The authors developed and tested a methodology for compiling interregional stratigraphic correlation schemes for the land-sea transition area of the Russian Arctic. The methodology combines seismic profiling results obtained with the common depth point seismic reflection method, geological structure data, litho-biostratigraphic data on offshore and onshore boreholes, geological survey results on islands and archipelagos, as well as information on outcrops and drilling in the coastal zone. To clarify the ideas about the areal sedimentation, the unified palaeogeographic maps of the Russian Arctic are created for subdivisions of the Phanerozoic systems. GIS technologies contributed to compiling new unified structural-facies zoning maps. Interregional stratigraphic correlation schemes are based on developed new zoning maps. The work was based on the modern General Stratigraphic Chart of Russia as well as updated and new stratigraphy data. The results obtained are of practical value for ongoing mapping works in the Russian Arctic and correlation of the subdivisions within the area of the Northern Kara Sea — Barents Sea, Southern Kara Sea, Laptev Sea — Siberian Sea, Chukotka, Taimyr — Severnaya Zemlya, and Ocean legends to series of State geological maps (scale of 1 : 1,000,000). The creation of a unite set including the combination of bio-lithostratigraphic data, dating of rocks and seismic horizons is important due to the insufficient knowledge on the geological structure of the offshore area of the Russian Arctic and the high oil and gas potential of the region as a whole.

The data cover a complex study of published and original geological and geochronological materials on the stratigraphy of the Gimoly (Upper Lopian) and Sumian (Lower Proterozoic) superhorizons in the Karelian region. The base of the Sumian Ozhijarvi Formation should locate the Archean–Proterozoic boundary. The Gimoly Superhorizon is divided into the Kostomuksha (lower) and Tunguda (upper) horizons with the timeframe of about 2,760 Ma. Mainly sedimentary rocks form the Kostomuksha Horizon, whereas felsic and basic volcanites construct the Tunguda one. Sumian basic volcanites underlying the Ozhijarvi formation should belong to the Tunguda Horizon. The completeness and age distinguish three types of superhorizon sections — West Karelian, Central Karelian, and North Karelian, which form independent structural and formational zones. The rocks of the Tunguda and Kostomuksha horizons represent the West Karelian and North Karelian zones, only the Tunguda Horizon describes the Central Karelian one. The geological and geochronological analysis reveals a number of unresolved issues. The major ones include the location and age of the Tunguda Horizon lower boundary, the age and structure of the Moroznoozerskaya strata and Pebozero series sections in the stratotypic section of the north-east part of the Lekhta structure.

The paper outlines the Triassic deposits palynostratigraphic data from Murmansk gas field well sections 24, 28, 26, 27 in the southwestern South Barents Depression. The palynological data verify the Triassic deposit stratigraphic breakdown and identify palynological zones. There are novel layers of Polycingulatisporites spp. and Aratrisporites spp. — Punctatisporites fungosus, as well as five palynological zones comparable to the Norwegian part of the Barents Sea Shelf: Verrucosisporites spp. — Baculatisporites verus, Aratrisporitess spp. — Apiculatisporis spiniger, Leschikisporis aduncus — Echinitosporites iliacoides, Leschikisporis aduncus — Gibeosporites lativerrucosus, and Dictyophillidi tes spp. — Zebrasporites interscriptus. The author describes index species of palynozones, redefines several miospore species. The spores and pollen method to explore the Triassic deposits on the Barents Sea Shelf well sections contributes to the detailed stratigraphic breakdown of the regional Triassic deposits.

Discovery of the Vilyuy Syneclise gas deposits in anticlinal traps, with gas observed at shallow depth, dates back to the 1960s. High reservoir properties are characteristic of the Kyzyl-Syr Formation reservoirs that wells in the study area encountered. The author used geophysical data to correlate the Lower Jurassic stratigraphic section within the study area: layer-by-layer and detailed intra-layer correlation, with sedimentological analysis data from the new well core included. The findings support unconformity between the Kyzyl-Syr and Suntar formations at the top of the Lower Jurassic deposits in the Khapchagai region of the Lena-Aldan structural-facies zone in the Vilyuy Syneclise. The author traced four consecutive cycles of deposit formation in the J1-1 bed and newly mapped the deposit erosion boundary in the last cycle; previous researchers had only assumed its presence. The author identified coastline location in the western part of the study area, as well as the sources position and direction of sedimentary material in the Early Jurassic period.

It is important to substantiate the presence of the Cenozoic Salic Complex in the southern part of the East Sikhote-Alin Volcanic Belt, since its age formational analogues relate to gold-silver epithermal mineralization. The Brusilovka Complex is emphasized to be ore-generating for this type of mineralization, and above all, it is mistakenly confused with the Bogopol Complex due to the differences in metallogenic specialization, petrogenesis, age, and geodynamic conditions of its formation. The paper presents the author’s geological work findings within the Brusilovka volcanic structure, including the content of the Brusilovka Complex rocks, which refer to the contrasting basalt-trachyrhyolite association; the paper notes their similarity to the Kedrovka Volcanic Complex rocks. There are listed discrepancies in the current study of the Brusilovka Complex geochronology: ignoring previous tectonic zoning diagrams of the territory and material criteria for identifying volcanic complexes of the trachydacite-trachy-rhyolite formation; insufficient sampling of volcanogenic formations taken not from the Brusilovka Complex stratotype; geological inaccuracies. It is necessary to resolve the dispute about the validity of identifying the Brusilovka Complex and comprehensively characterize the volcanogenic formations for reconstructing volcanic and tectonic structures.

