Research subject. This article presents new data on carbonate facies of the upperUk subformation, Upper Riphean of theSouth Urals. A particular attention is paid to the distribution of rare-earth elements (REE) and yttrium (Y) in stromatolitic and intraclastic limestones and calcareous shales (bulk samples and their acetic acid leachates).

Materials and methods. We have studied lithological features of limestones in the geological section and in thin sections. The contents of trace elements in rocks were determined by the ICP-MS method at the IGG UB RAS (Yekaterinburg), the composition of organic matter was determined at the IPGG SB RAS (Novosibirsk) by gas-liquid chromatography and chromatography-mass spectrometry.

Results. The most representative section of the Upper Uk Subformation located along the eastern edge of the town Ust-Katav can be subdivided into several members of different lithology and thickness: (1) biohermdominated member comprising large microbialitic build-ups and inter-bioherm sediments (intraclastic limestones, calcareous biolaminites); (2) transitional member characterised by small bioherms alternating with other carbonates; (3) interbedded coarseand fine-grained limestones. The presence of molar-tooth structures in the carbonate rocks of Uk Formation made it possible to constrain the age of thisUpper Riphean formation to pre-Cryogenian

Conclusions. There are similarities in REE and Y distribution in both clean (devoid of siliciclastic component) bulk limestone samples and in their acetic acid leachates. PAAS-normalised REE + Y patterns demonstrate positive La, Gd, Y anomalies and negative Eu, Ce anomalies. The latter suggest marine depositional environments for theUpper Uk stromatolitic limestones. The results of the pioneering research into the composition of bitumens and biomarkers from the Upper Uk Subformation have shown that carbonates and shales are depleted in the organic matter. The source material for the organic matter was provided by two types of communities comprising both eukaryotes and prokaryotes and inhabiting well aerated environment, perhaps with lowered salinity of marine water. 

Research subject. The metamorphic ultramafites of the Kalninsky and Ergaksky massifs located in the northeastern part of Western Sayan (Russia) constitute the Kurtushibinsky ophiolite belt. These rocks are considered to be potentially interesting as bearing chromium and noble metals, which fact determines the relevance of this research.

Materials and methods. Thin and polished sections of silicate and ore minerals from the ultramafic rocks under study were investigated using a polarizing microscope AxioScop, Carl Zeiss. The chemical composition of minerals was determined by the method of X-ray spectrum microanalysis using a scanning electron microscope Tescan Vega II LMU equipped with an energy-dispersive spectrometer INCA Energy 350 and a wave-dispersive spectrometer INCA Wave 700. The petrochemical composition of the rocks was studied by the methods of XRF analysis using an X-ray fluorescence energy-dispersive spectrometer Oxford ED-2000. A quantitative ICP-MS analysis was carried out using an Agilent 7500 spectrometer.

Results. The massifs are found to be composed of dunites and harzburgites, which were formed during an uneven depletion of the mantle. As a result of depyroxenization, the ultramafites were enriched with chromospinelides. Subsequent intense plastic deformations contributed to their segregation into ore bodies. Regenerated olivinites predominate in the northern part of the Ergaksky massif. The microstructural features of ultramafites and the composition of minerals indicate them to have been subjected to inhomogeneous high-temperature plastic deformations, which occurred during their migration in the upper mantle and crust.

Conclusions. The petrochemical studies have shown that the ultramafites of the Ergaksky massif are least depleted, frequently featuring clinopyroxene. The most depleted ultramafites of the Kalninsky massif are characterized by a more extensive distribution of dunites, the absence of clinopyroxene and lower contents of REE and rare elements in comparison with the ultramafites of the Ergaksky massif. The obtained geochemical data indicate a fluid-magmatic effect of boninite melts on depleted ultramafites, which apparently occurred under mantle conditions over the subduction zone and consequently led to their enrichment with incompatible LREE (La, Ce) and Sr, Zr and Hf, as well as to the formation of high-chromium chromitites. 

Research subject. This article presents new data on the content of rhenium (Re), selenium (Se) and a number of other rare elements in the rocks of the Gorodishi section located in the Central part of the Volga basin shale (upper Jurassic) in the South-East of the Russian plate. In this section, rocks are rich in organic matter (15–37 % wt in oil shale) and contain layers of oil shale with a thickness of up to0.7 m.

Materials and methods. The description and layer-by-layer testing of the Gorodishchi section was performed. Sulphides were isolated from two samples of carbonaceous shale for subsequent analysis. In the selected samples and isolated sulphides, the contents of Re, Se and a number of rare elements were determined at the VSEGEI central analytical laboratory. For the first time, the chemical composition of the samples was determined by ISP-MS using an Agilent 7700h device.

