The degassing of basic silicate minerals (olivines, pyroxenes, plagioclases) that make up mantle rocks similar in chemical composition to lunar mare basalts has been studied. A setup specially designed for these tasks was used, previously used in the study of chondrite degassing. The results of experimental studies on stepwise heating (without accumulation) with determination of the composition of released gases using gas chromatography methods in the temperature range from 200 to 1000°C are presented. The composition of the released gases was compared with the fugacity of oxygen in olivines. Raman and IR spectra of both the original minerals and minerals after isothermal annealing at various temperatures were obtained. Based on them, the course of thermal transformation of the crystalline structure of minerals was traced and estimates of their stability were obtained. The composition of silicate minerals was compared with samples of lunar soil delivered by the Chinese space mission Chang’e-5.

An Erratum to this paper has been published: https://doi.org/10.1134/S1028334X2307036X

An Erratum to this paper has been published: https://doi.org/10.1134/S1028334X2307036X

The features of the infrared (IR) spectra of various isotopic forms of water (–OH, –OD, H2O, HDO, and D2O) included in the crystal structure of the main rock-forming minerals of lunar basalts—olivines (forsterite)—have been studied. The results of numerical modeling (CUSTEP/Biovia Materials Studio) and experimental studies using the FT-801 IR Fourier spectrometer with a plug-in using the method of disturbed internal reflection (Simex, Novosibirsk) are presented. Numerical calculations have shown that forsterite can contain hydroxyl groups –OH(D) in its crystal lattice under certain conditions. The possibility of retaining various isotopic forms of molecular water on the surface of forsterite has been experimentally verified and the corresponding IR spectra of the mineral with a water film have been obtained. The IR spectra of forsterite containing isotopologues of water obtained theoretically and experimentally are compared with the observations of the Chandrayaan-1 and SOFIA artificial lunar satellites.

In this paper, we present a draft new experimental setup for studying the sublimation of water ice at low temperatures under different conditions. The sublimation temperature could be varied from − 196 to 0 °C. Also, the unit is connected to an Isotope Ratio Mass spectrometer (IRMS). An isotopic mass spectrometer allows measuring the isotopic composition of vapors of an evaporating substance and the rate of sublimation under specified physic-chemical conditions. The gas input into the mass spectrometer on-line mode distinguishes the developed setup from the existing analogues. The developed setup is equipped with a transparent quartz window through which the surface of the test substance can be heated using a halogen lamp. The setup can also be used to study the sublimation of gas hydrates and CO2, to study the sorption of gases on the surface of various samples.

We have updated the standard method for estimating the amount of carbonates in carbonaceous chondrites on the example of the Murchison meteorite (CM2). In contrast to the existing technique (passing carbon dioxide released from carbonates through brine and weighing the remainder of the substance, when a small volume of gas may be too small for analysis using a mass spectrometer, our method is more reliable because all carbonates are collected in the form of a precipitate and then decompose at once at high temperature to carbon dioxide CO2 and divalent metal oxides. This required the creation of a laboratory setup and development of the technique to calibrate mixtures of (Volcano Tolbachik, Kamchatka, Russia) with pure calcium carbonate CaCO3 for analysis (from 0.1 to 1.0 wt.

A study of the distribution of methane cycle microbial communities in the upper layers of bottom sediments above large hydrocarbon reservoirs in the South Kara petroleum region of the West Siberian Province revealed the presence in these layers of both aerobic methanotrophic bacteria and anaerobic methanogenic archaea, as well as numerous heterotrophic microorganisms of various phylogenetic groups. Research was carried out in the Baydaratskaya Bay and in the east of the Pukhuchan Depression (southern part of the Kara Sea). Aerobic methanotrophic bacteria belonged to the families Methyloligellaceae, Methylophagaceae and Methylomonaceae were detected in the surface oxidized layers (0–2 cm, Eh from 60 to 175 mV) of bottom sediments. Moreover, representatives of Methyloligellaceae were found in quite significant amount (1.52–2.61

In order to study the processes related to the origin and retention of water on the surface of the Moon, an experimental setup has been created at the Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences (GEOKHI RAS), for the analysis of (re)sublimation processes of water ice in a vacuum at low temperatures. The temperature range for (re)sublimation varies from –100 to 0°C. The setup is connected to an Isotope Ratio Mass Spectrometer (IRMS), which allows for measuring the isotopic composition of the vapor of the evaporating substance and providing an estimation of the (re)sublimation rate under specific physicochemical conditions. The direct introduction of gases into the mass spectrometer in real-time mode sets the developed setup apart from foreign counterparts. The setup is equipped with a transparent quartz window through which the surface of the studied substance can be heated using a halogen lamp, simulating the movement of solar rays on the surface of mineral grain compositions under conditions similar to those on the lunar surface. In addition to studying gas (de)sorption on the surfaces of mineral grains of various compositions, the setup can also be used for researching the (re)sublimation of gas hydrates and CO 2 .

