No 3 (2025)

The study presents the results of hydrocarbon biomarker analysis in bitumoids extracted from Middle Devonian Eifelian rocks of the Yarega field and Permian-Carboniferous deposits of the Usinsk field in the Timan-Pechora petroleum province. It also examines bitumoids from Upper Permian Ufimian rocks of the Ashalcha and Mordovo-Karmal fields in the Volga-Ural petroleum province using a comprehensive geochemical approach. The analyzed biomarker group includes normal and isoprenoid alkanes, aromatic compounds, and cyclic isoprenoids such as steranes and triterpanes. Key geochemical parameters were determined on the basis of paraffinic, aromatic, sterane, and hopane hydrocarbons. A comparative analysis revealed similar sedimentary environments and a consistent type of original organic matter across the studied deposits. This suggests a marine origin of the original organic material, which accumulated and underwent diagenetic transformation under reducing conditions. The thermal maturity of the organic matter corresponds to the main phase of oil generation.

The article presents the results of the study of the distribution of rare earth and trace elements in the weathering crusts of the Southern Timan, differing in age and bedding conditions, in the Dzhezhim and Asyvvozh quarries on the Zhezhimparma Upland and in the Vadyavozh quarry on the Nem Upland. On the Zhezhimparma Upland, a similarity of the geochemical characteristics of sandstones and clayey rocks at the base of the Devonian section was obsered, confirming the tectonic origin of the clayey formations previously considered to be the weathering crust. In the Vadyavozh quarry, a geochemical analysis was conducted on Mesozoic-Cenozoic areal and linear weathering crusts developed over basement rocks. The study confirmed a genetic link between the micaceous aleurolites of the Upper Riphean Dzhezhim suite and the Riphean weathering crust formation.

The papar studies the stromatoporoid association of the middle part of the Upper Devonian Lymbada Formation, of the (interval of marginifera–expansa). The stromatoporoid association is represented by nine species belonging to two orders — Labechiida and Clathrodyctyida. Three species were recorded for the first time in the study area: Labechia polaris Gorsky, Rosenella miniarensis Riab., and Anostylostroma cf. variabile (Riab.). The taxonomic composition of stromatoporoids is similar to that of the Upper Famennian of the Southern, Middle and Northern Urals.

March 19, 2025 marks the 90th anniversary of the birth of Yuri Andreevich Tkachev (19.03.1935—01.10.2020), Doctor of Geological and Mineralogical Sciences, Professor. He is widely known in Russia and abroad for his research and fundamental work in the field of geostatistics, mathematical modeling of geological processes and phenomena, geological and environmental assessment of mineral deposits. Based on the research materials, Yu. A. Tkachev published more than two hundred and seventy scientific works, including eight monographs, three inventions, computer programs in Turbo Pascal-7 for statistical data processing, and ten new training courses. In addition to courses in his main scientific profile, Yuri Andreevich gave students lectures on geodesy and engineering and geodetic works, aerospace methods, engineering geology, land hydrology, he developed and was the first to implement a system of testing students' knowledge, and trained seven Candidates of Science. The professor took part in the preparation and discussion of the law of the Komi Republic "On Subsoil", and developed an original model of economic management of geological production. Yuri Andreevich was awarded the medals "Veteran of Labor" (1975), "For Contribution to the Development of Invention" named after A. S. Popov, the Honorary Medal of the International Academy of Authors of Scientific Discoveries and Inventions "For Merits in Invention" (2000), the Honorary Certificate of the Russian Academy of Sciences (1999), the Commemorative Badge "For Merits in the Study of the Subsoil of the Komi Republic" (2000), the honorary title "Honored Scientist of the Komi Republic" (1993), the title "Honorary Veteran of the Ural Branch of the Russian Academy of Sciences" (2019). He was a Full Member of the International Academy of Authors of Scientific Discoveries and Inventions. The staff of the scientific library of FRC Komi SC UB RAS organized an exhibition of biographical works in memory of Professor Yu. A. Tkachev, reflecting his diverse activities.