pdf № 332, August

DOI: 10.19110/geov.2022.8.1

The article analyzes published and original data related to the carbon isotopic composition of individual aromatic compounds of fossil organic matter and oil. It has been shown that there is reliable evidence of the intramolecular isotopic heterogeneity of a number of molecules. For example the isotopically depleted carbon of the methyl group of alkylnaphthalenes and the terminal methyl of n-alkanes. The d¹³C inheritance from the biochemical precursor during the aromatization is also well documented in the example of diterpenes in the series abietic acid — dehydroabietane — simonellite — retene, as well as in the other terpene and steroid series. At the same time, there is evidence of carbon isotopic fractionation during the formation of several aromatic compounds from a single precursor. The increasing aromatization of the prebuild polycyclic structure does not change the d¹³C value of the molecule, and the formation of aromatic compounds with different numbers of aromatic rings in competing reactions leads to isotope differentiation in accordance with the thermodynamically determined distribution of carbon isotopes. If the suggestion is correct, it is the key to the understanding of specific petroleum aromatic hydrocarbons formation mechanism. It is possible that a comparison of d¹³C values for pairs of compounds formed during the transformation of one precursor will also provide information on the temperature conditions for the occurrence of the corresponding reactions.

Keywords: aromatization isotope effect, carbon isotopes of aromatic hydrocarbons, isotopic bond numbers.

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DOI: 10.19110/geov.2022.8.2

In the article, the author summarizes information about the extraction of hard-to-recover oil in various Arctic zones — Russian, Scandinavian and North American. Various estimates of the Arctic hydrocarbon reserves are presented, but the Russian Arctic occupies a leading position in terms of its reserves. The number of deposits in the Russian sector exceeds the number of deposits in the North American and Scandinavian sectors of the Arctic by 4 and 8 times, respectively. For Russia, the Arctic has become one of the main driving forces of the growth of the Russian oil and gas industry in the coming decades. The problems of stabilization and growth of the level of development of hard-to-recover oil in modern conditions of oil production are indicated. Based on the analysis of information from the database of the Institute of Petroleum Chemistry, consolidated information on the development of hard-to-recover oil production in the Arctic zone of Russia, in particular, in the European and Siberian parts of the macroregion, on the physico-chemical properties of hard-to-recover oil, conditions of occurrence and spatial distribution. It has been established that heavy and viscous oils of the Siberian part of the Arctic are characterized by lower viscosity values, low concentrations of asphaltenes, sulfur and metals compared to similar European Arctic oils. The solidification temperature is in the negative temperature range. The established differences determine the features of the development, production and transportation of heavy and viscous oils at critically low temperatures. The article may be of interest to companies in the oil and gas sector net monitor Arctic projects and prospects for their implementation.

Keywords: hard-to-recover Arctic oil, physical and chemical oil characteristics, oil-bearing basin, deposits, reserves, database.

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DOI: 10.19110/geov.2022.8.3

Amino acids are important records of geochemical processes in sedimentary rocks. The knowledge about changing the composition of amino acids is important for our understanding of genetics of organic compounds in the geological records. In the presented work, compositions of amino acids in natural solid bitumens, graphites and some synthesized carbonaceous materials were investigated. We determined that the content of amino acids decreases with increasing temperature of the formation of natural carbonaceous substances. the content of aliphatic amino acids gradually increases with increasing degree of transformation in the carbonization (dehydrogenation) series, mainly due to glycine, alanine and leucine. The revealed changes in the amino acid composition of natural carbonaceous substances are associated with the genesis of the initial organic matter, as with as the content of carbonaceous matter and its interaction with the mineral component.

We showed that the selection of dominant individual amino acids without involvement of statistical methods did not allow distinguishing some types of natural carbonaceous materials. At the same time, lots of amino acids were identified by statistical methods, statistically significantly distinguishing all the studied types of solid natural bitumen and graphite.

Keywords: natural solid bitumens; graphites; aminoacids; glassy carbon, carbon black Mann — Whitney U test; Generalized Dicriminant Analysis, Classification Trees Method.

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DOI: 10.19110/geov.2022.8.4

The article considers an approach to the reconstruction of the bioproductivity of Palaeozoic pelagic ecosystems based on the numeric modelling of the carbon isotope fractionation. The model uses information on the carbon dioxide content in atmosphere, water temperature, and carbon isotopic composition of carbonates and conodont elements. The developed model is tested on the material from the Upper Devonian — Lower Carboniferous of the northern Cis-Urals (successions of carbonate platform and slope of intrashelf depression). It allows reconstructing of the primary productivity of the Palaeozoic pelagic ecosystems and their dynamics on the basis of limited data. The results of the modelling are considered as rather qualitative than quantitative. The carbon isotope composition of total organic carbon was used for controlling the quality of the model.

Keywords: Palaeozoic, palaeoecology, modelling, conodonts.

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DOI: 10.19110/geov.2022.8.5

The instrumental processing of the seismic event on January 6, 2022 t₀ = 10:02:08.9 (UTC), М_L = 2.6, which occurred on the territory of the Komi Republic, is presented. The application of the criteria for identifying earthquakes and explosions showed that the event was an induced earthquake. The epicenter was located in close proximity to the Middle-Timan bauxite mine. Ore mining in quarries was carried out in an open way, where, among other things, blasting was used. We classified the seismic event of January 6, 2022 as an explosion. It will be added to the database of industrial explosions and the atlas of explosion records.

Keywords: seismic station, seismogram, epicenter, explosion, Komi Republic, Timan, bauxite mine.

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