The vertical sequence of the brachiopod association in the key sections of the Lower Permian in the Northern and Western Verkhoyansk regions is analyzed. The genus dominating in the Asselian-Sakmarian deposits of the Verkhoyansk Region is Jakutoproductus, which is represented by species Jakutoproductus verkhoyanicus (Fredericks), J. crassus Kaschirzew, J. talchanensis Makoshin, J. lenensis Makoshin, characterizing the Khorokytian Horizon, and J. insignis Abramov et Grigorjeva, J. terechovi Zavodowsky and J. rugosus Ganelin, characterizing the Echian Horizon. In all the sections studied, division into biostratigraphic zones was revealed, with the most complete zonal sequence established in the Northern Verkhoyansk Region – in the lower reaches of the Lena River (Kubalakh section, northeast of the Kharaulakh Ridge) and in the basin of the Sobolokh-Mayan River (Orulgan Ridge). In the Kuranakh subzone, the diachronicity of the boundary of the Khorokyt and Echij Formations is revealed. The most important marker of the boundary of the Khorokytian and Echian Horizons is the appearance of the Sakmarian species J insignis Abramov et Grigorjeva in the section. This species has a wide geographic and narrow vertical distribution; it is characterized by the presence of a direct ancestor – the species J. lenensis Makoshin in the underlying sediments (in the terminal part of the Khorokytian Horizon). The appearance of the species J insignis Abramov et Grigorjeva occurred at the initial stage of the Echian transgression simultaneously with the replacement of the Khorokytian ammonoid association by Arkachanian ammonoid association.

In the Emyaksinskaya formation of the Lower Carboniferous, exposed on the Viluy river, there is a fish occurrence known as “Emyaksin-Khayata”. Teeth, scales and bones of fossil fish were found in slightly compacted sandstones. Fossil parasites, represented by unicellular mucous microorganisms, were found on one of the scales of Crossopterygians by the author for the first time, as a result of the studies carried out using Jeol JSM–6480LV scanning microscope. In the Emyaksin-Khayata place, the relationship between fish and microorganisms was antagonistic. Microorganisms used the fish surface, places between tubercles, as a habitat, and possibly as a source of organic matter. Parasite settlement between scale tubercles, in the outer layer of the Crossopterygians skin, could cause occlusion of epidermis pores, blood supply disturbance, and the death of this fish. Along with natural-climatic and other habitat factors, parasite settlements on fish scales could be one of the possible reasons of their death and the formation of the “Emyaksin-Khayata” taphozonose. This place is subject to protection as a site of special scientific-educational interest.

This paper presents the results of the investigation of previously unstudied bone remains of woolly rhinos of different individual ages from the new location on the river Ogorokha (basin of river Indigirka, Abyiskii district, Yakutia). The basin of the Indigirka is known for findings of mammoth fauna across its length. Some of the unique findings, as well as numerous basic locations, were found and studied in that area, such as Mylakhchinskii bison and Abyiskii mammoth, Berelekh mammoth “graveyard”. During the last years, some well-preserved mummies of cave lion cubs, fragments of woolly rhino cubs were found. The possibility of new paleontological findings in this area remains high.

Field work was carried out for three years since 2014. During the work, the remains of almost all representatives of the so-called mammoth fauna were collected. Systematization was done by allocating each finding according to bone types and field numbering. Comparative determination of the bone remains of woolly rhinos involved the morphometric data from other previously studied locations. Individual age, sex and possible cause of death of these animals were determined. It is of interest to study the remains of the embryonic period of development of woolly rhino cubs, which are quite rare to find. The high concentration of bones and cadaveric remains on a relatively small area gives us the reason to suppose that, in the late Pleistocene, this area contained some form of natural trap. The new location of mammoth fauna on the Ogorokha river is of substantial scientific interest and certainly requires more detailed and comprehensive studies.

This article presents a list of radiocarbon dating (55 pcs.) with codes MPI-62 to MPI-117, performed at the Radiocarbon Laboratory of the IMZ SB RAS for the period from 2015 to 2017. The results of cross-dating executed in other laboratories indicated good reproducibility with a probability of 95 %. A brief description of the most interesting dates characterizing the age and chronological volume of the loamy sand dune cover of the D’yolkumin Series, ice-loess deposits of the Edoma Series, new findings of the mammoth fauna, etc. is given. In the light of new dates, attention is focused on some key issues of cryostratigraphy and paleogeography of Central Yakutia and Eastern Siberia at the turn of the Neopleistocene and Holocene.

A massive manifestation of native iron nodules weighing up to four hundred kilograms was established in a trap intrusive near Aikhal settlement. In addition to large segregations, native iron occurs as the drops in the rock-forming minerals of dolerites rimming the iron nodules. In terms of petrochemical composition, the dolerites of the sill belong to typical tholeiites of the traps of the Siberian platform, and correspond to low-Ti basites (TiO₂ ~ 1 %) with increased magnesium content (Mg# = 56–63) that have passed through the deep (pre-chamber) stage of melt crystallization.

