150 years of trace metal, Pb- and Os-isotope deposition to the Wildseemoor and its spatial variation

• Applicants: Dr. Michael Brauns; Dr. Gerhard Brügmann
• Subject Area: Mineralogy, Petrology and Geochemistry
• Term: from 2015 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 261995436

During the DFG project, variation of various trace metals and Pb isotopes in living Sphagnum mosses (peat bog surface) within a peat bog and between peat bogs of different regions was determined. The annual production of the living mosses, thereby, had a strong impact on the calculated accumulation rate. Pb isotope results were in good agreement with results from other archives. Based on this, we want to determine the temporal and spatial variation of atmospheric trace metal deposition as well as Pb- and Os isotope composition within a peat bog for the last 150 years. To do that five 1m deep peat columns of a northern black forest bog (Wildseemoor) will be analytically studied, dated (14C for the oldest peat layers, 210Pb for the upper 60 cm (around 150 years) and 14C bomb-pulse for the youngest peat layers (last 50 years)) and metal accumulation rates through time will be compared with each other. A main goal is to find out how well these five peat cores represent the atmospheric deposition into the whole peat bog and whether possibly less peat cores are sufficient to reconstruct atmospheric deposition reliably. Further goals will be to connect metal accumulation rates with Pb and Os isotopes as well as to optimize this method for using the archive peat bog for other tracers than the up to now well established. Moreover findings of Os deposition into peat bogs can help to improve our understanding about the whole cycle of PGE elements. Using the data of the last 40 years, the importance of catalytic converters can be compared to other Os sources. The whole project will be split into two projects following in time. First we want to analyze and study only two peat cores. The stress in interpretation will be on the comparison of Pb and Os versus time.

• DFG Programme: Research Grants
• International Connection: Canada
• Participating Person: Professor Dr. William Shotyk