South Yakutia Research Articles

Spatial and statistical analysis of seismic energy distribution in the Olekmo-Stanovoy seismotectonic zone (South Yakutia)

The seismic activity in the Republic of Sakha (Yakutia) is monitored across a vast territory of 1.5 million km² and is characterized by two major seismic zones of varying rank: the Olekmo-Stanovoy seismotectonic zone in the south andthe Arctic-Asian seismic belt in the north. This article explores the Olekmo-Stanovoy seismotectonic zone, which forms the eastern flank of the Baikal-Stanovoy seismic belt. For statistical analysis, we used a geological and geophysical model of the Southern Yakutia territory. According to this model, the Olekmo-Stanovoy seismotectonic zone is segmented into five structural-tectonic blocks. For the study area, we compiled a regional catalog of earthquakes, supplemented by data from the International Seismological Bulletin (ISC). Based on the seismotectonic features and geodynamic position of the region, a spatial-statistical analysis of seismic energy released during earthquakes over a 58-year instrumental period of regional seismological observations was conducted. The main parameter for calculations was the parameter ΣE (total released seismic energy), which is most often used in the comprehensive quantitative assessment of seismic activity in a region. This study examines the major earthquakes that made the largest contribution to the calculations of the total energy released in each of the five blocks. Analysis of seismic-statistical data collected in the aisles of large structural-tectonic blocks of the first rank revealed the following correlation: in the Olekmo-Stanovoy seismotectonic zone in the direction from west to east, with distance from the Baikal rift zone, seismic activity decreases by 104 times. This thesis also suggests a slowdown in the intensity of seismotectonic and geodynamic processes in the same direction. The results of spatial-statistical analysis of the distribution of seismic energy in large regional blocks of the Olekmo-Stanovoy seismotectonic zone can be relevant for conducting small-scale research to assess the potential seismic activity of poorly studied areas and for medium-term earthquake forecasting as an independent indicator of impending seismic events.

Errors in average strength estimates of sedimentary rock masses in South Yakutia based on geometric induction sounding data

The probabilistic model developed to describe the engineering and geological conditions for the operation of buildings and infrastructure in the city of Neryungri has been verified. The model is a power-function equation which correlates, by regression relationships, laboratory-determined compressive strength of saturated frozen sandstone samples with attenuation of the high-frequency harmonic field of a vertical magnetic dipole in warm permafrost composed of sandstone. The attenuation values were obtained by geometric electromagnetic induction sounding at a frequency of 1.125 MHz. The model verification was conducted at a fixed frequency on a section of the Amur-Yakutsk Railway located at a significant distance from Neryungri. The railway here is underlain by low-temperature dolomite masses. The statistical analysis indicates that the relative errors of the dolomite saturated strength estimates from the geometric EM induction data with a 73.0% probability do not exceed 20%. With this level of accuracy close to that of laboratory tests according to GOST 25100–2020, it is reasonable to suggest that the probabilistic model can be used region-wide in southern Yakutia to predict saturated strength of foundation materials composed of sandstone and dolomite. It can provide an effective solution for market-based construction and mining industries, as increasing anthropogenic and climatic impacts are anticipated to cause thawing and saturation of sedimentary rock masses.

Microclimatic and thermal balance studies in the natural conditions of the middle categories of South Yakutia

The article reveals the activities of the Zolotinka geocryological station in South Yakutia, one of the BAM expeditions of the Institute of Permafrost, USSR Academy of Sciences. Relevance. The article is dedicated to the 95th anniversary of the birth of Maria Gavrilova, a climatologist, permafrost scientist, famous in Russian and world science, Doctor of Geographical Sciences, professor, Honored Scientist of the Russian Federation and the Republic of Sakha (Yakutia), academician of the Academy of Sciences of the Republic of Sakha (Yakutia), the Russian Academy of Natural Sciences [1].The BAM expeditions of the Institute of Permafrost were united by a common research topic “Prediction of the evolution of the cryolithozone in the development of the territory adjacent to the BAM railway” to predict the state of geocryological conditions and make practical recommendations for the construction of engineering structures in settlements, stations and roads in the Maly BAM zone [2].In different natural conditions, landscapes of the foothills of the Stanovoi Ridge of South Yakutia (valleys, watersheds, as well as on the slopes of different exposures), special permafrost conditions are formed associated with the patterns of heat exchange of the upper layers of the earth’s crust – the earth’s surface – the atmosphere [2]. To identify permafrost, microclimatic and thermal balance conditions in the midlands of South Yakutia, on the territory of the village of Iengra of the Neryungrinsky City Council, on September 1, 1975, the Zolotinka geocryological station was organized under the leadership of Dr. Gavrilova. The year-round station conducted three full cycles of microclimatic and thermal balance studies from 1975-1978. A retrospective approach to the topic of the BAM expedition organized by the Institute of Permafrost made it possible in this article to familiarize and summarize in detail the scientific and organizational activities of Maria Gavrilova on the work of the Zolotinka geocryological station in 1975-1978.

