up palaeoenvironmental proxies of immediate relevance to the archaeological record of interest. In this project, we seek to develop palaeoenvironmental methods tailored to archaeological needs. These focus on a) developing ‘on-site’ proxies of immediate relevance to human behaviour and b) directly guiding the coring of long-term terrestrial sequences, such as lakes, with archaeological knowledge and questions.
The application of stable isotope analysis to studies of past climatic and environmental change has a long history in archaeology. In particular, stable isotope analysis of ice cores, tree rings, and marine foraminifera have been used to develop climatic ‘master sequences’ to which changes in the human cultural record can be linked. However, such records are often located at some distance from the archaeological sequences of interest, and often record conditions in climatic systems that are not of immediate relevance to human populations in different parts of the world.
The Isotope Group of the Department of Archaeology seeks to use stable isotope methodologies to develop palaeoenvironmental proxies of immediate relevance to past human interactions with terrestrial and marine environments. On the one hand we do this by developing ‘on-site’ studies of archaeological materials including faunal tooth enamel, ostrich eggshell, marine shell, sediment, sediment carbonates, and organic single-compounds within archaeological sediments. Application of these methods is helping to provide more accurate records of temperature in Lesotho, aridity in Saudi Arabia, and forest density in Sri Lanka and Melanesia.
The other branch of this project involves development of programmes of archaeologically-directed palaeoenvironmental sampling of long-term terrestrial sequences. Novel biogeochemical methods, including the stable isotope analysis of leaf waxes and cellulose-derived sugars have been demonstrated to provide detailed insight into vegetation, precipitation, and temperature in palaeoclimatological research around the world. However, while these have begun to be applied in archaeology, records often remain at some distance from archaeological sites of interest. We seek to not only develop these methods in an archaeological context, but also apply them to sequences that can be used to answer pressing archaeological questions relating to human-environment interactions.
Roberts, P., Henshilwood, C.S., van Niekerk, K.L., Keene, P., Gledhill, A., Reynard, J., Badenhorst, S., & J. Lee-Thorp. 2016. Climate, environment and early human innovation: stable isotope and faunal proxy evidence from archaeological sites (98-59ka) in the southern Cape, South Africa. PLOS ONE: doi:10.1371/journal.pone.0157408
Roberts, P., Perera, N., Wedage, O., Deraniyagala, S.U., Perera, J., Eregama, S., Gledhill, A., Petraglia, M.D. & J.A. Lee-Thorp. 2015. Direct evidence for human reliance on rainforest resources in late Pleistocene Sri Lanka. Science 347: 1246-1249.
Roberts, P., Lee-Thorp, J.A., Mitchell, P.J., & C. Arthur. 2013. Stable carbon isotopic evidence for climate change across the late Pleistocene to early Holocene from Lesotho, southern Africa. Journal of Quaternary Science 28: 360-369.