Conodonts from the Devonian–Carboniferous boundary deposits in two wells within the Sarailinskaya Depression of the Kama-Kinel Trough System were studied. The expansa conodont zone (Upper Famennian) was recognized, as well as the duplicata and quadruplicata conodont zones (Lower Tournaisian). Platform conodonts were absent in the intervals between the well-defined Famennian and Tournaisian deposits in both wells. These stratigraphic intervals span the praesulcata (uppermost Famennian) and sulcata (lowermost Tournaisian) conodont zones and are likely to be associated with the global Hangenberg Extinction Event. The conodont changes across the Devonian–Carboniferous boundary indicated a restructuring of the conodont assemblages between the Famennian and Tournaisian, with the dominant Devonian genera (Palmatolepis, Branmehla, and Bispathodus) replaced by the genus Siphonodella in the early Carboniferous. Data on the conodont distribution were presented, along with SEM images of index species.

Впервые проведено ихнологическое изучение пород терригенной толщи среднего девона Южно-Татарского свода (ЮТС). Анализ стратиграфического распределения ископаемых следов жизнедеятельности в разрезах позволил установить несколько уровней, содержащих биогенные структуры (ихнотаксоны и биотурбация), которые могут использоваться при сопоставлении разрезов. Приграничный интервал пашийского и тиманского горизонтов содержит последовательность пород: биотурбированные алевролиты с ходами Spirophyton, известняк, аргиллит с ходами Lingulichnus. Интервал прослеживается по всей территории ЮТС и может использоваться как дополнительный маркер границы горизонтов.

The radioisotopic dating of five stratigraphic levels within the Permian succession of the Kuznetsk Coal Basin refined the ages of the corresponding stratigraphic units and, for the first time, enabled their direct correlation with the International Chronostratigraphic Chart, 2024. The analysis revealed significant discrepancies between the updated ages and the previously accepted regional scheme (1982–1996). A comparison of regional stratigraphic units’ durations with estimated coal and siliciclastic sediment accumulation rates indicated that the early Permian contains the most prolonged stratigraphic hiatuses. The updated stratigraphic framework enabled re-evaluating the temporal sequence of regional sedimentological, volcano–tectonic and biotic events, allowing for more accurate comparison with the global record. Palaeoclimate reconstructions indicated that during the early Permian, the Kuznetsk Basin was characterised by a relatively warm, humid, and aseasonal climate, consistent with its mid-latitude position during the Late Palaeozoic Ice Age. In contrast, the middle-to-late Permian shows a transition to a temperate, moderately humid climate with pronounced seasonality, differing from the warmhouse conditions of low-latitude palaeoequatorial regions. The latest Lopingian reveals a distinct trend toward increasing dryness, consistent with global palaeoclimate signals associated with the end-Permian crisis.

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

The research covers the investigation of stratigraphically consistent intervals in well 1955 (Lower Nurlat area, Melekess Depression), for which facies features (lithology, textures, bioturbation intensity, ichnofossils) as well as indicators of water energy and oxygen content in the sediment were recorded. The methods included a detailed description of the section with assessing the ratio of fractions (sorting), determining bioturbation nature and intensity, features of interbedding and contacts with over- and underlying rocks, and post-sedimentary changes. A comprehensive study of the Visean terrigenous and coal-bearing deposits at the eastern edge of the Melekess Depression made it possible to develop facies models and sedimentation scenarios for rare (RE) and rare earth elements (REE) accumulation. The established relationships between changes in facies conditions, the degree of bioturbation and elemental composition permit to consider the Melekess Depression a regional model for the facies-geochemical zonality of the Visean basin. The developed approaches can be used to predict the enrichment intervals RE and REE in the Visean thicknesses of the Volga-Ural subregion and in other coal-bearing basins with similar structures of the sedimentary cycle.