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Re-Os isotopic system and formation age of subcontinental lithosphere mantle

Chinese Science Bulletin 2000年第3期45卷 193-200页

作者： ZHI XiachenDepartment of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China Advance Research Center for Earth Science and Astronomy, ustc, Third World Academy of Science, Hefei 230026, China laboratory of chemical geodynamics, ustc, Hefei 230026, China Department of Earth and Space Sciences University of Science and Technology of China Hefei China Advance Research Center for Earth Science and Astronomy USTC Third World Academy of Science Hefei China laboratory of chemical geodynamics USTC Hefei China

The determination of the formation age of subcontinental Lithosphere Mantle (SCLM) is a widely concerned issue in mantle geochemistry. it is difficult to obtain the formation age of SCLM using lithophile isotopic systems such as Rb-Sr, Sm-Nd, U-Th-Pb, ete., but as siderophile elements, the Re-Os isotopic system provides a powerful tool for that work. Here a comprehensive review on the recent development in Re-Os dating for SCLM has been given.

关键词： Re-Os isotopic dating subcontinental lithospheric mantle mantle derived peridotites Re depleted model age whole rock isochronological age.

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Oxidation Experiment of Natural Megacrystal Ch'nopyroxene: Implications for Assignment of Mossbauer Spectra

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Acta Geologica Sinica(English Edition) 2001年第1期 51-58页

作者： ZHI Xiachen, CHEN PengDepartment of Earth and Space Sciences, University of Science and Technology of China laboratory of chemical geodynamics, ustc Advanced Research Center for Earth Science and Astronomy in ustc, Third World Academy of Science, Hefei 230026 LIN Chengzhong, CHEN Shuqing, ZHANG GuilanInstitute of Mineral Resources, Chinese Academy of Geology Sciences, Beijing 100037LI Yuzhi and LIN Lei Open laboratory of Structure Analysis, ustc, Hefei 230026

The Mossbauer spectra of natural megacrystal clinopyroxene are usually fitted by 4 sets of symmetric doublets, A-A', B-B', C-C' and D-D', respectively, in terms of increasing Qs value in literature. But the assignments of those doublets are quite different, except the D-D' doublet assigned to Fe3+ at the lattice site Ml in previous papers. Particularly, the assignment and interpretation of the C-C' doublet are *** oxidation experiments of natural megacrystal clinopyroxene collected from the Hannuoba basalt, North China, were performed under controlled conditions of temperature at 1000℃ and oxygen fugacity of FMQ buffer in 1, 2, 3 and 5 days respectively. The oxidized samples were then measured by X-ray diffraction spectrometry and Mossbauer spectrometry. The oxidation of clinopyroxene is characterized by Fe2+→ Fe3+ at Ml under the subsolidus conditions, which is consistent with the increase of the area of the D-D' doublet when the heating time increases. Accordingly, the area of the A-A' and B

关键词： megacrystal clinopyroxene Mossbauer spectrum oxidation experiment anomalous doublet

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Re-Os isotopic composition of the Dongling ⅢCD iron meteorite

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Chinese Science Bulletin 2001年第6期46卷 518-520页

作者： SUN Weidong, DU Andao, YANG Gang, XIE Zhi & CHEN JiangfengDeparlmenl of Earth and Space Sciences, laboratory tor chemical geodynamics. University of Science and Technology of China, Hefei 230026. China:Institute of Rock and Mineral Analysis, Chinese Academy of Geological Sciences. Beijing 100037, China Department of Earth and Space Sciences Laboratory for Chemical Geodynamics University of Science and Technology of China Hefei China Institute of Rock and Mineral Analysis Chinese Academy of Geological Sciences Beijing China

Re, Os concentrations and Os isotopic compositions of the Dongling ⅢCD iron meteorite were determined by N-TIMS technique. The result was compared with that of the other irons and chondrites. The Re and Os concentrations of the Dongling iron meteorite were plotted on the trends of the group ⅢA and ⅣA irons. The Pt-Os relation of the Dongling iron meteorite is similar to that of the group ⅡA irons. That suggests a higher fractionation for the Dongling iron meteorite.

关键词： Dongling iron meteorite Re-Os isotopes N-TIMS.

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^(13)C NMR spectra of tectonic coals and the effects of stress on structural components

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Science China Earth Sciences 2005年第9期48卷 1418-1437页

作者： JU Yiwen1,2, JIANG Bo1, HOU Quanlin2, WANG Guiliang1 & NI Shanqin2 1. College of Mineral Resource and Geosciences, China University of Mining and Technology, Xuzhou 221008, China 2. laboratory of Computational geodynamics, College of Geosciences, Graduate School of Chinese Academy of Sciences, Beijing 100049, China College of Mineral Resource and Geosciences China University of Mining and Technology Xuzhou China laboratory of Computational geodynamics College of Geosciences Graduate School of Chinese Academy of Sciences Beijing China

High-resolution 13C Nuclear Magnetic Resonance (NMR) spectra of different kinds of tectonic coals were obtained using the NMR (CP/MAS+TOSS) method. On the basis of this, after simulation synthesis and division of spectra, the relative contents of carbon functional groups were calculated. Combined with results of Ro, max, XRD testing and element analysis, stress effects on the composition of macromolecular structures in tectonic coals were studied further. The results showed that Ro, max was not only the important index for describing coal rank, but was also effective for estimating the stress effect of tectonic coals. Under tectonic stress ac- tion, Ro, max was the most direct indicator of the coal structure and chemical components. Changes in the stacking Lc of the coal basic structure unit (BSU) and La/Lc parameters could distinguish the temperature and stress effects on metamorphic-deformed environments, and re- flected the degree of structural deformation. Therefore, on the whole, Lc and La/Lc can be used to index of the degree of structural deformation of tectonic coals. In different metamorphic and de- formed environments, different kinds of tectonic coals are formed under structural stress. The changes in characteristics of the macromolecular structure and chemical composition are such that as the increase in structural deformation becomes stronger, from the brittle deformation coal to ductile deformation coal, the ratio of width at the half height of the aromatic carbon and ali- phatic carbon peaks (Hfa/Hfal ) was increased. As carbon aromaticity was raised further, carbon aliphaticity reduced obviously and different compositions of macromolecular structure appeared as a jump and wave pattern except for in wrinkle structure coal, which might result chiefly from stress effects on the macromolecular structure of different kinds of tectonic coals. The macro- moecular changes of wrinkle structure coal are reflected mainly on physical structure. In the metamorphi

关键词： tectonic coal, NMR, macromolecular structure, chemical component, stress effect.

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