THE USAGE OF MODERN TECHNOLOGIES (GIS) IN THE CREATION OF THE LAKE GEOLOGICAL PROSPECTING MODEL AND THEIR USAGE IN PALEOLIMNOLOGY

66-6

FEATURES OF FORMATION OF AUTHIGENIC MINERALS IN HOLOCENE BOTTOM SEDIMENTS OF SMALL LAKES OF WESTERN SIBERIA

119-12

THE FEATURES OF MINERAL FORMATION PROCESSES IN LAKE PETUKHOVO (KULUNDA PLAIN)

77-8

Authigenic Carbonates in the Water–Biota–Bottom Sediments’ System of Small Lakes (South of Western Siberia)

We studied 46 small, drainless lakes in various landscape types: The sub-taiga (Vasyugan plain), forest–steppe (Baraba lowland), and steppe and subzone of ribbon forests (Kulunda plain). Sampling of lake components (sediments, water, and biota) was performed. The materials were analyzed via a combination of modern analytical methods (atomic absorption spectroscopy, X-ray fluorescence, scanning electron microscopy and X-ray diffractometry). It was found that in the south of Western Siberia, lakes with a bicarbonate-sodium water composition are widespread against the background of general landscape zoning. This composition contributes to the abundant growth of biota in the lakes, which leads to the processes of authigenic carbonate formation from calcite–dolomite series and aragonite on geochemical barriers, i.e., drifting biota–water, submerged biota–water, and water–bottom sediments against a background of terrigenous demolition and organic matter accumulation. The article shows the differences in the composition and structure of low-temperature carbonate minerals formed on various geochemical barriers. It was found that low-magnesium calcite and aragonite are the most common authigenic carbonates in small lakes in the south of Western Siberia and are formed on all three geochemical barriers in lakes. High-magnesium calcites and Ca-excess dolomites are formed only at the water–bottom sediment barrier in lakes with HCO3–Na and Cl–HCO3–Na water composition at pH > 9 and with a total dissolved solids > 3 g·L−1 (in some lakes of HCO3-Na composition with a TDS < 3 g·L−1 and pH > 9)

The carbon isotopes ratio in small lakes bottom sediments located in the forest-steppe and steppe zones of southern Siberia

Isotopic variations of carbon of the carbonates and organic matter in bottom sediments of lakes of two lake systems located in the South of Siberia are studied: Baraba (Baraba steppes) and Tazheran (Tazheran steppes). Isotopic studies of δ13C carbonates and organic matter of the lacustrine bottom sediments of the Tazheran and Baraba systems indicate two main mechanisms of authigenic carbonates formation: chemogenic deposition and biochemogenic deposition due to bacterial destruction of organic matter. The dependence of the δ13Corg and δ13Ccarb, the degree of water salinity is not revealed. Forms by chemogenic carbonates are similar to water isotopic values, i.e. with dissolved bicarbonate - ion reservoir. However, in most of the studied lakes the light isotopic composition δ13Ccarb was revealed, as carbonates are formed in the environment with a high content of isotope-light CO2 formed by the oxidation of carbon dioxide emitted by bacteria-decomposers in the mineralization process of the original organic matter in the stagnant waters in the anaerobic environment

THE USAGE OF MODERN TECHNOLOGIES (GIS) IN THE CREATION OF THE LAKE GEOLOGICAL PROSPECTING MODEL AND THEIR USAGE IN PALEOLIMNOLOGY

66-6

FEATURES OF FORMATION OF AUTHIGENIC MINERALS IN HOLOCENE BOTTOM SEDIMENTS OF SMALL LAKES OF WESTERN SIBERIA

119-12

THE FEATURES OF MINERAL FORMATION PROCESSES IN LAKE PETUKHOVO (KULUNDA PLAIN)

77-8

Concentration Levels and Features of the Distribution of Trace Elements in the Sapropel Deposits of Small Lakes (South of Western Siberia)

The processes of the migration and concentration of trace elements during sedimentation in small continental lakes in various landscape zones of the south of Western Siberia have been studied. We provide a quantitative assessment of the concentration levels and changes in the regional geochemical background of Cd, Hg, Sb, Zn, and Pb in sapropel deposits over the past 200 years. It was shown that complex natural processes determined by a combination of azonal factors play a fundamental role in the formation of the geochemical and mineral compositions of the bottom sediments of small lakes in various landscape zones in the south of Western Siberia. These consist of: the formation of sedimentary material in the lake catchment depending on the relief, geology, soil, and vegetation cover, as well as anthropogenic influences; the formation of authigenic organic and mineral matter as a result of biological, biochemical, and physicochemical processes; and the deposition of a complex mixture of allochthonous and autochthonous matter at the bottom of a lake, which flows under conditions of prolonged ice formation (anaerobic conditions)