Глобальное загрязнение территории Южной Якутии Cs-137 и дозы облучения населения

The aim of the work is to estimate the radioactivity of Cs-137 in the soils of South Yakutia and to calculate the dose of internal irradiation of a critical group of people caused by the consumption of local foods containing radionuclide. An assessment of the radioactive contamination of the soil cover of South Yakutia showed that the radioactivity of Cs-137 in the soils of eluvial landscapes varies between 714 and 1,665 Bq/m2 and is commensurate with the radioactivity of Cs-137 in the soils of the Primorsky Krai, the Western Siberia and the Kola Peninsula. The present soil contamination levels of Cs-137, compared to the 2003 data, have been reduced on average by half due to radioactive decay of the radionuclide, the soil deepening and removal with surface water and vegetation. At present time there is no appreciable additional input of Cs-137 from the atmosphere to the soil cover of automorphic taiga landscapes in the South Yakutia. The specific activity of Cs-137 in watershed soils and river floodplains is low and corresponds to the background level of global pollution. The vertical distribution of Cs-137 over the soil profile of eluvial landscapes is realized on regressive-cumulative and eluvial-illuvial types. In soil profiles of hydromorphic landscapes Cs-137 is distributed, without any clear patterns, which is a consequence of the impact of alluvial processes. Calculations showed that at the current level of contamination of local foodstuffs, the annual effective dose of internal exposure of a critical population group from this radionuclide is 87 times less than the annual dose limit for the Russian population.

Assessment of lipid and carbohydrate metabolism in the population of South Yakutia by the effective radiation dose level

Assessment of lipid and carbohydrate metabolism in the population of South Yakutia by the effective radiation dose level

Technology for studying the electrophysical characteristics of sedimentary rocks of South Yakutia at the railway station Kyurgellyakh using the method of remote inductive probing

The possibilities of a new technology for applying the method of remote inductive sensing at a frequency of 1,125 and 0,281 MHz in the separation interval of the emitting and receiving antennas in terms of quantitative assessment of electrophysical characteristics in the rock foundation of engineering structures at the railway station Kyurgellyakh in South Yakutia are studied. In the strata of icy and clay deluvial-eluvial formations and sedimentary rocks (dolomites, limestones), a general increase in depth of the effective values of the electrical resistance and the real part of the complex relative permittivity, which is atypical in AC geoelectrics, has been established. The range of variability of resistivity and permeability is 600–1600 Ohm·m and 3–7 arb. units. According to a sharp change (from a smaller to a larger one) in the growth rate of resistance and permeability, two boundaries were found. The first structural boundary lies at a depth of about 10 m and corresponds to the lower boundary of the area of intense weathering. The second petrophysical boundary lies at a depth of about 20 m and characterizes the transition of the highly weathered and highly fractured upper part of the sedimentary rock mass into the lower consolidated solid part located in the area of thermal rest. The obtained results give grounds to recommend a proven technology for solving the problems of geomechanics and thermophysics of frozen soils in terms of determining their strength and depth of the lower boundary of the layer of annual heat exchanges.

