The dissertation aims to advance the theory and methodology of soil magnetism with a view to applying it to issues in geology, ecology, and soil science. The present state of knowledge of soil magnetism and its applications in Ukraine and worldwide has been analyzed. The first research papers date back to the middle twentieth century in Cuba. There is nowadays a growing interest in soil magnetism research around the world, with the most topical issues in environmental pollution, land degradation and erosion, oil and gas prospecting. A systematic geophysical study of the Earth's soil layer (pedosphere) is the basis for the development of a consistent theory and methodology of applying soil magnetism in geology, ecology, and soil science. The fundamentals of the general theory and methodology of soil magnetism include interpretation and generalization of data on magnetic mineralogical composition, interaction of rocks and soils with the atmosphere, hydrosphere, biosphere, exogenous and biochemical processes, understanding of the nature of soil magnetism, and investigation of the physical and chemical parameters of soil. The practical examples of applying soil magnetism in solving soil and agrarian problems confirm the high information content of the method. The scientific novelty of the investigation has been formulated. There has been proved a close genetic relationship and a strong correlation between magnetic parameters and soil fertility, productivity, degradation, erosion, organic and inorganic matter content, physical and chemical indicators. The changes in the magnetic susceptibility are related to the presence and pedogenic formation of the single-domain stable and superparamagnetic grains of magnetite, maghemite, goethite and hematite with the grain size of tens of nm. Magnetic studies of polluted soils and atmospheric particulate matter accumulating in soil, tree bark, and other flat surfaces, demonstrated their high effectiveness in assessing the overall environmental pollution of the urbanized territories and big cities. It has been determined that the magnetic state of a magnetic material, its grain size and shape depend of the material origin. There has been identified a close genetic relationship between the magnetic properties of soil and the content of heavy metals and other technogenic admixtures. High coefficients of correlation between the magnetic susceptibility and copper, zinc, and lead content in soils have been obtained. Environmental pollution leads to an increase in the values of magnetic susceptibility up to 10-100 times. The frequency dependence of magnetic susceptibility was less than 3. The accumulation of technogenic particles in soils occurs to a depth of 20-30 cm depending on the structure of the soil genetic horizons. Convincing evidence for the man-made pollution of soils is the presence of coarse-grained multidomain magnetite with the sphere size of about 10 microns or larger. Our research results confirm the migration of hydrocarbons to the upper layers of the geological section and to the soil. Moreover, natural and anthropogenic accumulations of hydrocarbons in the soil were observed. These cause secondary authigenic changes in the magnetic mineralogy of soils. We have identified an increase in the magnetic susceptibility of the soil and underlying rocks and magnetization across the area of geological section in the zone affected by hydrocarbons. This increase was up to 2-15 times compared to the background values. The projections of the hydrocarbon deposits on the surface and the corresponding geological anomalies are often comparable with the zones of magnetic and geochemical anomalies. Hence changes in the magnetic characteristics of soils. Iron sulphides in a pseudo-single-domain state were determined as the authigenic magnetic minerals of soils of the Carpathian Foredeep of Ukraine.
