Relationship between large intracontinental depressions in the north-east of Russia (the system of Momo-Selennyakh depressions) and the regional Verkhoyansk-Kolyma fault system breaking through the zone of the Chersky Ridges to the north-west is considered. A review is presented over the data on the nature of these depressions, which developed since the Miocene till the Pleistocene as rift troughs, It is shown that a change of the tectonic regime occurred in the Middle Pleistocene, and the indicated structures are developing in the field of regional compression. This is confirmed by the entire set of geological, geophysical and geodynamic data and by the prevailing type of tectonic motions in the Verkhoyansk-Kolyma fault system corresponding to strike-slips, overthrusts and thrust-faults. The zone affected by the general Ulakhan fault is analyzed as an example. This zone is a shear boundary between the North American and Eurasian lithospheric plates, and it controls modern tectonic processes in the north-east of Russia.

The genesis and evolution of ore breccias of the main silver and gold deposits in Western Verkhoyanye corresponding to the richest types of ores are described. The duration of the ore process and ambiguity of the modern dating of ore formation relying only on the determination of the crystallization time of igneous rocks are demonstrated by the examples of ore relationships with each other and with intrusive formations. For this purpose, during long-term field studies, a set of the most representative ore breccias was collected, photo-documented and studied. The start of ore formation at the Vertikalnoe deposit refers to the time after the crystallization of the Endybal intrusive and a cluster of dykes; it includes not less than four stages. The Kis-Kyuelskoe deposit belongs to the intra-intrusove type, its formation is associated with solidification and cracking of the roof of the diorite-granodiorite intrusive. Silver amalgams in the Khachakchanskoe deposit were formed in the faults stretching to the north-east, intersecting the folded structures. The ores of the Endybal ore mountain were deposited in a series of differently oriented cracks and interlayered zones of thrust faults. We assume that the last manifestations of activity in the zones of ore-controlling faults occurred in the Cenozoic, and the long-standing process of ore deposition in multistage breccias could take place since 102-98 million years till the beginning of the Paleogene.

The results of the ecological geochemical monitoring in the regions where the separating parts of Soyuz-2 rocket carriers fall are analyzed. Ecological survey was carried out at monitoring sites at the territory of the Republic of Sakha (Yakutia): the state of environment was evaluated before the launch of the separating parts of rocket carriers and after their fall. Chemical analytical examination of snow and soil revealed local pollution of the snow cover and soil with heavy metals and petroleum pro- ducts at a level exceeding the background concentrations and corresponding to the permissible or low level of pollution.

The results of the statistical analysis of the resistivity of frozen loose sediments and sedimentary rocks in the left-bank part of the Lena river valley in its middle reach in the built-up suburbs of Yakutsk are presented. Resistivity is one of the basic characteristics of frozen geological formations on the Earth, and knowledge of the probabilistic laws and generalized values of resistivity allows rapid, inexpensive and environmentally friendly solutions to the problems of engineering geology and cryolithology. In particular, the average depth of the occurrence of sedimentary rocks comprising the basement of the Lena river valley may be determined by means of vertical direct-current sounding without expensive drilling or with its minimal amount, with a required confidence probability and acceptable error. This is essential for the design and survey works during the continuing development of the Lena river valley.

Results of the experimental studies of grinding processes under multiple dynamic impact in a centrifugal step mill designed at the MIN SB RAS are reported. To enhance the grinding effect, it is proposed to mount additional baffle elements at the movable bodies of the mill. However, this is not always a solution of the problem because there is a negative effect of air flows formed in the working space between the upper and lower movable bodies. A rational number of additional baffle elements, determined by the critical air flow rate in the working chamber of the laboratory step mill which should be up to 10 m/s was determined in research and development works. Under these conditions, a substantial increase in grinding degree is achieved, in comparison with the basic version of the laboratory centrifugal step mill without baffle elements.

