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131.
The mineral composition, distribution and fractionation of rare-earth elements in dissolved and suspended forms (solid residue) of atmospheric precipitation were studied by analyzing the snow sampled over urbanized territory by the example of the city of Blagoveschensk. Electron-microscopic studies revealed the own minerals of rare-earth elements in dust aerosols. It is shown that the main sources of the atmospheric pollution by rare-earth elements were emissions of TPP (heat and power plants) and boiler houses. Contrasting geochemical anomalies of rare-earth elements were found in the snow cover of the city. The REE concentrations in the solid phase of snow are few orders of magnitude higher than those of the liquid phase. The snow solid phase provides insight into the REE behavior, because it directly reflects the impact of different anthropogenic sources. The characteristic feature of the REE distribution in the solid residue of snow is their LREE enrichment relative to MREE and HREE. The average HREE content is 10% of total REE. In the snow water–solid phase system, most samples show weak fractionation between LREE and HREE owing to the low total mineralization of the snow liquid phase and the small content of organic matter. 相似文献
132.
L. M. Pavlova V. I. Radomskaya L. P. Shumilova A. M. Ionov V. V. Ivanov A. V. Poselyuzhnaya 《Geochemistry International》2018,56(5):450-461
Based on scanning electron microscopy, infrared spectroscopy, and X-ray photoelectron spectroscopy, it was shown that platinum sorption by the biomass of microscopic fungi occurs in several stages. Incipient interaction involves physical and chemical sorption and is followed by the reduction of adsorbed platinum ions to a zero-valence state at the expense of metabolic products of microorganisms and eventual aggregation of zero-valence particles to nanometer-sized forms. Model experiments revealed a high platinum sorption potential of the physiologically active biomass of microscopic fungi and their cell envelopes (chitin). 相似文献
133.
The variations in the electron number density of the ionospheric F2 layer maximum (NmF2) under the action of the zonal plasma drift in the geomagnetic west-geomagnetic east direction perpendicularly to the electric (E) and geomagnetic (B) fields during a geomagnetically quiet period on December 7, 1989, at high solar activity have been studied based on a three-dimensional nonstationary theoretical model of electron number densities and temperatures in the ionospheric F region. Calculated and measured NmF2 values for 12 low-latitude ionospheric sounding stations have been compared. When the zonal E × B plasma drift is ignored, the NmF2 values become smaller by up to a factor of 3 under nighttime conditions in the low-latitude ionosphere. The average effect of the zonal E × B plasma drift on NmF2 in the low-latitude ionosphere is larger during winter nights than under summer nighttime conditions. 相似文献
134.
135.
Marina KOLPAKOVA Stepan SHVARTSEV Vitalyi ISUPOV Sodov ARIUNBILEG Alexander VLADIMIROV Olga GASKOVA 《《地质学报》英文版》2014,88(Z1):142-144
正All the lakes are accumulative systems for the various chemical elements.However,the ratios of the elements in different lake types are very different.It is generally accepted that the composition of lake water determined by 相似文献
136.
Manuela Rossi Marcella Dell’Aglio Alessandro De Giacomo Rosalba Gaudiuso Giorgio Saverio Senesi Olga De Pascale Francesco Capitelli Fabrizio Nestola Maria Rosaria Ghiara 《Physics and Chemistry of Minerals》2014,41(2):127-140
Gem-quality alexandrite, hiddenite and kunzite, elbaite and topaz minerals were characterized through a multi-methodological investigation based on EMPA-WDS, LA-ICP-MS, and laser-induced breakdown spectroscopy (LIBS). With respect to the others, the latter technique enables a simultaneous multi-elemental composition without any sample preparation and the detection of light elements, such as Li, Be and B. The criteria for the choice of minerals were: (a) the presence of chromophore elements in minor contents and/or as traces; (b) the presence of light lithophile elements (Li, Be and B); (c) different crystal chemistry complexity. The results show that LIBS can be employed in mineralogical studies for the identification and characterization of minerals, and as a fast screening method to determine the chemical composition, including the chromophore and light lithophile elements. 相似文献
137.
