Geochemical features of soils of Valaam Island

The objects of the study are rocks and soils of the Valaam Archipelago. The archipelago is composed of igneous rocks of basic composition and Quaternary sediments, which caused the unique diversity of natural complexes on its territory. Due to a very weak expression of technogenic pollution, the study of the chemical composition of Valaam soils becomes especially relevant, as it allows tracing the connection between the geochemical composition of the upper soil horizons and rocks. The composition of the upper horizon (0—10 cm, 141 samples) and 141 samples of parent materials was analyzed by X-ray spectral analysis. Additionally, the geochemical composition of the main soil types was analyzed by genetic horizons of the profile. A database of the chemical composition of soils on Valaam Island was made. Information on the composition of the soil-forming rock, soil type, relief character and agricultural use was included for each sample. The data were processed using Statistica-5. We found that the type of parent material was one of the main factors determining the geochemical properties of the upper soil horizon. According to the associations of chemical elements, the island soils were divided into 4 groups: formed on gabbro-diabases, monzonites, lake-glacial clays and sands. Associations of chemical elements inherited by soil from bedrock, depending on relief and characteristic for different types of soils, were revealed.