Dynamics of REE accumulation and fractionation in the subcolloidal fraction of bottom sediments in the Razdol’naya River–Amur Bay section,Sea of Japan     

D. M. Polyakov 《Oceanology》2016,56(3):406-414

The REE contents (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) are determined by atomic emission spectroscopy in the subcolloidal fraction of bottom sediments in the Razdol’naya River–Amur Bay section. The mean contents of lanthanides in soils and river bottom sediments (before the mixing zone) are calculated. The increase in REE content and the fractioning in the series from light to middle and heavy REE in sediments of different estuary zones (river, water mixing, and marine), with the latter related to flocculation, sorption on iron and manganese hydroxides, clay minerals (hydromica, smectites), and lifetime accumulation of marine plankton, are dtermined. Via extraction of 0.5 N sodium hydroxide solution, the content of lanthanides associated with humic substances of subcolloidal fraction from the Amur Bay sediments are determined: 1.3 to 8.2% of La; 1.1 to 11% of Ce; and 0.3 to 1.5 of Gd.  相似文献   

Studying instrumental linear polarization at the Large Solar Vacuum Telescope (LSVT)     

N. M. Firstova  V. I. Polyakov  V. I. Skomorovsky  V. M. Grigoriev 《Geomagnetism and Aeronomy》2009,49(7):927-934

Impact linear polarization in solar flares is studied with the Large Solar Vacuum Telescope (LSVT) using the spectral polarimetric method. This method makes it possible to minimize the effect of instrumental polarization with an error of up to 10⁻² owing to the normalization of the spectral line intensity to the continuum spectrum intensity with negligible linear polarization. As a result, the Hα line intensity in two orthogonally polarized spectral stripes coincides in the absence of solar polarization. However, in the presence of linear polarization in a flare, the spectral polarimetric method does not rule out that the error can be present in determining the Stokes parameters Q and U because of their possible relative “leakage.” Linear instrumental polarization of LSVT has been performed using polaroid rotation before the major mirror. Twelve elements of a telescope matrix, characterizing linear polarization, have been determined. The usage of a matrix makes it possible to specify the observed Q and U values accurate to 10⁻³ of their magnitude.  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   

Using terrestrial LiDAR to measure water erosion on stony plots under simulated rainfall     

Li Li  Mark A. Nearing  Mary H. Nichols  Viktor O. Polyakov  Michelle L. Cavanaugh 《地球表面变化过程与地形》2020,45(2):484-495

Terrestrial LiDAR scanning (TLS) technology is widely used to detect terrain elevation changes. This study examines the potential use of terrestrial LiDAR to measure erosion on small experimental plots at high resolution. Multitemporal TLS scans were conducted at six positions around plots (12 m²) with three slope treatments through 11 simulated rainfall applications. Surface elevation changes were quantified by comparing scans between rainfall simulations, and elevation changes greater than the level of detection were used to obtain volumetric change estimations. Erosion mass was estimated both by using soil bulk density and the density of sediment collected in runoff, and then compared to the erosion estimated from the runoff samples. Results showed: (1) with the aid of fixed reference controls in the form of concrete target surfaces of varying roughness, registration accuracy was better than 1 mm and mean level of change detection was less than 2.2 mm; (2) the average absolute relative errors of TLS-estimated eroded mass ranged from 6.8% to 31.8%, with greater values on 5% slope; (3) the TLS-estimated erosion accuracy was affected by erosion magnitude, the utilized material density and number of scan positions, and a grid size of 10 mm was found to be appropriate for this scale to estimate the volumetric changes; (4) the number of scan positions could be reduced to three while not significantly impacting volumetric change estimations; and (5) elevating the scanner resulted in much better accuracy for eroded mass estimations. This study suggests that using LiDAR to monitor soil erosion at the plot scale is feasible, and provides guidance about the level of accuracy one might expect in doing so. © 2019 John Wiley & Sons, Ltd.  相似文献   

Euxinia as a dominant process during OAE1a (Early Aptian) on the Eastern Russian Platform and during OAE1b (Early Albian) in the Middle Caspian     

Svetlana O. Zorina  Oksana V. Pavlova  Bulat M. Galiullin  Vladimir P. Morozov  Alexey A. Eskin 《中国科学:地球科学(英文版)》2017,60(1):58-70

A detailed study of the mineral composition and microstructure of the black shales associated with OAE1a (Eastern Russian Platform), OAE1b (Middle Caspian), and the host rocks has been carried out using X-ray diffraction, scanning electron microscopic, and microprobe analyses. The results provide important constraints for depositional environments in the sedimentary basins. Black shales with pyrite framboids imply euxinic (sulfidic) conditions with increased organic matter preservation. Disintegrating framboids suggest partial or complete dissolution of the organic matter inside the framboids due to increasing water oxygenation. OAE1a on the Eastern Russian Platform is heterogeneous as it includes thin interbeds of concretionary coccolith limestones within the interval of bituminous shales, and correlates with the Lower Aptian Rhagodiscus angustus nannofossil zone. The coccolith limestones indicate short intermittent episodes of interrupted stagnation, rapid oxygenation, and restoration of normal marine conditions. The presence of montmorillonite, albite, microcline, and diopside in the bituminous siltstones and in the host siltstones of OAE1a on the Eastern Russian Platform, as well as a high content of titanium in the black siltstones correlated with OAE1b in the Middle Caspian allow proposing significant input of pyroclastic material into the extant sea.  相似文献   

Accumulation Properties of Major and Trace Elements of the Subcolloidal Fraction of Bottom Sediments in the Marginal Filter of the Razdolnaya River (Amur Bay,Sea of Japan) under the Influence of Increased Runoff     

Polyakov  D. M.  Zarubina  N. V. 《Oceanology》2020,60(3):362-371

Oceanology - The study reveals the distribution of contents of major (Si, Al, Fe, Mn) and trace elements (Ga, V, W, Th, Mo, U, Be, Y, Cd), Сorg, and clay minerals in the subcolloidal fraction...  相似文献   

Accumulation of Subcolloidal Fraction Elements of Bottom Sediments in Amur Bay (Sea of Japan)     

Polyakov  D. M.  Utkin  I. V. 《Oceanology》2018,58(6):900-908

Oceanology - The mean contents of elements (Fe, Mn, Zn, Pb, Cu, Cr, V, Co, Cd, Ni, As, Sc, Ga, Zr, Hf, Nb, Ta, W, Th, Mo) in the subcolloidal fraction of bottom sediments in the northern part of...  相似文献   

The Satellite Atmospheric Sounder IKFS-2: 2. Validation of the Temperature Sounding of the Atmosphere     

Polyakov  A. V.  Timofeyev  Yu. M.  Uspensky  A. B.  Kukharsky  A. V. 《Izvestiya Atmospheric and Oceanic Physics》2018,54(9):1391-1398

Izvestiya, Atmospheric and Oceanic Physics - The validation of measurements of vertical temperature profiles by the IKFS-2 instrument (the Meteor-M no. 2 satellite) in cloudless conditions was...  相似文献   

Study of Brightness Variability of the Components of the Visual Binary System 61 Cyg Based on Observations at the Normal Astrograph of the Pulkovo Observatory     

E. V. Polyakov  O. O. Vasilkova  D. L. Gorshanov  M. A. Pogodin  N. A. Shakht 《Astrophysics》2018,61(4):444-457

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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