This study presents the first U-Pb (CA-ID-TIMS) radioisotopic dating of zircon grains extracted from tonsteins within the uppermost Permian coal interval of the Minusinsk Coal Basin (Siberia, Russia). Petrographic, structural, and mineralogical analyses confirm the volcanic ash origin of the tonsteins. The parent pyroclastic materials are identified as rhyolite–pantellerite for tonstein I-22 and dacite–rhyodacite for tonstein I-12. Morphological analysis of zircon crystals, along with cathodoluminescence and melt inclusion studies, confirms their volcanic origin and crystallisation temperatures of 700–900 °C. New radioisotopic dates of 261.4 ± 0.7 Ma and 261.3 ± 0.4 Ma clarify the age of the Izykh Formation, enabling its direct correlation with the Capitanian Stage of the International Chronostratigraphic Chart. The results emphasise the possible discontinuity of the coal-bearing succession of Siberian palaeocontinent and highlight the potential for further stratigraphic refinement through continued radioisotopic dating of tonsteins.

This study presents the first U-Pb (CA-ID-TIMS) radioisotopic dating of zircon grains extracted from tonsteins (altered volcanic ashfalls) within the uppermost Permian coal interval of the Minusinsk Coal Basin (Siberia, Russia). Petrographic, structural, and mineralogical analyses confirm the volcanic ash origin of the tonsteins. The parent pyroclastic material is identified as rhyolite-pantellerite for tonstein I-22 and dacite-rhyodacite for tonstein I-12. Morphological analysis of zircon crystals, along with cathodoluminescence and melt inclusion studies, confirms their volcanic origin and crystallisation temperatures of 700–900ºC. New radioisotopic dates of 261.4 ± 0.7 Ma and 261.3 ± 0.4 Ma clarify the age of the Izykh Formation, enabling its direct correlation with the Capitanian Stage of the International Chronostratigraphic Chart. The results emphasise the possible discontinuity of the coal-bearing succession of southern Angaraland and highlight the potential for further stratigraphic refinement through continued radioisotopic dating of tonsteins.

This paper presents new data on the age of the Mastodonsaurus tetrapod fauna (Middle Triassic) of the East European Platform. The analysis of the section a

This article presents the first data on U–Pb LA-ICP-MS radioisotope dating of the Mastodonsaurus tetrapod fauna (Middle Triassic). The radioisotope a

Every year, the percentage of development of complex and unconventional hydrocarbon reservoirs is increasing, which is associated with the depletion of traditional oil and gas reserves. Carbonate reservoirs are hard-to-recover reservoir rocks due to the high degree of heterogeneity. A more detailed study of the lithological features and physical properties of carbonate rocks is an important and integral part of the complex reservoirs development. In the present work has done a comprehensive analysis of the lithological and geomechanical properties of the Middle Carboniferous strata deposits of the Dachnoye oil field, located in the southeast of the Republic of Tatarstan. The main attention in the research was focused on the estimation of the britleness of rocks. Britleness index is necessary for correct prediction of hydraulic fracturing. The result of the research is the identification of carbonate facies and their geomechanical characteristics, as well as the estimation of the britleness of rocks by various methods.