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441.
Tatsuo Nozaki Katsuhiko Suzuki Gregory Ravizza Jun‐Ichi Kimura Qing Chang 《Geostandards and Geoanalytical Research》2012,36(2):131-148
A simple, rapid method for the determination of Re and Os concentrations and isotope compositions using isotope dilution multi‐collector inductively coupled plasma‐mass spectrometry (ID‐MC‐ICP‐MS) combined with Carius tube digestion and sparging introduction of Os was developed. For Os measurement, four channeltron ion counters to detect different Os isotopes were used simultaneously, which led to a drastic reduction in the measurement time. Rhenium isotopes were measured by means of eight Faraday cups with solution nebulisation and an ultrasonic membrane desolvator. The representative 188Os count rate of an Os standard solution containing 50 pg of total Os was approximately 110000–120000 cps at the onset of measurement; the Re intensity of our in‐house 10 pg g?1 standard solution reached 1820 V/μg g?1 with a sample uptake rate of 95–99 μl min?1. These values indicate that the sensitivity of the method was sufficient even for samples with low Re and Os concentrations, such as chert. As the temporal variations of the amplification efficiency of the ion counters differed from one another, we adopted a sample‐calibrator bracketing method to correct the measured Re and Os isotope ratios. The Re and Os concentrations via the isotope dilution method and the 187Os/188Os ratios of two sedimentary rock reference materials (JMS‐2 and JCh‐1) on the basis of the isotope ratios determined by the MC‐ICP‐MS and by negative thermal ionisation mass spectrometry (N‐TIMS) were comparable within their ranges. Based on Os isotope measurement of the IAG reference material [Durham Romil Os (DROsS)], the average difference from the recommended value and precision of Os isotope measurements by the sparging method in combination with multi‐ion‐counters were 0.72% and 0.76% [1RSD (%), n = 29], respectively. The precisions in the 187Os/188Os ratios [1RSD (%)] of JMS‐2, JCh‐1 and DROsS were 0.35–0.71, 1.56–3.31 and 0.99–1.28%, respectively, which depended on their Os ion intensities. No systematic difference was observed between the Re and Os geochemical compositions of JCh‐1 and JMS‐2 obtained by means of digestion with inverse aqua regia and CrO3‐H2SO4 solutions, suggesting that either acid solution can be used for the sparging method of sedimentary rock samples. As CrO3‐H2SO4 solution is believed to liberate predominantly the hydrogenous Re and Os fraction from organic‐rich sediment, the sparging method combined with CrO3‐H2SO4 digestion and multi‐ion‐counters in the mass spectrometry is expected to be a powerful tool for reconstructing the secular change in marine Os isotope compositions with high sample throughput. 相似文献
442.
Akio Suzuki 《Physics and Chemistry of Minerals》2010,37(3):153-157
An in situ synchrotron X-ray diffraction study was carried out on ε-FeOOH at room temperature up to a pressure of 8.6 GPa
using the energy-dispersive method. The linear compressibility was determined to be β
a
= 1.69(3) × 10−3 GPa−1, β
b
= 2.86(6) × 10−3 GPa−1, and β
c
= 1.73(5) × 10−3 GPa−1. The b-axis of the unit cell is more compressible than the a and c axes. The pressure–volume data were fitted to a third-order Birch–Murnaghan equation of state. The best fit was found using
a room temperature isothermal bulk modulus of K
0 = 126(3) GPa and its pressure derivative K′ = 10(1). 相似文献
443.
SUN Ge SUN Chunlin SUN Yuewu ZHANG Shuqin WU Wenhao YANG Tao LIANG Fei FENG Yuhui Markevich V Ashraf A R Bugdaeva E Tekleva M Suzuki S 《世界地质(英文版)》2021,24(4):189-197
The non-marine Cretaceous-Paleogene boundary ( KPgB) in Jiayin of Heilongjiang was first defined and reported in China by the authors' research team in 2011 . Thereafter the continuous research on the KPgB and its related Late Cretaceous biota in Jiayin has been made by the authors in 2012-2020 . The achievements of the research are mainly reflected as follows:(1) a new drilling borehole with 60 m in depth carried out in the Xiaoheyan of Jiayin in 2016 , supplemented new palynological evidence for the KPgB definition in 2011;( 2 ) some radiometric dating newly made on the strata related to the KPgB in Jiayin and its neighboring Russian area, provided the supplemental evidence for the KPgB definition in Jiayin;( 3 ) many new fossils found by the au-thors, represented by the angiosperms Dalembia and Nelumbo, refresh understanding the Late Cretaceous envi-ronment of Jiayin;and (4) the TEM method is applied in the study of pollen exine ultrastructure of Pseudoin-tegricorpus, Wodehouseia, and Aquilapollenites, promoting the late Maastrichtian ecological study in Jiayin, re-lated to the KPgB. 相似文献