Specificity of elemental composition of Calcic chernozems of Rostov region at the background level and due to anthropogenesis environment

Abstract

The analysis of elemental composition (by ICP method for 70 elements) of Calcic chernozems of the Rostov region in a wide spectrum including rare and scattered chemical elements, the content of most of which was established for these soils for the first time, allowed to reveal geochemical features of these soils. In particular, they are characterized by a rich elemental composition. The mostly studied chemical elements have contents exceeding clarks for soils (clark - average contents for soils of continents). The group of stable excess elements includes: As, Ni, Co, Tl, Sc, Th, as well as rare earth elements (REE). The studied territory is characterized by the ubiquity of carbonate rocks, which are poor in elemental composition among all sedimentary rocks. Thus, the content of soils should be associated with general favorable natural-climatic conditions for soil formation processes and soil with fertile humus, which contributes to good accumulation of chemical elements. REE activity in soils reflects geochemical specialization of regional rocks. The performed traditional ranking of these elements in relation to North American shales allowed us to show the specificity of their regional fractionation, manifested in the predominance of the subgroup of medium and light REEs. It is known that REEs with similar chemical properties are recognized indicators of changing conditions, including anthropogenic activity. Such a pattern can be considered as a background baseline, which makes it possible to identify anthropogenic sources that caused these changes when REE distribution changes. Keywords: RARE EARTH ELEMENTS, SOILS, ANTHROPOGENESIS, FRACTIONATION