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The paper presents new data on the structural position, mineralogy, and geochemistry of ores of the Aliya ore cluster and their technological specifics. The mineralogical and geochemical zoning of the Verkhne-Aliinskoe gold deposit and the entire Aliya ore cluster is considered. We show the subordination of the local and horizontal zoning of mineralization within the ore cluster and the localization of granitoids of the late phase of the Late Jurassic Akatui Complex. A conclusion is drawn about the relationship of mineralization with granitoids within a single ore-magmatic system that existed under unstable shallow-depth P - T - X conditions transitional to subsurface ones. This specifics distinguishes the Verkhne-Aliinskoe deposit from the compositionally similar Sredne-Golgotaiskoe and Sosnovskoe deposits and partly determined the technological resistance of its ores.

This paper presents several opposing points of view on the ore-controlling structure of the large (~2000 t) Sukhoi Log gold deposit, as well as data on a detailed geostructural analysis. The deposit is located in the southern margins of the Siberian Craton in black shale deposits of the Khomolkha Formation (610-600 Ma) on the territory of the Baikal-Patom fold belt. It is revealed that the Baikal-Patom belt is characterized by a complex regional structure resulting from the accretion of the Baikal-Muya belt to the Siberian Craton. The formation of industrial ores of the Sukhoi Log deposit and ore-controlling folding dates back to the Late Ordovician- Early Silurian (~450-420 Ma). The second stage of the development of weakly gold-bearing ores falls on the Early Carboniferous (340-300 Ma). The study demonstrates the absence of an ore-controlling fault zone of the syn-folding stage (450-420 Ma). It is shown that the internal structure of the gold ore zone is comprised of intensely deformed rocks in the anticline core with bedding-plane gold-quartz-pyrite veinlets. It is concluded that the Sukhoi Log deposit is a classic example of disharmonic folding of plastic rocks in the anticline core, where the signs of two stages of structure formation are combined: buckle folding with flow and laminar flow. The present geostructural studies of the deposit and the previously published data suggest that this is an orogenic deposit with metamorphic-metasomatic redistribution of ore matter.

The paper summarizes the results of long-term geochemical studies on the regional geology of the Bodaibo synclinorium as a whole and the local (ore) geology of individual orogenic gold deposits located within the world’s largest Lena metallogenic province. The main attention is focused on the role of organic matter in ore genesis. The paper presents results of a study of the transformation of organic matter of carbonaceous shales (soluble (bitumen) and insoluble carbonaceous matter) during catagenetic and metamorphic transformations. The absence of a significant correlation between insoluble carbon and gold has been demonstrated. This is due to the low sorption capacity of graphitized organic matter relative to its primary (precatagenic) counterpart. Carboxylic esters (lipids) have been identified in bitumens of carbonaceous shales, thus confirming the bacterial and planktonogenic origin of the primary organic matter of sediments. The similar gold contents in bitumen from rocks within the studied deposits and in bitumen from remote rocks indicate the presence of gold in the organic fluid. It is concluded that carbon plays one of the leading roles in the gold mobilization and migration at the stage of catagenesis. However, the hypothesis that organic matter can be a barrier to metal-bearing hydrotherms is not confirmed. Based on the model of the catagenetic formation of oil fields, we show the high probability of the formation of gold mineralization at the Dal’naya Taiga-Zhuya stratigraphic level in the Neoproterozoic section of the Baikal-Patom region.

We carried out palaeontological studies of the Vendian-Cambrian boundary strata from the Leningrad Region in the north of the East European Platform (northern part of the Baltic Basin). A stratigraphic succession of micro- and macrofossil associations has been recognised in the Taitsy-2 drill-core section comprising three Upper Vendian associations: (I) Aataenia reticularis, (II) Vendotaenia antiqua - Incertae sedis Forma 1, and (III) Bicuspidata fusiformis - Vanavarataenia insolita of the Kotlin Regional Stage; and two Lower Cambrian associations: (IV) Ceratophyton sp. - Teophipolia lacerate of the combined Rivne-Lontova Regional Stage, and (V) Archaeodiscina umbonulata - Globosphaeridium cerinum - Skiagia orbiculare of the Dominopol Regional Stage. The early Cambrian taxa Ceratophyton sp., Granomarginata squamacea , Teophipolia lacerata , and Platysolenites antiquissimus first appearing at the base of the Lomonosov Formation and extending their stratigraphic range into the overlying Siverskaya Formation define the position of Precambrian-Cambrian boundary. The Rivne and Lontova regional stages are indistinguishable based on palaeontological data. The cooccurrence of fragmented metazoan fossils and acanthomorph acritarchs in the Lükati Formation expands the palaeontological characteristics of the Dominopol Regional Stage of the European part of Russia. We also conducted isotope-geochronological studies of sandstone-hosted glauconite from the Lower Cambrian Siverskaya Formation that yielded a Rb-Sr date of 457 ± 3 Ma. The glauconite appears to be altered and rejuvenated as suggested by mineralogy and crystallochemistry data, is not suitable for stratigraphic purposes, but provides information on timing and contribution of later geological processes.

