Geochemical evidence for atmospheric pollution derived from prehistoric copper mining at Copa Hill, Cwmystwyth, mid-Wales, UK

Abstract

This paper presents geochemical data from a blanket peat located close to a Bronze Age copper mine on the northern slopes of the Ystwyth valley, Ceredigion, mid-Wales, UK. The research objective was to explore the possibility that the peat contained a geochemical record of the pollution generateD by mining activity. Four peat monoliths were extracted from the blanket peat to reconstruct the pollution history of the prehistoric mine. Three different geochemical measurement techniques were employed and four copper profiles have been reconstructed, two of which are radiocarbon-dated. The radiocarbon dates at one profile located close to the mine confirm that copper enrichment occurs in the peat during the known period of prehistoric mining. Similar enrichment of copper concentrations is shown in one adjacent profile and a profile within 30 m away. In contrast, copper was not enriched in the other radiocarbon-dated monolith, collected approximately 1.35 km to the north of the mine. Whilst other possible explanations to explain the copper concentrations are discussed, it is argued that the high copper concentrations represent evidence of localised atmospheric pollution caused by Bronze Age copper mining in the British Isles. The results of this study suggest that copper may be immobile in blanket peat and such deposits can usefully be used to reconstruct atmospheric pollution histories in former copper mining areas.

Anthropogenic impacts in North Poland over the last 1300years — A record of Pb, Zn, Cu, Ni and S in an ombrotrophic peat bog

“…Numerous studies have concluded that ombrotrophic bogs are probably the best continental Pb archive since these ecosystems only receive Pb from the atmosphere (e.g., Shotyk et al, 1998;Weiss et al, 2002;Mighall et al, 2002). Lead is by far the most intensively studied heavy metal in peat mainly because it is considered by most authors to be immobile in ombrotrophic peat.…”

“…Numerous studies have demonstrated the potential of ombrotrophic bogs to record past anthropogenic activities (e.g., Le Roux et al, 2004;Shotyk et al, 2003 ;Weiss et al, 2002 ;Mighall et al, 2002 ;Brännvall et al, 1999). However, studies dealing with peat inorganic geochemistry in Eastern European countries are scarce (e.g., Fialkiewicz et al 2008;Syrovetnik et al, 2007 ;Mihaljevič et al, 2006;Novak et al, 2003 ;Vile et al, 2000).…”

Atmospheric lead and heavy metal pollution records from a Belgian peat bog spanning the last two millenia: Human impact on a regional to global scale

“…Shotyk et al, 1996Shotyk et al, , 2003Weiss et al, 2002;Martinez-Cortizas et al, 2002;West et al, 1997;Mighall et al, 2002;Novak et al, 2003;Le Roux et al, 2004). Most importantly, peat is particularly effective at preserving atmospheric metal deposition in the form of lead (e.g.…”

“…Most importantly, peat is particularly effective at preserving atmospheric metal deposition in the form of lead (e.g. Shotyk, 2002;Shotyk et al, 1998Shotyk et al, , 2003Vile et al, 1999;Weiss et al, 1999), copper (Rausch et al, 2005;Mighall et al, 2002), nickel (Krachler et al, 2003) and zinc (Rausch et al, 2005;Twardowska et al, 1999). Recent research has shown that ancient Pb contamination in peat can be traced by Pb isotopes and fingerprinted to a local or regional origin (e.g.…”

GEOCHEMICAL AND Pb ISOTOPIC SIGNATURE OFPEATY SEDIMENTS FROM CENTRAL-SOUTH CHILE: IDENTIFICATION OF PARTICLE SUPPLIES OVER THE HOLOCENE

“…This is principally due to possible mobilization of elements linked to the fluctuation of watertable, or leaching by groundwater 7,8 . However other authors [9][10][11][12][13] have demonstrated the potential of mineralotrophic peat to record past climatic or anthropogenic changes.…”