The dominant mineral in the nodules is native iron, with subordinate cohenite (Fe₃C), troilite (FeS) and magnetite (Fe₃O₄). X-ray phase analysis revealed that the native iron has the a-Fe structure with the unit cell parameter a = 0.2860 nm. The Brinell hardness is in the range of 110–117 HB units. X-ray spectral analysis showed that native iron belongs to a high-carbon variety (2.14–4.02 wt.% C). The high carbon content suggests that the iron is a Fe – C alloy. With regard to low Ni content (< 1 %) the native iron corresponds to the mineral species ferrite. It is assumed that the main condition for the presence of macro amounts of native iron in traps is fractionation of basaltic melt in the deep-seated (about 40 km from the paleosurface) intermediate chamber. In this situation, the interaction of the basaltic melt with a high-temperature intratelluric fluid, characterized by highly reducing properties, led to the dispersion of initially homogeneous basaltic liquid into liquates of silicate and metal composition. It is the finely dispersed state of the fluid-magmatic system that favored the appearance of the native phase, above all of iron.

Petrography, petrochemical and geochemical features of the Cretaceous volcanic rocks of the least studied Khara-Siss volcanogenic field, located in the North-east of the Verkhoyansk-Kolyma orogenic area, within the Indigirka extensional belt, are studied in the article for the first time. The volcanogenic stratum is divided into two masses – Early and Late Cretaceous. Dacites and rhyolites having normal alkalinity dominate in the composition of the early Cretaceous volcanic rocks. Late Cretaceous volcanic rocks are represented mainly by trachyandesites and trachyandesites. It is shown that volcanic activity began under the conditions of the active continental margin, and completed under the conditions of intraplate continental riftogenesis with the replacement of crust Early Cretaceous formations by the Late Cretaceous derivatives of mantle magmas, the primary melts of which were formed in deeper horizons of metasomatized mantle. Accordingly, the rocks of high-potassium late-orogenic series were replaced by the derivatives of latite and trachyte series during volcanism evolution, and alkaline lamprophyres completing magmatic activity within the studied area, belong to alkaline-basalt series. Increased concentrations of Rb, Th, U, REE, F, Cl, P in all Late Cretaceous volcanic rocks, that is explained by functioning of hot point and supply of the flow of fluids, related to the magmatic hearths of alkaline-basaltoid composition, to magma generation levels. The geochemical specialization of all the Late Cretaceous volcanic rocks in Au and crystallization under the conditions of high – up to abnormal high activity of chlorine, allows expecting the generation of gold occurrences during the formation of volcanogenic rocks.

This study presents unique permafrost and groundwater conditions in the Mir diamond pipe area, based on comprehensive analysis of the hydrogeology of western Yakutia. Permafrost in this area is anomalously thick and has a two-layered structure. The upper layer is perennially frozen ground containing local cryopeg lenses, while the lower layer is cryotic ground saturated with brines that have temperatures below 0°C. Subpermafrost aquifers which pose the most serious hazards for mining operations are briefly described. Mine dewatering is shown to be complicated by intensive degassing of subpermafrost brines, as well as by the formation of local cones of piezometric surface depression around the wells. Attention is drawn to the development of a zone of secondary rock fissuring around the mine. This process, along with the high dissolving capacity of drainage water, promotes the formation of underground channels and caves and thus the increased water flow into the mine. It is noted that subpermafrost brines hold promise for balneological and mineral extraction purposes. Measures are proposed to efficiently solve the groundwaterrelated problems in the Mir mine for its further development.

In connection with the expert assessment of the pasture suitability of the territory for breeding musk oxen (Ovibos moschatus Zimm.), in the summer of 2018, an express assessment of the productivity of lichen communities of Zavyalov island, located in the sea of Okhotsk, not far from Magadan, was carried out. The site of depression of the low mountain slope in the middle course of the Rassvet Stream was subject to examination. The stock of above-ground phytomass of fruticose lichens belonging to the group of «reindeer moss» was determined by the cut method on the sites of 1/16 (0.0625) m². In total, 5 cuts were taken on this site. The cuts were weighed in laboratory under air-dry condition. In the studied area, the dominant role is played by Cladonia stellaris (Opiz.) Pouzar et Vezda, C. arbuscula (Wallr.) Flot. s.l., C. rangiferina (L.) F. H. Wigg., Flavocetraria nivalis (L.) Karnefelt et Thell. and Cetraria laevigata Rass. Coverage of lichens averages 80 %, sometimes up to 100 %. The average height of lichens is 5–6 cm, sometimes 10 cm. The highest reserves of the top phytomass are those comprising the fragments of lichen tundra with the predominance of Cladonia stellaris (1228 – 2507 g/m²). In polydominant communities, the stock varies from 770.7 (in the fragments of lichen tundra with the predominance of Flavocetraria nivalis) to 843.5 g/m² (in the fragments with the predominance of Cladonia rangiferina). We obtained only primary data on the productivity of lichen communities at the Zavyalov island. In connection with the breeding of musk oxen here and the planned breeding of snow sheep (Ovis nivicola Eschsholtz), which will certainly lead to an increase in the pasture load, the study of the productivity of lichen communities should be expanded, and monitoring of changes in the stock of reindeer moss should be organized.