We report the results of deep magnetotelluric sounding, conducted for the first time within the Tunka basin system, which belongs to the southwestern flank of the Baikal Rift Zone. Despite the regional scope of the study, electrical conductivity anomalies were identified at virtually all intervals of the geoelectric section constructed to depths of 70 km. In the western part of the Tunka Rift, at the lower lithosphere level, there is an area of rocks that were presumably heated by a mantle plume, which was identified in previous studies in northern Mongolia. The position of the crustal conductive layer, which likely is a mineralized reservoir of planetary scale, is atypical: its thickness increases, and its roof rises towards the central part of the Tunka Basin. In the upper part of the Earth’s crust, subvertical conductive zones have been distinguished, which can be traced from the crustal conductive layer to sedimentary deposits. These zones are associated with fluid migration channels transporting geotherms of mantle origin. A correlation has been noted between these subvertical conductive anomalies and known thermal and/or mineral groundwater outlets, including “Nilova Pustyn”, “Arshan”, and “Zhemchug”. Additionally, one of the subvertical conductive zones in the eastern Tunka Rift, associated with a fluid migration channel, has been detected within sedimentary deposits (or does not reach them) near the Tibel’ti village, where the presence of geothermal waters had not been previously documented.

4D seismic is a series of time laps 3D seismic surveys employed during development of oil and gas fields. Its goal is to register changes in seismic wavefield within target interval caused by hydrocarbon extraction, which allows for optimization of field development plan (i.e. optimizing reservoir drainage, oil well placement, reducing reservoir development uncertainty, etc.). This article provides the first comprehensive analysis of the current state of 4D seismic in Russia, where, unfortunately, there are only a few cases of utilization of this technology, while global experience already includes hundreds of successful examples. Various options for its implementation for deep-sea (offshore) and onshore hydrocarbon exploration and production are considered. However, not numerous, practically all known cases of 4D seismic survey acquisition over Russian hydrocarbon fields are analyzed, and future prospects of this technology in Russia are assessed.

The article, by the example of a layered material which can be reduced to a two-layer equivalent illustrates the differences in the frequency and transient responses of interfacial polarization depending on which source - current or voltage - is used to excite the ground in electrical and EM geophysical prospecting methods. In material science, a voltage source is usually used to study interfacial polarization. In this case, the manifestations of interfacial polarization are known as the Maxwell-Wagner effect. As for the geophysical induced polarization method, it uses a current source to energize the ground, which causes frequency and transient responses of the interfacial polarization to differ from those predicted by the Maxwell-Wagner theory. In principle, using the interfacial polarization frequency or transient responses measured with both current and voltage sources, one can find all properties of the equivalent two-layered model. In practice, however, polarization of grounding electrodes complicates the in-situ studies of the Maxwell-Wagner effect using a grounded source. There is no such a problem in the time domain electromagnetic prospecting method: when the current in the transmitter loop is switched off, a vortex electric field is induced in the ground, which - in terms of the circuit theory - is equivalent to using the voltage source.

Quantitative analysis of the gas mixture absorption spectra is complicated by noise. The parameters of standard filters are related to the entire analyzed spectral range. This means that the filter parameters being optimal for strong absorption lines are not optimal for weak absorption lines and vice versa. An approach to create adaptive filter for denoising experimental spectra based on the combination of a windowed version of a standard filter with the independent component analysis is suggested and implemented with the Savitzky-Golay filter as an example. The numerical simulation was carried out at normal conditions for the absorption spectra of the model of mid-latitude summer atmosphere in the 100-1000 GHz spectral range. The efficiency of the suggested adaptive and the standard versions of Savitzky-Golay filter was compared using a quantitative criterion of the proximity between two spectral curves. Experimental validation of efficiency of the suggested adaptive Savitzky-Golay filter was conducted on the example of 200 ppm SO₂ and 10000 ppm H₂O gas mixture. The SO₂ concentration was evaluated using multivariate curve resolution method. The relative error in the concentration retrieved after noise reduction by this filter was 3.7 times less compared to the standard Savitzky-Golay filter. Thus, the suggested adaptive Savitsky-Goley filter makes it possible to increase the efficiency of noise suppression in experimental spectral data.

Atmospheric turbulence is one of the most significant factors affecting the propagation of waves of various nature and the operation of devices based on their application. The paper presents the results of experimental studies of the impact of short-term heavy rainfall on subsequent changes in the meteorological and turbulent state of the ground atmosphere based on processed synchronous acoustic and optical measurements of atmospheric parameters. An assessment is made of the impact of intense precipitation on the main turbulent characteristics of the surface atmosphere, such as the energy of temperature and wind fluctuations and vertical heat and momentum fluxes. It is shown that heavy rainfall significantly changes these characteristics. The results can be used to interpret optical and acoustic measurements used to study the atmosphere.

Observations of the state of the mesosphere of Venus from spacecraft have not yet revealed transient luminous events similar to those observed in the Earth's atmosphere. In this work, a possibility of such phenomena is proved in laboratory conditions. For this purpose, an experiment was conducted on the formation of apokamps in carbon dioxide at various pressure values. The results confirm the hypothesis that conditions at altitudes corresponding to the upper edge of clouds in the atmosphere of Venus are favorable for the generation of analogues of transients of the Earth's mesosphere. Based on this, recommendations have been developed for the design of detection systems for such phenomena from orbiting satellites or balloons.