Home – Home – Jornals – Advanced Search

Soil-erosion processes in the basins of the Tugnui and Sukhara rivers of the Selenga middle mountain region of the Republic of Buryatia were studied. It was revealed that the Tugnui basin is characterized by slope water-erosion, fluvial and aeolian processes. Five soil-erosion areas were identified. It was found that areas of rare, weak, medium and high density and the degree of density of gullies are typical for the southern slopes of the Tsagan-Daban mountain range, the northern slopes of the ridge Zaganskii range, the Tugnuiskii intra-depression low-mountain range, the river valleys, and the treeless cultivated areas. The gullies are affected by sub-mountain deluvial-proluvial aprons occupying the most extensive areas on the bottom of the depression, the ledges and surfaces of river terraces, and the bottoms of balkas. Toward the mountains surrounding the depression, the density and the degree of density of gullies decrease considerably. Territories with the degree of linear dissection ranging from 0,07 to 0,25 km/km ² and the density of gullies varying from 0,13 to 0,51 gully/km ² were identified. Compared to the deflation processes, the middle part of the Tugnui steppe region and the areas within the basins of the Barka, Galtai and Sutai rivers were severely destroyed by gullies. The base level of erosion in this locality is more than 400 m, according to absolute elevations the watersheds (average value) and the elevation at the mouth. Different groups of gullies were identified according to the distribution of gullies along the length, and to the indicator of the intensity of the erosion processes. It was found that most of the gullies with a length of more than 600 m are in the stage of rest, increasing more in volume and sometimes in length, due to the growing small side gullies holes, and the most widespread types are slope and bottom, and more rarely, less often coastal scours. It was found that the determining factors in the development of gullies of these types include the occurrence of slopes with a steepness of 3-5°, the complexity of the terrain, the heterogeneity of soil-forming materials, the occurrence of thick loose deposits, rain precipitation of significant intensity, and high agricultural development. It is estimated that the total length of the scours in the basins of the Tugnui and Sukhara rivers is 834 km, with 480 km of them corresponding to the gully network in the most plowed valley of the Tugnui river which has a catchment area of 2770 km ² .

Quantitative assessments are made of the formation of municipal solid waste, ash and furnace waste from heat power plants (boilers), and logging and timber processing activities in the central ecological zone of the Baikal natural territory. The mate rial and raw material balance method and the normative method were used as the basis, and calculations used potential volumes of waste produced (thematic industrial reference books) and specific indicators adopted for particular federal subjects of Russia. These authors are executors of several thematic research projects of federal and regional status, aimed at the environmental and socio-economic development of the central ecological zone of the Baikal natural territory (seven administrative districts and one urban district of Irkutsk oblast and of the Republic of Buryatia), which has allowed us, over the last two decades, to character ize, evaluate and predict the development of various economic processes in the environment and society of this territory, includ ing issues related to production and consumption waste management. Variants of a comprehensive solution to the problems of waste management are proposed: alternative sources of energy and heat supply in the central ecological zone (logging and timber processing waste and consumer waste) as well as applications in the construction sector and, in particular, in road construction (ash and slag). The findings of this research can serve as the substantiation of particular managerial decisions on the promotion of the ideology of the green economy by developing further the aforementioned individual types of reuse of waste produced in order to safeguard the World Heritage site, Lake Baikal, and sustainable development of society on its shores.

Based on our hydrological and hydrochemical studies in winter 2018 and on previous data (2001-2017), we analyze results on changes in the chemical components and water quality of the Selenga river and its tributaries obtained at the final stage of a long-lasting low-water period. It was found that after the historically minimum winter river runoff in 2012 and its slight rise in 2014, the winter river discharges in the subsequent period were again abnormally low and contributed to the deterioration of the Selenga water quality. During winter 2018, the concentrations of dissolved oxygen in the Selenga river and its tributaries changed from 6,0 to 10,5 mg/dm ³ (44-70 % of saturation). In some areas of the streams under study (the Selenga river near Novose lenginsk and downstream of the city of Ulan-Ude; the Uda river in Ulan-Ude), where the values were minimal, the water qual ity decreased to the “heavily polluted” category. At the beginning of the current century, the oxygen content in the river during the wintertime was significantly higher (67-99 % of saturation). This gives evidence to a decrease in self-purification capacity. It is found that sulphate concentrations as the indicators of industrial contamination of the river waters have increased through out the Russian section of the Selenga. In the lower reaches of the river, these values reach 16,5-22,2 mg/dm ³ , whereas in the pre-industrial period they varied within 7,2-10,4 mg/dm ³ . Concentrations of biogenic elements were the highest in the areas of input of wastewaters. On the whole, the hydrochemical studies made in 2018 unequivocally indicate the quality deterioration of the Selenga waters in the wintertime due to an anthropogenic impact and a decrease in the water runoff.

