共查询到20条相似文献，搜索用时 31 毫秒
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Yue‐Heng Yang Ming Yang Klaus Peter Jochum Shi‐Tou Wu Han Zhao Lie‐Wen Xie Chao Huang Xiu‐Chun Zhan Jin‐Hui Yang Fu‐Yuan Wu 《Geostandards and Geoanalytical Research》2020,44(3):567-579
To assess the homogeneity of and provide the first Sr‐Nd‐Hf‐Pb isotopic reference values for the Chinese Geological Standard Glasses CGSG‐1, CGSG‐2, CGSG‐4 and CGSG‐5, we measured these isotopes in several measurement sessions over the course of nearly 3 years. The results were obtained by high‐precision MC‐ICP‐MS and TIMS. Our investigation indicates that these CGSG glass reference materials are homogenous with regard to Sr‐Nd‐Hf‐Pb isotopic distribution and are therefore suitable geochemical materials for Sr‐Nd‐Hf‐Pb isotope measurements. Clear differences in Sr‐Nd‐Hf‐Pb isotopic composition were observed between the glasses and the original powdered rock reference materials (CGSG‐2 and GSR‐7, and especially CGSG‐5 and GSR‐2) because of flux addition during preparation of the glasses. The new Sr‐Nd‐Hf‐Pb isotope data provided here might be useful to the geochemical community for in situ and bulk analysis. 相似文献
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High‐Precision Mass‐Dependent Molybdenum Isotope Variations in Magmatic Rocks Determined by Double‐Spike MC‐ICP‐MS 
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下载免费PDF全文 Matthias Willbold Kate Hibbert Yi‐Jen Lai Heye Freymuth Remco C. Hin Christopher Coath Flurin Vils Tim Elliott 《Geostandards and Geoanalytical Research》2016,40(3):389-403
Small mass‐dependent variations of molybdenum isotope ratios in oceanic and island arc rocks are expected as a result of recycling altered oceanic crust and sediments into the mantle at convergent plate margins over geological timescales. However, the determination of molybdenum isotope data precise and accurate enough to identify these subtle isotopic differences remains challenging. Large sample sizes – in excess of 200 mg – need to be chemically processed to isolate enough molybdenum in order to allow sufficiently high‐precision isotope analyses using double‐spike MC‐ICP‐MS techniques. Established methods are either unable to process such large amounts of silicate material or require several distinct chemical processing steps, making the analyses very time‐consuming. Here, we present a new and efficient single‐pass chromatographic exchange technique for the chemical isolation of molybdenum from silicate and metal matrices. To test our new method, we analysed USGS reference materials BHVO‐2 and BIR‐1. Our new data are consistent with those derived from more involved and time‐consuming methods for these two reference materials previously published. We also provide the first molybdenum isotope data for USGS reference materials AGV‐2, the GSJ reference material JB‐2 as well as metal NIST SRM 361. 相似文献
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The creatures that gaze back at us through the binocular microscope are so uniquely well‐preserved and life‐like that had we not known better we would have thought that they were modern. Instead they are half‐a‐billion‐year‐old arthropods extracted from Cambrian rocks of Sweden. The microscopic fossils, colloquially known as the ‘Orsten’ fossils, are now world‐famous and basking in the light of the research catwalk since their discovery in the 1970s. These fossils have provided significant insight into the long lost Cambrian biotas and early animal evolution. 相似文献
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Yue‐Heng Yang Fu‐Yuan Wu Qiu‐Li Li Yamirka Rojas‐Agramonte Jin‐Hui Yang Yang Li Qian Ma Lie‐Wen Xie Chao Huang Hong‐Rui Fan Zi‐Fu Zhao Cheng Xu 《Geostandards and Geoanalytical Research》2019,43(4):543-565
Bastnäsite is the end member of a large group of carbonate–fluoride minerals with the common formula (REE) CO3F·CaCO3. This group is generally widespread and, despite never occurring in large quantities, represents the major economic light rare earth element (LREE) mineral in deposits related to carbonatite and alkaline intrusions. Since bastnäsite is easily altered and commonly contains inclusions of earlier‐crystallised minerals, in situ analysis is considered the most suitable method to measure its U‐Th‐Pb and Sr‐Nd isotopic compositions. Electron probe microanalysis and laser ablation (multi‐collector) inductively coupled plasma‐mass spectrometry of forty‐six bastnäsite samples from LREE deposits in China, Pakistan, Sweden, Mongolia, USA, Malawi and Madagascar indicate that this mineral typically has high Th and LREE and moderate U and Sr contents. Analysis of an in‐house bastnäsite reference material (K‐9) demonstrated that precise and accurate U‐Th‐Pb ages could be obtained after common Pb correction. Moreover, the Th‐Pb age with its high precision is preferable to the U‐Pb age because most bastnäsites have relatively high Th rather than U contents. These results will have significant implications for understanding the genesis of endogenous ore deposits and formation processes related to metallogenic geochronology research. 相似文献
