The Arctic shelf is an area of national priority for Russia. Huge reserves of hydrocarbon raw materials in addition to transport and logistics communications are concentrated within its borders. The article discusses the issues of identifying the spatiotemporal patterns of the formation of a potential oil-and-gas-bearing region in the junction zone of two noncoeval continental lithospheric plates: the ancient Archean (Russian) and the young Barents Sea plates (with the Grenville basement). A description of the geodynamic evolution of the region is given, and data on the geological structure of the Neoproterozoic complexes of the Sredny and Rybachy peninsulas (Kola Peninsula) and adjacent water areas of the Barents Sea are provided. The aggregate data suggest that the relief of the western Russian Arctic was mainly formed as a result of processes involved in closure of the Proto-Atlantic and Ural paleoceans (and later the Japetus paleocean). The oil and gas potential of the described region was formed as a result of a multistage and long-duration process that led to enrichment of Neoproterozoic complexes of the northern Kola Peninsula and adjacent waters of the Barents Sea in hydrocarbon raw materials.

The article discusses the preliminary results of geological and geophysical, geomorphological, and hydrophysical studies in the Barents and Kara seas during cruise 56 of the R/V Akademik Nikolaj Strakhov in 2023.

The ice-gouging topography of the southwestern part of the Kara Sea bed is a result of the impact of icebergs and sea ice. During 52 cruise of the R/V Akademik Nikolaj Strakhov using a multibeam echo sounder we collected a representative data of key parameters of ice scours (location, orientation, depth, width) for the first time, which allows us to draw conclusions on a regional scale. We revealed regularities in the distribution of the ice scours both in space and in depth and their density in different parts of the seabed. It was revealed that the maximum dimensions of the ice scours decrease with the distance from the sources of iceberg calving from NW to SE. The orientation of the ice scours correlates with the main drift directions of the icebergs. Most of the ice scours are located at depths up to 220 m and could have formed both at modern and at lower sea level (in post-glacial time). We identified a high degree of the seabed transformation by ice-gouging processes in the southwestern part of the Kara Sea.

The ice-gouging topography of bed of the southwestern Kara Sea is the result of the impact of icebergs and sea ice. During cruise 52 of the R/V Akademik Nikolaj Strakhov using a multibeam echo sounder, we collected representative data on the key parameters of ice scours (location, orientation, depth, width) for the first time, which allows us to draw conclusions on a regional scale. We revealed regularities in the spatial and temporal distribution of ice scours and their density in different parts of the seabed. It was revealed that the maximum dimensions of the ice scours decrease with distance from the sources of iceberg calving from NW to SE. The orientation of the ice scours correlates with the main drift directions of icebergs. Most of the ice scours are located at depths up to 220 m and could have formed both at the modern and lower sea levels (in postglacial time). We identified a high degree of seabed transformation by ice-gouging processes in the southwestern Kara Sea.

Comprehensive geological, geophysical, geomorphological, and hydrophysical studies were carried out on the R/V Akademik Boris Petrov in the eastern Barents Sea and western Kara Sea in fall 2022. The research included multibeam echo sounding and seismic profiling, hydrological sounding, and sampling of water and sediments in the areas of oil and gas field development and along the Northern Sea Route. The expedition studied in depth the structure of the seabed relief and upper sedimentary strata at the given research sites. The distribution areas of various glacial landforms and modern geohazards were refined during the expedition.

Late Mesozoic and Cenozoic geodynamics of the Arctic region is discussed in the context of possible mechanisms which provide multistage cyclic transformations and transport of carbon through crust and mantle. Geodynamic processes control the abiogenic generation of hydrocarbons and the patterns of their localization. Possible mechanisms of abiotic hydrocarbon generation are explained in the context of carbon transport from subduction zones to rifts and serpentinization of ultramafic rocks in the rifts in the case of the Laptev Sea and Gakkel Ridge areas. The carbon of shallow crust origin migrates with encapsulated fragments of marine sediments which are consumed in the Pacific subduction zone where they become destroyed and transformed by different chemical and physical processes. The resulting C-species are involved in mantle convection flows and reach the continental rifts of the Laptev Sea and the Gakkel mid-ocean ridge. Thus, the hydrocarbons formed in the crust and in the mantle acquire signatures of abiotic origin. According to the authors, the scale of manifestation of abiogenic methanogenesis in the lower parts of the lithosphere and in the upper mantle is not so wide. Numerous small (mm and fractions of the mm) particles of exogenous matter and dispersed carbon pulled into the mantle can only form a stable crustal geochemical plume that propagates in the plane of movement of convective flows. Indirectly, the scale of manifestation of this process can be judged by the volumes of degassing of hydrocarbon and carbon dioxide gases, as well as hydrogen and its compounds in the rift systems of the earth’s crust, which are extremely insignificant. However, in the cold seas of the Eastern Arctic, massive emissions of bubble methane of mixed genesis were found. As shown in the literature, the range of variability of stable isotopes of carbon and 14C of methane in certain areas of discharge associated with rifting demonstrates values (anomalously heavy 13C, and young 14C) that can be considered as examples of presumably abiogenic origin. Our work is mostly theoretical and suggests further discussion and improvement of the mechanism of formation of abiogenic hydrocarbons and the processes of their transformation.