It is shown that insufficient attention is paid to the assurance of the necessary coal quality level during coal delivery to hard-to-reach regions, which causes economic losses. The major reasons of this situation include only partial use of the modern approaches to quality management, while the complexity and specificity of the chains of long and multi-chain logistics are taken into account inadequately. The features of hard-to-reach regions of the North-East of Russia predetermine the reasonableness of the new approaches and method in the studies and evaluation of a wide range of coal deposits, under development It is shown that insufficient attention is paid to the assurance of the necessary coal quality level during coal delivery to hard-to-reach regions, which causes economic losses. The major reasons of this situation include only partial use of the modern approaches to quality management, while the complexity and specificity of the chains of long and multi-chain logistics are taken into account inadequately. The features of hard-to-reach regions of the North-East of Russia predetermine the reasonableness of the new approaches and method in the studies and evaluation of a wide range of coal deposits, under development

Productivity components, calculated and actual productivity, winter resistance, ability to ear­ ly maturing were studied for the varieties of eight genetic groups of black-currant during the years 1990– 2015. It was revealed that the potential productivity of the hybrids of the Siberian sub-species of blackcurrant Ribes nigrum ssp. sibiricum E. Wolf and R. dikusсha Fischer ex Turczaninow was the highest (511,4 centners/ha for Dubrovskaya, 467,1 centners/ha for Seyanets Golubki). The actual productivity was less than 10 % of the potential level during the first years of cultivation. The productivity of local species and varieties was lower (242,7 centners/ha – Sardaana variety), its realization reached 48 %. The main reasons of low actual productivity are insufficient winter resistance due to the genotype, and the lack of heat during blossoming and fruiting; as a consequence, up to 45 % of the yield is lost. The local species of black-cur­ rant, as well as the varieties of the 4^th, 5^th, 8^th genetic groups, are winter-resistant (winter resistance: 1 point), the varieties of the Siberian sub-species are characterized by winter resistance of 2 points. Gen­ eral warming of the climate in Central Yakutia caused an increase in actual yield. Realization of the potential productivity increased to 33–40 %. A strong positive correlation between the productivity and the number of berries in a bunch was established (r = 0,803, P = 0,04), and the mass of a berry (r = 0,811, Р = 0,05).

On the basis of the studies of freshly collected seeds of 187 plant species in Central Yakutia, three groups including 11 subgroups were distinguished on the basis of germination features. The scale of seed germination types is based on such parameters as the start, duration, rate of germination, germinating capac­ ity, and seed germination energy. It was detected that freshly collected seeds of the studied 52 species exhibit accelerated germination (I group), 57 species exhibit slow germination (II group), while 78 species do not germinate and/or germinate only weakly (III group). For the seeds of the species included in group III, the methods to overcome their dormancy are proposed: storage in dry air for 5–7 months under room conditions and stratification in a climatic chamber at decreased temperatures 0–3 and 5 °C. As a result of dry storage, the seeds of 23 species exhibited accelerated germination (subgroup IIIA), 14 species germinated slowly (subgroup IIIB), the seeds of 27 species exhibited weak germination, with the germination capacity 2 to 24 % (subgroup IIIC), nad the seeds of 14 species revealed zero germination capacity (subgroup IIID).

In 1997, 5024 steadily unfavorable sites for anthrax were registered in Siberia and in the Far East. Among all the Arctic territories of the Russian Federation, Yakutia contains a certain number of these sites, where numerous epizootics of anthrax among domestic reindeer and wild animals were recorded at the end of 19 century and at the beginning of the 20 century. According to archival documents, the first written evidence on anthrax appeared in the reports of district, alien and volost administrations of the Kolyma, Verkhoyansk districts, dating back to 1811. In the memorial book of the Yakutsk region for 1896, the data on the epizootic diseases in the Yakut, Vilyuisk and Kolyma districts are presented.

The locations of the main number of anthrax cattle burial grounds and the places of random burials of animals who died from anthrax were not clearly identified and were not included in the epizootological survey. The real danger of the historical burial places of dead animals was manifested by anthrax epizootic among reindeer in the Taimyr region of the Russian Arctic in 1969 and 1977, in Yakutia in 1988. A special revival of zoonosis was recorded in 1970 along river banks, in 1993 – in the vicinity of settlements. The epizootic-epidemiological situation of 2016, which took place in the Yamalo-Nenets Autonomous Territory, is didactive in its nature.