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High‐Precision Iron Isotope Analysis of Geological Reference Materials by High‐Resolution MC‐ICP‐MS 下载免费PDF全文
下载免费PDF全文 Yongsheng He Shan Ke Fang‐Zhen Teng Tiantian Wang Hongjie Wu Yinhuai Lu Shuguang Li 《Geostandards and Geoanalytical Research》2015,39(3):341-356
We report high‐precision iron isotopic data for twenty‐two commercially available geological reference materials, including silicates, carbonatite, shale, carbonate and clay. Accuracy was checked by analyses of synthetic solutions with known Fe isotopic compositions but different matrices ranging from felsic to ultramafic igneous rocks, high Ca and low Fe limestone, to samples enriched in transition group elements (e.g., Cu, Co and Ni). Analyses over a 2‐year period of these synthetic samples and pure Fe solutions that were processed through the whole chemistry procedure yielded an average δ56Fe value of ?0.001 ± 0.025‰ (2s, n = 74), identical to the expected true value of 0. This demonstrates a long‐term reproducibility and accuracy of < 0.03‰ for determination of 56Fe/54Fe ratios. Reproducibility and accuracy were further confirmed by replicate measurements of the twenty‐two RMs, which yielded results that perfectly match the mean values of published data within quoted uncertainties. New recommended values and associated uncertainties are presented for interlaboratory calibration in the future. 相似文献
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Jason Jweda Louise Bolge Cornelia Class Steven L. Goldstein 《Geostandards and Geoanalytical Research》2016,40(1):101-115
The Lamont‐Doherty Earth Observatory radiogenic isotope group has been systematically measuring Sr‐Nd‐Pb‐Hf isotopes of USGS reference material BCR‐2 (Columbia River Basalt 2), as a chemical processing and instrumental quality control monitor for isotopic measurements. BCR‐2 is now a widely used geochemical inter‐laboratory reference material (RM), with its predecessor BCR‐1 no longer available. Recognising that precise and accurate data on RMs is important for ensuring analytical quality and for comparing data between different laboratories, we present a compilation of multiple digestions and analyses made on BCR‐2 during the first author's dissertation research. The best estimates of Sr, Nd and Hf isotope ratios and measurement reproducibilities, after filtering at the 2s level for outliers, were 87Sr/86Sr = 0.705000 ± 11 (2s, 16 ppm, n = 21, sixteen digestions, one outlier), 143Nd/144Nd = 0.512637 ± 13 (2s, 25 ppm, n = 27, thirteen digestions, one outlier) and 176Hf/177Hf = 0.282866 ± 11 (2s, 39 ppm, n = 25, thirteen digestions, no outliers). Mean Nd and Hf values were within error of those reported by Weis et al. (2006, 2007) in their studies of RMs; mean Sr values were just outside the 2s uncertainty range of both laboratories. Moreover, a survey of published Sr‐Nd‐Hf data shows that our results fall within the range of reported values, but with a smaller variability. Our Pb isotope results on acid leached BCR‐2 aliquots (n = 26, twelve digestions, two outliers) were 206Pb/204Pb = 18.8029 ± 10 (2s, 55 ppm), 207Pb/204Pb = 15.6239 ± 8 (2s, 52 ppm), 208Pb/204Pb = 38.8287 ± 25 (2s, 63 ppm). We confirm that unleached BCR‐2 powder is contaminated with Pb, and that sufficient leaching prior to digestion is required to achieve accurate values for the uncontaminated Pb isotopic compositions. 相似文献
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Liam Courtney‐Davies Sarah E. Gilbert Cristiana L. Ciobanu Simon R. Tapster Marcus W. Richardson Nigel J. Cook Benjamin P. Wade Max R. Verdugo‐Ihl Kathy Ehrig Daniel J. Condon 《Geostandards and Geoanalytical Research》2021,45(1):143-159
