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The occurrence of metallic copper and redistribution of copper in the shocked Suizhou L6 chondrite

Acta Geochimica 2024年第05期43卷 827-837页

作者： Xiande Xie xiangping gu Yiping Yang Key Laboratory of Mineralogy and Metallogeny/guangdong Provincial Key Laboratory of Mineral Physics and Materials Guangzhou Institute of GeochemistryChinese Academy of Sciences School of Geosciences and Info-Physics Central South University

Copper possesses very strong chacophile properties, but under the conditions found in meteorites, its behavior is like that of siderophile elements. The Suizhou meteorite is a highly shocked L6 chondrite. Troilite and taenite are considered the main primary carrier of copper in this meteorite, and the post-shock thermal episode is considered the main reason that elemental Cu migrates from its original host phase and forms metallic grains. The Suizhou meteorite contains a few very thin shock melt veins. The occurrence and behavior of metallic copper in this meteorite were studied by optical microscopic examination, electron microprobe analyses, and high-resolution X-ray elemental intensity mapping. Our results show that metallic copper is abundant in the Suizhou chondritic rock. Metallic copper grains adjacent to small troilite grains inside FeNi metal are the most common occurrence, and those at the FeNi metal–troilite interface are the second most common *** metallic copper grains occurring at the interface of FeNi metal/troililte and silicate are rather rare. Metallic copper grains are not observed within the Suizhou shock veins,Instead, Cu in elemental form is transferred through shock metamorphism into FeNi metal + troilite intergrowths. Four different occurrence types of Cu in the FeNi metal + troilite intergrowths have been identified: the concentrations of Cu in the FeNi + FeS intergrowths for four occurrence types are rather close, we estimate it might be lower than 1 wt%.

关键词： Elemental intensity mapping Metallic copper Metal–troilite intergrowth Shock vein Suizhou chondrite

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The breakdown of diopside to(Ca,Mg)SiO_(3)perovskite–(Mg,Ca,Fe)SiO_(3)glass–(Mg,Ca)SiO_(3)glass–(Mg,Ca)SiO_(3)majorite in a melt vein the Suizhou L6 chondrite

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Acta Geochimica 2023年第2期42卷 183-194页

作者： Xiande Xie xiangping gu Key Laboratory of Mineralogy and Metallogeny/guangdong Provincial Key Laboratory of Mineral Physics and Materials Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China School of Geosciences and Info-Physics Central South UniversityChangsha 410083China

The Suizhou meteorite is a heavily shocked and melted vein-containing L6 *** contains a minor amount of diopside with a(Ca_(0.419)Mg_(0.466)Fe_(0.088))SiO_(3)composition,and a shock-metamorphosed diopside grain associated with ringwoodite and lingunite was found in a melt vein of this *** electron microprobe,transmission electron microscopic and Raman spectroscopic analyses revealed four silicate phases with different compositions and structures inside this shock-metamorphosed diopside grain,termed phase A,B,C and D in this *** A is identified as orthorhombic(Ca_(0.663)-Mg_(0.314))SiO_(3)-perovskite which is closely associated with phase B,the vitrified(Mg_(0.642)Ca_(0.290)Fe_(0.098))SiO_(3)*** D is assigned to be(Mg_(0.578)Ca_(0.414))SiO_(3)majorite which is associated with phase C,the vetrified Carich Mg-perovskite with a(Mg_(0.853)Ca_(0.167))SiO_(3)*** on high-pressure and high-temperature experiments,the diopside grain in the melt vein of the Suizhou meteorite would have experienced a P–T regime of 20–24GPa and 1800–>2000℃.Such P–T conditions are high enough for the decomposition of the diopside and the formation of four different silicate *** orthorhombic(Ca_(0.663)Mg_(0.314))SiO_(3)perovskite found in the Suizhou L6 chondrite might be considered as the third lower-mantle silicate mineral after bridgmanite and davemaoite after the detailed analyses of its crystal structure and physical properties being completed.