Results. Oil shale samples demonstrated the highest concentration of Re and Se, with the concentration of Re and Se being on average 0.13 g/t (ranging from 0.09 to 0.19) and 10.39 g/t (from 6.54 to 12.4), respectively. A statistical analysis of the data obtained (using principal component factor analysis) revealed a close relationship of Re and Se both with the rock organic matter and with Cu, Cd, U, Ag.

Conclusions. Anomalously high concentrations of Se and high concentrations of Re revealed in the oil shale of the section under study testifies to the need for specialized mineralogical and geochemical studies of the upper Jurassic carbon shale of the Central part of the Volga basin shale in terms of Re and Se content. 

Research subject. The Prikolyma terrain located in the Northeastern part ofRussia constitutes a long-lived Precambrian thrust-faulted structure hosting numerous Cu, Pb and Zn deposits of different types.

Materials and methods. The mineralization of the terrain was examined during a course of research and exploration works over the 2007–2012. The rock geochemistry was studied using ICP-OES analysis at the Stuart Geochemistry and Essay laboratory (Moscow). The microprobe analysis of minerals was carried out at the facilities of the Far Eastern Branch of the Russian Academy of Sciences (Magadan) using a Camebax X-ray microanalyzer. The isotopic ratios of sulphur in sulphides were measured using a Finnigan MAT 253 isotope mass spectrometer.

Results. The porphyry-copper deposit Nevidimka is represented by skarns and sulphide-quartz stockworks embedded in porphyry granites. The vein deposits Opyt and Glukhoye constitute sulphide-carbonate-quartz veins, the composition of which corresponds to copper-polymetallic ores of the peripheral parts of the copper-porphyry formation. These deposits feature a similar geochemistry and composition of sulphides and sulphur isotopes, which is characteristic of the Riphean complexes of the Prikolyma terrain. The stratiform Pb-Zn veins Nadezhda-3 and Khaya enclosed in Proterozoic dolomites represent parallel-bedding disseminated sulphides. The composition of these ores indicates their diagenetic origin. Tne stratiform copper deposit Oroyok is embedded in Proterozoic shales and can be referred to sediment-hosted copper deposits of a transgressive type.

Conclusions. The diversity of Cu-Pb-Zn mineralization types in the Prikolyma terrain is established to have resulted from multiple cyclic changes of the geodynamic ore formation regime. During each such cycle, syngenetic mineralization was followed first by epigenetic and then by vein mineralization. The mobile, thrust-faulted structure caused repeated rejuvenation of ores, which inherited the geochemical features of hosting rocks. 

Research subject. This paper presents data characterizing major occurrences and deposits of platinum group elements (PGE) of Kola belt layered mafic-ultramafic intrusions (Kola Peninsula).

Materials and methods. The study was based on extensive experimental data collected by the author over a long-term period and a comprehensive analysis of published and archive literature pertaining to this field.

Results. Certificates (so-called passports) were compiled for all major PGE objects in theKola Peninsula, which include diverse characterization parameters (geological, structural, isotope-geochemical, mineralogical). The formation of PGE mineralization was compared with both the age characteristics of large layered complexes and the sequence of intrusion of individual magmatic phases.

Conclusion. The proposed parameters can be used to determine specific features of PGE objects, thus allowing identification of objects promising in terms of industrial development. The obtained results demonstrate the importance of taking into account these specific features during mineral deposit exploitation. 

Research subject. The idea of forecasting fluid-dynamical parameters is based on the views connecting the processes of sedimentation, tectonogenesis and fluid flows into an active fluid-dynamical model of the “sedimentary cover–basement” system. In such models, main fluid-dynamical parameters of oil and gas collectors, i.e. penetration and the vector of the fluid flow, are functionally connected with the components of the current state of the rock massif having a discrete (block) structure. These parameters can be calculated using DFM-interpretation technology developed by the authors in their previous works.

Materials and methods. For the first time, DFM results are provided for the Yamal Novoportovsky oiland gas-condensing deposit. Here, the paleozoic basement stripped at a depth of 2700–3200 m is largely represented by metamorphic schists and marbled limestones. The basement has been covered by sediments and a platform cover since the early Jurassic age. The forecast of parameters describing modern geodynamical processes was performed on the basis of a comprehensive tectonophysical analysis of major geological and geophysical data.