In both nature and synthetic experiments, the common iron oxide haematite (α‐Fe2O3) can incorporate significant amounts of U into its crystal structure and retain radiogenic Pb over geological time. Haematite is a ubiquitous component of many ore deposit types and, therefore, represents a valuable hydrothermal mineral geochronometer, allowing direct constraints to be placed on the timing of ore formation and upgrading. However, to date, no suitable natural haematite reference material has been identified. Here, a synthetic haematite U‐Pb reference material (MR‐HFO) is characterised using LA‐ICP‐MS and ID‐TIMS. Centimetre‐scale ‘chips’ of synthesised α‐Fe2O3 were randomly microsampled via laser ablation‐extraction and analysed using ID‐TIMS. Reproducible U/Pb and Pb/Pb measurements were obtained across four separate chips (n = 13). Subsequently, an evaluation of the suitability MR‐HFO in constraining U‐Pb data via LA‐ICP‐MS is presented using a selection of natural samples ranging from Cenozoic to Proterozoic in age. The MR‐HFO normalised U‐Pb ratios are more concordant and ages more accurate versus the same LA‐ICP‐MS spot analyses normalised to zircon reference material, when compared with independently acquired ID‐TIMS data from the same natural haematite grains. Results establish MR‐HFO as a suitable reference material for LA‐ICP‐MS haematite U‐Pb geochronology. 相似文献
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Yimin Wang Xiaohong Wang Wenjun Qu Yushu Gao Tiexin Gu Xingtao Fan S.I. Andreev Xuefa Shi 《Geostandards and Geoanalytical Research》2011,35(3):341-352
Two Co‐rich seamount crust reference materials, MCPt‐1 and MCPt‐2, were prepared using ultra‐fine particle size milling technique and characterised for the platinum‐group elements (PGEs). The raw material for these two reference materials was collected separately from the Magellan seamounts of the western Pacific Ocean and the seamounts of the central Pacific Ocean by Russian and Chinese scientists. First, they were ground by ball mill to a ?200 mesh powder, then further processed by ultra‐fine jet mill and well‐mixed. The particle size distributions of the samples were tested by a laser particle analyser; the average particle size was 1.8 and 1.5 μm (equal to about 2000 mesh) respectively. The homogeneity of six major and minor elements in these two materials was tested at the milligram level of sampling mass by high‐precision wavelength dispersive X‐ray fluorescence (XRF) spectrometry and at the microgram level of sampling mass by electron probe microanalyser. The homogeneity of more than forty trace elements, including Pt, was tested at the microgram level of sampling mass by LA‐ICP‐MS. Except for Rh, all PGEs were determined by isotope dilution‐ICP‐MS. Platinum in MCPt‐1 and MCPt‐2 was characterised as certified values, whereas the other five PGEs in MCPt‐1 and MCPt‐2 were reported as reference values. In addition, the information values of sixty‐two major, minor and trace elements were obtained by XRF, ICP‐AES and ICP‐MS. The minimum sampling mass for the determination of PGEs was 1 g, while the minimum sampling mass for the determination of the other elements was 2–5 mg. 相似文献
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Accurate and Precise Silicon Isotope Analysis of Sulfur‐ and Iron‐Rich Samples by MC‐ICP‐MS 下载免费PDF全文
下载免费PDF全文 Xinyang Chen Thomas J. Lapen Henry S. Chafetz 《Geostandards and Geoanalytical Research》2017,41(3):427-435
Silicon isotope determination of sulfur‐rich samples by MC‐ICP‐MS can be challenging because cation‐exchange chromatography used for Si purification does not efficiently remove anionic sulfur species. Results for pure Si standard solutions with addition of sulfate showed shifts of up to +1.04 ± 0.10‰ (2s) in δ30Si. Doping of both standard solutions and samples with S to a fixed S/Si ratio can eliminate the relative change in instrumental mass fractionation due to variable S/Si in samples and also boosts the relative sensitivity of Si by up to 66%. Moreover, Fe hydroxide precipitation during sample processing adsorbs Si resulting in isotopic fractionations. Tests using Fe‐rich samples showed that this could be a major factor for observed shifts in δ30Si. Acidification of the sample and standard solutions to a pH < 1 aggressively dissolved any Fe hydroxide precipitates, even in relatively Fe‐rich samples such as chondrite meteorites. The pH values of the sample solutions were subsequently adjusted to a range of 2–3 by adding ultra‐pure NaOH solutions. The combination of sulfur doping and the pH adjustment protocol ensured a full recovery of Si and proved to be an efficient and reliable method for Si isotope determination of S‐ and Fe‐rich materials. 相似文献
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舒德干 《《地质学报》英文版》2018,92(2):II-II
正Dear Authors and Readers:First of all,on behalf of the new Editorial Board,I would like to express our sincere appreciation for your continuing support of our journal.This journal,founded in 1922,is the oldest geological journal in China.As the flagslhip journal of the Geological Society of China,it has become more and nmore influcntial in earth scicences in China and beyond.The journal is now indexed by SCI,CA and more than 20 other databases,with an impact factor varying between 1.58 and 2.15 from year to year.It is co-publishd by the Gcoloigical Society of 相似文献