The article provides the first description of the petrographic compositions of Mesozoic alkaline igneous rocks of the Khokhoy ore field. The Khokhoy field forms part of the Upper Amga area and is localized in the northwestern part of the Aldan-Stanovoy shield, at the junction of two major structural units – Olyokma granite-greenstone area and the Aldan granulite-gneiss area, in the zone of the meridional deep-seated Amga fault. Numerous of alkaline and sub alkaline igneous rocks of the Lebedinsky monzonite-syenite-granite complex present in this territory are related to the most productive stage – Mesozoic tectonic-magmatic activation of the Aldan shield. Within the Khokhoy ore fields, there are exposed the Northern Boskho, Western Boskho and Upper Khokhoy alkaline massifs of Mesozoic age, as well as rare mafic dikes whose mineral compositions have been poorly studied until recently. The purpose of this article was to obtain high-quality data on the quantitative mineral composition of all igneous rocks of the Khokhoy ore field with the use of crystallooptical methods. As a result of investigations carried out at the DPMGI SB RAS it was found that rocks of the Northern Boskho massif are largely leucocratic syenite porphyries with prevalent hypidiomorphic granular and porphyritic textures. The rocks of the Western Boskho massif differ in their quantitative mineral composition, primarily in structural characteristics, from the Northern Boskho syenites, and correspond to monzonites. They have a monzonitic texture with elements of hypidiomorphic and porphyritic textures. The rocks of the Upper Khokhoy massif mineralogically differ noticeably from those of the Northern Boskho massif; however, structurally, they are close to the Western Boskho monzonites. They show a well-defined monzonitic texture (with clear plagioclase idiomophism in contrast to K-feldspar). The crystallooptical studies of rare fragments of mafic igneous rocks of unclear genesis found during the field works showed they are tephrites. Also, the time sequence of intrusion of igneous rocks in the Khokhoy ore field is established. Generally, the data obtained may shed light on some problems concerning the evolution of Mesozoic tectonic-magmatic activation of the Aldan-Stanovoy shield.

Periodicity is peculiar to climatic changes that occurred for the last 400 kyr. During this period, 5 climatic cycles took place. In contrast to the present concept explaining the climatic cycles by changing solar activity, we consider the periodicity as a result of auto oscillations of self-regulating climatic system of the Earth. In the etalon, complete, penultimate (137-18 kyr B.P.) climatic cycle, 4 phases, corresponding to stadiality of selforganisation process, were separated. We named those as follows: ‘termination’ (in terms of nonlinear dynamics, corresponding to the state ‘dynamic chaos’), ‘reduction’ (corresponding to the state ‘bifurcation’), ‘moderation’ (corresponding to the state ‘dissipative structure’), and ‘culmination’ (corresponding to the state ‘stationary state’). Stadiality inside cycles and periodicity are provided by transformation of a relatively stable solar energy through its redistribution in internal energy reservoirs: heat, gravitational, geochemical, and biological.

This article discusses the thermal response of upper permafrost to anthropogenic disturbances. It presents the results of experimental geocryological investigations conducted in support of geotechnical exploration and construction of linear engineering projects. The geocryological conditions in the study area, as well as the methods of permafrost geocryological monitoring are described. The research focuseds on the upper permafrost within the depth of annual temperature fluctuations. The field observations involved repeated surveys of burned areas, including measurements of snow depth, snow density, soil properties, thaw depth, and ground temperature in the cold and warm seasons. The study aimed to explore the active layer thickness and near-surface permafrost temperatures, the variables that indicate changes to the ground thermal regime in the pipeline, railway, road and powerline corridors. The observation results demonstrated significant increases in mean annual temperature of the upper permafrost layers, as well as in seasonal thaw depth in the burning and deforestation on the burning. The depth of soil thawing in the burned areas increased every year, in places reaching the top of ice wedges and causing permafrost degradation. There are data on development of hazardous cryogenic processes causing surface deformation. The variability of the thermal regime of soils on burned and burned with felling areas depending on the stages of self-restoration of vegetation was quantitatively estimated. The research results were used in the research and construction of linear structures. The experimental data served the basis for geocryological forecast and development of recommendations for environmental management.

The problem of the thermal reaction of the upper ice horizons of the cryolithozone on the technogenic impact of linear structures was considered on the example of the railway in extreme geotechnical conditions and modern climate warming. The relevance, scientific and practical significance of the problem under study are substantiated, the features of the geocryological conditions of the work site are briefly characterized. The technique and organization of the observation network of the experimental railway construction site are considered. The results of engineering-geocryological monitoring of the railway line Tommot – Nizhny Bestyakh on the area of distribution of rocks of the ice complex, where innovative design was used, are presented. The thermal dynamics of the subgrade and embankment soils were quantified associated with the wide use of thermosyphons and insulation materials. The observations indicated a rise in the permafrost table and cooling of the subgrade under high and low embankments, and increased seasonal thaw depths and ground temperature warming on the right-of-way along the railroad. Where a zero embankment was placed with removal of the active layer, perennial thaw bulbs developed in the subsoil. Degradation of ice-rich permafrost was observed on the cut slopes and ditches in the cut sections. Thermosyphons on the berms in combination with Penoplex insulation showed a cooling effect on the subgrade and permafrost table. Overhanging snow sheds on the embankment slopes proved to be beneficial for reducing subgrade temperatures. The experimental data serve an information basis for the forecast of the thermal regime of the soil of the base of the roadbed and the surrounding area in a changing climate.

