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We studied geochemical compositions of the early Paleocene basaltic and andesite dikes associated to linear zones of the Lankovo-Omolon shearing system (Northern Okhotsk region) and basalts of the Evdyreveem volcanic field associated to the Okhotsk-Penzhinsk fault system, and compared them to other synchronous manifestations of basic volcanism: andesibasalts and andesites of the studied earlier Garmanda field, as well as with the Late Cretaceous basalts of the Mygdykit Formation of the Northern Okhotsk region, roofing the Okhotsk-Chukotka volcanic belt. The isotopic composition of Sr and Nd in dikes, the distribution of major and trace elements with the ratios of noncoherent elements indicate the formation of volcanic bodies in the environment of continental margin rifting, which is confirmed by the combination of depleted, intraplate and above subduction geochemical features of their composition. Such behavior of the elements indicates multi-stage processes of the earlier Mesozoic supra-subduction fluid metasomatosis. Melting of an ancient buried Cretaceous slab may explain the appearance of such “above subduction” marks as the Nb-Ta negative anomalies in the studied basaltoids. Andesite dikes are characterized by higher isotope ratios of Nd and lower Sr, with lower absolute concentrations of trace elements and more pronounced anomalies on spider plots.

We report results of a systematic paleomagnetic study of the Abinskaya Group of the Kuznetsk depression, including a typical volcanic complex that reflects important features of the evolution of the Permian-Triassic Siberian large igneous province (LIP). Four zones of magnetic polarity have been established in the group’s deposits. We revise the correlation of the volcanic sheets of the Mal’tsevo Formation (Fm.) at the base of the group with the Ivakinsky Fm. of the Norilsk region, which is linked to the initiation of trap magmatism. The beginning of the eruption of the Saltymak complex volcanic rocks in the Kuznetsk area corresponds to the boundary between subchrons LT1n.1n and LT1n.1r (251.2 Ma) within the Kedrovka sub-formation of the Mal’tsevo Fm. This boundary was traced in the magnetostratigraphic sections of the Maimecha-Kotui, Koltogor-Urengoy, Western Taimyr, and Norilsk regions of the Siberian LIP and suggests a correlation of the Mal’tsevo Fm. volcanic rocks with the upper part of the undifferentiated interval of the Onkuchak - Tyvankit (?) Fms., the base of the Korotchaev Fm., the Verkhnetam Fm. and the top of the Samoed Fm. The duration of this main pulse of volcanism in the Kuznetsk depression did not exceed 0.1 Myr. The volcanic sheets of the second, significantly weaker pulse of the Yamin Fm. are compared with the Maimecha Fm. of the Maimecha-Kotui area and the top of the Korotchaev Fm. of the Koltogor-Urengoy area. Thus, the accumulation of the entire Abinskaya Group, including the sedimentary complex of the Sosnovka Fm., lasted no more than 1.5 Myr. Except for the initial stage, this coincided with the eruption of most of the Maimecha-Kotui and Koltogor-Urengoy trap sections. The early magmatism of the Ivakinsky time and its analogs in other areas of the Siberian province during the Permian-Triassic boundary in the Kuznetsk depression probably corresponds to the break between the Tailugan Fm. and the Abinskaya Group. The mean paleomagnetic pole (PLat = 59.0°, PLon = 160.3°, A95 = 5.7°, N = 33) calculated for the entire studied section reflects the paleogeography of the Kuznetsk depression and can be considered a reference pole for the Permian-Triassic boundary.

This study presents the results of recent regional seismic exploration and deep drilling efforts in the Sayan-Yenisei syneclise and adjacent areas of the Lena-Tunguska petroleum province. These results were used to build a series of structure maps for Riphean, Vendian and Lower Cambrian reflectors; thickness maps of the Riphean and Vendian terrigenous geoseismic sequences within the syneclise, and a tectonic map of the Vendian-Paleozoic structural stage of the Sayan-Yenisei syneclise. The proposed oil and gas geological zoning of the Sayan-Yenisei potential petroleum area enabled us to identify eight potential petroleum regions and perform a quantitative assessment of the hydrocarbon potential. The original in-place resources of the Sayan-Yenisei potential petroleum area are estimated to be 3 billion 231 million tons of hydrocarbon equivalent, including 3 trillion 39 billion m³ of gas and 192.7 million tons of condensate. It is shown that over next 15-20 years, up to 1 trillion m³ gas reserves can be explored in the Sayan-Yenisei potential petroleum area. It is proposed to consider the Boguchany village as a large gas conversion and helium production center.

