Small cone/mound-shaped structures are widespread on the northern plains of Mars. They are usually interpreted as mud volcanoes because of their close morphological resemblance to mud volcanoes on Earth (for example, in Azerbaijan and near the Sea of Azov). If this interpretation is correct, the small cones/mounds could be evidence of the existence of an extensive subsurface mud source, which, in turn, could be formed by the bottom sediments of a large water reservoir (ocean) that existed on the northern plains of Mars in the past eras of this planet’s geological history. Compared to mud volcanoes on Earth, the morphology of small cones/mounds on Mars varies over a wider range and, which may be due to a greater variety of mechanisms of formation of Martian cones/ mounds. In this study, we studied the morphology of small hills in the Cydonia and eastern Acidalia regions, which are located near the dichotomous boundary within the northern plains of Mars and found that there are 5types of cones/mounds, whose morphology probably characterizes the water-mud reservoir features.

Associations of dislocations of sand deposits (probably — Holocene) have been identified on the southeastern margin of the Baltic Shield in the Petrozavodsk depression. Brittle disjunctives have a normal faults kinematics. The description of the identified dislocations and the patterns of spatial orientation characteristic of them, coinciding with the orientation of the Paleoproterozoic faults, the Shuya River valley and the eskers, are given. Possible hypotheses are considered and a model of their formation is proposed. The revealed consistency of the orientation of the studied dislocations with ancient disturbances indicates the tectonic nature and inherited nature of the processes occurring within the southeastern margin of the Baltic Shield of the East European Platform (EEP).

The regularities of the internal structure of salt uplifts have not been studied enough at present. Analysis of the shape of the cavities obtained by sonar in the cavities blurred in the Mozyr dome in Belarus shows that their walls in some cases have a rectilinear shape, and the shape of the cavity in horizontal sections looks like a polygon. The experience of previous studies suggests that the appearance of rectilinear walls is associated not only with the presence of insoluble interlayers, but also with the preparation of crack systems. The relative location of fractures and cavities suggests the stress field that created them. The conducted experiments on the dissolution of salt dams confirm the great role of fractures in the formation of the relief of salt walls.

А new anomalous section of the Bazhenov formation was described in the territory of the Urengoy oil and gas condensate field in the northern part of Western Siberia. Article 1 presents the results of the lithological description of the core, the division of the main rocks into lithotypes, the results of granulometric and palynological analyzes. It was revealed that gray-colored sandy-clay deposits and sandy vein-like bodies are younger than the host rocks of the Bazhenov Formation, represented by black kerogen-siliceous-clay rocks. On the basis of palynological studies, as well as the similarity of the mineral and granulometric compositions of the studied sandstones with the sandstones of the Achimov strata, it was assumed that the studied clastic rocks belong to the Achimov deposits, which were intruded into the deposits of the Bazhenov Formation.

Data on the abundance of petrogenic and trace elements (including rare earth elements) in the Quaternary deposits of Sevastopol Bay at the pre-technogenic stage of its development were obtained. Anomalies in the enrichment with Ag, Au, Hg, Pb and elevated levels of Cu, Zn, Cd, Sn, Sb in some layers were discovered. These features are apparently due to sulfide mineralization in the denudation area and the emergence of specific geochemical barriers (hydrodynamic and, possibly, saline ones) in the periods of changes in the paleogeographic environment. The ratios of the contents of elements sensitive to the change in the weathering type made it possible to establish the climate characteristics in the source area. During the accumulation of the liman deposits, relative warming and humidization took place, with the boundary strata of this period evidencing drier and colder conditions at the very beginning and completion of the deposit formation. The marine stage begins with warming (the lack of samples in the lower and middle parts does not allow us to trace further the prevailing conditions), but cooling and aridization are observed later on. These constructions fit into the general regional picture of climate change in the southwestern Crimea in the interval of 9.5–3.0thousand years ago.

The article presents the mineralogical and geochemical features of the types and grades of ores of the porphyry copper deposit Kalmakyr. The chemical, mass spectrometric results of analyzes of selected samples are given. When describing polished sections, ore minerals and their structural and textural features were established. The polyformation and potential ore content of the rocks of the deep horizons of the Kalmakyr deposit was revealed. It has been determined that the change of copper mineralization with depth to copper-molybdenum is due to the change of diorite by monzonitoids. Gold and silver ores appear to be superimposed, young, and associated with basic-felsic dykes.

