The paper considers pollen assemblages and their reflection of the vegetation cover in the southernmost Russian Far East. The research involved 53 samples of modern sediments collected in the coastal-marine forest steppe and oak open woodlands, as well as at the bottom of adjacent water areas. Pollen from Japanese red pine (Pinus densiflora) and Korean pine (Pinus koraiensis), birch and oak trees dominates in tree species. The pollen content of these species, excluding oak, does not adequately reflect the vegetation cover formed within most pollen assemblages. In forest steppe, only oak pollen reaching on average 35 % values in soil and lagoon-lacustrine sediments is fully associated with oak prevalence in island upland forests. The pollen assemblages in oak open woodlands development do not correspond to the vegetation cover to a lesser extent than in forest steppe due to reduced Korean pine pollen. Soil sediment assemblages, with the maximum oak pollen content of up to 60 %, are most representative of the open woodland vegetation. The same pattern of inadequacy to the vegetation cover is characteristic of herbaceous pollen. Grasses and various forbs outnumber wormwood dominating in the assemblages of coastal-marine forest steppe in sediments of various genesis, as well as sedges prevailing in soil samples from oak open woodlands.

The paper reveals pollen and spore findings from the Sea of Japan’s bottom sediments, namely the Tartary Trough, continental slope of Primorye, Russian Far East, as well as Northern Yamato and Pervenets rises in 2010. The Tartary Trough sediments contain a high percentage of pine, birch, and spruce pollen. Dominance of coniferous (spruce and pine) pollen is associated with the wide-spread distribution of the species as well as ability of this pollen to be aerially dispersed for hundreds of kilometers. Coniferous pollen (pine, spruce, and fir amount to approximately 90 %) and oak pollen (up to 20 %) dominate in the Pervenets Rise sediments. Pine and oak pollen prevail in the Northern Yamato Ridge sediments. Oak pollen presence in marine sediments increases from north to south, consistent with its range in the Sea of Japan region. The obtained data are likely to contribute to interpreting pollen records of marine sediments and paleoreconstruction of environmental conditions and climate.

Neogene sediments are widespread in the southern West Siberian Plain. Limited data on the Pliocene palynology were obtained mainly in the second half of the 20^th century and have poor stratigraphic correlation. The Peshnevo Formation is one of such frontier units. The eponymous faunal complex of the Early Ruscinian with the index species of Promimomys antiquus (MN14 Zone, 4.9–4.2 Ma) characterizes the formation. Formerly these sediments were dated from the Lower Miocene to the Upper Pliocene. Previous studies suggest no data on the Peshnevo level palynoflora. Three new small mammal sites of the Peshnevo level were studied near Irtysh and Om rivers (Omsk region). The pollen analysis data indicate the pre-dominant forest-steppe environment. Arboreal pollen accounts for up to 45 %, indicating local mixed forests with dark coniferous and broad-leaved species. Thus, the paper presents the first palynological characteristics of the Peshnevo Formation sediments, which include a reliable paleontological correlation with small mammals.

The paper characterizes glacier formation complexes resulting from interaction of the Scandinavian ice sheets and Lovozero Tundra mountain glaciers due to insufficient data of their development patterns. Correlating sections along the Lovozero Tundra periphery contributed to reconstructing stages of ice sheet and mountain glacier oscillations during the Podporozhye and Ostashkov periods of the Late Neopleistocene. Their development and interaction scenarios are similar: before the Scandinavian ice sheet spread into the Lovozero Tundra, a vast mountain glacier had been formed here, but later, during a warming period, the ice sheet retreated to the west. The analyzed fluvioglacial–moraine pair as an oscillatory warming-cooling indicator in their interlayer strata (in both ice sheet and mountain glacier formations) proves the glaciation history. Two main differences pertain to the studied glaciations: the ice sheet penetrated the Lovozero Tundra region only once during the Podporozhye period, while it occurred twice during the Ostashkov period; after the glacier retreat, six approximately equal cooling periods were recorded in the Podporozhye period, while the Ostashkov period was associated with five periods, the last of which caused the ice sheet to re-enter the Lovozero Tundra. The Late Neopleistocene glaciation reconstruction specifies the area’s geological development history.