In bottom sediments of the New Siberian sedimentary basin and adjacent geostructures of the East Siberian Sea, we identified СН₄, as well as its limit and unsaturated homologues (up to and including C₅H₁₂), CO₂, CO, H₂, He, H₂S, O₂, N₂, and Ar. Isotope-gas-geochemical parameters δ¹³С СО₂, СН₄ and С₂Н₆, of the molecular mass of hydrocarbon fraction and genetic coefficients indicate the presence of both syngenetic and epigenetic gases of various gas sources in sediments, including recent sediments, peatlands, coal-bearing and gas-bearing formations, solid bitumen, igneous formations, accumulations of gas hydrates and prognostic condensate-gas, condensate, oil-and-gas and gas-and-oil reservoirs. Concentrations of CO₂ and CO reach 29.25 and 0.06 cm³/kg, CH₄ and the sum of its homologues - 5.93 and 0.031, Н₂ and He - 0.78 and 0.318, H₂S - 0.092 cm³/kg; this indicates that gas-geochemical anomalies, exceeding the anomaly criteria by 6-124 times, form in bottom sediments. The formation and distribution of abnormal concentrations of natural gases depend on the complex influence of gas-controlling factors - geological structure, fold and fault tectonics, magmatism, coal-oil-gas content, bituminous content, organic saturation, lithological composition, water-physical and reservoir properties of sediments, hydrogeological, geocryological and other conditions for accumulation of natural gases or their degassing.

Investigating Early Eocene and Paleocene deposits within the Punjab Platform, Pakistan, involved comprehensive analysis using advanced geochemical and petrophysical techniques. This study evaluates the source potential of three formations: Nammal and Sakesar of Early Eocene age and Dungan and Ranikot of Palaeocene age. The Sakesar Formation, a reservoir rock, was evaluated through interpretation of wireline logs to estimate key petrophysical properties-porosity, water saturation, and hydrocarbon saturation. Geochemical investigations focused on total organic carbon content and Rock-Eval pyrolysis of twenty-one cutting samples from a well. These samples displayed TOC values ranging from 0.21 to 2.04 wt.% and S2 values ranging from 0.09 to 2.14 mg HC/g rock. Analysis positioned all samples within the immature window zone with Type II/III and Type III kerogen, suggesting limited generative potential. Findings suggest limited hydrocarbon generation from these formations. Petrophysical analysis indicated average porosity of 11.2%, water saturation of 32.58%, and hydrocarbon saturation of 67.42% for the Sakesar Formation, categorizing it as average to good reservoir potential. This study highlights complex geochemical and petrophysical characteristics of these formations. While Sakesar shows promising reservoir qualities, significant hydrocarbon generation potential from Nammal, Dungan, and Ranikot formations is constrained. Informed decision-making is crucial when considering these formations as hydrocarbon sources.

The Lucaogou Formation in Jimsar sag is an important shale oil-producing layer in the Junggar basin. In this paper, core data, organic carbon, rock pyrolysis, biomarker compounds, and organic matter group component separation were used to study the sedimentary environment, parent material type, organic maturity and oil-bearing property of mud shale of the Second member of the Lucaogou Formation. The results showed that the sedimentary environment is a semi-oxidation and semi-reduction environment. The parent material is mainly aquatic with minor input of higher plants. The average TOC is 7.43%, the average value of hydrocarbon generation potential ( S ₁+ S ₂) is 50.54 mg/g, and the average value of T_max is 446 °C, showing high maturity of the mud shale. The chloroform bitumen “A” features high saturated hydrocarbon content (34.10% on average), low aromatic hydrocarbon content (15.39% on average), and high saturated/aromatic ratio (2.54). The carbon number of saturated hydrocarbons is distributed between n-C₁₃ and n-C₃₃. Their peak are mainly n-C₁₇ and n-C₂₃, which are biased toward medium-low molecular weight alkanes. The average of the ΣC^-₂₁/ΣC⁺₂₂ is 1.19, indicating that the alkane has advantage of short chain. The mud shale in the Second member of the Lucaogou Formation has a large sedimentary thickness, high organic matter content, and high oil generation potential. It is an important replacement target for shale oil in Jimsar sag and has important exploration significance in the future.

