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Mantle-genetic tremolite in metamorphic peridotite from Kuda, China

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Chinese Science Bulletin 1996年第18期41卷 1538-1541页

作者：沈步明周云生邓万明韩秀伶张汝藩 Institute of Geology Chinese Academy of Sciences Beijing 100029 China

The mantle-genetic pargasites in peridotite inclusion of basalt have been studied, but the mantle-genetic tremolite has not been reported in past studies. Four kinds of as semblage with tremolite in metamorphic peridotite from Kuda, Xinjiang will be reported in this note. 1 Kuda ophiolite The Kuda ophiolite occurs in Kunlun orogenetic belt and was formed in the period from Sinian to Early Ordovician. The metamorphic peridotite in ophiolite is a tectonic exotic block napp and is a highly depleted harzburgite, which consists of forsterite (Fo=91), enstatite (En=90—95), chromespinel (Cr/ (Cr+Al)=0.5—0.61) and very little of clinopyroxene. The exsolution lamellae in pyroxene and Kink bandings in olivine can be observed clearly under a microscope. The plastic deformation fabrics, such as free dislocation, dislocation wall and subgrain structure, can also be observed in decorated olivines. The minerals in the studied rock samples are very fresh, which offers a good condition for this study.

关键词： tremolite harzbnrgite metasomatism in upper mantle.

Mineral association and graphite inclusions in nephrite jade from Liaoning, northeast China: Implications for metamorphic conditions and ore genesis

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Geoscience Frontiers 2019年第2期10卷 425-437页

作者： Cun Zhang Xiaoyan Yu Tianlong Jiang School of Gemology China University of Geosciences (Beijing)

The Liaoning Province in the northeastern part of the North China Craton(NCC) hosts several tremolite jade(nephrite) deposits. Here we investigate the Sangpiyu tremolite jade deposit where the relationship between abundant graphite inclusions within the jade remains enigmatic. We employ petrography, electron probe microanalysis, X-ray-diffraction, and Raman spectroscopy to characterize the tremolite jade and its inclusion minerals. The Sangpiyu jade is predominately composed of tremolite with minor calcite, dolomite, serpentine, titanite, zoisite, allanite, chlorite,apatite, chromite and graphite. Raman spectroscopy of graphite inclusions shows that the D1/G intensity ratio ranges from 0.78 to 0.88 in deep green samples and from 0.05 to 0.23 in dark green samples. The ranges of D1/(D1 + G) integral area ratio for these types are from 0.0548 to 0.3037 and 0.5528 to 0.7355 respectively. The formation temperature of graphite inclusions in the dark green tremolite jade is computed as 549.8 ℃, whereas that for the deep green sample is about343.2 ℃. Our results suggest that the jade formation occurred in a multi-stage process through the action of hydrothermal fluids and metamorphism possibly in a subduction-related setting at moderate to high temperatures.

关键词： tremolite jade Petrology and Raman spectroscopy Graphite Sangpiyu North China

Transformation of olivine to diopside via interaction with carbonatite melts

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Science China Earth Sciences 2023年第10期66卷 2332-2339页

作者： Jing WANG Ben-Xun SU Sanjeewa P.K.MALAVIARACHCHI Patrick Asamoah SAKYI Prasanna L.DHARMAPRIYA Key Laboratory of Mineral Resources Institute of Geology and GeophysicsChinese Academy of SciencesBeijing100029China University of Chinese Academy of Sciences Beijing100049China Department of Geology Faculty of ScienceUniversity of PeradeniyaPeradeniya20400Sri Lanka Department of Earth Science School of Physical and Mathematical SciencesUniversity of GhanaLegon-AccraGhana