The Lenenergo section located on the Oyat River left bank in the south-eastern Lake Ladoga region is critical for studying the Holocene transgressions of Lake Ladoga. Uncertainty in the previously published organic-rich deposits age data substantiates the use of paleogeographic methods to reexamine them. The article presents lithological characteristics of the section as well as results of detailed pollen analysis and radiocarbon dating of peat and gyttja. The organic-rich deposits accumulation occurred from 8,900 ± 150¹⁴C yrs BP (9,960 ± 210 cal BP) to 3,530 ± 80 ¹⁴C yrs BP (3,810 ± 110 cal BP). On the territory, the Preboreal period marked peat accumulation and sparse vegetation cover. Gyttja, whose age was 8,420 ± 90 ¹⁴C yrs BP (9,400 ± 100 cal BP), accumulated during the Boreal period and was characterized by dominance of pine and birch forests in the environment. The sedimentation hiatus lasting at least 3,500 years was revealed at the turn of the Boreal and Atlantic periods. Gyttja accumulation continued in the conditions of the Lake Ladoga paleolagoon during the Atlantic and Subboreal periods from 4,880 ± 200 ¹⁴C yrs BP (5,610 ± 250 cal BP) to 3,530 ± 80 ¹⁴C yrs BP (3,810 ± 110 cal BP). Pine, spruce, and birch forests with an admixture of broad-leaved species dominated. Diatom analysis and geochemical studies are projected to fully characterize sedimentation conditions in the southeastern Lake Ladoga region during the Holocene.

The Tatyshev section of the Karginsky pedocomplex on the 35–45-meter Lagernaya terrace of the Yenisei River was comprehensively studied in the Krasnoyarsk depression. Radiocarbon and thermoluminescence dating demonstrated that the soils were formed in the Early, Middle, and Late Karginsky periods. There were characterized macro- and micromorphological characteristics, physical and chemical properties of the soils: grain-size composition, humus content and its fractional composition, carbonates content, pH, sum of exchangeable bases, and gross macroelement composition. Phytolith and spore-pollen analyses showed the dynamics of climate change and vegetation cover composition during the soil formation within the terrace itself (Tatyshev section) and adjacent elevated areas of the left bank of the Yenisei River valley (Yasnoe-1 section). During the Karginsky interstadial the Krasnoyarsk depression highlights three periods of soil formation and two periods of sedimentation, which correlate well with climate changes in other areas of Siberia in this period. Loess-like deposits from the time of the Karginsky soil formation contain a very small amount of pollen and spores, which is associated not only with the deposits genesis, climatic conditions of their formation, but also with their preservation.

The paper explores the Upper Berriasian dinocysts in the Crimean– Caucasian–Caspian Sea region, the only territory within Russia that belonged to the northern margin of the Tethys paleoocean in the Cretaceous, as opposed to the entire Boreal territory of the country. The emergence of the Caspian Sea paleostrait in the Late Berriasian contributed to the Tethyan and Boreal water masses exchange. This time is considered ideal for correlating the Boreal and Tethyan paleogeographic provinces. The dinocyst assemblages of the Crimean–Caucasian–Caspian Sea region are strikingly similar to one other, while their similarity with the coeval complex of the Boreal Volga region is significantly lower. There are single representatives of the Tethyan and Boreal provinces in the Upper Berriasian assemblage of the Crimean–Caucasian–Caspian Sea region, most of whose species are cosmopolitan. The study aimed to identify the correlation potential of dinocysts found in the Upper Berriasian Crimean–Caucasian–Caspian Sea region, whose first and last appearance correlates to regional ammonite scales of the Boreal and Tethyan regions. The evolutionary changes in dinocysts were analyzed to establish the correlative species Amphorulacysta? expirata, Palaecysta palmula, Egmontodinium torynа, Phoberocysta neocomica. The bioevents for these species are relatively synchronous, which provides additional grounds for comparing the Berriasian deposits in the Boreal and Tethyan regions.