This paper describes the geocryological investigations conducted in the northeastern part of the Verkhoyansk Mountains comprised of the Orulgan, Kular and Kihilyakh ridges. The study area is characterized by a harsh climate and cold, continuous permafrost, which favor widespread occurrence of ground ice. Despite the shallow depth to ground ice, thermokarst development is limited. This is probably due to low temperatures of the permafrost and its large cold storage. The Batagay sinkhole is a current thermokarst feature representing a normal evolution process in the eastern Verkhoyansk Mountains.

Considering the significant impact of wildfires on properties, content and regime of automorphic soils of the permafrost area, we have suggested the term ‘Pyrogenesis’, which describes processes and events that occur in natural landscapes under the influence of fire. In the forest phytocenoses of South Yakutia also characterized by the increased amount of forest fuels (14.92-42.20 tons/ha). Mosses, lichens and litter that belong to the 1st group of fire conductors make up 37-62 % of the total phytomass. Frequent summer thunderstorms are common in the studied area. Thus, the average number of wildfires caused by lightning during summer period makes up 49 % of the total number of wildfires. Basing on the study of the patterns on geographical distribution, development of properties and composition of pyrogenically transformed cryogenic soils with a polycyclic profile in Yakutia their geographic-genetic traits were found. It was demonstrated that pyrogenic buried humus horizons were characterized by the increased content of humus and nitrogen, as well as clay fractions, silt and Са+2 and Mg+2 exchangeable bases. In the humus composition of these buried horizons, one can clearly observe the increase in calcium-bound humic acids (HA-2). The type of humus in such horizons change from fulvatic to fulavtehumatic and humatic. In the frozen taiga region of Yakutia, especially in humid mountain regions, wildfires have negative effect on soil cover.

This article presents the results of a study of new paleontological material collected during field work in 2014, the field summer school “Lena Pillars” of 2018. In addition, the bone remains of mammals of the mammoth fauna, which are stored in the museum of Kachikattsy village, as well as, found in the summer of 2016 by students of the Oktemsky Lyceum. The descriptions of the most valuable bone residues, their metric and nonmetric features are given. As a result of studying the remains of mammals of the mammoth fauna, we determined the presence of the mammoth, woolly rhinoceros, Lena horse, red deer, moose, bison and bighorn sheep in the basin of the Buotama River and the adjacent territories. The presence of a cave lion in this region was reliably established for the first time. The remains of predators are much less common than the remains of more numerous herbivorous animals, due to the rule of the Elton ecological pyramid. In this regard, the finding of a fragment of the skull of a cave lion at Buotama is extremely rare. New finds of the remains of mammals of the mammoth fauna complement the information on the species composition and distribution of the mammoth fauna in the modern territory of the Lena Pillars Nature Park. The locations of the mammoth fauna in this protected natural area should be included in the list of natural monuments.

The analysis of sociological studies of the population of Lensky and Olyokminsky Districts of the Sakha Republic (Yakutia) was carried out.

The activity of research is strategic course for the socio-economic development of the Sakha Republic (Yakutia), which ensures the development of human capital and the improvement of the quality of life of the population. At the same time, since 2012, there are no official statistics on average per capita incomes of the population in the districts of the republic.

Objectives of the study:

- identification of factors determining the material well-being and quality of life of people;

- study of the scale, depth, dynamics and main factors of poverty among the rural population of the Sakha Republic (Yakutia);

- use of research results in the formation of economic policy in the Sakha Republic (Yakutia), to develop recommendations for improving the quality of life of the population.

Objectives of the study:

- assessment of the scale and causes of the rural poverty;

- identification of the main sources of income of the population;

- determining the level of poverty based on household consumption;

- comparison of the level of socio-economic development of the territory with the standard of living of the population.

Research methods: sociological research using the method of a formalized questionnaire of respondents on a supporting questionnaire consisting of 15 questions. In order to reach the sample, local residents aged 18 to 75 years old were interviewed, working with civilians (unemployed, retired, disabled, students), taking into account the principles of homogeneity of groups by gender, age, educational level and social status.

An analysis of data indicates that there are differences in many incomes and the current number of poor people in the studied regions of the republic.

The data obtained as a result of the research conducted on the standard of living of the population of Lensky and Olyonminsky Districts will be used to formulate economic policies in the Sakha Republic (Yakutia), to improve the methodology and methodology of financial support for municipal unots of the republic, to develop recommendations for improving the quality of life of the population.