Genesis of Organomineral Deposits in Lakes of the Central Part of the Baraba Lowland (South of West Siberia)

Abstract

—A quantitative assessment of the fractionation of elements during sedimentation is made based on long-term comprehensive studies with the participation of geochemists, hydrobiologists, soil scientists, and chemists. Analytical studies of the chemical composition of water, soil, bottom sediments, and biota were carried out at the Center for Collective Use of Scientific Equipment for Multielement and Isotope Studies and at the Institute of Catalysis, Novosibirsk. Based on a mineralogical and geochemical approach, we chose lakes with different types of biogenetic formation and different classes of organomineral sediments and performed detailed studies of the relationship between the organic and mineral parts of the sediments. It has been established that the organomineral sediments of different classes and biogenetic types of formation differ not only in the contents of major elements (Si, Ca, C, and O) but also in the group composition of organic matter. The direct effect of the transformation of organic matter on the mineral composition of bottom sediments has been revealed. The contents of other elements vary in a narrow range of values. At the same time, the difference in the contents of elements between organomineral sediments of different types and classes is comparable with their difference within a class. The leading role in the formation of the geochemical and mineral compositions of the organomineral sediments of small lakes belongs to intricate biological, biochemical, and physicochemical processes depending mainly on azonal factors and occurring under prolonged freezing-up (anaerobic conditions).

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

“…However, the autochthonous organic matter was significantly modified while recycled in the "microbial loop", and this notably affected the final forms of compounds coming to the sapropel. The significant biogenic contribution to the organic matter flow into the bottom sediments of small lakes in the south of Western Siberia was considered circumstantially in various papers [33][34][35].…”

“…Most lakes are mixed in terms of the dominant production type. Features of the composition and genesis of bottom sediments of various classes are considered in detail in [35].…”

Features of the formation of primary production in small lakes of various natural zones in the south of Western Siberia

“…The work was carried out on the basis of longterm studies (2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016)(2017)(2018)(2019) of the productivity of aquatic phytocenoses of small lakes located in various natural (forest, forest-steppe, steppe, mountain-forest, mountain-steppe) and hydrological and climatic zones of the south of Western Siberia (Zarubina, 2013;Strakhovenko et al, 2019;Zarubina and Fetter, 2019;Zarubina and Sokolova, 2019).…”

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

“…This is manifested within a single lake system (a system of compactly located lakes in the same landscape-climatic and geological-geochemical conditions) [1]. These lakes are sensitive to climate change and anthropogenic impacts, which allow us to study the role of these factors in the formation of the geochemical composition of sapropel deposits [2][3][4][5]. Sapropel is the bottom sediment of reservoirs formed under anaerobic conditions because of biochemical, microbiological, and mechanical processes and consisting of the remains of dying plant and animal organisms and organic and mineral impurities introduced into the reservoirs [6][7][8].…”

“…We have previously conducted complex lithological studies with the establishment of the material composition features of sapropel lake systems and the identification of geochemical and mineral composition patterns depending on the hydrochemical, hydrobiological, geological, and hydrological conditions of sapropel formation. Based on the resulting database of analytical data, sapropels were classified according to types, depending on their ash contents and classes according to their Si/Ca ratio, as well as the dominant primary products, i.e., planktonic, macrophytic, and mixed [2,3,24,25]. The major element composition of the sapropels of the studied lakes is dominated by silicon (SiO 2 59-5%), aluminium (Al 2 O 3 14-1%), and calcium (CaO 20-1%).…”