Detailed geological and petrogeochemical studies carried out using the techniques developed by the authors have made it possible to complete the picture of the formation of supracrustal complexes of the Keivy structure. The studies have shown that the metasedimentary complexes of the Chervurt and Vykhchurt suites were formed mainly due to the material of the underlying strata. In the development of the Vykhchurt Formation, starting from its upper part, the material of the domains surrounding the Keivy takes an active part. The authors have come to the conclusion that at least the middle part of the Keivy section was formed as a result of washing and redeposition of the material of the structure itself, it confirms the conclusions about the presence of redeposited weathering crusts within the Keivy. The results obtained testify to the correctness of the earlier conclusion about the formation of the Keivy structure under conditions most similar to the middle massifs, and to a certain extent explain the formation of a giant deposit of aluminum raw materials within the Keivy.

Studies of lithotectonic formations within the Keivy domain of the NE Baltic Shield have shown that the domain was tectonically overlapped by adjacent microcontinents during regional collision processes in the Late Archean. As a consequence, the continental crust of the Keivy domain was submerged, relative to other blocks of the continental crust, and the described domain acquired the features of a classical median massif. Surrounded on all sides by collision systems, the Keivy median massif entered the cratonization regime. This led to intensive processes of denudation of the surrounding domains of the crust and the accumulation of a thick sedimentary cover on the surface. The described processes occurred during the formation of the first supercontinent (Monogea) in the history of the Earth and the manifestation of the Early Precambrian Huronian glaciation, which left its traces on most domains of the Earth’s continental crust. Thus, the processes of peneplain formation within the Keivy massif occurred under the cold weather conditions, high volcanic activity in the peripheral zones, and sedimentary cover saturation with the products of the physical and chemical mineral transformation of tonalite–trondhjemite and greenstone rock assemblages. The unique combination of certain geodynamic and climatic cycles on the Baltic Shield in the Late Archean led to the accumulation of extensive stratiform deposits of alumina raw materials within the Keivy median massif.

This paper is focused on the problems of studying the thermal conditions of the Earth’s crust in the transition zone from the Baltic Shield to the Barents Sea Plate, based on temperature measurements in the deep well P-1 located on the isthmus between the Srednii and Rybachii peninsulas (northeast of the Baltic Shield). A brief description of the comprehensive geophysical studies on the wellbore is given. The measurements of thermal conductivity and the concentration of radiogenic elements in borehole core rock samples are reported. The role of hydrogeological conditions has been proved to be minor in the temperature field disturbance in the well. Horner’s method has been used to calculate undisturbed temperatures at the bottoms of drilling intervals and to estimate the geothermal gradient of the Archean horizons in the section where the heat flow is estimated at 32 mW/m2. The undisturbed heat flow is estimated at 20 mW/m2 for the Riphean complex of the section. The study results characterize the thermal conditions of the Earth’s crust in the transition zone from the Baltic Shield to the Barents Sea Plate.

An Erratum to this paper has been published: https://doi.org/10.1134/S0001437022330013

The monograph provides consolidated geological-geophysical data on the Neoproterozoic (Riphaean) sediments on the north-eastern Baltic Shield. The study pioneers in summarizing all previous and present-day materials on the geology of the Rybachy and Sredny Peninsulas obtained both in field research and by drilling of the Poranichnaya-1 (5202 m) and Rybachinskaya (3001 m) parametric boreholes, as well as a series of smaller (less than 1 km) prospecting boreholes. The study results indicate a high oil, gas and diamond potential of the regional lithological units that may host major accumulations of these minerals. This can be evidenced by a sustainable inflow of gas (methane) in one of boreholes and by fragments of diamond crystals found in the study area. Since issues of the oil and gas deposits generation and diamond-bearing magmatism are always tightly woven with uniform global patterns of the Earth’s evolution, the book outlines its history at early stages. The book is intended for multidiscipline geologists, engineers engaged in prospecting for oil, gas and diamonds, students and experts in the Earth’s evolution and spatial-temporal formation patterns of the mineral deposits.

