Eastern Transbaikalia Research Articles

Breeding success of the interspecies hybrids: Reduced fertility in the hybridogeneous magpie population (<i>Pica pica</i> × <i>Pica serica</i>, Aves)

Data on the breeding success of hybrids, collected during direct field observations, are principally important for understanding nature of the species isolating factors and future fate of the hybridogeneous populations. In the zone of secondary contact between Eurasian magpie Pica pica and Oriental magpie Pica serica, emerging right now, limited hybridization occurs, what has been shown in our reported data on nuclear single nucleotide polymorphisms (SNP). In the present work, we have analyzed composition of 119 nesting pairs and content of 89 nests in the hybridogeneous population of P. pica leucoptera × P. serica jankowskii in Eastern Mongolia, then in the recent contact zone in Eastern Transbaikalia (South Siberia) and the relatively pure populations of P. p. leucoptera in Central Transbaikalia and P. s. jankowskii in Northeast China. In the hybridogeneous population of Mongolia, significantly increased portion of nonviable clutches with all dead eggs was recorded, as well as a portion of partly dead clutches, compared with the data on the pure population of Central Transbaikalia. The egg mortality was found to be much less dramatic in the population of the Eastern Transbaikalia, where hybridization is less pronounced than in Mongolia. Several possible mechanisms of genetic incompatibilities breaking the reproductive barriers are discussed. The future fate of this magpie contact zone is considered, taking in account selection against hybridization which was revealed in this study. Among possible scenarios, reinforcement of prezygotic isolation may occur, i. e., in the species-specific calls. It is possible that a kind of mosaic hybrid zone with some features of tension zone will appear. Monitoring of the unique situation with the emerging zone of contact and hybridization of two young magpie species is needed, as a necessary addition to genomic studies.

First Data on the Age of Zircon Grains from the Upper Mesozoic Leskovo Unit of the Unda–Daya Basin, Eastern Transbaikalia

First Data on the Age of Zircon Grains from the Upper Mesozoic Leskovo Unit of the Unda–Daya Basin, Eastern Transbaikalia

Mineralogy and Primary Sources of Gold in the Davenda-Klyuchevskiy Ore-Placer Cluster (Eastern Transbaikalia)

Mineralogy and Primary Sources of Gold in the Davenda-Klyuchevskiy Ore-Placer Cluster (Eastern Transbaikalia)

Ecological and geochemical assessment of soils in residential areas of Eastern Transbaikalia

Relevance. Environmental pollution by mining wastes is one of the most urgent environmental problems. Aim. To determine the degree of soil pollution in the residential areas of Eastern Transbaikalia. Objects. Total soil pollution according to the Saet formula (Zc) was studied in 30 settlements of Eastern Transbaikalia, including 14 settlements related to mining. Methods. In order to determine the degree of soil contamination, the settlements were grouped: settlements at gold ore, molybdenum lead-zinc and rare-metal deposits, as well as settlements not related to mining. The factual material was obtained during the research under the basic projects of the Institute of Natural Resources, Ecology and Cryology of the Siberian Branch of the Russian Academy of Sciences from 2000 to 2022. In addition, published data and materials of the territorial geological funds (Chita) were used. The X-ray fluorescence method was used to determine the concentrations of chemical elements in analytical laboratories of the Geological Institute of SB RAS (Ulan-Ude), ISP-MS of ZAO "SGS Vostok Limited" (Chita). Results. Among the considered groups of settlements the following indicators of total soil contamination degree (Zc) were established: mining settlements of lead-zinc deposits – 68.87; gold deposits – 30.67; molybdenum deposits – 32.25; rare-metal deposits – 0.03; settlements not related to mining activity – 0.32. According to the total degree of soil contamination Zс, the settlements of lead-zinc deposits correspond to extremely hazardous, molybdenum deposits – hazardous; gold deposits – moderately hazardous; the settlements of rare-metal deposits and the ones not related to mining activities – low levels of pollution.

