Western Transbaikalia Research Articles

Reforestation in Postagricultural Areas of Western Transbaikalia

Reforestation in Postagricultural Areas of Western Transbaikalia

Structure and Depositional Environment of the Upper Cenozoic Ulan-Zhalga Reference Section, Western Transbaikalia

Structure and Depositional Environment of the Upper Cenozoic Ulan-Zhalga Reference Section, Western Transbaikalia

Structure and Depositional Environment of the Upper Cenozoic Ulan-Zhalga Reference Section, Western Transbaikalia

The results of a comprehensive study of the Upper Cenozoic Ulan-Zhalga reference section in western Transbaikalia are presented. The paleontological, paleomagnetic and rock magnetic, lithological-mineralogical, and geochemical data obtained allowed us to identify and characterize the Lower, Middle, and Upper Pleistocene and Holocene deposits in the section and to reveal the features and conditions of sedimentation. Five members recognized in the section are combined into two sequences: the lower (layers 1–27, units 1–3) and the upper (layers 28–35, units 4–5). The boundary between Matuyama and Brunhes chrons (0.773 Ma) is determined at a depth of 15 m and the upper boundary of the Jaramillo subchron (0.990 Ma) at a depth of 23 m. The Matuyama/Brunhes boundary coincides with the boundary of Lower and Middle Pleistocene faunal complexes. The formation of the section corresponds to two major stages of sedimentation, which boundary is between the units 3 and 4 (depth 11.8 m). Changes in rock magnetic and granulometric parameters over the section has a climatic nature and reflect environmental changes. The formation of the lower part of the section (unit 1), which was accompanied by active pedogenesis, is characterized by the most heat- and moisture-enriched conditions. The upper strata of the section accumulated in colder and drier conditions with increased dynamics of aeolian processes.

Zoning of Desert, Steppe, Steppe-Forest and Forest Ecosystems By Carbon And Nitrogen Isotope in Mongolia and Western Transbaikalia

The Mongolian–Transbaikalian region of the Central Asia is known for its wide range of intracontinental ecosystems from desert through steppe to taiga forest and mountain tundra. Data on the isotopic composition of carbon and nitrogen in the bone and dental tissues of herbivorous animals inhabiting the desert, steppe, and forest–steppe landscapes of Outer Mongolia and Western Transbaikalia are presented. The maximum values of the carbon isotope ratio are observed in animals from the desert (Gobi Desert) and the semi-desert landscapes, median (mean) δ13C is -17.9‰. The minimum values of δ13C were obtained by herbivorous animals of the forest-steppe and the forest landscapes (Transbaikalia), which median δ13C is -23‰. The fauna of the steppes (median δ13C is -21.7‰) has intermediate values of the carbon isotopic composition. According to the isotope composition of nitrogen, the isotope-geochemical isolation of ecosystems is less pronounced.

Interpopulation Variability of Polyphenol Concentration in the Leaves of <i>Spiraea aquilegifolia</i> (Rosaceae) from the Republic of Buryatia

Abstract—Composition and content of flavonoids and phenol carboxylic acids in the leaves of Spiraea aquilegifolia Pall. from natural populations of the Republic of Buryatia (Western Transbaikalia) are given in the article. Aqueous ethanol (40%) extracts from raw materials were used for chromatographic study of phenolic compounds. The analysis of phenolic compounds was carried out on an analytical High-Performance Liquid Chromatography (HPLC) system consisting of an Agilent 1200 liquid chromatograph (USA) with a diode array detector, an autosampler, and a system for collecting and processing chromatographic data ChemStation. At least 24 phenolic compounds were identified in aqueous ethanol extracts from Spiraea aquilegifolia Pall. leaves by HPLC. Three acids (chlorogenic, p-coumaric and p-hydroxybenzoic) and six flavonols (hyperoside, isoquercitrin, avicularin, astragalin, quercitrin and kaempferol) were identified among them. Flavonols hyperoside (2.9–8.2 mg/g), avicularin (3.0–5.8 mg/g) and isoquercitrin (0.8–2.5 mg/g) are the main substances in aqueous ethanol extracts from leaves. Plants from populations located at the northern distribution limit in the Western Transbaikalia have a higher content of phenol carboxylic acids (near the village Koma) and flavonols (near the village Klyuchi). Plants from populations located to the eastern limit (near villages Kusoty and Zagan) have the lowest concentration of identified phenolic compounds. A high and very high level of interpopulation variability of the studied biochemical parameters has been established. This can be explained by the functional significance of the identified compounds and their active participation in general metabolic processes in the plant. The content of identified free phenolic acids and flavonols in S. aquilegifolia was characterized by medium and high levels, compared to other studied Spiraea species. This confirms the prospects for further study of the composition of phenolic compounds of S. aquilegifolia.