Tectonic and geodynamic models of the formation of the Amerasian Basin are discussed. The Arctic margins of the Chukchi region and Northern Alaska have much in common in their Late Jurassic–Early Cretaceous tectonic evolution: (1) Both have a Neoproterozoic basement and a complexly deformed sedimentary cover, with the stage of Elsmere deformations recorded in their tectonic history; (2) the South Anyui and Angayucham ocean basins have a common geologic history from the beginning of formation in the late Paleozoic to the closure at the end of the Early Cretaceous, which allows us to consider them branches of the single Proto-Arctic Ocean, the northern margin of which was passive and the southern margin was active; (3) the dipping of the oceanic and, then, continental lithosphere took place in subduction zones southerly; (4) the collision of the passive and active margins of both basins occurred at the end of the Early Cretaceous and ended in Hauterivian–Barremian time; (5) the collision resulted in thrust–fold structures of northern vergence in the Chukchi fold belt and in the orogen of the Brooks Ridge. A subduction-convective geodynamic model of the formation of the Amerasian Basin is proposed, which is based on seismic-tomography data on the existence of a circulation of matter in the upper mantle beneath the Arctic and East Asia in a horizontally elongated convective cell with a length of several thousand kilometers. This circulation involves the subducted Pacific lithosphere, the material of which moves along the bottom of the upper mantle from the subduction zone toward the continent, forming the lower branch of the cell, and the closing upper branch of the cell forms a reverse flow of matter beneath the lithosphere toward the subduction zone, which is the driving force determining the surface kinematics of crustal blocks and the deformation of the lithosphere. The viscous dragging of the Amerasian lithosphere by the horizontal flow of the upper mantle matter toward the Pacific leads to the separation of the system of blocks of Alaska and the Chukchi region from the Canadian Arctic margin. The resulting scattered deformations can cause a different-scale thinning of the continental crust with the formation of a region of Central Arctic elevation and troughs or with a breakup of the continental crust with subsequent rifting and spreading in the Canadian Basin.

The article briefly describes the results of research during cruise 52 of the R/V Akademik Nikolaj Strakhov. Hydrophysical sounding was carried out, and water samples were taken using bathometers and bottom sediments were taken using a bottom grab and a gravity corer at complex stations. Geophysical studies have identified areas manifesting modern hazardous natural processes.

The paper presents data on geology and composition of rocks from the Ustoyarvi region (the North-Western Arctic zone of Russian Federation). Their compositional analysis (including mathematical evaluation of the similarity/difference measure) provided much reliable conclusion that the rocks from this area, which are presumably attributed to the Ustoyarvi structure (Ustoyarvinsky Greenstone Belt) were similar to those from the Ura-Guba area in the Kolmozero-Voronya Belt and continued it. In addition, it has been shown that from west to east lithotectonic units in the adjacent (Suormussky) Block become gradually impregnated with tectonic wedges of rocks of the Ustoyarvi Greenstone Belt. It indicates increasing collisional interaction between rock associations with a varied genesis. P-T formation parameters have been specified for komatiites from greenstone belts, i. e. the Kolmozero-Voronya, Ura-Guba, Ustoyarvi and Western Litsa area. It has been defined that komatiites of the Ustoyarvi Greenstone Belt were formed under pressure of about 5 hPa, komatiites of the Ura-Guba area - about 4.5 hPa, komatiites of the Kolmozero-Voronya - about 2 hPa. Thus, komatiites of the Ustoyarvi Greenstone Belt are more high-pressure formations.

The popular rotational hypothesis of the formation and evolution of the main structures of the Eastern Arctic lithosphere during the Late Jurassic–Early Cretaceous, in particular, the opening of the Canadian Basin, the closure of the Angayucham and South Anyui paleoceans, and the formation of collision structures during the movement of the Alaska and Chukotka blocks, is discussed. The difficulties of this hypothesis and other kinematic schemes of the evolution of the Arctic lithosphere are noted, and it is concluded that it is impossible to make a good choice in favor of any model of Arctic evolution within the framework of a purely kinematic approach. A generalization of the basic geodynamic model of Arctic evolution previously developed for the Late Cretaceous and Cenozoic to the earlier period of evolution of the Amerasian Basin in the Late Jurassic–Early Cretaceous is proposed.