Geochemical and isotopic features of the Early Cretaceous volcanism of the Torey Volcanic Field (Eastern Transbaikalia, Russia) as a record of the transition from pyroxenite to eclogite mantle source

The Mesozoic magmatic activation in Central and Northeast Asia resulted in the formation of a large volume of volcanic rocks with diverse compositions. The most dramatic compositional change occurred at the end of the Early Cretaceous, when mainly alkaline basaltic lavas began to erupt after subalkaline differentiated lavas. The nature of crustal and mantle processes that led to this change in volcanism remains unclear. The Torey Volcanic Field (TVF) of Eastern Transbaikalia (Russia) demonstrates a similar compositional change. Therefore, the TVF is crucial to studying the cause of the difference in geochemical and isotopic signatures of the Mesozoic volcanism in Central and Northeast Asia.TVF belongs to the northeastern end of the Eastern Mongolia Volcanic Area (EMVA). Like other volcanic fields of the EMVA, TVF formed in two stages: early (∼121–129 Ma) and late (∼101–119 Ma). The TVF is composed of subalkaline and alkaline basaltic trachyandesites – trachyandesites. All TVF rocks are characterized by negative Ti and Sr anomalies and positive Ba and Pb anomalies. Compared to the late TVF rocks, the early TVF rocks have distinct negative Ta and Nb anomalies and are highly enriched in light rare earth elements relative to heavy rare earth elements. TVF rocks have the following isotopic characteristics: 87Sr/86Sr(t) = 0.70477–0.70540, εNd(t) = − 0.9 – +2.4, 206Pb/204Pb(t) = 17.9–18.4, and 207Pb/204Pb(t) = 15.5–15.6. However, older rocks mainly have higher εNd(t) values and 206Pb/204Pb(t) and 207Pb/204Pb(t) ratios.Geochemical and isotopic data of samples suggest that the TVF formed by melting in the continental metasomatized lithospheric mantle (CMLM). Phlogopite-amphibole-rutile-bearing pyroxenite veins played a major role in the formation of older rocks. Eclogite, represented by the recycled oceanic crust or the buried lower continental crust, was dominant in the source of younger rocks. The common source for both groups of the TVF rocks was metasomatized hydrous peridotite.Lithospheric extension and subsequent asthenospheric upwelling led to melting in the CMLM and the formation of the TVF. At the early stage of the volcanism, melting occurred at relatively low temperatures where amphibole, phlogopite, and rutile were stable. Due to ongoing lithosphere extension, the melting of eclogite occurred at a higher temperature and/or lower pressure at the late stage of the volcanism.

Local fractal and wavelet analysis of aerogeophysical data: An integrated approach in target generation of Cu-Au-Fe skarn and gold-polymetallic epithermal porphyry-related systems in eastern Transbaikalia, Russia

Three geophysical fields (anomalous magnetic, exposure dose rate, and apparent resistance) were investigated by local fractal and two-dimensional wavelet analyses for ore prospectivity mapping (scale 1:25000). The study region is part of the Gazimuro-Zavodsky gold-polymetallic ore district (Transbaikalia, South-East Russia) and includes 9 recognized hypogene ore deposits and 40 ore occurrences of Au, Fe, Cu, Pb, W, Sb, As, boron, talc, and fluorite (skarn and hydrothermal formations related to felsic and mafic magmatism). The results show that fractal and wavelet analyses of the geophysical fields demonstrate a certain specialization in the delineation of different mineralization types. The best prospective efficiency (in terms of quality/cost) was achieved by integrating the six individual prospective maps using the ensemble approach.

The Jurassic–Cretaceous K-rich Volcanism of the Nercha Depression in Eastern Transbaikalia and Its Geodynamic Nature

The Jurassic–Cretaceous K-rich Volcanism of the Nercha Depression in Eastern Transbaikalia and Its Geodynamic Nature

Lattice defects in the disordered quartz structure of gold deposits of the Darasun ore field (Eastern Transbaikalia)

Research subject. The composition, properties, and connection of the lattice defects in the disordered s tructure of quartz with the conditions of its formation. Materials and methods. The quartz of the gold deposits of the Darasun ore field – Darasun, Teremkinskoye, and Talatuy – were studied. For the purpose of comparative analysis, gold-ore quartz from the deposits of Northern Kazakhstan was used. Registration of centers in quartz samples was carried out by the EPR method. When interpreting the obtained results, genetic information consisting in the distribution of substitutional Ge and Ti impurities in quartz was used. Results. Two groups of paramagnetic centers were identified in the quartz under study. One of them is associated with substitutional Al, Ti, and Ge impurities in quartz zones with an ordered crystal structure, while the other is associated with the lattice defects localized in the disordered crystal structure of quartz. The latter group includes several types of E'-centers formed in quartz glass and Al-X-centers caused by Al3+ ions associated with oxygen vacancies. In the case of stable thermodynamic conditions of mineral formation, a linear relationship was established between the concentrations of Al-X-centers (CAl-X) and E'-centers (CEs). Under a change in thermodynamic conditions, a deviation of the points from the CEs(CAl-X) dependence was observed. Conclusions. The type of CEs(CAl-X) dependence is determined by the thermodynamic conditions of mineral formation and can be used to identify cases of non-equilibrium solidification of quartz.