The paper comprehensively discusses the Lower Cretaceous in the junction zone of different structure-facies areas in northeastern West Siberia: Turukhansk, Tazovsky, and Malaya Kheta structure-facies sub-areas of the Ust-Yenisei region. The authors analyze three-dimensional seismic survey data, well logs, as well as sedimentological and biostratigraphic investigation of core samples. The current Lower Cretaceous regional stratigraphic scheme does not provide a single correlation between coastal and shallow marine types of the Ryazanian and Valanginian productive beds. The research findings pertain to the Tagrinskoye clay unit. An unconformity surface at its bottom in two (out of three) analyzed structure-facies areas gives grounds for extending the results to adjacent territories. Identification of stratigraphic hiatuses after analyzing ichnofacies and lithological composition changes at rock contacts, as well as correlating the results to geological and geophysical data contribute to the stratigraphic hiatus problem solution. It is proposed to consider the regional unconformity surface reflecting the boundary of two formation complexes as a validation criterion when correlating well logs. This statement should be included in the current stratigraphic schemes. Using the regional stratigraphic hiatus surface as a correlation criterion will increase reliability of stratigraphic schemes in various structure-facies zones.

The paper covers palynological analysis of the Middle Triassic samples from the SSD 31 well section drilled in the Kara Sea. Biostratigraphic analysis of spores and pollen newly identified the assemblage with Aratrisporites spp. — Perotrilites minor in the sedimentary basin and dated the host deposits as Anisian. The assemblage is compared to the Anisian pollen assemblages from different regions (East Urals, West Siberia, Barents Sea region). The established spore and pollen taxa are grouped according to their botanical affiliation and ecological distribution. Sporomorph ecogroup analysis (SEG) led to interpret paleoecological conditions of the Middle Triassic unit sedimentation. During the sedimentary unit accumulation, the climate was found to be warm and humid, and the environment was similar to a coastal plain.

The paper comprehensively investigates ore mineralization in the Mayskoe deposit, which involves examining structural relationships of mineral associations in mine workings, mineralogical and petrographic ore analysis, interpreting chemical and isotopic composition of sulfur sulfide. The findings identify three ore formation stages naturally associated with key geological events in North-East Russia. The first stage includes ore preparation, which corresponds to the Early Triassic sedimentary hydrothermal system when terrigenous siltstone-pelitic, less often psammitic sediments accumulated on the Carboniferous carbonate base in a passive continental margin. The stage involves lead-zinc and pyrite-arsenopyrite mineral association formation. The second stage is productive or ore-forming, pertains to the hydrothermal metasomatic system and is the most fertile for gold. During this stage, “greisen”, polymetallic, and gold-sulfide mineral associations were formed. The latter includes the bulk of refractory gold. The third stage is subvolcanic, which aligns with a hydrothermal metasomatic system, whose severe decompression resulted in forming quartz breccias with antimonite and visible gold. Sulpho-salt-polymetallic and gold-antimonite mineral associations characterize this stage, which completes the Mayskoe deposit formation. The period featured the ore co lumn in a cross-cutting position against mineral associations of the productive stage, which is notable for coarse (up to 2 mm) free gold.

The paper presents new data of primary diamond potential in the north-western Aldan province (within the Chara-Sinsk zone). The authors describe the geological structure, pattern, and features of various transformants and anomalous geophysical fields. They all are ranked by time, the occurrence characteristics, and kinematics. There are identified fault systems expected to control the kimberlite field location. The findings specify heavy mineral concentrate sampling, morphological and microprobe analysis data of kimberlite indicator minerals. They are considered as criteria and signs of primary diamond potential, along with modeling the potential area position of kimberlite magmatism and intermediate reservoirs. The data of morphology, composition, preservation rate of kimberlite indicator minerals in the area, as well as their distribution pattern demonstrate that their halos in the Myraya, Khatystyr, Markha, Markhachan, and other river valleys are confined to a single northeastern mineralogical field within the Chara-Olyokma segment of the Chara-Sinsk zone. Here the potential kimberlite field can be located in the articulation area of the Chara-Sinsk zone and younger northwestern strike-slips in the Namyldilakh River valley.