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New Data on the Composition of Magnetic Minerals from Paleosols of Southern Tajikistan |
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| Authors: | Dodonov A E Gorshkov A I Verkhovtseva N V Sivtsov A V Zhou L P |
| Institution: | (1) Geological Institute (GIN), Russian Academy of Sciences, Pyzhevskii per. 7, Moscow, 109017, Russia;(2) Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry (IGEM), Russian Academy of Sciences, Staromonetnyi per. 35, Moscow, 109017, Russia;(3) Pedological Faculty, Moscow State University (MGU), Vorob'evy gory, Moscow, 119899, Russia;(4) Peking University, Peking, 100871, China |
| Abstract: | A dependence of the magnetic susceptibility ( ) on the alternation of paleosol and loess has been revealed for loess sections of southern Tajikistan: the value increases in paleosols and decreases in loesses. The magnetic signal intensification in the paleosol is caused by an elevated content of ferromagnetics. New electron-microscopic data on magnetic minerals from the paleosol have demonstrated that the principal ferromagnetic responsible for high values of the paleosol is biogenic fine-dispersed magnetite. Its particles vary from 0.0n to 0.n  m in size and exhibit crystallochemical characteristics typical for this mineral. Under pedogenetic conditions and participation of Fe-reducing bacteria, the activity of biomineralization is controlled by paleoclimatic variations. |
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