Numerical Simulation of Variations in Ozone Content,Erythemal Ultraviolet Radiation,and Ultraviolet Resources over Northern Eurasia in the 21st Century     

Pastukhova  A. S.  Chubarova  N. E.  Zhdanova  Ye. Yu.  Galin  V. Ya.  Smyshlyaev  S. P. 《Izvestiya Atmospheric and Oceanic Physics》2019,55(3):242-250

Izvestiya, Atmospheric and Oceanic Physics - The influence of different factors on the total ozone content (TOC) and erythemal UV radiation (Qery) in the atmosphere over northern Eurasia from 1979...  相似文献   

Arsenic Speciation in a Contaminated Gold Processing Tailings Dam   总被引：1，自引：0，他引：1  

Olga V. Shuvaeva  Svetlana B. Bortnikova  Tamara M. Korda  Elena V. Lazareva 《Geostandards and Geoanalytical Research》2000,24(2):247-252

Gold recovery in ores containing arsenopyrite releases significant amounts of arsenic into the environment due to mineral processing and oxidation during storage. The extent of arsenic weathering in a tailings dam has been investigated. Speciation of As in surface and pore waters and pond sediments showed that for gold tailings in the dam, As enrichment took place in the pore water relative to the surface water. In pond sediments As was predominantly present as residual arsenopyrite and partly as a substance co-precipitated with iron hydroxide. The arsenic release from the sediment results from a reductive dissolution of the arsenopyrite and Fe oxides. In the surface water, arsenate and arsenite are the main arsenic species (arsenate is dominant), but in the pore waters methylation processes play a significant role. Arsenic transport is accompanied by the transformation of As into the less toxic compounds (methylated species) co-existing with the most toxic species (arsenite).  相似文献   

Insight into the Last Glacial Maximum climate and environments of the Baikal region     

Pavel E. Tarasov  Boris P. Ilyashuk  Christian Leipe  Stefanie Müller  Birgit Plessen  Philipp Hoelzmann  Svetlana S. Kostrova  Elena V. Bezrukova  Hanno Meyer 《Boreas: An International Journal of Quaternary Research》2019,48(2):488-506

This study presents a multi‐proxy record from Lake Kotokel in the Baikal region at decadal‐to‐multidecadal resolution and provides a reconstruction of terrestrial and aquatic environments in the area during a 2000‐year interval of globally harsh climate often referred to as the Last Glacial Maximum (LGM). The studied lake is situated near the eastern shoreline of Lake Baikal, in a climatically sensitive zone that hosts boreal taiga and cold deciduous forests, cold steppe associations typical for northern Mongolia, and mountain tundra vegetation. The results provide a detailed picture of the period in focus, indicating (i) a driest phase (c. 24.0–23.4 cal. ka BP) with low precipitation, high summer evaporation, and low lake levels, (ii) a transitional interval of unstable conditions (c. 23.4–22.6 cal. ka BP), and (iii) a phase (c. 22.6–22.0 cal. ka BP) of relatively high precipitation (and moisture availability) and relatively high lake levels. One hotly debated issue in late Quaternary research is regional summer thermal conditions during the LGM. Our chironomid‐based reconstruction suggests at least 3.5 °C higher than present summer temperatures between c. 22.6 and 22.0 cal. ka BP, which are well in line with warmer and wetter conditions in the North Atlantic region inferred from Greenland ice‐cores. Overall, it appears that environments in central Eurasia during the LGM were affected by much colder than present winter temperatures and higher than present summer temperatures, although the effects of temperature oscillations were strongly influenced by changes in humidity.  相似文献   

Taphonomic phenomenon of ancient hair from Glacial Beringia: perspectives for palaeoecological reconstructions          下载免费PDF全文

Irina V. Kirillova  Johannes van der Plicht  Stanislav V. Gubin  Oksana G. Zanina  Olga F. Chernova  Elena G. Lapteva  Svetlana S. Trofimova  Eugeny V. Zinovyev  Anton A. Zharov  Elena O. Fadeeva  Thijs Van Kolfschoten  Fedor K. Shidlovskiy  Alexey A. Kotov 《Boreas: An International Journal of Quaternary Research》2016,45(3):455-469

An accumulation of mammoth hair, discovered in the Bol'shaya Chukochya River valley (northeast Yakutia, Russia), was found to contain remains of terrestrial and aquatic organisms, including plants, insects, crustaceans, birds and mammals. Radiocarbon dating indicated that this post‐mortem taphocoenosis represented multiple time periods. The mammoth hair was dated to older than 45 ka BP, the plants were dated to 12 750±50 a BP (which corresponds to a shift in the environmental conditions and landscapes during the formation of thermokarst in northeastern Russia) and the bird feathers were dated to 4115±40 a BP. A scenario of the formation of this fossil assemblage is proposed, covering the MIS 3‐1 time range. The hair also yielded various Arctic branchiopod crustaceans, which inhabit shallow temporary water bodies and therefore are important for reconstruction of palaeoenvironments. The cladoceran subgenus Daphnia (Ctenodaphnia), currently absent from the Asian part of Beringia, is reported from this region for the first time. The study demonstrates that the discovered permafrost‐preserved hair is a unique repository of Ice Age organisms.  相似文献   

