Mercury in a Spanish peat bog: Archive of climate change and atmospheric metal deposition

A. peat core from a bog in northwest Spain provides a record of the net acc umulation of atmospheric mercury since 4000 radiocarbon years before the pr esent. It was found that cold climates promoted an enhanced accumulation an d the preservation of mercury with Low thermal stability, and warm climates were characterized by a lower accumulation and the predominance of mercury with moderate to high thermal stability. This record can be separated into natural and anthropogenic components. The substantial anthropogenic mercur y component began similar to 2500 radiocarbon years before the present, whi ch is near the time of the onset of mercury mining in Spain. Anthropogenic mercury has dominated the deposition-record since the Islamic period (8th t o 11th centuries A.D.). The results shown here have implications for the gl obal mercury cycle and also imply that the thermal lability of the accumula ted mercury can be used not only to quantify the effects of human activity, but also as a new tool for quantitative paleotemperature reconstruction.