Some aspects of soil formation on biogenic silicious rocks in Trans-Urals

Diatomites of the Paleocene-Eocene age are widespread in the Trans-Urals and act as soil-forming rocks in river valleys. At the same time the direction and nature of the processes of soil formation on such deposits are practically not studied. The paper presents the results of studying soil formation on diatomites for the territory of the Middle Trans-Ural region within the Sverdlovsk region. The main methods used for studying the soil formation process on diatomites were the soil-morphological and micromorphological ones. The studied soils, formed under pine forests on the indigenous banks of the river, can be classified as sod-podzolic ( Albic Luvisols ). They are characterized by the presence of the strong bleached eluvial strata, with a characteristic structure and visually diagnosed traces of dissolution of the original rock. When studying in thin sections and using a scanning electron microscope, it is found that the processes of soil formation occur synchronously with the dissolution and destruction of silicon microfossils. The preliminary results obtained indicate that soils on diatomites and other rocks enriched with biogenic silica are unique natural objects, and their study can be useful for understanding the role of the lithogenic base in the formation of the silicon cycle and the contribution of biogenic silicon to soil formation.