There are represented results of Krasnoyarskiy subaqueous landslide researches in this paper. Landslide is located at subaqueous part of delta of the Selenga river. A multidisciplinary approach was applied to the study of the landslide, including seismo-acoustic, lithological, gas-geochemical and geotechnical studies. Obtained data from landslide and surrounding soils allowed to put forward a hypothesis, whereby a key factor to landslide origin was been high gas saturation of the soils and reason of landslide was an earthquake. The proposed approach to the studying of bottom soils in lakes and seas can be applied both in assessing their stability and in searching for focus fluid discharging zones at the bottom in areas associated with hydrocarbon deposits in the sedimentary section. Also, approach can be applied in mapping of permafrost melting in Arctic region offshore, where gases are often accumulating below it.

Fluid inclusions in quartz crystals from the Abalak formation carbonate rocks of 5 wells on the Em-Egovskaya summit of the Krasnoleninsky arch (Western Siberia) were investigated. Two-phase fluid inclusions with water-salt solutions, inclusions containing organic liquid, and single-phase gas fluid inclusions were found. For fluid inclusions with two-phases, the values of the homogenization temperature were obtained. For single-phase inclusions, the temperature of the second phase forming was revealed. It was established that two types of primary inclusions are present in one well, with oil and with water-salt solution. The homogenization temperature of the primary fluid inclusion containing a water-salt solution is 267°C, the homogenization of the oil-containing inclusion exceeds 300°C. In primary-secondary inclusions, the homogenization temperature reached 136 °C. Studies of the composition of inclusions by infrared spectrometry have shown that in single-phase inclusions, the gas is represented by methane. In primary-secondary inclusions, the composition may vary, while in the gas phase, the predominant components may be hydrocarbons with two or more carbon atoms. Studies of organic matter from the deposits of the Tutleim source-rock formation overlying the Abalak formation have shown that the stage of catagenetic transformation of kerogen in the studied wells changes. It was found that in wells in which organic matter is most transformed, the homogenization temperature of fluid inclusions exceeds 130°C. Thus, it is proved that on the territory of the Em-Egovskaya summit of the Krasnoleninsky arch, Jurassic deposits were effected by heat flows created by high-temperature fluids. Not only rocks of the Abalak formation were exposed by thermal processes, but also organic matter from the Tutleim formation was changed, as a result its maturity increased and the generation of hydrocarbon compounds was stimulated. The results obtained explain the difference in the catagenetic transformation of the organic matter of the Tutleim formation in this area. The study of the molecular composition of inclusions will allow us to more accurately reconstruct the conditions of hydrothermal processes. The study of fluid inclusions makes it possible to develop new criteria for the search for oil and gas deposits.

The article presents the methodology of the approach to substantiate the coefficients of residual oil saturation and displacement of oil by water (hereinafter Kro and Kdis). A functional dependency that is not included in the GD “Rules for the preparation of technical projects for the development of hydrocarbon deposits” is recommended for use.

The problems of simulation of pumping hydrogeological wells with constant hydraulic head on the finite-difference flow models are considered. The original algorithms for determining the flow rate of the well at confined, unconfined and confined-unconfined model layer are developed. Practical techniques are tested on simulation models by using analytical solution for flow toward a well with constant head in infinite unconfined homogeneous aquifer.

Aquifers may represent suitable storage systems for both heat and cold. An example of a supercomputer cooling system using groundwater has been successfully implemented at the Australian Science Center Pawsey. The authors tried to evaluate the possibilities of groundwater use for the cooling system of the “Lomonosov” supercomputer with a capacity of 2,8MW to meet its needs for efficient summer cooling due to the insufficiently stable performance of the available air-cooling systems. The article gives the results of the experiment on pumping the heated water into fractured limestone. Based on the experiment interpretation, the authors chose the model (double porosity) of heat transport and determined its parameters. The authors created a numerical-analytical program code for the interpretation of the field data of the experiment. They modeled several scenarios for the design of the cooling system. The simulation results showed that the continuous operation of the projected system using the limestone aquifer would provide the maximum need for cooling a 2,8 MW supercomputer within 10 years, while the required operation interval in the summer period is 1month.