SEISMICITY of YAKUTIA in 2018–2019

According to the information received from 20 stationary digital seismic stations of the Yakutia Branch of Geophysical Survey of the Russian Academy of Sciences, two-year (2018–2019) seismic monitoring of the territory of the Republic of Sakha (Yakutia) was carried out. During this time interval, more than 730 earthquakes with an energy class of KR≥7.2 (magnitude M≥1.8) were registered. During the previous two years, their number was 801. Manifestations of seismicity fixed the spatial position of the contact zones and their constituent blocks of known lithospheric plates: the Eurasian and North American plates in the northeastern and arctic regions, as well as the Eurasian and Amur plates – in the southern areas of Yakutia. The epicentral fields traced individual relief lineaments and identified active boundary structures combined into two large-scale seismic belts – BaikalStanovoy and Arctic-Asian. Their outlines are seen as bands of earthquake epicenters, elongated from the Olekma River to the Sea of Okhotsk in the south and as ensembles of separate groups and chains of earthquakes between the Laptev and Okhotsk Seas in the northeast and in the Arctic. Significant seismic activity has been detected in the northeast of the region – in the Olekminsk region and the Aldan Highlands (South Yakutia), as well as in the Yano-Oymyakon Highlands, the Chersky Ridge and the Laptev Sea. A map of epicenters was constructed for the entire territory of the region, where 12 districts were identified and an analysis of the seismotectonic situation in each of them was given. The map of Arctic earthquakes in the Lena River delta is considered separately. It is compiled according to the processing of digital seismograms obtained at 25 autonomous field stations installed in accordance with the Russian-German project "Seismicity and Neotectonics of the Laptev Sea Region" (SIOLA). In this area during 2016–2019 more than 2 thousand shocks of small energy classes KR≥7.2–10.7 (M≥1.8–3.7) were recorded within the depth interval of 1–36 km of the Earth's crust. The characteristics of the most seismically active local tectonic structures developed in this region are given.

Cryogenesis of granites and gneisses in South Yakutia

Based on field and laboratory studies of the rock massifs in South Yakutia using remote earth sensing technologies, methods of scanning electron microscopy, X‐ray 3D tomography, lithological‐mineralogical and optical‐petrographic studies, quantitative data on the intensity of cryogenesis of granites and gneisses in this area were obtained. A 16%–20% increase in the fracturing of rocks at the near‐surface part of the rock massif was shown to have occurred over a 10‐year period; during this time, vertical landforms, represented by granites and gneisses, retreated at a rate of 3 mm per year. However, no variations in the chemical and mineral composition of these rock types were identified over the study period.

Radiation and Environmental Safety in the Exploration and Development of Metal Deposits in South Yakutia

Radiometric surveys of mining dumps on spent placers of gold, monazite and the exploited gold-uranium ore deposit in South Yakutia were carried out. It is established that the dumps of alluvial, overburden and waste rocks in terms of the effective specific activity of radionuclides when used in construction work are characterized by different degrees of tolerance. It is shown that stacked radioactive ore dumps at the “Lunnoye” deposit after heap leaching of gold become powerful uncontrolled sources of radioactive pollution of the environment. It is recommended to conduct periodic monitoring of their radioactivity levels by express methods of field radiometry for the safe use of mining dumps as building materials.

Geocryological conditions of the Tokarikan and Guvilgra grabens (South Yakutia)

This article presents the results of geocryological studies of the Tokarikan and Guvilgra grabens of the Aldan Shield. Expedition research on the hard-to-rich region since 1996 has allowed us to determine the temperature regime, thickness, and nature of permafrost rock distribution and characterize its geocryological conditions for the first time. We have established that the lowest temperatures (up to –3.4 °С) are characteristic of peatmoss bog landscapes, whereas the highest (–0.5 °С) are for well-drained and watershed areas. The results of the measurements in deep wells, information on the process of drilling deep exploration wells, and the analysis of data on the thermophysical properties of rocks allowed us to estimate a permafrost thickness capacity that varied in the range of 40–260 m. The presented schematic permafrost and geological cross-sections and geocryological condition maps can be used to plan the industrial development of the territory.

Assessment of the traditional activity of the indigenous peoples of South Yakutia collection of non-timber forest resources

Assessment of the traditional activity of the indigenous peoples of South Yakutia collection of non-timber forest resources

Geodynamic factors in the formation of large gold-bearing provinces with Carlin-type deposits on continental margins in the North Pacific

<abstract> <p>Several similar indicators in Nevada (USA) and South Yakutia (Russia) gold-bearing provinces have been identified based on modern tectonic, geophysical and seismic tomography observations, followed by the analysis of the main geodynamic factors of the formation and distribution of large gold-bearing provinces in the North Pacific. One of the significant metallogenic peculiarities is a wide variety of formational and mineral deposits concentrated in the areas. Both provinces are situated at active margins surrounded by fold-thrust belts. In South Yakutia, a combination of sublatitudinal Baikal-Elkon-Ulkan and submeridional Seligdar-Verkhnetimpon gravity field gradient zones is recorded. In contrast, significant positive gravity anomalies of the Northern Nevada Rift and higher-order gradient zones are presented in Nevada. Large pluton and transform fault zones in both provinces support a conclusion about the fundamental role of geodynamic factors in developing ore-magmatic systems in the regions. Significant differences in the scale of the gold mineralization in the considered provinces are explained by the existence under the North American continent not only of the Mendocino transform fault zone but also of the Juan de Fuca paleo-spreading center. In contrast, the Inagli-Konder-Feklistov magmatic-metallogenic belt alone controls mineralization under the Asian continent.</p> </abstract>

