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Boron isotopic fractionation in laboratory inorganic carbonate precipitation:Evidence for the incorpora-tion of B(OH)_3 into carbonate

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Science china Earth sciences 2008年第12期51卷 1776-1785页

作者： XIAO YingKai1,2, LI HuaLing1,3, LIU WeiGuo4, WANG XiuFang1 & JIANG ShaoYong5 1 Qinghai institute of Salt Lakes, chinese academy of sciences, Xining 810008, china 2 state key laboratory of environmental geochemistry, institute of geochemistry, chinese academy of sciences, guiyang 550002, china 3 Nanjing institute of Geology and Mineral Resources, Nanjing 210016, china 4 state key laboratory of Loess and Quaternary Geology, institute of Earth Environment, chinese academy of sciences, Xi’an 710075, china 5 state key laboratory for Mineral Deposits Research, Department of Earth sciences, Nanjing University, Nanjing 210093, china Qinghai institute of Salt Lakes Chinese Academy of Sciences Xining China state key laboratory of environmental geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang China Nanjing institute of Geology and Mineral Resources Nanjing China state key laboratory of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi’an China state key laboratory for Mineral Deposits Research Department of Earth Sciences Nanjing University Nanjing China

A laboratory inorganic carbonate precipitation experiment at high pH of 8.96 to 9.34 was conducted, and the boron isotopic fractionations of the precipitated carbonate were measured. The data show that boron isotopic fractionation factors (αcarb-3) between carbonate and B(OH)3 in seawater range 0.937 and 0.965, with an average value of 0.953. Our results together with those reported by Sanyal and collabo-rators show that the αcarb-3 values between carbonate and B(OH)3 in solution are not constant but are negatively correlated with the pH of seawater. The measured boron isotopic compositions of carbonate precipitation (δ11Bcarb) do not exactly lie on the best-fit theoretical δ 11B4-pH curves and neither do they exactly parallel any theoretical δ 11B4-pH curves. Therefore, it is reasonable to argue that a changeable proportion of B(OH)3 with pH of seawater should also be incorporated into carbonate except for the dominant incorporation of B(OH)4- in carbonate . Hence, in the reconstruction of the paleo-pH of sea-water from boron isotopes in marine biogenic carbonates, the use of theoretical boron isotopic frac-tionation factor (α4-3) between B(OH)4- and B(OH)3 is not suitable. Instead, an empirical equation should be established.

关键词： boron isotopic fractionation biogenic carbonate B(OH)3 incorporation

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Regulation mechanism of EM parameters in natural ferrite and its application in microwave absorbing materials

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Science china(Technological sciences) 2006年第1期49卷 38-49页

作者： ZHENG Yongchun1,2, WANG Shijie2, FENG Junming2, LI Chunlai1, OUYANG Ziyuan1,2, LIU Jianzhong1 & LI Xiaobiao2 1. National Astronomical Observatories, chinese academy of sciences, Beijing 100012, china 2. state key laboratory of environmental geochemistry, institute of geochemistry, chinese academy of sciences, guiyang 550002, china National Astronomical Observatories Chinese Academy of Sciences Beijing China state key laboratory of environmental geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang China

Electromagnetic (EM) parameters (ε ′, ε ″, μ ′, μ″ ) of several M2+Fe2O4 and Fe2O3 type natural ferrites with different geological occurrences are measured in this pa-per. The measurement results show that EM parameters of a magmatic-occurring natural ferrite is very different from other types occurring from sedimentary-metamorphic iron deposit, hydrothermal vein iron deposit, outer contact of magmatic iron deposit. It has potential to be used as magnetic absorbent in microwave absorbing materials. After min-eral separation and concentration, this magmatic-occurring natural ferrite was processed into type A ferrite absorbent. Type A natural ferrite absorbent is a kind of magnetic material with low dielectric constants, high magnetic conductivity and high EM loss. Its EM pa-rameters are ε ′ = 58.60, ε ″ = 10.0, μ ′ = 1.2-1.5, μ ″ = 1.0-1.2, respectively. In order to illuminate the regulation mechanism of EM parameters, we studied the chemical and mineral composition of type A ferrite absorbent. There is high concentration of natural impurities, which regulate the EM parameters of type A ferrite greatly. For comparison, the other types of natural ferrite, single-phase magnetite and two-phase iron minerals (ilmen-ite and magnetite), have few impurity. Thus regulation mechanism of EM parameters was absent in these ferrites. As a result, the regulation of EM parameters is advantageous to develop type A natural ferrite as excellent absorbent, lowers the reflectivity coefficients and enhances the absorbing efficiency of MAM made from it. Furthermore, the impurities in type A natural ferrite and its effects on EM parameters are very difficult to simulate in the synthesize ferrite. The carbonyl-iron powder is another kind of absorbent that is used ex-tensively in MAM. To compare the absorbing properties of these two absorbent, type A natural ferrite and carbonyl-iron powder were mixed with rubber and processed into mi-crowave absorbing sheets with the same procedures and tec

关键词： natural impure ferrite, complex permittivity, complex permeability, microwave absorbing materials.

