Д.С. Рыбаков.
Влияние палеопротерозойских образований онежской структуры на геохимические особенности почв Заонежья
Keywords: Zaonega Formation; soils; sod horizon; forest floors; clarkes of concentration; geochemical spectra; ranked geochemical series
The article presents the results of a comparative study of soils developed on Paleoproterozoic rocks, mainly shungite shales, and on the shungite moraine in forest and meadow landscapes of the Zaonezhye region. The comparison was made on the basis of geochemical spectra and ranked geochemical series of different horizons of the studied soils and rocks of the Zaonega Formation of the Ludicovian Superhorizon of the Paleoproterozoic, which are widely represented in the area. The elemental composition was normalized based on clarkes in the earth’s crust and the geometric means (background) content of elements in rocks of the Zaonega Formation taken from the Internet. The rocks have an unusual geochemical specialization (As, Mo, Y, Li, Sc, Be, V, Ba, Cu, Zn, etc.). The content of As, less often Ag, Zn, Cu, V and Mo in the soils is high (above clarkes in the earth’s crust) throughout the area. This is somewhat more characteristic of sod soils without the forest floor horizon. Nb, Ca, Na, Bi, Al are accumulated in mineral soil horizons compared to rocks, Ag and Mg are also added to these elements in the sod horizon. The forest floor accumulates Mn, the content of other elements in it is usually lower than in humus-accumulating horizons. Clarke concentrations of chemical elements in soils are more closely aligned with those in rocks due to differences in the migration ability of elements and the way they are involved in biogeochemical cycles. At the same time, differences in the content of Mo, Be, Li, Y, Sc, As, Cu, Ba, V, Ni, which determine the specialization of the “background” rocks, are particularly high.
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