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981.
Sorption edges and isotherms for Eu(III) uptake on Ca-montmorillonite and Na-illite in 0.066 mol/L Ca(ClO4)2 and 0.1 mol/L NaClO4 background electrolytes, respectively, were modelled using a quasi-mechanistic sorption model (the two site protolysis non electrostatic surface complexation and cation exchange (2SPNE SC/CE) model). For both clay minerals the Eu sorption edges could be quantitatively modelled in the pH range ∼3 to ∼10 using cation exchange reactions for Eu3+/Na+ and Eu3+/Ca2+ and three surface complexation reactions on the strong sorption sites forming ≡SSOEu2+, ≡SSOEuOH+ and ≡SSOEu(OH)2° inner sphere complexes which appear successively with increasing pH. Time resolved laser fluorescence spectroscopy (TRLFS) measurements of Cm(III) loaded Ca-montmorillonite and Na-illite were available from Part 1 of this work. De-convolution of the normalised fluorescence spectra measured at different pH values indicated three distinct Cm surface complexes, Cm complexes 1, 2 and 3 for both clay minerals, in agreement with model predictions, but with different distribution functions for the individual species. Under the assumption that Eu and Cm exhibit essentially the same hydrolysis and sorption behaviour, the Eu surface complexation constants were used to predict surface species distribution functions for Cm under the same experimental conditions used in the TRLFS measurements. Comparison of modelled and experimentally deduced species distributions indicated that for both clay minerals peak heights and widths of the three peaks did not correspond particularly well. It is shown that the calculated species distribution functions are sensitive to the values of the hydrolysis constants used in the calculations, whereas modelling the sorption edge measurements by applying the 2SPNE SC/CE approach is much less sensitive. By modifying the values of the hydrolysis constants within their uncertainty range and re-modelling the sorption edges, considerably better correspondence between the modelled and TRLFS species distribution functions was found. In particular, peak positions, heights and widths for the model predicted peaks for the ≡SSOCm2+ and ≡SSOCmOH+ species distribution, and those for Cm complexes 1 and 2 derived from TRLFS, were found to be very close for both clay minerals. However, discrepancies were still apparent between the profile for the calculated ≡SSOEu(OH)2° surface species and the Cm complex 3 species, especially in the case of Na-illite. 相似文献
982.
Samantha B. Joye 《Geochimica et cosmochimica acta》2005,69(23):5633
983.
Caledonian high-pressure metamorphism in the Strona-Ceneri Zone (Southern Alps of southern Switzerland and northern Italy) 总被引:3,自引:0,他引:3
The Strona-Ceneri Zone comprises a succession of polymetamorphic, pre-Alpidic basement rocks including ortho- and paragneisses,
metasedimentary schists, amphibolites, and eclogites. The rock pile represents a Late Proterozoic or Palaeozoic subduction
accretion complex that was intruded by Ordovician granitoids. Eclogites, which occur as lenses within the ortho-paragneiss
succession and as xenoliths within the granitoids record a subduction related high-pressure event (D1) with peak metamorphic
conditions of 710 ± 30 °C at 21.0 ± 2.5 kbar. After isothermal uplift, the eclogites experienced a Barrowtype (D2) tectonometamorphic
overprint under amphibolite facies conditions (570-630 °C, 7-9 kbar). U-Pb dating on zircon of the eclogites gives a metamorphic
age of 457 ± 5 Ma, and syn-eclogite facies rutile gives a 206Pb/238U age of 443 ± 19 Ma classifying the subduction as a Caledonian event. These data show that the main tectonometamorphic evolution
of the Strona-Ceneri Zone most probably took place in a convergent margin scenario, in which accretion, eclogitization of
MOR-basalt, polyphase (D1 and D2) deformation, anatexis and magmatism all occurred during the Ordovician. Caledonian high-pressure
metamorphism, subsequent magmatism and Barrow-type metamorphism are believed to be related to subduction and collision within
the northern margin of Gondwana.
Editorial handling: Edwin Gnos 相似文献
984.
W. Bae D. Han E. Kim R. A. de Toledo K. Kwon H. Shim 《International Journal of Environmental Science and Technology》2016,13(7):1675-1684
The upflow anaerobic sludge blanket process followed by the biological aerated filter process was employed to improve the removal of color and recalcitrant compounds from real dyeing wastewater. The highest removal efficiency for color was observed in the anaerobic process, at 8-h hydraulic retention time, seeded with the sludge granule. In the subsequent aerobic process packed with the microbe-immobilized polyethylene glycol media, the removal efficiency for chemical oxygen demand increased significantly to 75 %, regardless of the empty bed contact time. The average influent non-biodegradable soluble chemical oxygen demand was 517 mg/L, and the average concentration in effluent from the anaerobic reactor was 363 mg/L, suggesting the removal of some recalcitrant matters together with the degradable ones. The average non-biodegradable soluble chemical oxygen demand in effluent from the aerobic reactor was 87, 93, and 118 mg/L, with the removal efficiency of 76, 74, and 67 %, at 24-, 12-, and 8-h empty bed contact time, respectively. The combined anaerobic sludge blanket and aerobic cell-entrapped process was effective to remove the refractory compounds from real dyeing wastewater as well as in reducing organic loading to meet the effluent discharge limits. This integrated process is considered an effective and economical treatment technology for dyeing wastewater. 相似文献
985.