Numerous empirical and experimental studies have documented the consumption of orthopyroxene and production of clinopyroxene in mantle peridotite during carbonatite metasomatism,whereas little attention has been paid to whether and how olivine is compositionally modified through the same process of carbonatite ***,we present the discovery of well-preserved reaction features in olivine from typical calciocarbonatites from Sri *** olivine grains experienced serpentinization along the cracks and in their rims and are generally surrounded outwardly by serpentine,tremolite and diopside *** inner serpentine zone is dominated by serpentine with tiny magnetite,whereas the mantle tremolite zone is characterized by euhedral tremolite and intergrowth of dolomite with small amounts of serpentine relics and *** outer diopside zone shows spongy texture and commonly encloses olivine,serpentine,tremolite and dolomite,which are also observed in interstitial diopside grains in the *** profile analyses reveal that these olivine grains display decreasing FeO and increasing MgO contents and thus elevating Fo values from their cores to the reaction rims,while the serpentine inherits compositions from the *** mapping images demonstrate outward diffusion of Si and Mg in the serpentine zones and contribution of Ca from carbonatite melts during tremolite *** interaction with carbonatite melts produced Si-and Mg-poor and Ca-rich diopside relative to the reactant *** observations suggest that the interaction with carbonatite melts first transformed olivine to diopside through serpentinization,followed by *** diopside formed through olivine-carbonatite melt interaction is anomalously depleted in Na and Al and enriched in Ca,which are distinct from those generated in interactions between orthopyroxene and both carbonatite and silicate *** implies that for the first time some w

关键词： Olivine Carbonatite Diopside tremolite Melt-mineral interaction

Study of the minerogenetic mechanism and origin of Qinghai nephrite from Golmud, Qinghai, Northwest China

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Science China Earth Sciences 2016年第8期59卷 1597-1609页

作者： YU HaiYan WANG RuCheng GUO JiChun LI JiaGui YANG XiaoWen State Key Laboratory for Mineral Deposits Research School of Earth Sciences and Engineering Nanjing University Nanjing 210023 China College of Materials Engineering Jinling Institute of Technology Nanjing 211169 China Center for Jewelry Research Nanjing University Nanjing 210093 China Jewelry Inspection Station Nanjing University Nanjing 210093 China Station of Precious Metal Gemstone Quality Control and Inspection Qinghai Province Xi'ning 810008 China

Electronic microprobe analysis showed that all QN samples are mainly composed of tremolite and minor accessory minerals, such as diopside, calcite, serpentinite, and magnetite. According to the cation coefficients, the crystallo-chemistrygenesis illustration demonstrates that all QN deposits are contact metasomatic. Depending on the mole percent of Fe^(2+(3+))/(Mg^(2+)+Fe^(2+(3+)) and the content of Cr, Co, and Ni in all QN samples measured by X-ray fluorescence spectroscopy(XRF) and inductively coupled plasma-mass spectrometry(ICP-MS), green and azure-green QNs are characterized as serpentinite-related contact metasomatic deposit(S-type), whereas white, green-white, brown, blue-violet, yellow, and viridis QNs are dolomite-related contact metasomatic deposit(D-type). The assemblages and chemical composition of accessory minerals of the eight-color QN samples show evident characteristics, which reveal four possible ore-forming processes. We also measured trace and rare earth elements(REEs) in these samples through ICP-MS to deduce the origin of and the changes in metallogenic conditions. The chondrite-normalized REE patterns of D-type QN exhibit moderately negative Eu anomalies with moderate light REE enrichment, flat heavy REE(HREE), and low(50)REE concentrations, similar to dolomitic marble. Green QN samples of S-type show enrichment in HREE and moderately negative Eu anomalies, which is consistent with characteristics of dunite. Whereas azure-green QN samples of S-type exhibit a right-dipping V-type curve with severe depletion in Eu(δEu=0.36–0.47), in accordance with the characteristics of gabbro from Yushigou ophiolite in North Qilian mountains. Furthermore, this finding is consistent with the content of trace elements and the petrographic analysis results. On the basis of several significant differences in the characteristic elements, which may have been affected by the metallogenic environment, we inferred the differences in oxygen fugacity and basicity of mine

关键词： Qinghai Nephrite tremolite Type Process Origin Environment

AN ENHYDROUS TECTONIC GLASS

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Chinese Science Bulletin 1989年第14期34卷 1212-1216页

作者：邵济安傅英奇减启家王玉芳 Department of Geology Peking University

The glasses already found in nature fall into three categories: (1) volcanic glass related to volcanic eruptions, (2) diaplectic glass related to meteoritic impactions or nuclear explosions, and (3) pseudotachylite related to high-speed faulting movements. The volcanic glass, resulting from rapid cooling of high-temperature magma, is closely connected to volcanic rocks and does not contain any water. The diaplectic glass,

关键词： enhydrous tectonic glass tremolite glass displectie glass pseudotachylite

Age determination of nephrite by in-situ SIMS U-Pb dating syngenetic titanite:A case study of the nephrite deposit from Luanchuan,Henan,China

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Age determination of nephrite by in-situ SIMS U-Pb dating sy...