Apatite Geochemistry As a Fertility Tool for Porphyry Systems (Using the Example of the Shakhtama Mo-Porphyry and Bystrinsky Cu–Au–Fe-Porphyry–Skarn Deposits, Eastern Transbaikalia, Russia)

Apatite Geochemistry As a Fertility Tool for Porphyry Systems (Using the Example of the Shakhtama Mo-Porphyry and Bystrinsky Cu–Au–Fe-Porphyry–Skarn Deposits, Eastern Transbaikalia, Russia)

U–Pb Ages and Whole-Rock and Zircon Geochemistry of Granitoids from the Zhireken Mo-Porphyry Deposit, Eastern Transbaikalia: New Insights into the Link to Mineralization

U–Pb Ages and Whole-Rock and Zircon Geochemistry of Granitoids from the Zhireken Mo-Porphyry Deposit, Eastern Transbaikalia: New Insights into the Link to Mineralization

Apatite geochemistry as a fertility tool for porphyry systems (using the example of the Shakhtama Mo-porphyry and Bystrinsky Cu–Au–Fe-porphyry–skarn deposits, Eastern Transbaikalia, Russia)

Быстринское Cu-Au-Fe-порфирово-скарновое и Шахтаминское Mo-порфировое месторождения расположены в Восточном Забайкалье, Россия. Вмещающими промышленную минерализацию породами на месторождениях служат многофазные гранитоидные плутоны средне-позднеюрского шахтаминского комплекса. Промышленное оруденение генетически связано с небольшими телами гранит-порфиров и гранодиорит-порфиров поздних фаз внедрения. С целью выявления специфики рудоносного магматизма был изучен состав летучих компонентов и редкоземельных элементов в апатитах из магматических пород рудоносных и безрудных интрузий. Отдельное внимание было уделено доказательству первично-магматического происхождения апатита и отсутствия влияния на их состав наложенных процессов. Было показано, что для рудоносных интрузий Быстринского и Шахтаминского месторождений типично повышенное содержание S в апатите, что указывает на их формирование из окисленных расплавов. Кроме того, показано, что наличие сульфатной серы в расплаве является необходимым условием для формирования сульфидной минерализации. Установлено, что характерным различием между апатитом Cu-порфировых и Mo-порфировых систем является высокая концентрация Cl (более 0.8 мас. %), который обеспечивает перенос халькофильных элементов. Содержание летучих в апатите может быть использовано в качестве признака рудоносности магматических пород. Анализ редкоземельного состава апатита позволил установить, что для минерала из рудоносных гранитоидов Шахтаминского и Быстринского месторождений характерно значение Eu/Eu* 0.4, что указывает на окисленность и водонасыщенность исходного расплава. Выявленные характеристики состава летучих компонентов и редкоземельных элементов апатита из рудоносных интрузий и их дискретность от апатита из безрудных гранитоидов могут служить признаком рудоносности магматических пород на порфировое оруденение.

U–Pb ages and whole-rocks and zircon geochemistry of granitoids from the Zhireken Mo-porphyry deposit, Eastern Transbaikalia: new insights into the link to mineralization

Жирекенское Mo-порфировое месторождение расположено в пределах Западно-Станового террейна Забайкальского сектора Монголо-Охотского складчатого пояса и приурочено к одноименной многофазной интрузии средне-позднеюрского возраста. Несмотря на длительную историю освоения месторождения, на сегодняшний день остается невыясненным целый ряд вопросов касательно магматизма и рудной минерализации. В частности, до сих пор не установлена рудопродуцирующая гранитоидная интрузия, с внедрением которой связано формирование месторождения. В исследовании представлены новые U-Pb LA-ICP-MS цирконовые возрасты, а также геохимический состав цирконов и магматических пород Жирекенского месторождения. Проведенные исследования показывают, что месторождение пространственно ассоциирует с серией интрузий высоко-K известково-щелочных — шошонитовых гранитоидов I-типа, внедрившихся в интервале 158–166 млн лет на постколлизионной стадии эволюции Монголо-Охотского океана. Последовательность внедрения включает биотитовые лейкограниты (U-Pb возраст ок. 164–166 млн лет) → биотит-амфиболовые граниты и гранодиориты (U-Pb возраст ок. 161–163 млн лет) → дайки гранит-порфиров (U-Pb возраст ок. 162–163 млн лет), лейкогранит-порфиров и (кварцевых) диорит-порфиров → дайки кварцевых монцонит-порфиров (U-Pb возраст ок. 158 млн лет). Полученные U-Pb возрасты и геологические взаимоотношения между гранитоидами и минерализацией предполагают, что внедрение рудогененирующей гранитоидной интрузии и формирование Mo-порфирового рудного штокверка на Жирекенском месторождении произошло в интервале 158–161 млн лет. Оценка рудного потенциала этих гранитоидов по комплексу геохимических валовых и минеральных (цирконы) индикаторов фертильности показала, что изученные интрузии не могут быть генетически связаны с порфировой минерализацией, поскольку являются производными слабоокисленных магм. Гранитоидная интрузия, с которой генетически связано молибденовое оруденение Жирекенского месторождения, либо не вскрыта, либо представлена породами, не охваченными настоящим и более ранними исследованиями.

