Geochemistry of Early Diagenesis in Sediments of Russian Arctic Glacial Lakes (Norilo–Pyasinskaya Water System)

The Russian Arctic region is lacking in studies on geochemical changes reflecting early sediment diagenesis lake environments. paper presents new data the compositions of bottom sediments and pore water from two lakes Norilo–Pyasinskaya system Siberia. Lakes Pyasino Melkoye occupy basins left by glaciers that originated Putorana Plateau during Last Glacial Maximum (LGM). Clayey were continuously deposited lakes, depositional environment has changed only slightly for last ca. 20 ka. Two cores with lengths 4.0 3.2 m collected Melkoye, respectively, a Livingstone-type piston corer providing undisturbed, stratigraphically consistent sedimentary sequences. Their analyses revealed change oxidized to reduced conditions at depth ~10 cm. concentrations Ca2+, Mg2+, Na+, K+, as well HCO3−/Ca2+ ratio water, showed depthward increase indicating progressive degradation organic matter. Another trend was gradual decrease SO42− alongside increasing HCO3−/SO42− caused bacterial sulfate reduction, although this rather weak, judging low S (II) bound Fe-sulfides, H2S, etc. Additionally, microbial digestion matter release its mobile components, which led enrichment NO3−, PO43−, DOC. Most analyzed elements (Al, B, Ba, Co, Cu, Mo, Ni, Si, Sr, V, Zn) reach higher than above water-sediment boundary, evidence diagenetic processes. As result redox change, immobile Fe (III) Mn (IV) natural oxides species migrated solid phase eventually precipitated authigenic sulfides carbonates. results are useful better understanding processes different geographical settings over huge Eurasian continent.