Climatic features of the Belaya River runoff formation     

N. N. Krasnogorskaya  T. B. Fashchevskaya  A. V. Golovina  Yu. I. Ferapontov  N. V. Zhdanova 《Russian Meteorology and Hydrology》2012,37(1):57-63

Spatiotemporal regularities of changes in mean annual air temperature and annual precipitation amount values for the Belaya River basin were revealed on the basis of the analysis of statistical homogeneity of their long-term series. It is established that warming has occurred by now and the increase in precipitation amount is registered in the Belaya River basin. Revealed was the contribution of mean seasonal air temperature and precipitation changes to the changes in their mean long-term values.  相似文献   

A new approach to precious metals recovery from brown coals: Correlation of recovery efficacy with the mechanism of metal-humic interactions     

Svetlana Yu. Bratskaya  Alexandra S. Volk  Alexander Yu. Ustinov  Valentin A. Avramenko 《Geochimica et cosmochimica acta》2009,73(11):3301-176

The presence of gold and platinum group elements (PGE) in low-rank brown coals around the world has promoted interest in the industrial exploitation of this alternative source of precious metals. However, due to low efficacy of the methods traditionally used for the processing of mineral ores, there exists a high demand for new strategies of precious metal recovery from refractory carbonaceous materials that could significantly increase the economic potential of gold- and PGE-bearing organic resources. Here we discuss the possibility of gold and PGE recovery from alkaline extracts of brown coals using the difference in colloidal stability of bulk organic matter and its fractions enriched with precious metals. This approach enables one to avoid complete oxidation or combustion of brown coals prior to gold recovery, to minimize organic content in gold concentrate, and to obtain a valuable by-product - humic extracts. Using gold-bearing brown coals from several deposits located in the South Far East of Russia, we show that up to 95% of gold can be transferred to alkaline extracts of humic acids (HA) and up to 85% of this gold can be recovered by centrifugation at pH 4.0-6.0, when only 5-15% of HA precipitated simultaneously. We have shown that the high efficacy of gold recovery can be attributed to the occurrence of fine-dispersed elemental gold particles stabilized by HA, which differ significantly in colloidal stability from the bulk organic matter and, thus, can be separated by centrifugation.  相似文献   

Electrical conductivity at mid-mantle depths estimated from the data of Sq and long period geomagnetic variations     

Oldřich Praus  Jana Pěčová  Václav Červ  Svetlana Kováčiková  Josef Pek  Jakub Velímský 《Studia Geophysica et Geodaetica》2011,55(2):241-264

We present results of a classical global induction analysis of the geomagnetic variation data in the range of daily Sq variations, as well as for long period variations within the period range of about 8 to 400 days. The Sq data from 88 to 94 world observatories are processed in two ways, first by constructing and analyzing average monthly daily variations for the whole months of the International Quiet Sun Year (IQSY) 1995, and second by analyzing the individual, especially quiet Q* daily records from the same year. The electrical images of the Sq response functions obtained via the Schmucker’s ρ* — z* procedure show a good fit with results of other induction studies, though especially our global impedance phases show a larger scatter than two other published data sets used for comparison.  相似文献   

Radiochemoecological Monitoring of the Salt Lakes of the Crimea     

Natalya MIRZOYEVA  Sergey GULIN  Olga PLOTITSINA  Alexandra STETSUK  Svetlana ARKHIPOVA  Nina KORKISHKO  Oleg EREMIN 《《地质学报》英文版》2014,88(Z1):155-157

正1 Introduction The salt lakes of the Crimea contain the practically inexhaustible sources of salts of sodium,magnesium,bromine and other chemical elements(Ponizovskii,1965),being the potential powerful raw materials base for the  相似文献   

Natural Molecular Hydrogen Seepage Associated with Surficial,Rounded Depressions on the European Craton in Russia     

Nikolay Larin  Viacheslav Zgonnik  Svetlana Rodina  Eric Deville  Alain Prinzhofer  Vladimir N. Larin 《Natural Resources Research》2015,24(3):369-383

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How global are the Jurassic–Cretaceous unconformities?     

Svetlana O. Zorina  Oksana S. Dzyuba  Boris N. Shurygin  Dmitry A. Ruban 《地学学报》2008,20(5):341-346

The reality of the global‐scale sedimentation breaks remains controversial. A compilation of data on the Jurassic–Cretaceous unconformities in a number of regions with different tectonic settings and character of sedimentation, where new or updated stratigraphic frameworks are established, permits their correlation. Unconformities from three large reference regions, including North America, the Gulf of Mexico, and Western Europe, were also considered. The unconformities, which encompass the Jurassic‐Cretaceous, the Lower–Upper Cretaceous and the Cretaceous–Palaeogene transitions are of global extent. Other remarkable unconformities traced within many regions at the base of the Jurassic and at the Santonian–Campanian transition are not known from reference regions. A correlation of the Jurassic–Cretaceous global‐scale sedimentation breaks and eustatic curves is quite uncertain. Therefore, definition of global sequences will not be possible until eustatic changes are clarified. Activity of mantle plumes is among the likely causes of the documented unconformities.  相似文献