Comparative analysis of hydroclimatic characteristics on the territory of the Amur, Angara-Yenisei and drainage Torey basins (Eastern Transbaikalia)

A comparative analysis of hydroclimatic characteristics was carried out on the territory of the Amur, Angara-Yenisei and Torey closed drainage basins of Eastern Transbaikalia. According to monitoring weather stations, high rates of air temperature growth have been established for the territory of the mountain-taiga zone of the Angara-Yenisei basin, where the linear trend was 2.2, while for the arid steppe zone of the Torey endorheic basin – 1.8. The smallest linear trend of 1.5 was identified for the territory of the Amur Basin. In all studied basins, synchronous cyclicity of precipitation and water levels was revealed against the background of their average annual decrease.

Features of the structure and spatial distribution of microbial communities of river ecosystems of the Amur Basin (Eastern Transbaikalia)

The spatial distribution and structure of microbial communities of river ecosystems in the Amur basin of Eastern Transbaikalia have been studied. The Argun River and its 7 main tributaries have been studied. It was established that the microbial communities of the upper reaches of the rivers under study are formed under the influence of the temperature factor, and are characterized by the total number of bacteria, which in water averages 1.83 × 106 cells/ml, in soil – 2.21 × 109 cells/ml. In the middle reaches of rivers, a stable rheophilic microbial community is formed, the structure and spatial distribution of which depends on the specific hydrological regime of the river and the landscape of the territory. The total number of bacteria in river water here reaches on average 3.03 × 106 cells/ml, in the soil – 2.52 × 109 cells/ml. In the lower reaches, a microbial community with the characteristics of limnosystems is formed, which has a close relationship with water mineralization and is characterized by an average total number of bacteria in water - 3.12 × 106 cells/ml, in soil - 3.06 × 109 cells/ml. Microbiological assessment of water quality showed that the studied rivers belong to pollution classes I - III, and their waters are characterized as oligosaprobic - transitional from β- to α-mesosaprobic.

Исследование реагентного режима флотации одного из золоторудных месторождений Восточного Забайкалья

The relevance of the problem is that the final product of flotation of the Eastern Transbaikalia deposit to be sold, has a low content. The object of the research is as follows: technological sample of the original ore of the gold deposit in Eastern Transbaikalia. The purpose of the research includes the search for the optimal reagent regime during the flotation process to improve technological performance. The research objectives are to study the chemical and mineral composition and to investigate the possibility of using reagents based on alcohols and C4-C8 esters “KETGOL”, “KETGOL improved”, “KON-92”. The research methodology is based on studying the properties of the components and their influence on the flotation process. The material composition of the ores has been studied by methods of atomic emission spectral quantitative analysis, X-ray fluorescence, phase atomic absorption analyzes and atomic emission analysis with inductively coupled plasma ICP-AES. The mass fraction of total and organic carbon is determined by the infrared absorption method. The gold content in the original ore is based on assay data. When conducting flotation experiments, the equipment of JSC Irgiredmet has been used. As a result of the research, the material composition is studied and laboratory studies of flotation enrichment of the ore sample are carried out. Conclusions on the material composition are as follows: the studied ore sample belongs to the primary gold-quartz, moderate sulfide mineral type of ore. The gold content is 3.12 g/t, silver – 6.9 g/t. The gold in the ore is mostly small and thin, its fineness is 708. The results of flotation enrichment have showed that the use of the KETGOL reagent as an additional collector to potassium butyl xanthate (BX) in a 2:1 ratio with a total consumption of 90 g/t is an effective means of increasing gold recovery to ~87–89 %, with In this case, the quality of the main flotation concentrate remains at the level of ~15.5–16.5 g/t.