关键词： Suizhou chondrite Diopside Shock metamorphism (Ca,Mg)SiO_(3)-perovskite (Mg,Ca,Fe)SiO_(3)glass (Mg,Ca)SiO_(3)glass (Mg,Ca)SiO_(3)majorite

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High-pressure polymorph of TiO_2-Ⅱ from the Xiuyan crater of China

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Chinese Science Bulletin 2013年第36期58卷 4655-4662页

作者： CHEN Ming gu xiangping XIE XianDe YIN Feng State Key Laboratory of Isotope Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences School of Geosciences and Info-Physics Central South University Key Laboratory of Mineralogy and Metallogeny Guangzhou Institute of Geochemistry Chinese Academy of Sciences

Abundant TiO2-Ⅱ,a high-pressure polymorph of titanium dioxide,was found in the gneiss fragments of impact-produced breccias from the Xiuyan *** in the gneiss was severely fragmented and fine-grained clasts less than 2 m in size had been transformed to *** thin layered TiO2-Ⅱ is also observed in coarse-grained rutile fragments,where the TiO2-Ⅱ layers distributes along fractures and cracks in *** 30 percent of rutile in the gneiss had been transformed to TiO2-Ⅱ.Fine grains of TiO2-Ⅱ display light bluish grey to light yellow brown in plane-polarized reflected *** investigation shows that TiO2-Ⅱ has an orthorhombic structure with space group *** cell parameters are a=4.543(1),b=5.491(9)and c=4.895(2).Its empirical formula calculated on the basis of two oxygen atoms can be written as(Ti0.985Fe0.008Nb0.006-Si0.003Zr0.001)1.003O2,or simply formula *** to the shock effects of quartz and feldspars,the peak shock pressure and post-shock temperature in the TiO2-Ⅱ-bearing gneiss are estimated to be between 35 and 43 GPa and 300–900°C,*** finding of TiO2-Ⅱ in the shock-metamorphosed gneiss provides another mineral physics evidence for shock origin of the Xiuyan crater.

关键词：陨石坑纳米岫岩高压二氧化钛中国经验公式平面偏振光

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Determination of Fe^(2+)/Fe^(3+)Ratios of Magnetite using Different Methods:A Case Study from the Qimantag Metallogenic Belt

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Acta Geologica Sinica(English Edition) 2022年第6期96卷 2135-2147页

作者： YI Liwen LI Qiuping LU Anhuai gu xiangping CHI guoxiang School of Geographical Sciences Hunan Normal UniversityChangsha 410081China School of Geosciences and Info-Physics Central South UniversityChangsha 410083China School of Earth and Space Sciences Peking UniversityBeijing 100871China Department of Geology University of ReginaReginaSaskatchewan S4S 0A2Canada

Determination of Fe^(2+)/Fe^(3+) ratios from metallogenic belts to explore controlling physical and chemical conditions of rock formation is of great *** order to explore magnetite Fe^(2+)/Fe^(3+) ratios of the Qimantag metallogenic belt,part of the Eastern Kunlun orogenic belt in the northeastern margin of the Qinghai–Tibetan plateau,western Central Orogenic Belt of China,and overcome the limitation of the traditional electronic probe,five different measurement methods are proposed and their respective advantages and disadvantages evaluated,with the composition data of the magnetite obtained using electron probe microanalysis(EPMA).The direct oxygen measurement method has a significant impact on the determination results of FeO and Fe2O3,but the accuracy and uniformity of the results are *** valence method(Flank method)based on the spectral intensity ratio of Lαto Lβfor iron is also unreliable for FeO and Fe_(2)O^(3) measurements because it is difficult to establish a relationship between Lβ/Lα,the spectral intensity ratio,and the Fe^(2+)/Fe^(3+) content *** comparison,the charge difference method,the surplus-oxygen method and the Mössbauer spectrum method are still the most favorable.Mössbauer spectroscopy,with its isomer movement particularly sensitive to the oxidation state of iron,yields results closer to 0.5,which is relatively *** magnetite deposits are located in intrusions or contact zones and formed by magmatic fluids with high Fe2+/Fe3+ratios,whereas later magnetite deposits are farther away from intrusions and have low Fe^(2+)/Fe^(3+) *** transformation mechanism of hematite and magnetite in the Qimantage metallogenic belt is also *** large volume changes,such as pore filling and shrinkage fracture,were detected in the metallogenic belt,and the transformation mechanism is more similar to a reoxidation and reduction mechanism.