To clarify unanswered questions of site formation, geology and the archaeology of the Berelekh geoarchaeological complex, a special survey was undertaken in 2009 of the area surrounding the site. Several geological units have been revealed. By establishing the spatial and temporal relationship of these deposits—as well as their age—we have reconstructed the formation history of the Berelekh bone bed. The mammoth bone deposit belongs to a paleochannel. Radiocarbon dating of mammoth remains at Berelekh demonstrates rapid accumulation during the Bølling warming. Human involvement in its formation is, at best, questionable, since there is no real overlap between the radiocarbon dates associated with past human activity, and those of the mammoth bone bed. This study confirms that humans used mammoth bone remains after the bone bed was deposited. Culturally, the Berelekh “site” does not have any relationship to the so‐called “Dyuktai culture.” Instead, the Berelekh archaeological finds (side notched stone pendants) show certain similarities to non‐microblade terminal Pleistocene assemblages found from Yenisei to Kamchatka. Additionally, the Berelekh complex presents a clear analogy with lithics found in Eastern Beringia. Teardrop‐shaped incomplete bifaces found in the assemblage are comparable to the Chindadn points of Alaska. The nature of this “Chindadn connection” is intriguing but it is the only visible cultural link between Western and Eastern Beringia. 相似文献
138.
Wind-induced sediment resuspension as a potential factor sustaining eutrophication in large and shallow Lake Peipsi 总被引:1,自引:0,他引:1
Olga Tammeorg Juha Niemistö Tõnu Möls Reet Laugaste Kristel Panksep Külli Kangur 《Aquatic Sciences - Research Across Boundaries》2013,75(4):559-570
Using sediment traps, we aimed to elucidate the temporal and spatial variations in sediment fluxes in large and shallow Lake Peipsi, over the May to October 2011 period, and analyze the factors behind those variations. The effects of weather factors (mean and maximum wind velocity, water level and water temperature) on sediment resuspension and the concentrations of suspended solids (SS), total phosphorus (TP), soluble reactive phosphorus (SRP), and chlorophyll a (Chl a) were investigated. Moreover, the internal loading of TP due to sediment resuspension was determined. The sediment resuspension rates were significantly higher in the shallower waters than in the deeper parts of the lake. Resuspension was a major factor in sedimentation dynamics of the lake, which is presently subject to eutrophication. The rates of sediment resuspension followed the same pattern as gross sedimentation during the study period, and their respective values differed significantly between sampling dates. The highest resuspension rates were observed in September (mean 55.4 g dw m?2 day?1), when the impacts of wind events were particularly pronounced. Weather factors that were recorded approximately 2 weeks before water and sediment sampling affected the gross sedimentation and sediment resuspension. The water quality variables of SS, TP, SRP, Chl a were similarly affected. During the study, TP concentrations of the water were mainly determined by the resuspension of sediments containing a large pool of organic material. Although internal loading of TP due to resuspension was several times greater than external loading, external loading determines the amount of phosphorus that enters the lake and can be resuspended. 相似文献
139.
G. Yu. Pavlova P. Ya. Tishchenko N. D. Khodorenko M. G. Shvetsova S. G. Sagalaev 《Russian Journal of Pacific Geology》2012,6(3):251-262
The complex study of the river water and pore solutions from the bottom sediments in the lower reaches of the Razdol’naya River was conducted in February 2010. The major ion composition of the waters indicates the submarine origin of the near-bottom and pore waters in the lower reaches of the Razdol’naya River in the winter. The river estuary extends upstream for more than 20 km. It was established that the studied sediments are reduced oozes containing pyrite, hydrotroilite, and iron monosulfide, which is direct evidence for sulfate-reduction in the sediments. The diagenesis of organic matter is the main reason for the considerable decrease in the amount of sulfates and the increase in the alkalinity of the sediment pore water. The sedimentary pore water sampled from the deep river pits is characterized by excess alkalinity that cannot be explained by sulfate-reduction and methane genesis. It was suggested that the chemical weathering of silicate minerals and the bacterial mineralization of salts of organic acids could result in the excess alkalinity of the sediment pore water. 相似文献
140.
Ludger Timmen Olga Gitlein Volker Klemann Detlef Wolf 《Pure and Applied Geophysics》2012,169(8):1331-1342
The Nordic countries Norway, Sweden, Finland and Denmark are a key study region for research of glacial isostasy. In addition, such research offers a unique opportunity for absolute gravimetry to show its capability as a geodetic tool for geophysical research. Within a multi-national cooperation, annual absolute gravity measurements have been performed in Fennoscandia by IfE since 2003. For the Hanover gravimeter FG5-220, overall accuracy of ±30?nm/s2 is indicated for a single station determination. First results of linear gravity changes are derived for ten stations in the central and southern part of the uplift area. Comparing with the rates predicted by glacial rebound modelling, the gravity trends of the absolute measurements differ by 3.8?nm/s2 per year (root-mean-square discrepancy) from the uplift model. The mean difference between observed and predicted rates is 0.8?nm/s2 per year only. A proportionality factor of ?1.63?±?0.20?nm/s2 per mm has been obtained, which describes the mean ratio between the observational gravity and height rates. 相似文献