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GEOCHEMISTRY OF POROUSWATER OF ORGANIC-MINERAL DEPOSITS OF LAKE KOTOKEL (EASTERN PRIBAIKALYE) AND THEIR TRANSFORMATION IN EARLY DIAGENESIS

A. E. Maltsev 1, G. A. Leonova 1, L. V. Miroshnichenko 1, L. M. Kondratieva 2, V. A. Bobrov 1, Iu. S. Vosel 1, S. B. Zaiakina 1, A. S. Shavekin 1, S. K. Krivonogov 1, 3

1 V. S. Sobolev Institute of Geology and Mineralogy, SB RAS, Novosibirsk, Russia; 2 Institute for Water and Environmental Problems, FEB RAS, Khabarovsk, Russia; 3 Novosibirsk National Research State University, Novosibirsk, Russia

The chemical composition of the pore waters of organic-mineral sediments of Lake Kotokel (Eastern Baikal) and their transformation in the early diagenesis has been studied. Regularities of changes in the basic chemical composition of pore waters (HCO3–, SO4 2–, Cl–, Ca2+, Mg2+, K+, Na+), the distribution of biogenic elements (silicon, phosphorus, ammonium and nitrate-ion) and trace elements are considered (Fe, Mn, Sr, Ba, Pb, As, Co, Ni). An increase in pore water concentrations has been established HCO3–, NH4+, PO4 3– и Si, which is a consequence of the organic matter destruction. In the process of bacterial sulfate reduction in the pore waters, the concentration of SO4 2– decreases along the depth of the section and there is an increase in S (II) and framboidal pyrite in the sediment.

Keywords: pore water, geochemistry, diagenesis, organic matter, trace elements.

DOI 10.20403/2078-0575-2019-1-71-85