pdf № 297, September

DOI: 10.19110/2221-1381-2019-9-3-9

Monitoring of changes in carbon dioxide concentration in the Kungur Ice cave was conducted from September 2017 to February 2019. Carbon dioxide was an important component of the gas composition of the cave, since its elevated values during excursion activities could be dangerous to human life. Constant monitoring allows to avoid negative consequences and take measures to prevent them.

This paper presented a generalized analysis of factors that affect the concentration of carbon dioxide in the underground space. In the course of the research, the main (temperature conditions on the surface and in the cave) and secondary (pressure in the cave, fracturing, mineralization of water) factors influencing the dynamics of carbon dioxide content in the grottoes were identified. A correlation estimate was made between CO₂ variations, microclimatic parameters (surface and cave temperatures, pressure in the cave) and lake water mineralization. In winter and summer periods of 2019, one-time measurements of air flow velocities were carried out in different microclimatic zones of the cave, fracture coefficients of the massif of Ledyanaya gora within the development of the cave and air flow were calculated to establish a relationship between carbon dioxide concentration, air flow and mass fracture.

Keywords: Kungur Ice Cave, carbon dioxide, air temperature, CO₂ dynamics, fracturing of rocks.

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DOI: 10.19110/2221-1381-2019-9-10-16

The hydrocarbon composition of organic matter from outcrops of Domanik Formation along the Pymvashor river at the Chernyshev swell was studied. The biomarkers distribution in the samples was variable. It depended on the lithological composition of the rocks and depositional environment of organic matter. The extracted bitumens from calciferous argillite had differences in the distribution of n-alkanes (maximum at n-С_13 — n-С₁₈), higher Pr/Ph ratio and higher content of hopanes. Organic matter maturity was defined based on sterane and homohopane biomarkers indicators and aromatic maturity parameters. All maturity indicators suggest that the organic matter of Domanik Formation was in the peak stage of oil generation (R_o ~ 0.6—0.75 %). This level of maturity is also confirmed by conodont Color Alteration Index (CAI) values in the range of 2.5—3. Based on the differences in the biomarkers distribution of the organic matter Domanik Formation, the oils generated by it would have different hydrocarbon features.

Keywords: Chernyshev swell, Domanik Formation, organic matter, biomarkers.

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DOI: 10.19110/2221-1381-2019-9-17-22

For the first time, information is provided on the discovery of rare dolomite-calcite carbonatite in the dyke in the Svetlinsky gold ore deposit in the South Urals, rare sulfides of Ni, Zn, Cu, Cr and V: vaesite, kalininite, sulvanite and patronite. With each other and with the surrounding crystals of dolomite and calcite, they have surfaces of simultaneous growth. Extremely small sizes crystals (less than 30 microns) make it impossible to study the physical properties of minerals, to give their X-ray characteristics. Data on the chemical composition of sulfides was obtained by SEM REMMA-202 M. Sulfides (including pyrite) were found in the form of very fine dispersed impregnation in the dark bands of carbonatites enriched with fluorophlogopite crystals, native sulfur and hydrogen sulfide localized in microporous areas of calcite crystals. The confinement of such sulfides in all their occurrences mainly to carbonate rocks is emphasized. The ubiquitous enrichment of mineral impurities in such carbonatites with fluorine, chromium, vanadium and nickel may indicate the participation of ultrabasic-alkaline magma fluids in their formation. This was favoured by the presence of carbon dioxide and hydrogen sulfide in them.

Keywords: vaesite, kalininitie, sulvanite, patronite, carbonatites, South Urals.

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DOI: 10.19110/2221-1381-2019-9-23-32

The age (U-Pb, SIMS), features of the distribution of REE, Ti, Hf, Y in zircons of granitoids of the Narta block (Subpolar Urals) were established, isotope-geochemical data (O, Lu-Hf) were obtained for the first time, allowing to establish the isotope-geochemical characteristics of protolith rocks. Two age groups of zircons were found that differ in their age, geochemical (REE distribution), thermal (t crystallization), isotopic (Lu-Hf) characteristics, as well as the estimated model ages of protoliths. Zircons with an age of 619 Ma crystallized at a temperature of 702—684 °С, have a crust-mantle hafnium isotopic composition (–2.09—+1.76) and a model age of protolith TDM2 1.48—1.29 Ga. Zircons with an age of 517 Ma were formed at a temperature of 795—737 °С, have crustal characteristics of the hafnium isotopic composition (+3.58—+5.16) and the model age of the protolith TDM2 is 1.03—1.11 Ga. The data obtained confirm that granitization processes in the central part of the Nyarta block manifested themselves repeatedly ~ 620 and ~ 520 Ma.

Keywords: S-granites, zircons, U-Pb (SIMS), isotope-geochemical characteristics, Subpolar Urals.

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DOI: 10.19110/2221-1381-2019-9-33-37

The capacities and oil and gas properties of terrigenous-carbonate Tournaisian-Visean sediments of the Lower Carboniferous of the Kosyu-Rogovskaya depression of the Timan-Pechora province are analyzed. The conducted geochemical studies of the organic matter of the rock complex made it possible to clarify the assessment of their hydrocarbon potential and the degree of maturity of the organic matter contained in them, as well as to identify the zones of the most likely foci of hydrocarbon generation in the Lower Carboniferous deposits.

Keywords: organic matter, generation potential, hydrocarbon potential.

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DOI: 10.19110/2221-1381-2019-9-38-42

The article is devoted to the main theorem of classic crystallography — on the impossibility of n-fold axes of symmetry with n = 5 and n > 6. It is fundamental in the natural sciences, sharply separating mineral and biological structures. The proofs of the theorem in many academic monographs and university textbooks over the past 170 years are considered. Attention is paid to the methodological nuances of proofs of the theorem.

Keywords: the main theorem of crystallography, symmetry axes, crystalline lattice.

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