The magnetic diagnostics of cosmic and industrial silt in humus horizons of soils (abstract)

Abstract

In the early 50s the increase of magnetic susceptibility in head horizons of soils has been observed. The reason was accepted to be forest and steppe fire. Later we discovered that the increasing of susceptibility and magnetic saturation was observed more clearly in the soils developed on weak magnetic native rock (loam, carbonate) and the magnetic fraction was separated from these soils in a more simple fashion. An abnormal increase in magnetic parameters is observed in primitive soils and the debris layer of dry forest (particularly of pine forest). The investigations have shown that magnetic particles (MP) are contained in ash of electrostations, in buried and modern soils, in humocoll and coal sheets, and in air of industrial cities and of the country. A high magnetic separated fraction (MV) contains particles (P) that differ by morphology and color. MF of soils is separated in a difficult manner from the rest mass (it also contains α-Fe, magnetite, hematite) and is contaminated by magnetic particles from native rock. We obtained that only spherical particles contribute to the soil magnetism from (10...50)×10−6 sm3/g to (100...150)×10−6 sm3/g. MP come into modern soils from all sources. Magnetic particles are well conserved in automorphic and nonlogging buried soils, and in humocoll layers. Among humocoll layers investigated by us there were layers dating over 50 thousand years ago.