MINERALOGY OF CONTINENTAL SEDIMENTS FROM THE ULAN-ZHALGA KEY SECTION (WESTERN TRANSBAIKALIA): RESPONSE TO QUATERNARY CLIMATIC CONDITIONS

We present the results of studying the material composition of Quaternary subaerial-slope sediments of the new key section Ulan-Zhalga (Western Transbaikalia) with a thickness of about 30 m. The research methods include X-ray diffractometry (XRD), infrared spectroscopy, laser grain size analysis, elemental analysis. Quartz, feldspar, clay minerals, carbonates, hematite and traces of amphibole were found in the mineral composition of the studied sediments. For the first time the composition and structure of carbonate minerals were shown as a reliable indicator of climatic changes in the Pleistocene and Holocene for the subaerial section. For correct identification and determination of quantitative ratios of carbonates the mathematical modeling of their XRD patterns by the Pearson VII function was used. It has been established that the structure of the section involves two thick sequences differing in lithological and mineralogical features corresponding to two major stages of sedimentation. The lower sequence was formed under conditions of moderate wind activity and relatively high humidity as evidenced by the widespread development of soil horizons and the presence of low-Mg carbonates. The upper sequence, formed under colder and drier conditions with increased dynamics of aeolian processes is characterized by the presence of calcite, high-Mg calcite and excess-Ca dolomite.

Khengerekte-Sukhotino-An Upper Paleolithic Culture in Transbaikalia

During the studies at the Barun-Alan-1 stratified site in Western Transbaikalia, a lithic industry was described, providing a basis for a new archaeological culture, termed Khengerekte. Similar materials were excavated from nearby sites such as Sloistaya Skala and Khenger-Tyn-3 Svyatilishche. A comparative analysis of the Khengerekte industry of Barun-Alan-1 and that from the Sukhotino-4 in southern Chita, Eastern Tranbaikalia, reveals that most of their typological groups are quite similar. On that basis, the culture’s distribution area was extended, and the culture itself was renamed Khengerekte-Sukhotino, spanning ~400 km from Barun-Alan-1 in the west to Unenker in the east. The calendar age of excavated layers of key Khengerekte-Sukhotino sites, Barun-Alan-1 and Sukhotino-4, was estimated at 12–33 ka BP. Their lithic industry, based mainly on microblades, is described. Bifaces, unifaces, and high side-scrapers are common. The origin of the Khengerekte-Sukhotino culture is an open question.

Phosphorus Sorption by Saline Soils of Western Transbaikalia

Phosphorus Sorption by Saline Soils of Western Transbaikalia

Phosphorus Sorption by Saline Soils of Western Transbaikalia

The sorption of phosphorus by salt marshes of the dry-steppe zone of the Republic of Buryatia from an aqueous solution of KN2PO4 in the concentration range from 0.25 to 5.0 mM/L (mmol/L) was studied under static conditions. The interaction time is 24 hours with a soil: solution ratio of 1 : 10. The amount of sorbed phosphorus was calculated from the difference in its content in the initial solutions and in the filtrates of soil suspensions. Based on experimental data, phosphorus adsorption isotherms were constructed by soil and sorption parameters were calculated using the Langmuir and Freundlich equations. Typical and quasi-clay Solonchaks have relatively high sorption properties with respect to phosphorus. The value of the maximum adsorption capacity (Amax) in the humus horizons of these soils varied in the range of 23.04–42.74 mM P/kg, in the underlying horizons 16.26–30.39 mM P/kg. In general, all soils, with the exception of the sorov Solonchaks, had an Amax value in the range of 17.70–42.74 mM P/kg. A low sorption value of phosphorus was found in the Solonchaks of sorovy. The Langmuir adsorption constant (KL) varied in the range of 0.3–14.0 l/mmol. Solonchaks dark and typical most strongly bind phosphorus. The Freundlich coefficient (KF) in the studied soils varied in the humus horizon from 5.34 to 63.43 mM P/kg, in mineral from 1.74 to 22.68 mM P/kg. The distribution coefficient (Kd) ranged from 1.95–145.04 l/kg with high values for quasi-clay Solonchaks and low for sorov Solonchaks. The correlation between Kd and Amax was estimated as average (r = 0.51), Kd and KL – high (r = 0.84, p ≤ 0.05). The studied soils according to the values of SPR (the amount of phosphorus that must be sorbed by the soil to maintain a concentration of P = 0.2 mg/kg (0.0065 mM/l) in soil solution) from (0.0723 to 3.4836 mM/kg) refer to weakly absorbing phosphorus. According to the ability to sorb phosphorus, soils form the following decreasing series: quasi-glay solonchaks typical solonchaks dark solonchaks glay solonchaks alluvial light humus saline sorov solonchaks.

