POSSIBLE HYDROGEOCHEMICAL PRECONDITIONS FOR KASHIN－BECK DISEASE IN TRANSBAIKALIA

In the basin of the Amur River at the territory of Russia, in the northern regions of China and Korea the osteal-articulate disease of people and animals, well known as Kashin-Beck disease is spread. About 20 hypotheses had been suggested for explaining the disease causes. some of them are briefly introduced. The hydrogeochemical researches in Transbaikalia. Russia, showed that natural water of the endemic areas have several features in chemical composition.some of them are considered by existing hypotheses as the causes of the disease.others do not concern the possible etiologic factors of the disease for the present. The author examines these features respectively.

Late Mesozoic topographic evolution of western Transbaikalia:Evidence for rapid geodynamic changes from the Mongol-Okhotsk collision to widespread rifting

The Mesozoic geodynamic evolution of Transbaikalia has been largely controlled by the scissors-like closure of the Mongol-Okhotsk Ocean that separated Siberia from Mongolia-North China continents.Following the oceanic closure,the tectonic evolution of that region was characterized by collisional uplift and subsequent extension that gave rise to the formation of metamorphic core complexes.This complex tectonic setting prevailed simultaneously between 150 Ma and 110 Ma both in Transbaikalia,North Mongolia,and within the North China Craton.Published paleobotanical and paleontological data show that the oldest Mesozoic basins had formed in western Transbaikalia before the estimated age of extension onset.However no precise geochronological age is available for the onset of extension in Transbaikalia.The Tugnuy Basin,as probably the oldest Mesozoic basin in western Transbaikalia,is a key obj ect to date the onset of extension and following changes in tectonic setting.In this study,U-Pb(LA-ICP-MS)dating of detrital zircons from three key Jurassic sediment formations of the Tugnuy Basin are used to identify the potential source areas of the sediments,understand the changes in sediment routing and provide insights on the topographic evolution of western Transbaikalia.Our results show several significant changes in tectonic regime after the closure of the Mongol-Okhotsk Ocean.A wide uplifted plateau formed during the closure of the Mongol-Okhotsk Ocean,determining the Early Jurassic drainage system reaching the AngaraVitim batholith to the north and shedding sediments to the continental margin to the South.The following collisional event at the end of the Early Jurassic led to the uplift of the collision zone,which partially inverted the drainage system toward the North.A strike-slip displacement induced by the oblique collision initiated some of the early Transbaikalian depressions,such as the Tugnuy Basin at about 168 Ma.A phase of basin inversion,marked by folding and erosion of the Upper Jurassic sediments,could correspond to the short-term collision event that took place during the latest Jurassic-earliest Cretaceous in the eastern Central Asian Orogenic Belt.The following inversion in tectonic regime from compression to extension is consistent with the mid-lower-crustal extension that led to the formation of the numerous metamorphic core complexes throughout northeastern continental Asia during the Early Cretaceous.

Thermodynamic Evaluation of Mineral Balance in Water Thickness of the Soda Lake Doroninskoe(Eastern Transbaikalia,Russia)

In recent years,lakes,including salted,attract the attention of researchers,also when reconstructing last climate changes using the bottom sediments(Solotchina et al.,2008,et al.).In this case the different geochemical

Early Holocene climate signals from stable isotope composition of ice wedges in the Chara Basin,northern Transbaikalia,Russia

Stable isotope composition of syngenetic and epigenetic ice wedges, radiocarbon age, and pollen spectra of the surrounding deposits were studied during long term investigations at the "Belyi Klyuch" site on the first(6-8 m height) terrace of the Chara River(720 m.a.s.l.) in northern Transbaikalia to assess climatic conditions during ice-wedge formation. It was revealed that Holocene ice wedges had been formed from 10 to 7.5 ka 14 C BP. The isotope composition(δ^(18)O, δ~2 H) of relict ice wedges is the lightest and amounts-23‰ and-185‰, correspondingly. The isotopic compositions of ice lenses from sandy loam above ice wedges are-15.7‰, and-133‰; of small ice wedge in peat and sand are-15.3‰ and-117.9‰, accordingly.Interpretation of the ice wedge isotope composition has yielded that mean winter temperatures during cold stages of Holocene optimum were lower than today, during warm stages they were close to modern ones. During the coldest stages of Holocene optimum the total annual freezing index varied from-5100 to-5700 ℃ degree days, i.e. 300-600 ℃ degree days colder than during extremely severe modern winters. The total annual thawing index varied from 1300 to 1800 ℃ degree days, which was slightly higher than modern ones.