关键词： iron magnetite direct oxygen measurement flank-charge difference-surplus-oxygen methods Mössbauer spectra Qimantage

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Transmission electron microscopic study of the fine-grained vein matrix in the Suizhou L6 meteorite

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Acta Geochimica 2016年第2期35卷 105-110页

作者： Xie Xiande Wang Jianbo gu xiangping Xiong Yi Jia Shuangfeng Key Laboratory of Mineralogy and Metallogeny Guangzhou Institute of Geochemistry Chinese Academy of SciencesGuangzhou 510640 China Center for Electron Microscopy Wuhan UniversityWuhan 430072 China School of Geosciences and Info-Physics Central South University Changsha 410083 Hunan China guangdong Provincial Key Laboratory of Mineral Physics and Materials Guangzhou 510640 China

The mineralogy of shock vein matrix in the Suizhou meteorite has been investigated by optical and transmission electron microscopy. It was revealed that the vein matrix is composed of majorite-pyrope garnet, mag- aesiowtistite, and ringwoodite, with FeNi-FeS inter- growths. The observation and character of ring-like selected electron diffraction （SAED） patterns indicate that Lhe idiomorphic garnet crystals in the vein matrix have different orientations. The polycrystalline nature of magnesiowtistite is also confirmed by a ring-like SAED pattern. Both garnet and magnesiowtistite crystals showed sharp Jiffraction spots, signifying the good crystallinity of these ：wo minerals. The SAED pattern of cryptocrystalline 5ngwoodite shows only diffuse concentric diffraction tings. FeNi metal and troilite （FeS）, which were molten during the shock event, occur in the matrix as fine eutectic FeNi-FeS intergrowths filling the interstices between garaet and magnesiowiistite grains. Based on the phase dia- gram of the Allende chondrite and the results of this TEM study, it is inferred that majorite-pyrope garnet first crystallized from the Suizhou chondritic melt at 22-26 GPa, Followed by crystallization of magnesiowtistite at 20-24 GPa, and then ringwoodite at 18-20 GPa. The eutectic intergrowths of FeNi-metal and troilite are proposed to have crystallized during meteorite cooling and solidified at the last stage of vein formation.

关键词： Suizhou meteorite Shock vein matrix. High-pressure minerals Transmission electron microscopy

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The discovery of TiO_(2)-Ⅱ,the α-PbO_(2)-structured high-pressure polymorph of rutile,in the Suizhou L6 chondrite

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Acta Geochimica 2023年第1期42卷 1-8页

作者： Xiande Xie xiangping gu Ming Chen Key Laboratory of Mineralogy and Metallogeny/guangdong Provincial Laboratory of Mineral Physics and Materials Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China School of Geosciences and Info-Physics Central South UniversityChangsha 410083China State Key Laboratory of Isotope Geochemistry Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China

We report the discovery of TiO_(2)-Ⅱ in the unmelted rock of the shocked Suizhou L6 *** TiO_(2)-Ⅱ was previously found in ultrahigh-pressure metamorphic and mantle-derived rocks,terrestrial impact structures,and *** microscopic,Raman spectroscopic,electron microprobe and transmission electron microscopic investigations have revealed:(1) All observed TiO_(2)-Ⅱ grains are related with ilmenite and pyrophanite;(2) TiO_(2)-Ⅱ occurs as needle-and leaf-shaped inclusions in llmenite and patch-,tape-shaped body in pyrophanite;(3)The composition of TiO_(2)-Ⅱ is identical with that of its precursor rutile;(4) The Raman spectrum of TiO_(2)-Ⅱ is in good agreement with that of natural and synthesized α-PbO_(2)-type TiO_(2);(5) TiO_(2)-Ⅱ occurs mainly in the form of well-ordered nano-domains and small mis-orientation among the domains can be observed.(6) All electron diffraction reflections from TiO_(2)-Ⅱ can be indexed to α-PbO_(2)structure in space group Pbcn with lattice parameters of a=4.481 ?,b=5.578 A and c=4.921 A;(7) The exsolution inclusions of rutile from host ilmenite are mostly connected with an alternation process along the lamellar twinning plane of ilmenite induced by shockinduced high pressure and high temperature;(8) The P-T regime of 20-25 GPa and 1000 ℃ estimated for the Suizhou unmelted rock is suitable for phase transition of rutile into TiO_(2)-Ⅱ phase.