V. O. Davydova V. D. Shcherbakov P. Yu. Plechov 《Moscow University Geology Bulletin》2018,73(5):444-450
Intrusion of magma of contrasting composition into a magma chamber often triggers eruptions of arc volcanoes. Application of the diffusion chronometry method allowed us to determine the time when fresh magma was supplied to the shallow chamber of Bezymianny volcano in the case of six eruptions in 2006–2012 and to compare them to the recorded seismic activity of this volcano. Two types of eruptions of Bezymianny volcano were distinguished, with a contrasting orthopyroxene rim being formed in the respective magmas (a) up to 3 years and (b) up to 2 months before the beginning of an eruption. It was shown that these differences are caused by two different paths of magma supply to the shallow chamber of Bezymianny volcano. 相似文献
986.
The pre-Mesozoic, mainly Variscan metamorphic basement of the Col de Bérard area (Aiguilles Rouges Massif, External domain)
consists of paragneisses and micaschists together with various orthogneisses and metabasites. Monazite in metapelites was
analysed by the electron microprobe (EMPA-CHIME) age dating method. The monazites in garnet micaschists are dominantly of
Variscan age (330–300 Ma). Garnet in these rocks displays well developed growth zonations in Fe–Mg–Ca–Mn and crystallized
at maximal temperatures of 670°C/7 kbar to the west and 600°C/7–8 kbar to the east. In consequence the monazite is interpreted
to date a slightly pressure-dominated Variscan amphibolite-facies evolution. In mylonitic garnet gneisses, large metamorphic
monazite grains of Ordovician–Silurian (~440 Ma) age but also small monazite grains of Variscan (~300 Ma) age were discovered.
Garnets in the mylonitic garnet gneisses display high-temperature homogenized Mg-rich profiles in their cores and crystallized
near to ~800°C/6 kbar. The Ordovician–Silurian-age monazites can be assigned to a pre-Variscan high-temperature event recorded
by the homogenised garnets. These monazite age data confirm Ordovician–Silurian and Devonian–Carboniferous metamorphic cycles
which were already reported from other Alpine domains and further regions in the internal Variscides. 相似文献
987.
Zoning of diamonds from the Mir kimberlite pipe: Results of Fourier-transformed infrared spectroscopy 总被引:1,自引:0,他引:1
Plates prepared of diamonds from the Mir kimberlite pipe were examined with FTIR spectroscopy. It is shown that B1 defects were formed by annealing during crystal growth, whereas B2 centers arose after growth cessation. The development of B2 centers in a natural diamond is the secondary process with respect to the aggregation of the nitrogen admixture. The kinetics of this process is related to the breakdown of an oversaturated solid solution. The results obtained make it possible to estimate the temperature and duration of natural diamond growth. 相似文献
988.
A. Iu. Iurchenko N. Takahata K. Tanaka Y. Sano N. S. Balushkina G. A. Kalmykov 《Moscow University Geology Bulletin》2016,71(6):466-471
Dispersed and concretionary pyrite in chert–clay–carbonate and carbonate rocks of the Abalak Formation (Salym oil field) have been studied. The study was conducted using Scanning Electron Microscopy (SEM), Electron Probe Microanalysis (EPMA), and high spatial resolution Secondary Ion Mass Spectrometry (Nano-SIMS). As a result, three morphological groups of pyrite have been distinguished: large cubic crystals, framboidal pyrite, and fine-crystal aggregates that replace organic remnants. The sulphur isotope ratio allows one to distinguish two genetic types of pyrite. The source of the sulphur for the first genetic group was H2S produced by bacterial sulphate reduction, while the second group pyrite was formed with sulphur as a product of thermochemical sulphate reduction. 相似文献
989.
N. A. Ekimova P. A. Serov T. B. Bayanova I. R. Elizarova F. P. Mitrofanov 《Doklady Earth Sciences》2011,436(1):28-31
This paper presents data on the distribution of REEs in sulfide minerals from ore-bearing gabbronorites in the Penikat layered
intrusion and the results of their isotopic-geochronological Sm-Nd study. A new procedure for determination of REEs in the
samples without preliminary separating and concentrating was tested on standard samples to be further used for analysis of
sulfide minerals. Analysis of the spectra of the REE distribution in sulfides represents a distribution trend that is similar
to the already studied bulk rock and allows deducing that the character of the REE distribution in sulfide minerals from gabbronorites
in the Penikat layered intrusion was inherited from the parent magma melt; while the formation of sulfides took place at the
stage of rock crystallization. The performed complex studies allow considering that sulfides can be successfully used together
with the rock-forming minerals in Sm-Nd dating of ore-bearing mafite-ultramafite intrusions. 相似文献
990.
A. B. Kotov A. A. Sorokin E. B. Sal’nikova A. P. Sorokin A. M. Larin S. D. Velikoslavinskii T. V. Belyakov I. V. Anisimova S. Z. Yakovleva 《Doklady Earth Sciences》2009,429(2):1457-1461
U-Pb geochronological results confirm the Mesozoic age (124 ± 1 Ma) of the Beket granitoid complex, previously interpreted
as being one of the markers amongst the Early Proterozoic magmatic complexes within the Amur superterrane (microcontinent)
of the Central Asian Fold Belt. This implies that the structural and metamorphic amphibolite facies overprints documented
either in the Beket granitoids or Gonzha host rocks are evidently Mesozoic rather than Early Proterozoic in age. 相似文献