Patterns of Potassium Sorption by Soils in Western Transbaikalia

Patterns of Potassium Sorption by Soils in Western Transbaikalia

Frequency of Endogenous Events in Western Transbaikalia and Northern Mongolia (Eastern Segment of the Central Asian Orogenic Belt) According to U–Pb Dating of Detrital Zircon Grains from Modern Fluvial Deposits

Based on the correlation of U–Pb isotopic age of detrital zircon grains from modern fluvial deposits of the largest rivers of Western Transbaikalia and Northern Mongolia and U–Pb isotopic ages of bedrock of the Mongol-Transbaikal sector of the Central Asian Orogenic Belt, five main stages of formation and processing of the continental crust are identified in the region: (1) the Neoarchean-Paleoproterozoic stage (2.7–1.7 Ga), corresponding to the global crust-forming processes of the Precambrian cratons’ basement formation; (2) the Neoproterozoic (early and late Baikal) and (3) the Early Paleozoic (Caledonian) stages reflecting the processes of formation of juvenile crust through island-arc magmatism and accretion of island arcs, which led to the formation of folded structures of the southern margin of the Siberian craton; (4) the Late Paleozoic and (5) Early-Middle Mesozoic stages reflecting the processing of the Early Precambrian and Caledonian crust through intraplate magmatism and riftogenesis. It is shown that the peak values of the probability density distribution curve of the detrital zircon grains’ age depend on various, often unrelated factors, such as the absolute age of the rock, the area of the eroded surface, the amount of zircon in rocks of different composition, the distance of transport, etc., therefore, the statistics of age distribution cannot be considered as an indicator of the intensity of endogenous events. The absence of Cenozoic grains of detrital zircon in the fluvial deposits of the region where basalt volcanism of this time is widely manifested (Mongolia, Baikal region) indicates that endogenous events, which are mainly expressed in basalts, are not manifested in the “zircon chronicle”.

Native Gold and Unique Gold–Brannerite Nuggets from the Placer of the Kamenny Stream, Ozerninsky Ore Cluster (Western Transbakalia, Russia) and Possible Sources

We carried out a comprehensive study of native gold (morphology, composition, intergrowths, and microinclusions) from alluvial deposits of the Kamenny stream (Ozerninsky ore cluster, Western Transbaikalia, Russia). The study showed that there were four types of native gold, which differed significantly in their characteristics and probably had different primary sources from which placers were formed: gold–quartz, oxidized gold–sulfide, gold–silver, and zones of listvenites with copper–gold and gold–brannerite (Elkon-type). Particular attention was paid to the study of unique, both in size and in composition, gold–brannerite nuggets of the Kamenny stream. It was established that the gold in the gold–brannerite nuggets (GBNs) had wide variations in chemical composition and mineral features. According to them, there were five different fineness types of native gold: 750–800‰; 850–880‰; 880–920‰; 930–960‰; and 980–1000‰. The data obtained indicated a multistage, possibly polygenic, and probably polychronous formation of GBN gold–uranium mineralization. The first stage was the formation of early quartz–nasturanium–gold–W–rutile–magnetite association (Middle–Late Paleozoic age). The second was the crystallization of brannerite and the replacement of an earlier pitchblende with brannerite (Late Triassic (T3)–Early Jurassic (J1) age). The third was the formation of the hematite–barite–rutile–gold association as a result of deformation–hydrothermal processes, which was associated with the appearance of zones of alteration in brannerite in contact with native gold with 8–15 wt.% Ag. The fourth was hypergene or the low-temperature hydrothermal alteration of minerals of early stages with the development of iron hydroxides (goethite) with impurities of manganese, tellurium, arsenic, phosphorus, and other elements. The carbon isotopic composition of an organic substance indicates the involvement of a biogenic carbon source. In the OOC area, there were signs that the composition of the GBNs and the quartz–chlorite–K–feldspar-containing rocks corresponded to Elkon-type deposits.

Amino Acid Composition and Biological Value of Irrigated Potato Tubers on Chestnut Soil at Increasing Doses of Sulfur Fertilizers (with NPK)

Application of sulfur fertilizers at the doses of 15 and 30 kg/ha (with NPK) for irrigated potatoes on chestnut soils of Western Transbaikalia is the most effective for production of marketable tubers with the maximum value of bioenergy coefficient. With increasing the doses of sulfur, in spite of the insignificant increase of crude protein content, the amount of amino acids and the index of essential acids significantly increased in comparison with the control and the background. Replacement of limiting sulfur-containing amino acids (methionine + cystine) with leucine was noted. The highest biological value of potato protein at the level of 72–74% was found at the doses of 15 and 30 S kg/ha (with NPK).