Raising sheep in environmentally friendly conditions of Eastern Transbaikalia

A comprehensive assessment was carried out on a population of purebred sheep of the Trans-Baikal breed of the intra-breed Hangilsky type. 7985 heads were subject to a comprehensive assessment, of which there were 5211 heads of ewes, 859 heads of overage ewes, 1832 heads of 1.5- year-old ewes, 41 heads of main and sample breeding rams and 42 heads of replacement rams. The sheep were assessed in the second half of June 2022. before shearing, according to the “Procedure and conditions for the assessment of breeding sheep of fine-fleece, semi-fine-fleece breeds and breeds of meat productivity” dated 10/05/2010 No. 335, as amended from 05/30/2013 No. 235. As a result, the characteristics of the herd were comprehensively studied and given Khangil meat-haired type of the Transbaikal breed. The assessment data showed that the flock of sheep in question was represented mainly by animals of the desired type. The examined adult population of sheep had a strong, dense constitution, which was expressed, first of all, in a lightweight, but slightly rough skeleton and dense, fairly thin skin, which produces rather thick, thin wool.

Special aspects of ecosystem recreation in the area of dumps of sub-standard zeolite-containing rocks of Holinsky deposit of Eastern Transbaikalia

The research presents the problem of liquidation of dumps of substandard raw materials of zeolite-containing rocks of the Holinsky deposit, measures for the reclamation of disturbed lands. The most effective way to restore ecosystems is renaturation. Time intervals of succession are considered. Renaturation of disturbed lands consists of 6 stages. Possible dominant plants for the proposed options are considered in detail: Stipa lessingiana, Poa platensis, Festuca valesiaca, Poa angustifolia, Elytrigia intermedia, Artemisia vulgaris, Trifolium pratense , Trifolium repens, Agropyron desertorum.

Use of visual and echo sounding surveys: case study of submerged aquatic vegetation of lake Kenon (Eastern Transbaikalia)

The paper presents the results of studying of the aquatic vegetation of Lake Kenon based on the integrated use of traditional methods of visual survey with an echo sounding. The use of echo sounding surveys makes it possible to study better the features of the distribution of submerged aquatic plants. It allows you to speed up the process of sampling in the field, and also facilitates office processing of the received data. Based on the measurement results, a bathymetric map was built, and the boundaries and areas of dominant phytocenoses were determined. It was revealed that at present the total area of thickets is 489 hectares, which is 33 % of the lake area. The maximum depth of plant growth was 5.1 m. The data obtained is higher than the percentage of overgrowth in 1993, but lower than the values for the 70s and 80s. At present, as in previous years, Chara algae are leading in terms of overgrowing area. The decrease in the distribution area of Nitella flexilis and Potamogeton crispus was revealed.

The Partisan Movement of Eastern Transbaikalia in the «White» periodical press (1919–1920)

This article examines the coverage in the White Guard press of events related to the actions of the partisans of Eastern Transbaikalia against the regime of ataman G.M. Semenov. The research was based on the issues of the newspaper «Zabaikalskaya Nov», published in Chita in 1919 and 1920, as well as the newspaper «Far East», published in Vladivostok. Many of the materials of these newspapers devoted to the actions of the East Trans-Baikal partisans are being introduced into scientific circulation for the first time. As a result of the analysis of newspaper publications, it was found that on the pages of these newspapers there are practically no pronounced propaganda materials directed against the actions of the partisans or their leaders. At the same time, the newspaper issues contain a large number of published reports reflecting the fighting of the Semenov troops against the partisans. A large amount of this data allows to trace the actions of the warring parties with high accuracy and is a good basis for further study of the Civil War in the territory of Transbaikalia. Of particular interest are publications devoted to the Bogdatsky Battle, the largest battle of the Civil War in Eastern Transbaikalia. These materials make it possible to reconstruct the details of the battle with high accuracy, significantly complementing the memoir sources available on this issue.

Aurostibite, Silver-Bearing Gold, and Electrum As a Part of Post-Gold Antimony Mineralization in the Darasun Deposit (Eastern Transbaikalia)

Aurostibite, Silver-Bearing Gold, and Electrum As a Part of Post-Gold Antimony Mineralization in the Darasun Deposit (Eastern Transbaikalia)