ИСТИНА

The object of the study are hydrothermal clays common in the thermal fields of the Pauzhetsko-Kambalno-Koshelevo region of South Kamchatka. Hydrothermal clays are soils formed during hydrothermal processing from volcanic rocks in areas of modern volcanism. Previous studies have shown that such formations contain areas composed of mineral nanostructures. The authors refer to the nanostructure as the spatial organization of a substance composed of structural elements less than 100 nm (nanocrystals, nanoparticles, nanolayers, etc.). Hydrothermal clays are characterized by zonal development of clay minerals. In the upper zone (up to a depth of 0.5 m), the so-called “sulfuric acid leaching” zone, kaolinite and mixed-layer formations like kaolin-smectite prevail. In the lower zone (with a capacity of 0.5-1.5 m and more) - “carbon dioxide leaching”, dominated by minerals of the smectite group, mainly montmorillonite. The granulometric composition of clay samples contains from 5-8 to 28-30% nanoparticles. The mineral composition was studied with a Rigaku Ultima IV X-ray diffractometer. Nanofraction consists mainly of kaolinite (Fig. 1 a), illite, smectites (Fig. 1 b) and mixed-layer minerals kaolinite-smectite, opal, iron oxides. Studies using a scanning electron microscope (SEM LEO1450VP) have shown that the microstructures of hydrothermal clays are most often of an inherited (pseudomorphic) nature. Nanostructures have very high porosity and belong to the domain-like (Fig. 1 a), globular-lamellar, honeycomb (Fig. 1 b) and spongy types of structures. The high physicochemical activity of such clays, as well as the concentration of basic ore, alkaline and rare-earth elements in them can be explained using the data obtained. This research was supported by Russian Foundation for Basic Research (Grants 17-05-01045a). The studies were carried out using the equipment obtained as part of the MSU Development Program.