New Materials on the Morphology of the Teeth of the Three-Toed Horse (Hipparion houfenense) from the Pliocene of Western Transbaikalia (Russia).

This article is devoted to the morphological features of the teeth of the three-toed horse (Hipparion houfenense) from the Early Pliocene of Western Transbaikalia (Russia). It contains a number of diagnostic features that are unique to this taxon and distinguish it from other Hipparion species, which allows us to speak about their true diversity at the final stage of their existence in the northeast of Inner Asia.

Taxonomic and ecophysiological characteristics of actinobacteria in soils of the dry steppe zone of the Selenga Highlands (Western Transbaikalia).

Arid habitats have recently attracted increasing attention in terms of biodiversity research and the discovery of new bacterial species. These habitats are among the target ecosystems suitable for isolating new strains of actinobacteria that are likely to produce new metabolites. This paper presents the results on the isolation of actinobacteria from soils of the dry steppe zone of the Selenga Highlands, the characterization of their taxonomic diversity, as well as ecological and trophic properties. The bacterial counts on ISP 4 medium ranged from 6.6 × 105 to 7.1 × 106 CFU/g. The highest bacterial counts were observed in the subsurface and middle horizons of the studied soils. 28 strains of Gram-positive bacteria represented by thin-branched mycelium, coccoid and bacilliform forms were isolated. According to the results of 16S rRNA gene analysis, the isolated strains were representatives of Streptomyces, Arthrobacter, Glycomyces, Kocuria, Microbacterium, Micromonospora, Nocardioides, Pseudarthrobacter, and Rhodococcus (Actinomycetota). One isolate that showed low 16S rRNA gene sequence similarity with previously isolated and validly described species was a new species of the genus Glycomyces. It was shown that all tested strains are mesophilic, prefer neutral or slightly alkaline conditions, have growth limits in the temperature range of 5-45 °C and pH 6-9. The optimal NaCl concentration for growth of most strains was 0-1 %. The strains under study were capable of utilizing a wide range of mono- and disaccharides and polyatomic alcohols as a carbon source. The isolated strains were capable of using both organic (proteins and amino acids) and inorganic (ammonium salts and nitrates) compounds as nitrogen sources. The examinations of extracellular enzymes showed that all isolates were capable of producing catalase and amylase; 78.6 % of the total number of isolates produced protease and lipase; 53.6 %, cellulase; and 28.6 %, urease. The data obtained expand current knowledge about the diversity of microbial communities in soils of the Selenga Highlands and also confirm the potential of searching for new actinobacteria species in these soils.

NEW MATERIALS ON THE MORPHOLOGY OF THE TEETH OF THE THREE-TOED HORSE (<i>HIPPARION HOUFENENSE</i>) FROM THE PLIOCENE OF WESTERN TRANSBAIKALIA (RUSSIA)

This article is devoted to the morphological features of the teeth of the three-toed horse (Hipparion houfenense) from the Early Pliocene of Western Transbaikalia (Russia). It contains a number of diagnostic features that are unique to this taxon and distinguish it from other hipparion species, which allows us to speak about their true diversity at the final stage of their existence in the northeast of Inner Asia.

Mongolian gazelle (Procapra cf. gutturosa Pallas, 1777) in the Pleistocene of Transbaikalia and Altai

More than 1500 bones of the skull and postcranial skeleton of the Mongolian gazelle (Procapra cf. gutturosa Pallas, 1777) from 4 Paleolithic sites of Western Transbaikalia (Varvarina Gora, Kamenka, Khotyk, Tolbaga) and 3 cave localities of the northwestern Altai (Denisova, Strashnaya, Kaminnaya) were studied. For comparison, a large collection of skeletal bones from 56 individuals of modern P. gutturosa, collected on the territory of the “Dzeren Valley” nature reserve, was used. A number of morphometric differences in the structure of the lower jaw and bones of the postcranial skeleton between modern and fossil Mongolian gazelle have been revealed. Pleistocene P. cf. gutturosa had shorter and relatively massive limb bones and was significantly smaller in body size than the modern one. At the sites of Transbaikalia, Mongolian gazelle bones can account for up to half of all megafauna remains, in the Middle-Late Pleistocene layers of Altai caves, up to 3–4%. During the periods of glaciation, the Mongolian gazelles of Transbaikalia and Altai lived in conditions of cold, dry and little snow steppe or mountain-steppe landscapes. In the interglacial and interstadials, they continued to live here in the conditions of steppe or forest-steppe landscapes.