The issues of permafrost degradation and its impact on the life-support system are discussed in the example of the Ulakhan-An village (Khangalassky ulus, central Yakutia). The extent and forms of manifestation of thermokarst - the main negative cryogenic process in the area - and its consequences for the local population have been studied. To achieve the goal of the research, field observations of thermokarst have been conducted, an ortophotomap of the key area has been developed, and a survey of residents via questionnaires and narrative interviews has been performed. As a result, the extent and intensity of thermokarst development have been clarified. At present, thermokarst is mainly at its initial stage. The main consequences of permafrost degradation for the local population and key actors of agricultural activity have been determined. The Ulakhan-An residents’ perception of and adaptation to the natural challenges that have arisen are noted.

Enrichment cultures of psychrophilic and psychrotolerant bacteria capable of reducing ferric iron at temperatures of 6 to 15 °C were obtained from samples of two tundra soils from the Bykovsky Peninsula (Northern Yakutia, eastern sector of Russian Arctic). The highest concentrations of Fe(II) ions were observed in enrichment cultures grown with the use of a soluble ferric salt in the form of Fe(III) citrate. Furthermore, anaerobic communities from two enrichment cultures derived from permafrost soil samples of the Mammoth Khayata tract and cultivated at 15 °C demonstrated a preference for insoluble Fe(III) oxide as an electron acceptor while utilizing acetate and formate as electron donors. Experimental data on the composition of microbial communities inhabiting permafrost soils were obtained through molecular biology and bioinformatics methods. Notably, this study presents a novel comparison between the composition of a naturally occurring microbial community that developed over an extended period under natural conditions at low temperatures, and a laboratory-cultivated microbial community. The results demonstrate that prokaryotic communities of the soils of Arctic ecosystems of Yakutia are phylogenetically diverse despite the cold and oligotrophic (nutrient-poor) conditions. While representatives of Proteobacteria and Actinobacteria phyla dominate in natural samples of tundra soil (~30-50 %), the cultivated microbial community obtained in vitro from natural samples was dominated by Firmicutes (38 %).

A new constructive device for temperature stabilization of frozen soils is suggested. The advantage of the proposed system is the ability to install the evaporative part of the system under construction and operating facilities. The difference from analogs is the ability to repair and replace individual evaporator pipes without dismantling the entire device while maintaining its high freezing capacity. To assess the efficiency of the proposed system, an analytical mathematical model of its functioning has been developed. The modeling of the functioning of the seasonal cooling device for the climatic conditions of the Arctic cities Varandey, Salekhard, and Igarka has been carried out. It is shown that this device can always freeze the soil under emergency buildings and structures.

Deglaciation history of the Syltrankel high-mountain lake basin (Mt. Elbrus region, Northern Caucasus) from the end of the 19th to the end of the 20th centuries was reconstructed. In 2022, a comprehensive examination of the area was carried out, including sampling of the bottom sediments and following radioisotope dating, structural and textural analysis. Simultaneously, a set of published sources; topographic maps; ground, satellite, and aerial photographs; and field observations was analyzed to determine the positions of the edges of glaciers at different times. In the formation of bottom sediments, four stages were identified correlating with the state of mountain glaciation and changes in the configuration of the lake’s drainage area. Converging results obtained on the basis of independent sources indicate the high methodological value of studying bottom sediments of mountain lakes as one of the few environmental archives that record glaciation changes in the dynamic conditions of high mountains.