New data about structure and time of formation of the Khamar-Daban terrane: U-Pb LA-ICP-MS zircon ages     

S. I. Shkol’nik  A. M. Stanevich  L. Z. Reznitskii  V. B. Savelieva 《Stratigraphy and Geological Correlation》2016,24(1):19-38

This paper provides new data on the age of detrital zircons from metaterrigenous rocks of the Khamardaban Group (Kornilovskaya and Shubutuiskaya formations) which crown the succession of the Khamar-Daban terrain. It was established that the accumulation of the protoliths of both formations occurred in the interval between the Late Riphean and Early Ordovician. In this case, there is a difference between sequences of Shubutuiskaya and Kornilovskaya formations due to a sharp change in a provenance area and depositional conditions, which is a consequence of the change in the paleogeodynamic environment. In addition, this indicates the tectonic juxtaposition of these sequences and probability of accumulation of deposits of the Shubutuiskaya Formation within Dzhida island arc system.  相似文献   

High-temperature phase transition and local structure of a hydrous anorthoclase     

Y. Yang  Z. P. Wang  Z. Z. Tian  Q. K. Xia  G. W. Li 《Physics and Chemistry of Minerals》2016,43(2):111-118

The in situ Raman spectra of a hydrous anorthoclase at temperatures of 20–800 °C have been measured using a LABRAM-HR spectrometer and Linkam TS 1500 heating stage. The frequencies of modes at 54, 99, 130 and 162 cm^?1 related to M–O vibrations decrease sharply and then increase drastically or keep steady at temperatures above 200 °C. A knee point can be clearly seen at about 200 °C for those modes. The frequency of the mode at 282 cm^?1 shows little temperature dependence. However, for the two strongest modes at 471 and 512 cm^?1, the frequencies decrease linearly with increasing temperature. From evolution of the frequencies of modes at 54, 99, 130 and 162 cm^?1 with temperature, the following conclusions can be drawn: (1) The distance of the local M–O bond shortens rather than lengthens at temperatures above 200 °C; (2) The abrupt changes of the local structure of M site induce a collapse of the framework structure and displacive phase transition at 200 °C; and (3) The H atoms incorporated in anorthoclase are located at the M site. These results are indicative for the structure and properties of anorthoclase at deep earth conditions.  相似文献   

Analysis of temperature variability in the mountain regions of the North Caucasus in 1961–2013     

A. A. Tashilova  L. A. Kesheva  N. V. Teunova  Z. A. Taubekova 《Russian Meteorology and Hydrology》2016,41(9):601-609

Annual and seasonal series of temperature values are analyzed using the data of Akhty, Teberda, and Terskol weather stations (the height above the sea level is >1000 m) for 1961-2013 as well as from 1976 to 2013 in order to reveal changes in the mountain climate in the period of contemporary global warming. Mean values, standard deviations, norms, and anomalies of annual and seasonal values of temperature as well as the rate of their variation in the mentioned periods are obtained. It is found that the temperature rise is observed in all seasons and for the year as a whole at the mountain weather stations except Terskol station. According to the results of studying temperature variability, Akhty and Teberda weather stations were united into the group “mountain weather stations” with the subsequent averaging of climatic variables. Terskol weather station was singled out as an independent high-mountain weather station.  相似文献   

Noble metal specialization of Lower and Middle Riphean terrigenous rocks in the South Urals     

S. G. Kovalev  A. V. Maslov  E. Z. Gareev 《Lithology and Mineral Resources》2016,51(6):467-483

Results of the study of noble metal specialization of Lower and Middle Riphean terrigenous rocks in the Bashkir Anticlinorium (South Urals) are reported. The study revealed their genetic differences in the relatively unaltered, i.e., “background” terrigenous rocks in type sections of the Burzyan and Yurmatau groups and in sedimentary rocks of the same stratigraphic levels from tectonic zones subjected to local dynamothermal metamorphism of the greenschist facies and intruded by mafic rocks. It has been established that Ru serves as a geochemical marker of the impact of magmatic processes on sedimentary rocks and the redistribution of noble metals during metamorphism and local metasomatism. A generalized model is proposed for the formation of noble metal geochemical specialization of Lower and Middle Riphean terrigenous rocks in the South Urals.  相似文献   

Using wavelet tools to analyse seasonal variations from InSAR time-series data: a case study of the Huangtupo landslide   总被引：3，自引：3，他引：0  

R. Tomás  Z. Li  J. M. Lopez-Sanchez  P. Liu  A. Singleton 《Landslides》2016,13(3):437-450

Synthetic aperture radar interferometry (InSAR) has proven to be a powerful tool for monitoring landslide movements with a wide spatial and temporal coverage. Interpreting landslide displacement time-series derived from InSAR techniques is a major challenge for understanding relationships between triggering factors and slope displacements. In this study, we propose the use of various wavelet tools, namely, continuous wavelet transform (CWT), cross wavelet transform (XWT) and wavelet coherence (WTC) for interpreting InSAR time-series information for a landslide. CWT enables time-series records to be analysed in time-frequency space, with the aim of identifying localized intermittent periodicities. Similarly, XWT and WTC help identify the common power and relative phase between two time-series records in time-frequency space, respectively. Statistically significant coherence and confidence levels against red noise (also known as brown noise or random walk noise) can be calculated. Taking the Huangtupo landslide (China) as an example, we demonstrate the capabilities of these tools for interpreting InSAR time-series information. The results show the Huangtupo slope is affected by an annual displacement periodicity controlled by rainfall and reservoir water level. Reservoir water level, which is completely regulated by the dam activity, is mainly in ‘anti-phase’ with natural rainfall, due to flood control in the Three Gorges Project. The seasonal displacements of the Huangtupo landslide is found to be ‘in-phase’ with respect to reservoir water level and the rainfall towards the front edge of the slope and to rainfall at the higher rear of the slope away from the reservoir.  相似文献   