Modern data indicate that the survival of B. anthracis spores and the existence of anthrax soil foci under the climatic conditions of the Far North actually take place. Their recovery (activity) is recorded after several decades or more. The possibility of a microbe to survive through a full life cycle in permafrost soil (sporogenesis, spore initiation, germination, reproduction of vegetative cells, sporulation) was proved. The absence of officially registered soil foci in Yakutia does not exclude their potentially actual secrecy not only under the cover of “mor fields” but also in paleontological remains (mammoths, cave lion, woolly rhinoceros, and lining soils).

Although the northern part of the Transbaikal Territory is situated in the taiga zone, a combination of the taiga with the landscapes of the subarctic zone is a characteristic of the region. This fact had a substantial effect on the formation of ichtyofauna in water reservoirs of the northern regions of the taiga in Transbaikalia, where Kodar national park was established in 2018. A description of the structure of ichtyocenoses of various aquatic ecosystems is presented in the work. A unique combination of fish of the Arctic, boreal-foothill, boreal-plain complexes is shown. Characterization of fish from the Chara river is presented. The representatives of the Boreal-foothill complex and the arctic complex were dominating in the ichtyofauna of the river. Grayling occurred most frequently. Round whitefish and tugun were rare. The data on the growth and nutrition of grayling, round whitefish, tugun in the Chara are reported. A description of fish in deep lakes is presented. The lakes relate to Salvelinus (Charr) and whitefish types according to the composition of the ichtyofauna. Representatives of the boreal foothill complex dominate in deep-water lakes. Species domination is lakes varies noticeably in spite of the close location of these lakes. The growth and nutrition of Brachymystax lenok, Salvelinus (Charr), humpback whitefish are characterized. The data on the species diversity for the Chkalovo group of lakes are presented. Reasons affecting the changes in the species diversity of fish at the territory under study are analyzed, first of all those connected with the construction of the BAM, pollution of water ecosystems, increased fish poaching.

The macrostructure of wearproof powder coatings with the modifying additives of four types are investigated: corundum Al₂O₃, tungsten W, tantalum Ta, and a rare-earth concentrate from the Tomtorsky field in the Republic of Sakha (Yakutia). It is shown that a characteristic feature of the macrostructure of the modified powder coatings is their layered nature, which has a substantial effect on the formation of open porosity. The levels of open porosity of the modified powder coatings were estimated by menas of hydrostatic weighing. It is shown that the open porosity of the gas-thermal coating is also dependent on the technological modes of its preparation and on the concentrations of modifying agents. A theoretical distribution of the porosity of powdered coating on a smooth substrate is proposed on the basis of the statistical modeling of the formation of layered macrostructure of powder coatings.

Results of the studies of the effect of montmorillonite modified with organics (oMMT) grade 101/102, on the mechanical, tribological and thermodynamic characteristics of ultrahigh molecular weight polyethylene UHMWPE are reported. The filler was introduced into the polymeric matrix in the amount of 0,5, 1 and 2 mass %. The samples for tests were obtained by hot pressing. It was established that the introduction of 0,5 mass % oMMT into ultrahigh molecular weight polyethylene causes an increase in the tensile strength by 23 %, and elastic modulus by 14 % in comparison with the non-filled polymer. It is shown that the rate of mass wear of the material under dry sliding friction decreases by a factor of 1,5, while the linear wear decreases by a factor of 2,8 in comparison with the initial ultrahigh molecular weight polyethylene. Differential scanning calorimetry was used to reveal that the enthalpy of melting and the degree of crystallinity decrease by 4 % with an increase in the fill content in the polymeric matrix. It was shown by means of structural studies that the introduction of organic clay into the polyethylene promotes the formation of the spherulite structure of the composites, with filler particles acting as crystallization centers. Materials with this kind of structure are characterized by increased strength and wear resistance in comparison with the initial polymer.