The frequency of metabolic syndrome and its components in the non-indigenous population of South Yakutia

The frequency of metabolic syndrome and its components in the non-indigenous population of South Yakutia

Northern piroplasmosis of domestic reindeer in Southern Yakutia

In South Yakutia, in the Aldansky district, at the end of July, more than 50 deer fell to the reindeer herd No. 7 of OAO KMNS "Khatystyr". Earlier in Central Yakutia, in 2008, an outbreak of pyroplasmosis was recorded for the first time in domestic reindeer of the farm of JSC NAOK "Taba" at the Tomtor site of the Gorny district and the YaGSHA Tabsylyn educational and production farm at the Kangkeme site of the Yakutsk city district. There was a mass death of the main deer population in the "Kangkeme" section up to 90% and "Tomtor" up to 30%. During laboratory studies, a parasitic disease, pyroplasmosis, was registered. Pyroplasmosis is one of the most severe and acute parasitic diseases of animals. Especially in the abnormal summer heat, blood parasites multiply very quickly, piroplasmids destroy red blood cells in the body of deer, the process of oxidation and intoxication occurs, bilirubin is formed from the released hemoglobin by complex transformations, 2-3 days after infection, in the absence of medical care, a lethal outcome is observed. Carriers of parasites can be ticks (Ixodidea, Ixodes ricinus) and other blood-sucking. Blood parasitic diseases (hemosporidiosis) of animals in Yakutia have not been previously recorded, a case of infection of domestic reindeer in 2008 in Central Yakutia is known. Isolated cases of tick attacks on people have been recorded in the Aldan, Neryungrinsky, Olekminsky and Suntarsky districts. A case of tick attack, infection and disease with tick-borne borreliosis of one person was registered. In the warm season, a distinctive feature of the temperature regime in most of the territory of Yakutia is a rapid increase in average daily temperatures in spring, and the maximum summer temperature can reach +38 ° C. At this time, there is a massive flight of blood-sucking insects and an attack of ticks on animals and people on the territory of Yakutia.

Complex streamflow responses to climate warming in five river basins in South Yakutia, Russia

The climate is warming much faster than the global average at the northern mid–high latitudes, leading to intensified hydrological cycles. However, it is unclear whether the response of streamflow to climate change is uniform across river basins with areas of 104–105 km2. In this study, monthly streamflow data from five river basins (Bol’shoy Patom, Chara, Olekma, Timpton, and Uchur) and gridded monthly temperature and precipitation data from the Russian South Yakutia at 53.5–61.5°N were analysed to investigate changes in their annual streamflow from 1934 to 2019 and their responses to climate warming. The results showed significant increasing trends in air temperature for all five basins at rates of 0.20°C–0.22°C/decade (p < 0.001), with faster warming after the 1980s. Apart from the Uchur River Basin, increasing trends in annual precipitation were observed in the other four river basins at rates of 9.3–15.7 mm/decade (p < 0.01). However, temporal changes in streamflow were much more complex than those in air temperature and precipitation among the five basins. Only two of the five basins showed significant increasing trends in annual streamflow with change rates of 17.1 mm/decade (p < 0.001) for the Chara River and 7.7 mm/decade (p < 0.05) for the Olekma River. Although the other three basins showed slightly increasing trends in annual streamflow (1.8–4.0 mm/decade), these trends did not pass significance tests (p > 0.05). By analysing the temperature-precipitation-streamflow relationships, we determined that the annual streamflow positively responds to precipitation, while winter streamflow is most sensitive to temperature. With climate warming, the streamflow during the winter period (October-April) increased significantly in four of the five river basins at rates of 1.4–3.1 mm/decade (p < 0.001), suggesting that warming-induced permafrost thawing increases baseflow. Although the streamflow response of large Siberian rivers to climate change is consistent, our results suggest that the streamflow response to climate change in relatively small river basins (104–105 km2) is much more complex.