Magnetite nanoplates decorated on anodized aluminum oxide nanofibers as a novel adsorbent for efficient removal of As(III)     

O. Moradlou  S. Dehghanpour Farashah  F. Masumian  A. Z. Banazadeh 《International Journal of Environmental Science and Technology》2016,13(4):1149-1158

In this study, arsenic as an environmental top-ranked hazardous substance was efficiently removed by a novel adsorbent fabricated by magnetite Fe₃O₄ nanoplates decorated on anodized aluminum oxide (AAO) nanofibers. AAO nanofibers were prepared by anodic polarization method, and then Fe₃O₄ nanoplates were grown on AAO-based substrate by hydrothermal method to fabricate AAO/Fe₃O₄ nanosorbent. Morphology of the fabricated adsorbents was characterized by field emission scanning electron microscopy (FE-SEM), and their crystallinity was studied by X-ray diffraction (XRD). Arsenic (III) removal potential of the proposed adsorbent from contaminated water samples was investigated by the determination of As(III) amounts in the samples by inductively coupled plasma optical emission spectroscopy before and after adsorption process at sub-μg L^?1 levels. The results showed that without pre- and post-treatments such as pH adjustment, As(III) was removed effectively from contaminated water samples by using the proposed adsorbent. AAO/Fe₃O₄ sorbent showed excellent ability to remove 0.1 mg L^?1 As(III) from water samples up to 96 % uptake. Freundlich adsorption isotherm model was used to interpret the As(III) adsorption on proposed sorbent. The Freundlich isotherm parameters n and k _F were obtained to be 2.2 and 10.2, respectively, representing the high affinity of proposed adsorbent for arsenic removal.  相似文献   

Development of attapulgite composite ceramsite/quartz sand double-layer biofilter for micropolluted drinking source water purification     

Z. Wang  M. G. Zhong  J. F. Wan  G. J. Xu  Y. Liu 《International Journal of Environmental Science and Technology》2016,13(3):825-834

This study compared start-up and steady-state affecting factors of attapulgite composite ceramsite/quartz sand double-layer biofilter (ACC/QSDLBF) and quartz sand single-layer biofilter (QSSLBF) on micropolluted drinking source water treatment. Results showed that the ACC has suitable pore size distribution in the range of 5–850 nm which is conducive to biofiltration. Turbidity removal efficiency of ACC/QSDLBF was a little lower than QSSLBF, but organic matters and ammonia removal efficiencies of ACC/QSDLBF were much higher than QSSLBF due to biodegradation and nitrification by microorganisms colonizing on the ACC. At stable state, the growth of head loss for ACC/QSDLBF was lower than that of QSSLBF. The complete filtration cycle of ACC/QSDLBF was 52 h. The total COD_Mn removal rate of ACC/QSDLBF was 20.93 %, in which 90 % of removed total COD_Mn was achieved at the upper 60 cm of ACC filter layer. The removal of COD_Mn decreased from 35.89 to 13.16 % in ACC/QSDLBF when increasing hydraulic loading from 2 to 16 m/h. After analysis of efficient EBCT in ACC/QSDLBF, optimized hydraulic loading was 12 m/h. These conclusions would be helpful to practical application of ACC as functional material for new construction of waterworks, especially upgrading of existing waterworks treating micropolluted drinking source water.  相似文献   

Comparison of different phases of bismuth silicate nanofibers for photodegradation of organic dyes     

S. S. Batool  S. Hassan  Z. Imran  K. Rasool  M. Ahmad  M. A. Rafiq 《International Journal of Environmental Science and Technology》2016,13(6):1497-1504

Two different phases of bismuth silicate nanofibers [Bi₂SiO₅ and Bi₄(SiO₄)₃] were synthesized using electrospinning technique. BS nanofibers were tested for the photocatalytic degradation of methyl orange and safranin O dyes. Different phases of BS affect the photodegradation efficiency of nanofibers. Impressive enhancement in photocatalytic efficiency and BET surface area of Bi₄(SiO₄)₃ was observed over Bi₂SiO₅. A speedy reduction in dyes concentration was attributed to the rapid formation of oxygenated radicals by the capture of electrons and holes, generated in the BS nanofiber by UV irradiation. Therefore, the photocatalytic mechanism was elucidated using impedance spectroscopy at room temperature. The lower impedance value of Bi₄(SiO₄)₃ nanofibers had improved high-efficiency charge transfer capability. The cycling efficiency (30 times) and recovery characteristics pointed out that Bi₄(SiO₄)₃ nanofibers photocatalysts had high constancy, resilience, and regeneration ability.  相似文献   

Application of ultrasound for degradation of benzophenone-3 in aqueous solutions     

H. Zúñiga-Benítez  J. Soltan  G. A. Peñuela 《International Journal of Environmental Science and Technology》2016,13(1):77-86

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Efficiency and kinetics in treatment of wastewater from garages and residential oil spills using membrane bioreactor technology     

M. C. Sichinga  J. Frazee  A. Z. Tong 《International Journal of Environmental Science and Technology》2016,13(1):135-146

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