The Oymyakon District of the Republic of Sakha (Yakutia), due to the specificity of orography and climate, is of great interest in terms of the study of organisms-extremophiles, namely lichens. The article summarizes and complements the information about 18 rare species of lichens of the Oymyakon District of Yakutia as one of the most severe climatic territories. The climate of the area is continental with little rainfall; the annual amplitude of the maximum and minimum temperatures is 100 °C, the area is located within continuous permafrost. Rare lichen species for Asia (Absconditella sphagnorum, Verrucaria bryoctona) and Eastern Siberia (Lepraria albicans) have been found here. The species Aspilidea myrinii, Brodoa oroarctica, Catapyrenium daedaleum, Stereocaulon lambii, which are rare in Yakutia, occur in single localities only in the Oymyak District. The species Asahinea scholanderi and Masonhalea richardsonii are included in the Red Book of Russia and Yakutia. Lichen Neofuscelia ryssolea is listed in the Red Book of Yakutia as a rare steppe species, and the information about its state in nature is insufficient at present. For each species, the typical morphological characteristics, ecological features, location coordinates, data on habitat, substrate, distribution are indicated. The information about the collector, the author of the definition of the species and herbarium where samples are stored is also provided.

Vegetation is one of the most dynamic components of the landscape, so the dependence of vegetation indicators on ecological and geographical indicators and factors is important and most studied in Natural Sciences. It is expected that climate change will have a big impact on the Northern ecosystems. The most important component of the vegetation of the cryolithozone, which is of fundamental importance for the ecological balance in mountain communities in close connection with the ecosystems of the Arctic, are mosses, and the main factor affecting the distribution of mosses by habitat types, and, accordingly, the behavior of mosses in cenoses, is the moisture regime.

The area under study is located at the junction of the Sette-Daban Ridge and the Suntar-Khayata Ridge to the Oymyakonsky plateau of the Verkhoyansky mountain system, in Eastern Yakutia. In order to identify the changes in the spectrum of plant communities, 5 sections of the profile were laid, four of which cover the vegetation of mountain areas and one – plain. During field work in the years 2015–2017, more than 110 of the main geobotanical descriptions of plant communities were made (Alpine tundra, swamps, forests, grasslands, etc.); more than 200 herbarium sheets of vascular plants, more than 1000 specimens of mosses, liverworts and lichens were collected. For bioplastics studies, more than 3 thousand specimens of mosses were collected, in particular at the adjacent territory. Floristic lists were compiled for the bryophytes of individual local floras, investigated with regard to their abundance, biomorf and the underlying rocks, macroand microrelief, permafrost landscapes, moisturizing and vertical zones to be entered in the computer database. In total, we analyzed 265 species of mosses, which are dominated by mesophytae (39,6 %), while xeromesophytes and mesohygrophytes (19 and 19.6 %) occupy the second and the third place; the fourth place is for hygrophytes (13 %), the share of xerophytes accounted for 6 %, and hydrophytes account for only 2.3 %. This number is typical for the bryoflora mountain systems of Eastern Siberia and is due to the climatic conditions of the region.

A bioclimatic model of the distribution of Scotch pine (Pinus sylvestris L.) was created using geoinformation modeling in the MaxEnt. The new map of this species was built with the differentiation into “preferred”, “suitable” and “not suitable” locations. Climatic factors limiting the range of this species in the Republic of Sakha (Yakutia) were identified, and their role in creating the model was estimated (%). These factors include Bio 01 – the average annual temperature (the contribution to the model is 52.2 %) and Bio 08 – the average temperature of the wettest quarter of the year (34.5 %). The remaining bioclimatic variables had a too high permutation coefficient, or their contribution to the model was less than 1 %.

Using the EVI vegetation index, the model was verified. The similarity of the MaxEnt model data and the positive EVI values for April 2016 was estimated at 69.5 %. The data of the analysis can serve as the basis for creating a new map of the area of Scotch pine not only in Yakutia, but throughout Northern Eurasia. In addition, the model allows us to understand how the species composition of forests and the forest cover of Yakutia will change under various climatic scenarios.

The antiradiation effect of the biological product from the internal fat of young Yakut horses on the resistance of white outbred male lab mice subjected to a single X-ray exposure dose of LD 100/30 was studied. It was established that a 30-day use of the biological product containing the fat of young Yakut horses and a 0.1 % stabilizing supplement of the Yagel dietary supplement after X-ray exposure contributes to 84 % survival of mice with full body weight, relative to biological control, restoration of the total number of leukocytes, neutrophils and lymphocytes in the peripheral blood of animals to the level of the physiological norm, and also normalizes the intensity of lipid peroxidation processes in hepatocytes. The effect is achieved due to the very high content of poly-unsaturated fatty acids, especially w-3 and w-6-polyunsaturated fatty acids.