The paper establishes structural and tectonic properties of deposits in order to assess hydrogeological and geotechnical conditions of their development (based on individual deposits in the Central Kyzylkum region). The research methodology involved selecting samples to determine physical and mechanical properties of rocks as well as analyzing and assessing structural and tectonic properties and their relationship with hydrogeological and geotechnical conditions when developing deposits. There were explored mine workings of deposits located in the southern ridge of Tamdytau, within the Auminza-Beltau, Auminzatau mountain ranges. The deformations locations were found to be confined to faults and contacts of lithological rock differences. There are two large groups of well represented faults in the ore field, as they relate to scale and fold structures: regional and local fault structures. The overburden rock mass is mostly tough and hard, but soft rock interlayers, carbonaceous clayey shales, and clay gouge with a thickness of several millimeters to 10–15 cm, accompanied by tectonic disturbances, reduce the massif strength.

The paper analyzes the history of discovering and developing gold ore deposits and placers of the Amur River region since its annexation to Russia in 1858. From 1868 until the Baikal-Amur Mainline construction, gold was mined mainly from placers. The end of the 20th century marked the significant depletion of placers. An increase in the gold mining level required identifying and operating gold ore deposits. The beginning of the Baikal-Amur Railway construction substantially expedited this process. The influence of the Baikal-Amur Mainline construction on developing the Amur Region infrastructure and intensifying geological exploration for ore gold led to identify new gold ore deposits (Pokrovsk, Pioneer, Bam, Solovyovsk, etc.) and reassess the already known ones (Berezit, Malomyr, Albyn, etc.). The gold ore deposits operation resulted in a considerable rise in the total gold production in Amur Region. The Baikal-Amur Mainline construction produced new data on the geological and structural position, and age of gold ore deposits, which identified the Amur River gold-bearing province in Amur Region. There were established patterns of placing metallogenic zones, ore-placer clusters, gold ore deposits, and placers in the province.

The paper proposes a bed-by-bed description and new lithostratigraphic classification of the Middle Ordovician Kunda and Aseri stages of the Lava River. The Obukhovo Formation (Kunda Stage) includes the Voka, Lava, Il’yinskoye, Cherna vino, and Simankovo members. The first two are also common in more western sections of the Baltic-Ladoga Klint (Loobu type), the others — with the eastern sections (Obukhovo type). The Lava Member is a new subdivision introduced to replace the Utria Member, which initially had a smaller volume and different identification principle. The upper “Oolite Bed” is not considered as an independent unit and refers to a local “facies” of the Chernavino Member and Lower Simankovo Member; with its appearance, the clay content of limestone can increase shar ply. The Duboviki Formation (Aseri Stage) includes the Kavra, Mel’nitsa, Suosaari, and Zhikharevo members; the Lower Porogi-Valim Formation (top of the Aseri Stage and lower part of the Lasnamägi Stage) has the new Perevelje Member. The Kavra Member is developed only in the east of the Klint (south of the Lake Ladoga region) and the more carbonate Saksolovo Member replaces it to the west. The Mel’nitsa-Perevelje members are distributed over most of the Ingermanland Klint. A reinterpretation of the stratigraphy of five drillholes in the Putilovo Upland was carried out based on their correlation with the key section of the Lava River.

The paper focuses on hydrothermokarst cavities of ore deposits. They differ in morphology, genesis, and location in ore fields. Hydrothermal cavities relate to an additional search sign of mineralization. Cavities often contain unique mineralogical aggregates and can serve as valuable sightseeing and tourist sites.

Dividing the Archean complex of the Aldan Shield into structural and material complexes, and structural and formational zones, as well as matching the chemical composition of the Archean main crystalline shales to basalts led to identify the complex’s geodynamic regimes. Meanwhile, the ratio of such elements as K and Ti, K and P in metabasalts varies in different geodynamic settings. The paper considers the Timpton-Dzheltulin structural and material complex located in the eastern half of the Aldan Shield, mainly the Timpton-Uchur inter-stream. The Sm-Nd dating method attributed the complex to the Late Archean (2.6–2.8 bn years). There are four structural and formational zones in the complex (from east to west): Uchur, Tyrkandin, Dzheltulin, and Timpton. The geodynamic diagrams K–Ti and K–R, which locate figurative points of the metabasalts chemical analyses in each zone, demonstrate that the zones belong to different geodynamic regimes. Zones of forming Late Archean rocks in the Timpton-Dzheltulin complex establish the following regimes: the Uchur zone relates to a series of small (hundreds of km) island arcs, the Tyrkandin zone — a carbonate-volcanogenic island arc, the Dzheltulin zone — a sedimentary basin on a passive continental margin, the Timpton zone — an intracontinental sedimentary basin developed from continental rifts (aulacogens). All these geodynamic regimes are likely to demonstrate how the mechanism of lithospheric plates tectonics works during the continental crust formation already in the Archean period.