Изучена дегазация вещества углистого хондрита Murchison (тип СМ2) на специально сконструированной для этих задач установке. Представлены результаты экспериментальных исследований по ступенчатому нагреву (без накопления газов) и изотермическому отжигу образцов метеорита с определением состава выделяемых газов методами газовой хроматографии в интервале температур от 200 до 800°C. Для учета сорбированной воды дополнительно изучена дегазация при 50 и 110°C. Получены ИК-спектры метеорита Murchison после отжига при разных температурах, и на их основе прослежен ход тепловой деструкции. Проведено сравнение с результатами дегазации обыкновенного хондрита Челябинск (тип LL5) и показано существенное увеличение выделения углеродсодержащих газов для метеорита Murchison.

Samples of the Murchison meteorite (carbonaceous chondrite, type CM2) were kept isothermally in a specially designed device at temperatures of 200, 500, and 800°C. After the samples cooled down in an inert helium atmosphere, Raman scattering spectra were taken. An increase in the intensity of the G- and D‑lines of graphite was detected depending on the degree of heating. It is shown that using such a characteristic parameter of these lines as the area ratio, SD/SG, it is possible to define a geothermometer to determine the maximum temperature of thermal metamorphism of the parent bodies of carbonaceous chondrites. A comparison with the known data for carbonaceous chondrite Allende (CV3), which has experienced a significant thermal metamorphism, is carried out.

During the expedition of cruise 81 on R/V Akademik Mstislav Keldysh in 2020, extensive material, representing columns of bottom sediments up to 6 m deep in the Kara Sea, was selected. After the lithological description of the columns, sediment samples were taken from the different horizons for degassing of pore gases. The extracted gas samples were analyzed for the content of the main gases, such as methane (CH 4 ), carbon dioxide (CO 2 ), and light hydrocarbons. The characteristic features of changes in the CH 4 and CO 2 content with the depth of the bottom sediments at station 6879 (the Kara Sea shelf) were studied. A model of gas diffusion was constructed taking into account the biochemical reactions of methanogenesis and methane oxidation. The rate of methane formation can be estimated by the value J ≈ 3 × 10 −10 μg s −1 L −1 (per liter of sediment). The coefficient of rate of methane consumption by microorganisms is K ≈ 0.5 × 10 −10 s −1 . The methane flow from the bottom surface of the Kara Sea near station 6879 is q ≈ 3.47 × 10 −1 μL m −2 yr −1 .

In the early stages of the Moon’s formation, its growing lithosphere experienced complex time-varying temperature and gravitational stresses. Despite the subsequent intense impact transformation of the surface, during the gravimetric study of the GRAIL space mission, the presence of ancient deep intrusions was detected. The analysis of linear gravitational anomalies shows the expansion of the outer rigid layer of the Moon at a certain early stage of its evolution due to the excess of temperature stresses over gravitational compression. Obtaining the dependence of the time interval of the lithosphere expansion on a number of dimensionless thermal conductivity parameters will make it possible to refine the existing models of the thermal and geochemical evolution of the early Moon.

Samples of the Dhajala meteorite (ordinary chondrite, type H3.8) were kept isothermically in a specially designed device in the temperature range from 300 to 800°C for 90 minutes. The composition and content of the released gases were studied on a gas chromatograph. The following were detected: CO, CO2, and H2O in concentrations of 10–60 µg/g of the sample; in addition, H2, CH4, and H2S in concentrations of 0.3–2 µg/g. The total nitrogen content during degassing increased quasi-linearly over time from 1–2 to 10–12 µg/g at each fixed temperature. Based on experimental observations of the change in the rate of nitrogen release depending on temperature, it was concluded that the effect of phase transitions depends on the permeability of the mineral matrix.

The degassing of Allende carbonaceous chondrite (CV3 type) was studied using a setup specially designed for this purpose. The experiments involved stepwise heating (without gas accumulation) and isothermal annealing of meteorite samples with the composition of released gases determined through gas chromatography methods in the temperature range from 200 to 800°C. To account for sorbed water, degassing at 50 and 110°C was additionally analyzed. The Raman and IR spectra of both the primary Allende substance and the substance after its annealing at three temperatures (200, 500, and 800°C) were obtained. These spectra were used to trace the thermal transformation of the substance of the meteorite’s parent body and estimate the maximum temperature of metamorphism. The results were compared with the degassing of the Murchison carbonaceous chondrite of another type (CM2).

Raman spectroscopy and scanning electron microscopy methods were used to study the fragment of the Markovka (H4 chondrite) meteorite. A characteristic set of silicate minerals (olivine and pyroxene), oxides and hydroxides (maghemite and goethite), troilite, and carbonates (aragonite) was determined. The structural features revealed by Raman spectroscopy allow us to draw important conclusions on thermal history of the parent body including both the temperature experienced by the rock on the parent body and their cooling rate as well as the constraints on the size of the parent body and the Mg composition of the assumed fluid.