ПРОГНОЗ СКРЫТОГО ОРУДЕНЕНИЯ В ПРЕДЕЛАХ СЕВЕРНОГО СКЛОНА АЛДАНСКОЙ АНТЕКЛИЗЫ ПО ДАННЫМ ЭЛЕКТРОРАЗВЕДКИ И ГРАВИМАГНИТНЫХ ПОЛЕЙ

Prospects for the discovery of solid minerals within the northern slope of the Yakut uplift of the Siberian Platform remain unclear to the end. However, in the light of new data and reassessment of old materials, this district is of interest for the identification of rare-earth mineralization in apatites. The isolated Tolon anomaly associated with a massif of alkaline rocks can be considered as a prospective target for commercial development within the framework of “Integrated Development of South Yakutia” project.

Speed of propagation of a longitudinal refracted seismic wave in the river valley Lena Tuymaade

The values of the velocities of longitudinal refracted waves obtained in 1979–1999 are generalized. by the method of refracted waves during the work of the Yakut trust of engineering and construction surveys in the built-up area of the valley of the river. Lena Tuymaada. A normal probabilistic law for the spatial distribution of velocity values in all lithotypes of Quaternary deposits has been established. In the permafrost zone of the Central Yakut Plain in the Tuymaade valley, the general law of the growth of velocities with depth depending on the growth of volumetric weight has been confirmed. Local variations in the spatial variability of the speed of the refracted wave are due to the combined effect of the main ground-frost factors: salinity, ice content and porosity. The most variable was the speed of the refracted wave in clay facies — loams and sandy loams of lacustrine-marsh deposits. The average velocity with an equal volumetric weight of sedimentary rocks is practically the same in the Tuymaade valley and in the permafrost zone of South Yakutia. Such a regional petrophysical feature creates favorable engineering and geocryological conditions for the application of the refracted wave method in the permafrost zone, both in Central and South Yakutia, to solve one of the important basic engineering geological problems. Namely, determining the depth of occurrence of semi-rocky and rocky bedrocks of sedimentary genesis in the bases of the foundations of engineering structures. The analysis of theoretical variograms of refracted wave velocities showed that the reliability of probabilistic-statistical solutions in recognizing the boundary between the frozen strata of Quaternary deposits and bedrock in the Tuymaade valley is very high and amounts to 99.5 %. With a maximum but small error of 15.5 %, the boundary between the seasonally thawed cultural layer and loamy-sandy lacustrine-marsh deposits is recognized.

Mining Industry of the Republic of Sakha (Yakutia) and Problems of Environmental and Social Security of Indigenous Peoples

The Republic of Sakha (Yakutia; RS(Y)) is located in the northeast of Siberia (Russia) in the basins of the Lena, Yana, and Indigirka rivers, in the lower reaches of the Kolyma River. Yakutia is an industrial–agrarian republic with a developed mining, fuel, and energy industry. Indigenous peoples live mainly in the Arctic regions, where the large-scale development of mineral resources is planned, and South Yakutia, where the mining industry is well developed. The aim of this study is the development of methodological approaches to assessing the impact of the mining industry on the natural environment and the social sphere in the places of residence and traditional economic activities of the indigenous peoples of the North. We used the results of research work (R&D), materials of expeditionary work, and regulatory documents of the Republic of Sakha (Yakutia) and the Russian Federation (RF). The state of the environment (ES) was assessed on the basis of the analysis of indicators for three areas: (a) anthropogenic load, (b) environmental and social consequences, and (c) resistance of natural complexes to technogenic impacts. In total, 22 indicators were used for the 3 areas, for example, population density, person/km2; the volume of extraction of rock mass, million m3; and emissions, t/year. To bring dissimilar indicators into comparable ones, we used a methodological approach with the use of the social risk index (SRI). In Arctic regions (mainly agricultural), the ES is in a favorable and relatively favorable state: SRI 0.61–0.70; in the central regions (mainly agricultural), it is satisfactory and relatively satisfactory: SRI 0.71–1.0; in the southern and western regions with a developed mining industry, it is relatively tense and tense: SRI 1.01–3.0. An extremely tense state of environmental conditions has developed in the city of Yakutsk: SRI ≥ 3. Generally, the deterioration of the environmental situation and vital activity of the indigenous peoples in investigated Arctic region correlated with the impact of the mining industry.

Petro- and geochemical composition of mesozoic magmatic rocks of the Taezhny massif (South Yakutia, Evotinsky gold bearing region)

Petro- and geochemical composition of mesozoic magmatic rocks of the Taezhny massif (South Yakutia, Evotinsky gold bearing region)

An “Overlooked Tradition”: Gathering as Occupation and Trade Among the Evenkis of South Yakutia

An “Overlooked Tradition”: Gathering as Occupation and Trade Among the Evenkis of South Yakutia