pdf № 352, April

DOI: 10.19110/geov.2024.4.1

The article is devoted to the archaeological and mineralogical analysis of metal products from burial No. 59 from the Kokpomyag burial ground of the Vym culture in Vychegda Permian, dating from the mid-12th to the first half of the 13th century. The chronological framework of the burial is determined, a description of the grave goods is given, and imported silver jewelry from the Perm Kama region and Volga Bulgaria is found. Using analytical SEM, 13 artifacts of copper, bronze, brass and silver composition, the phase and chemical composition of the objects have been studied in detail. The results of the research indicate that Perm foundry workers from Vychegda possessed not only the technology of bronze foundry production, but also silver jewelry making.

Keywords: archaeomineralogy, Kokpomyag burial ground, Vychegda Perm, bronze and silver jewelry

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DOI: 10.19110/geov.2024.4.2

Based on the study of core material, the lithological features of the deposits of the Kolgan formation of the Frasnian stage in the southwestern part of the East Orenburg arch uplift are considered. This formation is an important oil and gas play. Since picking, almost nonintermittent prospecting and exploration works have been carried out. A large bulk of heterogeneous material is received and processed, which complement and expand the knowledge of the geological structure and genesis of sediments. The research was carried out by petrographic and lithological methods. As a result, 5 lithotypes were identified according to the ratio of carbonate and terrigenous components and structural and textural features. It was found that the carbonate component prevailed in all the selected lithotypes, which distinguished this formation from other similar sections, where terrigenous rocks predominated. The presence of bioturbation of varying degrees of intensity and the presence of tempestites is characteristic.

Keywords: Frasnian stage, Kolgan formation, lithotypes, tempestites, carbonates, bioturbation

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DOI: 10.19110/geov.2024.4.3

We briefly outlined the history of discovery and study of concentration flows accompanying the growth and dissolution of crystals in solutions. Various crystallogenic consequences associated with concentration flows (changes in the mechanisms of transport of matter to the growing crystal, differences in the growth of the upper and lower faces, distortion of crystal shape, occurrence of hydrodynamic boundary layer around a crystal together with the diffusion layer, etc.) were described. The phenomenon of concentration differentiation (stratification) of the solution under the influence of concentration flows was especially analyzed. The criteria conditions for differentiation of the solution during crystal growth were determined.

Keywords: Growth and dissolution of crystals, concentration flows, differentiation of solution during crystal growth, holographic and shadow methods for observing concentration flows

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DOI: 10.19110/geov.2024.4.4

The paper proposes the derivation of 25 combinatorial-geometric kinds of tetrahedrons belonging to 8 point symmetry groups. Among them are 3 simple forms: cubic (-43m), tetragonal (-42m) and rhombic (222) tetrahedrons; and 5 combinations: trigonal pyramid and monohedron (3m), 2 planar dihedrons (mm2, 2 kinds), 2 axial dihedrons (2, 3 kinds), planar dihedron and 2 monohedrons (m, 5 kinds), 4 monohedrons (1, 11 kinds). It is shown that tetrahedrons with symmetry 23, -4 and 3 — subgroups of the point symmetry group of the cubic tetrahedron — are impossible. The example is recommended for consideration in the course of crystallography on «simple forms and their combinations».

Keywords: tetrahedron, simple form, combinatorial geometric kind, combination of simple forms, symmetry point group
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