Results. The main axes of the neo-tectonic activity of the plate complex break the area under study into a quite regular block system that reflects a right-sided shift of fundamental blocks, that, in its turn predetermines the block shift in plate complex with the turn of the shift axis by 30 degrees. The most significant oil and gas holes in terms of influx demonstrate a connection with the described scheme of block activity. Thus, practically all high-debit boreholes were drilled in active axial zones.

Conclusion. The proposed scheme of block activity satisfies the general principles of geodynamics. The developed model of abnormal pressure estimations by main productive intervals shows a good agreement with the distribution oiland gas boreholes in terms of productivity. Contact zones of active blocks present a particular interest from the standpoint of selecting the location of high-debit boreholes. These zones should be taken into account when developing new oil and gas deposits. 

Research subject. The relative deformation of rock masses, which was obtained in the Urals at depths below500 m, i.e. below the zone of massif disintegration, through the use of traditional geodetic measurement methods, allows correction of the results of determining the massif basis to obtain its true value.

Materials and methods. A method for determining natural stresses was developed on the basis of a physical law stating that the natural stress state of the Earth’s crust is formed as a result of the application of stress fields due to the gravitational and tectonic forces of the Earth, as well as astrophysical forces caused by physical processes in space.

Results. The Earth’s stress state is largely formed by the contribution of the gravitational and astrophysical components. The value of the astrophysical component varies in time with a cycle of up to twelve years and reaches tens of MPa at depths of more than500 meters, while the tectonic component, on average, does not exceed the value of 1 MPa. The experimentally obtained deformation of the Earth’s crust, i.e. lithospheric plates in the Pacific, Indian and Atlantic oceans, as well as continental plates inAsia and the Urals, indicates their identical and volumetric deformation in all regions of the world.

Conclusions. On the basis of experimental data on a cyclic change in the linear parameters of the Earth’s crust, it is concluded that satellite navigation systems determine geographical coordinates with an error. A significant increase in the astrophysical component of stresses over a short period of 2-3 years in the eleven-year cycle is the main reason for the activation of earthquakes and the destruction of structures constructed in the rock environment. 

Research subject. This study was aimed at examining the strike-slip related tectogenesis of the Asia-Pacific transition zone (APTZ).

Materials and methods. The research was based on the materials collected by the author during long-term fieldwork across the territories of Primorye, Khabarovsk Krai and, partly,Vietnam. Extensive materials on the topic of the APTZ tectogenesis published by researchers fromRussia,China andJapan were analysed. Investigations involved the study of structural and kinematic assemblages representing the forms, directions and time of crustal mass flows under the strike-slip related tectogenesis of the East Asian global strike-slip fault zone (EAGSSFZ).

Results. The EAGSSFZ consists of three transit strike-slip fault systems (zones) playing the role of the APTZ basic deep fault structures. Its master system (MS) is NNE (25–30°) trending longitudinally to theAsia edge. The MS is bordered by diagonal NE 50–70° trending near-continental and meridional near-oceanic EAGSSFZ systems. The MS controls the East Asian volcano-plutonic belt (EAVPB), demarcating the APTZ into internal (near-continental) and external (near-oceanic) zones. Two stages of the strike-slip related tectogenesis were established: orogenic-constructive (Jurassic–to–Late-Cretaceous) and riftogenic-destructive (Late Cretaceous–to–Cenozoic). The riftogenic destruction broke the previously formed orogenic foldedthrust structures, thus causing the EAVPB magmatic succession from intracrustal intrusions (Early Cretaceous) to volcanics (Late-Cretaceous-to-Cenozoic). An increase in the crustal destruction during the end of Cretaceous to Cenozoic resulted in the formation of epicontinental sedimentary basins and deep-sea riftogenic depressions of marginal seas. The structure-forming flow of the APTZ crustal masses occurred in the SSW 180–250° direction being opposite and obliquely opposite towards the NNW subduction direction of oceanic plates.

Conclusion. The kinematic disconformity as well as the coincidence of the continental crust flow (plate flows) with the direction of inertial-and-equator-oriented forces allowed the author to determine the structuring of the transition zone as a process independent of the geodynamics of oceanic plates and subordinate to the rotational geodynamics of the non-uniformly rotating Earth. 

October 14, 2019 there is the 100th Anniversary of Mark V. Fishman – one of the most famous person of the Institute
of Geology of Komi Science Centre UB RAS and organizers of fundamental explorations in Komi Republic, professor,
well–known scientist in regional geology and petrology. His name symbolizes an entire era in history of geological research in Komi Republic and on the North–East of European part of Russia. About twenty five years M.V. Fishman was
director of the Institute of Geology and did a lot as a scientist and an organizer of the geologic research.