U-shaped and V-shaped palleovalleys and paleodepressions are identified on multifrequency seismic data in near-surface section (NSS) within three study areas in Vostochno-Prinovozemelsky area. Valleys of the Late Cretaceous and Quaternary ages and of different genesis are found in the first area of study. The palleovalleys of the Late Cretaceous age are V-shaped and U-shaped by its characteristic morphological properties and are likely formed as a result of the rivers erosional activity. Burried valleys filled with Quaternary glacial sediments are similar to U-shaped paleovalleys, genesis of which is usually connected to glacial plucking in the Late Quaternary glaciation. The tunnel valleys of Quaternary age result from impact of ice sheet existing to the east of the Novaya Zemlya archipelago in the Late Quaternary were revealed in the second study area. In contrast to the first two sites, isometric depressions of Quaternary age and controversial genesis were revealed in the third one. The direction of the identified paleovalleys in some cases coincides with the submarine valleys indicated on the USSR Northern Seas submarine valleys map [Lastochkin, 1977] and the Kara Sea geomorphological map [Miroshnikov et al., 2021].

Despite the fact that the history of studying the geology of the achimov formation spans several decades, the volume of depletion of the reserves of these deposits is small, and the number of fields where the achimov formations have been put into commercial development is few. This is due to the complex geological structure of the reservoirs, vertical and lateral heterogeneity, reduced porosity and permeability properties, and low values of the oil saturation factor.

In the presented work, a generalization and analysis of all petrophysical information was made, typification of sections according to well logging with the possibility of using individual petrophysical function to assess the nature of reservoir saturation and the hydrocarbon saturation index. To create a petrophysical substantiation of well logging interpretation, both historical and current core studies in the framework of this study by the authors of the article were involved.

The typification of the sections of the achimov formation was carried out on the basis of a detailed lithological study of the core using special studies such as scanning electron microscopy and computed microtomography.

Identification of different types of section will allow in the future to correct the further hydrodynamic model for predicting the nature of the inflow and will significantly increase the reliability of assessing the nature of saturation and the hydrocarbon saturation index of heterogeneous deposits of the achimov formation.

This study was carried out to evaluate the content of major ions (Ca2+, Mg2+, Na+, K+, NН4+, Cl–, SO42–, НСO3–, NO3–) and trace elements (Sr, Ba, Fe, Mn, Co, Ni, Cu, Zn, Cd, Pb, Al, Ti, Rb, U, V, Cr, As, Se, Mo, Ag) in the waters of 12 springs in the of Balashikhа urban district of the Moscow region. The district is located within the Uchinsko-Balashikha hydrogeological block, confined to the western part of the Meshchersky hydrogeological region of the Moscow artesian basin. The macro- and micro-component composition of groundwater of various aquifers was characterized according to the sampling data of springs. It has been established that the waters are slightly acidic— near neutral (pH 5,3–6,9), with a mineralization of 130–670 mg/l. Water has highly variations in macrocomponent composition and predominantly high content of nitrate ion and ammonium ion. It is shown that the mean contents of trace elements in the waters of springs are at the level of concentrations characteristic of groundwater in the leaching zone of a temperate climate. Based on the thermodynamic calculation using the Visual-MINTEQ, it was found that the predominant dissolved forms of Ba, Sr, Fe, Mn, Zn, Cd, Ni, Co in the waters of the surveyed springs are free ions, and Cu and Pb are carbonate and organic complexes.

Experimental modeling of reductive dissolution during periods of hypoxia in freshwater reservoirs of manganese (IV) oxyhydroxides from bottom sediments, one of the main components, along with iron (III) oxyhydroxides, causing secondary pollution of the water column, was carried out. It was shown that in the hypoxia periods, not only dissolved forms of manganese can accumulate in the water column, but also trace elements sorbed on manganese(IV) oxyhydroxides. The mass ratios to manganese of trace elements-impurities passing into solution Δ[i]/ Δ[Mn]·103 were estimated: Li 0.41, Rb 1.65, Cs 0.010, Sr 31.7, Ba 50.3, Co 0.093, Ni 0.65, Сd 0.046, Y 0.070, La 0.030, Ce 0.086, Tl 0.015, U 0.23.