GEOCHEMICAL CHARACTERISTICS OF DEPTH PROFILE FROM THE HIGHMOOR PEAT (WESTERN SIBERIA, RUSSIA)

Abstract

We investigated the changes in element content and distribution in peat profile in a study aimed to monitor the geochemical changes accruing in the process of peat accumulation. Changes in the chemical composition of peat ash and underlying sediments have been studied in the central part of the Ubinskoye bog in the foreststeppe zone of Western Siberia. Two parallel peat cores were sampled to a depth of 310 cm. The upper peat layers are characterized by oxidative environment and increased concentrations of elements with variable valence. In addition, high levels of chalcophilic elements have been recorded here, which are associated with the high anthropogenic load of recent decades. In deeper high-ash peat horizons, with an increase in the reducing environment along the peat bog profile, the content of rock-forming elements increases. For Br, Sr, Zn, Se, Mo and Ag, there is a peak in concentrations at a depth of 150-180 cm as a result of the groundwater inflow in this interval. Early diagenetic processes lead to the deposition of autigenic minerals. Therefore, barite is formed on the redox line, pyrite is found in the reducing environment. With depth, the content of Ca, Mg and Sr increases, which leads to the formation of autigenic carbonates.