We examine the formation conditions for the resources and chemical composition of mineral lakes located in the vicinities to the unique natural site of the Barguzin intermontane depression, Nizhnii Kuitun. Presented are the results from studying the surface structure of this sand massif. It is shown that its formation is associated with peculiar features in the tectonic development of the Barguzin depression. It is pointed out that the block of rocks forming Nizhnii Kuitun is broken up by tectonic faults into several smaller parts, and this had a determining impact on its modern appearance. The lakes under study are situated in the northern part of Nizhnii Kuitun, in the Nukhe Nur urochishche, in the topographically clearly pronounced drainless depression. The formation of this depression occurred during the uplifting stage of the block of rocks when intensively fragmented rocks, located at the interface of the faults, lagged behind in vertical movement. The depression receives the runoff of surface and underground waters which drain sedimentary deposits of Nizhnii Kuitun. Data are provided to demonstrate that the lakes are situated in the ablation funnels of sand-clay sediments. On the basis of a quantitative determination of the chemical composition of water and gases, it is proved that seepage waters of sandy sediments of Nizhnii Kuitun and nitrogenous fissure-vein waters play the main role in the formation of resources and chemical composition of the lake water in the area of the Nukhe-Nur uro chishche. The hydrological-hydrogeological model of the formation of the lakes under study is suggested. In a dry period when the amount of water infiltrating through the sand deposits of Nizhnii Kuitun decreases, the proportion of deep fissure-vein waters increases; therefore, water mineralization increases in the lakes as well as fluorine, sodium, tungsten and molybdenum contents. In wet years, the contribution of drainage waters to the formation of the lake’s resources increases, and the concentration of these elements decreases.

Boreholes exposed the structure of the loess cover on four key sites along the line from the Eastern Azov region to the Terek-Kuma plain. In order to obtain the most preserved loess paleoarchives, the profiles and boreholes were established located at subhorizontal flat interfluves unimpaired by modern and relict erosion. A stratigraphic subdivision of sediments was carried out on the basis of the loess-paleosol scheme developed under the direction of A.A. Velichko. A set of laboratory analyses of 411 samples was carried out: granulometric analysis, loss on ignition, and magnetic susceptibility. A gradual decrease in the thickness of the Upper Pleistocene and Holocene loess-paleosol sequence and particle size from east to west was determined. Data obtained indicate that the source of loess material is located east to Ciscaucasia - in the deserts of the Caspian lowland and, possibly, of Central Asia. The main direction of the aeolian transport during the Late Pleistocene and Holocene was from east to west. The differences in thickness and grain size between the loess and paleosol horizons reveals a differentiation in the intensity of aeolian processes. The intensity was higher during cold stages and lower during warm stages. The loess paleo-archives located in the eastern Ciscaucasia have higher temporal resolution and more responsive paleoclimatic indicators than the western ones. They reflect regional climate changes better. In western Ciscaucasia, the sedimentation conditions were more constant throughout the Late Pleistocene and Holocene than in the east of the region.

The chemical (macro and trace element) composition of the waters of eutrophic and mesotrophic swamps and rivers is pro vided, based on of expedition investigations on the territory of the Northern, Central and Southeastern Altai. An increased content of a number of elements was observed, which is determined by the botanical composition of peats as well as underlying rocks. Special features in the formation of the composition of swamp waters in peat deposits of a different genesis are determined; the influence of swamps on the hydrochemical regime of surface waters are identified. A dependence of the hydrochemical composition of swamp rivers on swamp waters is confirmed, which is manifested in the content of humic acids. It was found that a change in the amount of humic and fulvic acids indicates the dynamism of their input from the peat deposit to the swamp waters as well as a higher content of humic acids in the waters of mountain swamps in comparison with the swamps of the West Siberian plain. It is shown that in the swamp waters of the Northern Altai there is an increased content of a number of elements, which has a sig nificant impact on the hydrochemical regime of intra-swampy rivers. In the Central Altai, there is an increase in mineralization of swamp waters due to a predominance of shallow swamps and the close occurrence of underlying rocks. It was determined that there is no accumulation of chemical elements in the swamp waters and in intra-swamp rivers of the Southeastern Altai, but an increased content of humic acids was determined. The content of trace elements does not exceed the value of maximum permis sible concentrations, which indicates that there is no input of man-made substances to the swamps of the territory of Altai. It is proposed to evaluate the elemental composition of swamp waters that has formed as a background composition to date.

This article presents the results of a comprehensive geochronological study of organic-rich sediments lying at the base of the sand suite in the well-known reference Belyi Yar II section on the left bank of the Irkut river (Tunka depression, Southwestern Cisbaikalia). It was found that in the 1960s, a pack of lake-marsh sediments from the lower part of the section was assigned to the upper Eo-Pleistocene, and the overlying sands to the Samarovo period of the Middle Pleistocene. Later, based on the first ¹⁴ C datings, the stratigraphy of these sediments was revised. The lower part of the sediments was attributed to the Kargian time, and the overlying sands to the Sartanian glaciation. However, the questions concerning the genesis, age and conditions of forma tion of these sediments remain controversial. In particular, the individual dates of ¹⁴ C differ greatly different from one another; therefore, they require further verification. A renewed study of the lower part of the Belyi Yar II section discovered peat and gyttjas deposits of alluvial origin. It was shown that their numerical age is beyond the ¹⁴ C dating method limits. Paleobotanical data showed that the gittya was formed in conditions of a relatively warm and humid climate, and the overlying layers accumu lated in the cooling and more xerophytic condition. Evaluation of the ²³⁰ Th/U isochronous age of these organogenic deposits, combined with palynological data, suggested that the bottom of the sand layer in the Belyi Yar II section was not formed during the Kargian time (MIS 3), as was thought previously, but during MIS 5. The gittya could have formed during MIS-5c, where as the overlying peat layers formed, possibly, at the transition to MIS-5b.

