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Identification of palaeocontinental affinities is important to place Moesia in the global context of palaeogeographical reconstructions. In the absence of palaeomagnetic data and relevant macrofauna, palynological data and especially chitinozoans represent an important tool, recently used to unravel palaeogeographical affinities. Chitinozoans from three main boreholes (Călăraşi 2881, Zăvoaia 2581 and Ţăndărei 1052) located in East Moesia have been studied. They indicate a predominant palaeogeographical affinity with northern Gondwana. 相似文献
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A. F. Tuck D. J. Donaldson M. H. Hitchman E. C. Richard H. Tervahattu V. Vaida J. C. Wilson 《Climatic change》2008,90(3):315-331
This paper is in response to the Editorial Essay by Crutzen and the Editorial Comment by Cicerone in the August 2006 issue
of Climatic Change. We reprise the evidence from atmospheric nuclear weapon testing in the 1950s and 1960s which is salient to the mooted maintenance
of an artificial sulphate aerosol layer in the lower stratosphere, including a hitherto and now posthumous unpublished analysis
of the 185W Hardtack data. We also review recent investigations by ourselves, which have considerable bearing on some relevant questions
concerning meteorological dynamics, aerosol chemistry and physics and the photodissociation of stratospheric sulphuric acid. 相似文献
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Thomas Meisel Nina Schöner Vaida Paliulionyte Elisabeth Kahr 《Geostandards and Geoanalytical Research》2002,26(1):53-61
Data are reported for rare earth elements (REE), Y, Th, Zr, Hf, Nb and Ta in four geological reference materials using sodium peroxide (Na2 O2 ) sintering and inductively coupled plasma-mass spectrometry. The described procedure was used by students during their thesis work. A compilation of their reference material data acquired over one year of laboratory work demonstrates the ease and reliability of the method and the high reproducibility of the analytical results. Relative standard deviations of up to thirty six measurements of one reference material were lower than 5% for Y and the REE. Reproduciblities of Zr, Hf, Nb, Ta and Th were higher at between 5% and 10%, and can be attributed to the inhomogeneous distribution of zircon and other trace mineral phases and uncorrected drift effects. The concentration data are compared to reference and literature values and demonstrate that the procedure is also accurate. New data on G-3 show some systematic deviations from G-2, which are statistically significant. 相似文献
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Vaida Paliulionyte Thomas Meisel Peter Ramminger Peter Kettisch 《Geostandards and Geoanalytical Research》2006,30(2):87-96
New concentration data for Ru, Rh, Pd, Re, Os, Ir and Pt are presented for three chromitite reference materials. A simple and very effective procedure was applied for the measurements. Samples were spiked with enriched isotopes and digested in a HNO3 /HCl (5+2) acid mixture at 300 °C and 125 bar (1.25 × 107 Pa) pressure in a high pressure asher (HPA-S, Anton Paar). The programme settings were changed as a function of mass (0.5, 1, 2 and 4 g) and time (5 and 15 hours). Complete chromitite dissolutions for three digestions at each setting were monitored using XRD analyses of the amorphous residue after digestion. The osmium concentration was determined by sparging the OsO4 that was formed during digestion into a quadrupole ICP-MS. After drying and re-dissolution of the remaining residue, the other PGEs were separated on-line from their matrix in a simple cation-exchange column that was coupled to the ICP-MS. The concentrations were determined through isotope dilution and external calibration (Rh). By using the on-line separation, we were able to control interference effects (isobaric and molecular), which resulted in highly reproducible data. Replicate measurements of the reference material CHR-Bkg (SARM CRPG-CNRS) with sample masses ranging from 0.5 to 4 g showed very small standard deviations compared to the results from the initial collaborative trials and published data (e.g., 3.2% RSD vs. 32% RSD for Ru). Results for platinum showed the largest scatter, which is currently attributed to the small size of the test portion. In addition to CHR-Bkg, the first results for two chromitite reference materials "platinumore" GAN Pt-1 and "chromiumore" HHH issued by the Central Geological Laboratory of Mongolia are presented. 相似文献
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Synthesis of PGE sulfide standards for laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) 总被引：1，自引：0，他引：1
Cora C. Wohlgemuth-Ueberwasser Chris Ballhaus Jasper Berndt Vaida Stotter née Paliulionyte Thomas Meisel 《Contributions to Mineralogy and Petrology》2007,154(5):607-617
Sulfide compositions with known Re, Os, Ir, Ru, Rh, Pt, and Pd contents are synthesized to be used as standards for noble
metal analysis in solid solution in sulfides. Major elements were added as metals and elemental S. The noble metals, i.e.
35 and 60 ppm each, were added as solutions by micro syringe. Following synthesis at 1 atm the sulfides were sintered at 1.5
to 2 GPa to obtain pellets with theoretical density. Aliquots of the pellets were analysed by isotope dilution ICP-MS for
bulk Re and platinum-group elements (PGE). The spatial noble metal distribution was investigated with an ArF excimer laser
coupled to a single collector ICP mass spectrometer. Sample homogeneity is shown to depend on the metal/S spectrum and the
major element composition of the sulfide, as well as on more subtle factors like oxygen partial pressure during synthesis,
run temperature, and degree of partial melting. The most homogeneous sulfide composition is a (Fe,Ni)1 − x
S monosulfide with 5 wt % Ni and 1-sigma variations in 34S-normalized noble metal count rates of <3.6%. Nearly as homogeneous is a pure Fe1 − x
S monosulfide with 1-sigma variations in 34S-normalized noble metal count rates of <5.8 %. A Cu-bearing Fe1 − x
S monosulfide with 2 wt % Cu was found to be considerably more heterogeneous, suggesting that Cu in solid solution in monosulfides
promotes noble metal heterogeneity. The sulfide composition least suitable for the synthesis of noble metal sulfide standards
is NiS. 相似文献
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Little is known concerning climate changes in the Eastern Baltic region during the last interglacial–glacial cycle and in particular, climate changes during the Weichselian. In this study, a quantitative reconstruction of the mean January and July temperature for the Medininkai-117 site in Lithuania is presented. The reconstruction is based on pollen and plant macrofossils from this site, which reveal that the vegetation was characteristic of many northern Europe sites during the Eemian and Early Weichselian. Gradual evolution of the vegetation suggests that relatively uniform climate conditions existed during the Eemian. Our reconstructions support the view of a relatively stable Eemian, with short cooling phases of low amplitude. A strong increase in temperature was apparent during the beginning of the interglacial and decrease during the transition to the Weichselian. Reconstructed July temperatures of the Eemian interglacial were approximately 2 °C higher than today (18.5 °C; today: 16.2 °C) and were similar to today for January (− 5.2 °C; today: − 5.1 °C). July temperatures during the Early Weichselian were only ~ 2°C lower than during the Eemian, whereas the January temperatures gradually decreased. Winter temperatures were relatively high (above − 10 °C) during the Early Weichselian. 相似文献
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