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Stable carbon isotopic composition of soil organic carbon in karst area in Central Guizhou, china

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chinese Science Bulletin 1999年第S2期44卷 87-88页

作者： ZHENG Leping~(1,2), LI Tingyu~2, WAN Guojiang~2, WANG Shijie~2 and OUYANG Ziyuan~2 1. Department of environmental Science and Engineering, Shanghai University, Shanghai 200072, china 2. state key laboratory of environmental geochemistry, institute of geochemistry, chinese academy of sciences, guiyang 550002, china Department of environmental Science and Engineering Shanghai University Shanghai 200072 China state key laboratory of environmental geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China

THE stable carbon isotopic composition of soil organic carbon is a powerful tool for discussing the source ofsoil CO2 and the relationship of CO2 source and sink between soil CO2 and atmosphere CO2 and has beenwidely studied. However, few similar researches have been done in karst area which comprises 15%global terrestrial area. Preliminary research results about the stable carbon isotopic composition of soil organic carbon in karst area are reported here. In April and August 1998, the samples were collected continuously at 5-cm intervals from 0 to -45cm depth in meadow soil profile described by Zheng and located in the Hongfong Lake area in the central Guizhou Plateau which lies in the central East-Asia karst area. CO2 for δ13 C analysis was prepared

关键词： δ13C of soil organic carbon karst area Guizhou Province.

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Enrichment mechanism of gold during the process of lateritization in southern area of the Yuanmou ancient landmass, Yunnan, china

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chinese Science Bulletin 1999年第S2期44卷 90-91页

作者： SUN Chengxing~1, WANG Shijie~1, DAI Fusheng~2 and LUO Yi~2 1. state key laboratory of environmental geochemistry, institute of geochemistry, chinese academy of sciences, guiyang 550002, china 2. Department of Geology, Kunming University of Science and Technology, Kunming 650093, china state key laboratory of environmental geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China Department of Geology Kunming University of Science and Technology Kunming 650093 China

SINCE the first discovery of lateritic gold deposit which is easier to mining and dressing at Boddington inWestern Australia at the beginning of the 1980s, geologists have paid much attention to it, and it wasfound in tropical and subtropical regions. However, recently the metallogenetic mechanism has notbeen understood very well. In this note we reported some research results on the enrichment mechanism ofgold during the process of lateritization in the case of three lateritic profiles with some degree of gold enrichment located in southern area of the Yuanmou ancient landmass, Yunnan Province. The parent rocks of the investigated profiles （about 5-8 m thick） is metamorphic schist, in whichmean content of gold is 13.3×10-9. Samples were collected from two pits at Xujie （Mouding County）and an outcrop of gully at Menglingou （Yuanmou County）, dried in air and ground in agate mortar to

关键词： gold enrichment lateritizafion Yunnan.

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The seasonal and daily CO_2 concentration variance in karst meadow soil profile with depth in Central Guizhou, china

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chinese Science Bulletin 1999年第S2期44卷 93-94页

THE seasonal variance of soil CO2 concentration with depth in soil profile was widely studied. Few similarresearches on this topic have been done in karst area which comprises 15% global terrestrial area. In thisnote, the research results about the seasonal and daily soil CO2 concentration variance in karst area arereported. The soil gases were collected respectively by the sampling device at 200, 5,0, -5, -10,-15, -25, -35 and -45 cm from the land surface in meadow soil profile described by Zheng andlocated in the Hongfeng lake area in the central Guizhou Plateau which lies in the central East-Asia karstarea. Sampling time is in the morning, midday and at night in April, August and November, 1998 aswell as in January, 1999, respectively. Concentrations （volume percent） of CO2 in soil gas samples

关键词： soil CO2 concentration karst area Guizhou Province.

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Pollution of mercury in soil and some plants of guiyang City, china

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Acta Geochimica 2006年第S1期 240-241页

作者： Wei ZHENG1,2, Xinbin FENG1, Zhonggen LI1,2 1 state key laboratory of environmental geochemistry, institute of geochemistry, chinese academy of sciences, guiyang 550002, china 2 Graduate School of the chinese academy sciences, Beijing 100039, china

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Determination of Hg and MeHg complexation with dissolved organic matter by fluorescence quenching titration

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Acta Geochimica 2006年第S1期 264-265页

作者： Pingqing FU1, Fengchang WU1, Feiyue WANG2 1 state key laboratory of environmental geochemistry, institute of geochemistry, chinese academy of sciences, guiyang 550002, china 2 Department of Environment and Geography, and Department of Chemistry

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关于《贵州关岭“6.28”特大滑坡特征和成因机理》一文的商榷

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山地学报 2011年第2期29卷 254-256页

作者：张信宝中国科学院水利部成都山地灾害与环境研究所山地环境演变与调控重点实验室中国科学院地球化学研究所环境地球化学国家重点实验室

就滑坡组成和发生机制,与《贵州关岭'6.28'特大滑坡特征和成因机理》一文作者进行商榷。笔者认为'超压密岩土边坡失稳理论'可以较好的解释大寨滑坡-碎屑流灾害的突然发生。'上硬下软'坡体结构,是大寨滑坡发生的地质基础;强降雨快速入渗... 详细信息

就滑坡组成和发生机制,与《贵州关岭'6.28'特大滑坡特征和成因机理》一文作者进行商榷。笔者认为'超压密岩土边坡失稳理论'可以较好的解释大寨滑坡-碎屑流灾害的突然发生。'上硬下软'坡体结构,是大寨滑坡发生的地质基础;强降雨快速入渗,是导致岩层裂隙和大气突然贯通,负压立即消失,高陡坡体迅即失稳的诱因。

关键词：商榷关岭滑坡超压密岩土边坡失稳

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