Detrital input to spring‐fed fen deposits – a problem or an opportunity in palaeoenvironmental studies? A Holocene palaeoclimatic reconstruction from central Europe

The sedimentary sequence of a spring‐fed fen located in north‐east Poland was investigated to verify the applicability of spring‐fed fen deposits in palaeoenvironmental studies. We hypothesize that spring‐fed fen deposits accumulated on the hill slope are a reliable proxy for regional hydrological changes, although they may be modified by local factors. Results of combined sedimentological, plant macrofossil, geochemical and isotopic analyses were compared with palaeoclimatic reconstructions at the nearby lakes Purwin, Kojle and Perty situated within the same sedimentary basin. The 700‐cm‐long sediment sequence from the fen was deposited between 10 900 cal a BP and recent times. The sequence starts with a lacustrine stage, but ca . 9200 cal a BP the lake changed into a spring‐fed fen functioning within a fen surrounding Lake Purwin. Highly variable SiO 2 content and stable isotope (δ 13 C and δ 18 O) values of carbonates, both controlled by inwash of detrital material from young glacial deposits, were found to reflect changes in hydrology with major regional shifts in climate humidity being recorded. Links were found with lake level changes and peatland record of humidity in northern and eastern Poland, the Baltic area and Central Europe, and with climatic records in Scandinavia.