Tourmalinization at the Darasun goldfield,Eastern Transbaikalia:Compositional,fluid inclusion and isotopic constraints

Zoned tourmaline （schorl-dravite） in the matrix of hydrothermal explosive breccia and ore veins in gold deposits, Chita region, Eastern Transbaikalia, Russia, are associated with Na- and K-rich porphyry-type subvolcanic intrusives. 61So values of tourmaline from three gold deposits （Darasun, Talatui, Teremkinskoye） are ＋8.3%, ＋7.6%, and --6.0% and calculated 6180 values of fluids respon- sible for the tourmalinization are ＋7.3%, ＋7.7%, and ＋4.2%, respectively. These data imply an igneous fluid source, except at the Teremkin deposit where mixing with meteoric water is indicated. Wide ranges of Fe3＋/Fetot and the presence of vacancies characterize the Darasun deposit tourmaline indicating wide ranges off（O2） and pH of mineralizing fluids. Initial stage tourmalines from the gold deposits of the Darasun ore district are dravite or high mg schorl. Second stage tourmaline is characterized by oscillatory zoning but with Fe generally increasing towards crystal rims indicating decreasing temperature. Third stage tourmaline formed unzoned crystals with XMg （mole fraction of Mg） close to that of the first stage tourmaline, due to a close association with pyrite and arsenopyrite. From Fe^3＋/Fetot values, chemical composition and crystallization temperatures, logf（O2） of mineralizing fluids ranged from ca. -25 to 20, much higher than for the gold-bearing beresite-listvenite association, indicating that tourmalinization was not related to gold mineralization.

横穿贝加尔湖铁路路基的冻胀性研究(英文)

The paper features the results of field measurements and numerical research of embankment behaviour in permafrost soils of Transbaikalia railway section following implementation of preventive works to eliminate action of heaving forces on the main area of embankment subgrade.

Taxonomic and Ecological Characterization of Cyanobacteria from Some Brackish and Saline Lakes of Southern Transbaikal Region

Brackish and saline lakes are common in the arid zones of the Earth.They are unique ecosystems with extremely high p H values and high mineralization levels(up to saturating concentrations).These lakes are inhabited by

外贝加尔土地覆盖变化驱动机制研究

外贝加尔地区位于东西伯利亚南部,是全球气候变化敏感区域,对我国具有重要的生态安全以及地缘政治、经济意义。本研究基于1992～2009年间4期土地覆盖数据,应用动态度模型等方法描述外贝加尔地区近二十年来土地覆盖时空动态特征,应用偏最小二乘回归(PLSR)分析了研究区土地覆盖与驱动因子间的定量关系。结果显示:外贝加尔地区后备耕地资源丰富,林地、裸地呈扩张趋势;研究区经济增长对天然植被的压力较大;城镇和建成区持续萎缩,如无法采取有效措施遏止人口下降、刺激经济恢复,未来仍会有大量居民点被废弃。

俄罗斯外贝加尔氟的水文地球化学异常(英文)

在本文中,5种类型的氟的水文地球化学异常被确定,它们的形成过程、在水环境中的流入物源以及浓度水平各异。对它们的特征也进行了讨论。

Metallogenic focus-area and superlarge mineral deposits in the bordering zones between China,Russia and Mongolia

A correlative study of geology and metallogenic process in the bordering zones between China,Russia and Mongolia shows that the region of the western slope of the Da Hingan Mts. Eastern Transbaikalia Eastern Mongolia is a metallogenic focus area associated with Late Mesozoic intraplate tectono magmatic activation. During the period of 160\120 Ma a great number of multiplex deposits with similar genesis including large and superlarge mineral deposits were formed.

中国的“瓦西里”与他的俄罗斯朋友——走私者与他们的跨文化身份

二十世纪二十年代末至三十年代初中苏边境上走私者的生活是值得探讨的一个问题。除了走私行为的经济维度,历史学家通过走私现象也可以了解走私者超越"民族"或"文化"概念的身份构成。货物的流通如何与走私者的身份联系起来,以及相反,走私者的身份又如何决定了他们走私的网络及策略?对中苏边境地区走私者的跨文化身份的分析,有助于对这一核心问题的回答。