THE KUYTUN VALLEY AS AN EXOGEODYNAMIC TEST SITE FOR PRACTICING THE APPLICATION OF METHODOLOGY FOR INTERDISCIPLINARY RESEARCH IN THE SEDIMENTATION SETTINGS OF LOESS-LIKE COVER DEPOSITS IN THE LATE PLEISTOCENE TRANSBAIKALIA

An interdisciplinary research in the Late Quaternary loess-like cover deposits in the valley of the Kuytunka River (Western Transbaikalia) was aimed at reconstructing the conditions and dynamics of regional sedimentation. Particular attention is paid to assessing the information capacity of the methods involved therein: lithofacies analysis, grain-size analysis, and petromagnetic and lithochemical analyses. It is shown that the results of each method independently provide additional information on the processes of sedimentation, are not duplicated, and make it possible to obtain a full characterization of the factors and features of sedimentogenesis. It was found that the valley sedimentation was of cyclic character: warm (soil formation) periods changed to the periods of cooling-(accumulation of sandy-loamy strata); all processes occurred predominantly in semi-arid climate with slight fluctuations in humidity. The mode of the normal formation of a blanket of sedimentary material manifests itself in the structure and properties of deposits exposed on the southern slope of the valley (Kuytun-1 section). Intensive slope processes, and reworking and remixing of sediments on the gentle valley north-exposure slope by catastrophic flows (slope mudflows) and cryogenesis are reflected in the structure and properties of the deposits exposed in the Kuytun-2 section. There are shown the advantages of an integrated approach for detailing the structure of the sections, explaining the genesis of sediments, determining the most probable source areas for the sediment and modes of sediment transport, and reconstructing sedimentary environments.

Morphology and Composition Changes in Fluid Inclusions from Quartz under Progressive Deformation: Case Study of a Vein System in the Western Kelyan-Irokinda Fold Zone (Western Transbaikalia)

Abstract —The behavior of fluids during plastic deformation is studied from the morphology and distribution of fluid inclusions in quartz grains of different microstructure types from a vein system controlled by thrusting and strike-slip faulting in the eastern Sayan–Baikal fold area. The analytical work includes electron backscatter diffraction (EBSD) for quartz microstructure and crystallography, as well as Linkam heating-and-freezing analysis and Raman spectroscopy for the composition of fluid inclusions. The studied fluid inclusions are of seven types that differ in morphology and position in the deformed quartz structure. A model is suggested to describe successive structural changes of quartz aggregates during dislocation sliding and subsequent creep-related recrystallization associated with redistribution of fluid. Fluid inclusions undergo qualitative and quantitative changes due to water leakage at all stages of plastic deformation. The changes occur by two main mechanisms: (i) mass transfer during dislocation sliding at medium temperatures and strain rates and (ii) diffusion creep at low strain rates and high temperatures. The contribution of creep increases gradually with temperature, which maintains the interaction of inclusions with migrating grain boundaries.

НОВЫЕ ИССЛЕДОВАНИЯ НАСКАЛЬНОГО ИСКУССТВА НА ЗАПАДЕ ХРЕБТА ЦАГАН-ДАБАН (ЗАПАДНОЕ ЗАБАЙКАЛЬЕ)

The western spurs of the Tsagan-Daban mountain range (Western Transbaikalia), fringing the right bank of the Selenga river valley from the mouth of the Khilka to the mouth of the small river Zhirimka, are poorly studied in archaeological terms. Only in the last decade, objects of ancient rock art have become known here, most of which are difficult to access — removed from the Selenga coast, and located high above the river level, which makes it difficult to find them. All currently discovered rock carvings in this area and the immediate vicinity are painted with ocher of various shades. Many of the rock paintings are poorly preserved and are visible on the reddish surface of syenite and granite rocks in the form of indistinguishable spots, which makes their simple visual examination impossible. To study such rock carvings, the method of digital processing of their photographs was used, which makes it possible to reveal the contours of ancient drawings. One of these objects is an archaeological site, called Kamennaya Baba, after the name of the rocky peak located nearby. More than half of the drawings of this locality are not visually distinguishable, and the general layout of the entire rock panel, without special research methods, cannot be traced. While studying the archaeological object, an opinion was proposed about the appearance of individual drawings on the surface of the rock at different times. This opinion is confirmed by various stylistic features of the drawings, as well as their varying degrees of preservation. The drawings found on the surface of the rock belong to the Selenga type of ancient images, among which anthropomorphic and ornithomorphic images form the basis.