Composition and distinction of white nephrite from Asian deposits

中国科学院地质与地球物理研究所2015年度（第15届）学术年会

作者： Xiao-Xiao Ling Esther Schmadicke Qiu-Li Li Jurgen Gose Rui-Hua Wu Shi-Qi Wang Yu Liu Guo-Qiang Tang Xian-Hua Li State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of Sciences School of Gem Studies China University of Geoscience Gem Appraisal Center Peking University

Nephrite is a kind of valuable jade which forms during metamorphism under greenschist facies *** investigations focus on the genesis of nephrite,however,the formation age of nephrite remains poorly constrained due to the lack of suitable dating *** this paper,the petrological,chemical characteristics,and mineral inclusions of nephrite collected from Luanchuan,Henan,China have been studied by optical and electron microscopy and wavelength-dispersive electron microprobe(EMP).The petrological observations show that nephrite consists mainly of tremolite,minor calcite and titanite,occasionally with rutile,quartz,serpentine,chlorite,pyrite,and *** titanite and tremolite which are intergrown with each other share low-energy grain *** indicates that the two phases are equilibrated and can be considered as *** chemical composition of tremolite is high in Si,Mg,Ca,but low in Fe,Cr,and Ni,which indicates that the nephrite from Luanchuan belongs to the dolomite type rather than the serpentinite *** petrography of different nephrite structures suggests that the grain size of tremolite was determined by the stress intensity undergone during the nephrite formation ***-situ Secondary Ion Mass Spectrometer(SIMS)U-Pb dating of titanite from nephrite yielded an age of 361±4 Ma,which is the first estimate for the time of formation of the Luanchuan nephrite *** investigation provides a powerful in-situ dating method to unravel the age of nephrite,which could be served as a tool for future research on other nephrite deposits.

关键词： Nephrite Geochronology Titanite tremolite SIMS U-Pb dating

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Composition and distinction of white nephrite from Asian dep...

河西走廊地区早期透闪石玉开采年代的考古学观察

中国科学院地质与地球物理研究所2013年度（第13届）学术年会

作者： Xiaoxiao Ling Esther Schmdicke Ruihua Wu Shiqi Wang Jürgen Gose State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of Sciences GeoZentrum Nordbayern Universitt Erlangen-NürnbergSchlossgarten 5aD-91054 ErlangenGermany. School of Gem Studies China University of Geoscience Gem Appraisal Center of Peking University GeoZentrum Nordbayern Universitt Erlangen-NürnbergSchlossgarten 5aD-91054 ErlangenGermany

The major and minor element compositions and textures of white nephrite samples from 6 different deposits including Xiaomeiling district(Jiangsu province,China),Luanchuan district(Henan province,China),Hetian district(Xinjiang province, China),Geermu district(Qinghai province,China),Chuncheon district(Korea) and Baikal district(Russia) were investigated by means of optical and electron microscopy and wavelength-dispersive electron microprobe analysis(EMPA).The white nephrites from all deposits display similar fine-grained textures and white ***,as the main mineral of the white nephrite,roughly has a similar composition in all samples mcluding high amounts of Si,Mg,Ca,and low Fe ***,the samples show small but specific differences that allow distinguishing samples from different *** of sample N1 from Xiaomeiling has the most extreme composition,because it contains considerably more F(average 1.8wt.%) than all other samples,and also shows the highest Na and K *** tremohte of white nephrite N2 from Luanchuan shows the highest Fe content of the sample *** Ca content is also comparably high,while Na,K,F,and Al concentrations are below the detection *** of sample N3 from Hetian is characterized by the second highest F content(0.4-0.7 wt.%) and a stoichiometric Si *** of sample N4 from Geermu has the highest nonstoichiometric Si content(～8.1 Si pfu(per formula unit)) and a relatively high Ca content(～2.0 Ca pfu).Other elements(Na,K,F,and Al) are below or close to the detection *** tremohte of Korean sample N5 from Chuncheon can be distinguished on the basis of its low F content(～0.2 wt.%) and its characteristic mosaic *** though sample N6 from Russia has no unique compositional feature that distinguishes it from other samples,it can be distinguished from the other samples if all textural and compositional data are *** study demonstrates that fluorine of tremohte is one of

关键词： tremolite white nephrite electron microprobe analysis Asian nephrite deposits archaeology

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