For the first time, a monitoring was carried out for assessing the volume of the ice of the Peretolchin Glacier in the Munku-Sardyk mountain range (Eastern Sayan) using georadar profiling both directly to measure the thickness of the ice and to refine the parameters of mathematical models for determining the volume of the glacier. Based on results of the area radar survey, the volume of the various structures of the glacier (firn, the main icy body, and bottom moraines) was assessed. 3D models of these components of the glacier have been constructed. It was found that, in comparison with results of georadar profiling for other glaciers, the modern bed of the Peretolchin Glacier consists of deposits of the previous glaciation which ended 11 ka. Measurements of the ice thickness on the northern Peretolchin Glacier were made in June 2014, and in May 2016 and 2017, with a constant increase in the study area using the Oko-2 radar with the ABDL Triton antenna unit at 100 MHz. Maps of the ice thickness of the Peretolchin Glacier were updated, and its volume was determined, equal to 0,007 ± 0,0001 km ³ . The section of the glacier of direct study (the lower open part) measures 0,00297 km ³ . The method of sections, taking into account the relief of the glacier from additional profiles, proved to be the most accurate. In the surveyed portion, the proportion of firn, the ice and the bottom moraine makes up 25 %, 29 and 46 %, respectively. On the other hand, the proportion of the clean ice reduces from the middle part of the glacier to its bottom. Over more than 100 years, the Peretolchin Glacier (northern) has decreased in length, area and volume by factors of 1,75, 2,9 and 3,71, respectively. It has been established that the rate of reduction of the Peretolchin Glacier has been increasing since 2009.

This research focuses on Holocene polygenetic burozems on red residue (Rikord Island). We determined the particle-size distribution, analyzed the spore-pollen composition of genetic soil horizons, and obtained burozem radiocarbon datings. It is shown that the upper part of the profile is dominated by the fraction of coarse silt whose content gradually decreases down the profile, followed by a marked increase at depths from 145 to 180 cm. This indicates an active cyclonic activity and sheet wash in the Late Holocene, which is also confirmed by a high level of adventitious Pinus densiflora pollen in AYEL horizon spore-pollen spectra. Profile distribution patterns for silt and clay fractions give evidence of clearly pronounced argillification of the lower part of the profile caused by intense processes of weathering at the period of formation of the ВМС and С horizons (LU 7127:4530 ± 180 BP). Silica accumulation in the AYEL horizon is due to podzolization in the cold climatic conditions of the Late Holocene (LU-7563:1550 ± 110 BP), which was reflected in the composition of spore-pollen spectra: a decrease in the amount of pollen from broad-leaved species and an increase in pollen from small-leaved species (birch). Palynological data indicate that the C and BMC horizons of the profiles under study largely formed in warmer (compared to the present time) climatic conditions of the Middle Holocene, whereas the BM horizon formed in the latter part of the Middle Holocene in cli matic conditions similar to the present-day conditions. The AYBM, AYEL and AY horizons formed in colder (than present-day) climatic conditions of the Late Holocene, as indicated by recent deluvial deposits overlying red residue and giving rise to poly genetic burozems. The O horizon (leaf litter) formed under present-day climatic conditions, with a general trend in climate warming.

Presented are the results of experimental studies into the interaction between the surface and subsurface water in 16 moun tain river basins of East Sayan and Lake Baikal as carried out by the Irkutsk-based Institute of Geography during 1984-1990. The research program included regular measurements of the thickness, area and volume of the surface and underground ice along the entire length of the valleys, pressure in closed lenses of underground waters, daily measurements of water discharges and chemical composition throughout the channel network. It was found that at the end of winter about 80-90 % of the area of the valleys of the rivers under study are covered by aufeis and by the seasonal subsurface ice of a different genesis. Furthermore, about half the volume of the seasonal ice corresponds to the surface ice (river ice and aufeis), and the other half to the subsur face segregated and injected ice. It was further shown that the period of formation of the main bulk of ice begins and ends earlier in the sections closer to the mouth. The “wave” of maximum intensity of ice formation gradually moves the river upstream. The ice volume is the last to form in the upstream components of the river network. At this time, the ice formation of the other area of the watershed has terminated or its main part has formed already. A cryogenic barrage phenomenon occurs, as a result of which the channel network receives subsurface water which, under normal conditions, is not drained by the river. The winter river runoff increases from 50 % in the sections close to the source to 5-10 % at the mouth of the river.