A Palaeoenvironmental Investigation of Sediments from the Prehistoric Mine of Copa Hill, Cwmystwyth, mid-Wales

This paper investigates the use of mine sediments to reconstruct the vegetational changes and atmospheric pollution history associated with prehistoric and Mediaeval metal mining in the Ystwyth valley, Dyfed, mid-Wales. Pollen, charcoal, plant macrofossils, fossil insects and chemical analyses are presented from radiocarbon-dated sediments contained within a prehistoric mine situated on the upper slope of Copa Hill, close to the village of Cwmystwyth. The results provide additional support to the hypothesis that prehistoric mining had a negligible impact on woodland and that deforestation took place after Bronze Age mining ceased. Although high concentrations of Cu, Pb and Zn were determined from sediments of prehistoric and Roman Age, the patterns bear little resemblance to off site atmospheric pollution records and to the archaeological evidence for metal mining. Interpreting geochemical data from mine contexts is problematic as numerous factors influence the distribution and concentration of metals. However, an on-site and off-site approach to investigate human-environment interactions caused by metal mining is advocated.