关键词： Rutile TiO_(2)-Ⅱ High-pressure polymorph Shock metamorphism Suizhou meteorite

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Mineralogical characteristics and photocatalytic properties of natural sphalerite from China

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Journal of Environmental Sciences 2020年第3期32卷 156-166页

作者： Can Shen xiangping gu Bin Yang Dexian Zhang Zhilin Wang Zhengxiang Shu Jeffrey Dick Anhuai Lu Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring Ministry of Education Central South UniversityChangsha 410083China School of Geoscience and Info-physics Central South UniversityChangsha 410083China

Different natural sphalerites have a range of photocatalytic properties that can potentially be exploited for environmental remediation *** develop value in the exploitation of sphalerite,samples were collected from 19 ore deposits in China and characterized for their mineralogical and photocatalytic properties.X-ray diffraction(XRD) and electron probe micro analysis(EPMA) measurements indicated that all the natural sphalerites from various localities crystallized in cubic phases with various chemical *** substitution of Fe for Zn ranged from 0.235% to 14.826% by weight,Mn from 0.004% to4.868%,Cu from 0.009% to 5.529% and Cd from 0.133% to 1.576%.As Fe became more abundant,the color of natural sphalerite darkened,becoming almost black;and higher Fe content was associated with stronger visible light *** spectra showed emission mainly related to S-vacancies and progressively decreasing fluorescence intensity with increasing Fe *** of the photocatalytic degradation of methyl orange indicated that the sample with the highest Cd content but moderate Fe content had the highest photocatalytic ***,the degradation of Methyl Orange(30 mg/L)attained 82.11% efficiency under visible light irradiation for 4 hr of natural sphalerite with4.262% Fe and 1.576% ***,the Fe content in sphalerite was found to contribute to the visible light absorption ability and the recombination rate of photo-generated electrons and holes,while substitution by Cd was observed to have a greater effect on the photocatalytic *** findings provide a scientific basis for the profitable utilization of base metal resources like sphalerite.

关键词： Natural sphalerite Mineralogical properties Band gap Photodegradation of Methyl Orange

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Re-Os Isotopic Age of Molybdenite of the Jingren Deposit and its Mineralogical Significance of Magnetite,Pyrite and Chalcopyrite

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Acta Geologica Sinica(English Edition) 2021年第4期95卷 1236-1248页

作者： CAO Li YI Liwen DAI Wei XIE Binggeng LI Xiaoqing LU Anhuai gu xiangping College of Geographic Sciences Hunan Normal UniversityChangsha 410081China Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring(Central South University) Ministry of EducationChangsha 410083China The Third of Qinghai Geological and Mineral Exploration Institute Xining 810012China College of Geosciences and Info-Physics Central South UniversityChangsha 410083China

The Jingren deposit is part of the Qimantage metallogenic belt within the eastern Kunlun orogenic belt,the largest metallogenic belt in Qinghai Province,northwestern *** data show that the metal resources of the Jingren deposit are greater than 93000 t in a mining area of 76.15 km2,which indicates significant exploration potential in the near *** W–E-trending faults,F1-3,dominate the extension of the mineralization zone,which consists of chalcopyrite,pyrite,magnetite,galena,sphalerite,and molybdenite as well as bismuth-bearing *** deposit contains a large amount of late Triassic intrusive rocks,however,previous research did not reach a consensus on the timing or the origin of the mineralization owing to a lack of geochronological data and poor exposure *** the present study,Re-Os isotopic dating from six molybdenite samples collected from a borehole of the granodiorite in the Jingren deposit using negative thermal ionization mass spectrometry(NTIMS)showed 187 Re and 187 Os concentrations of 0.26–4.40 ppm and 1.03–16.46 ppb,respectively,with an initial 187 Os/188 Os value of 0.06±*** proves that the Jingren deposit has a metallogenic age of(225±4)Ma and is the product of united mineralization of the Qimantage metallogenic belt and that the Jingren deposit might actually be an Indosinian *** addition,the Re content of these samples,at 0.42 ppm to 7.00 ppm shows that the mineralization was derived mainly from a crustal ***,electron probe microanalysis(EPMA)conducted on chalcopyrite obtained from 22 metallic mineral samples revealed(Fe+Cu)/S ratios of 1.801–1.947 with an average of 1.852,which is lower than the ideal value(1.875).Besides,the main ore body formed in a relatively higher temperature environment than the surrounding rocks in the Jingren *** data indicate that the Jingren deposit formed in a metallogenic environment at lower ***,according to the TiO_(2)-Al_(2

关键词： mineralogy Re-Os isotopic dating molybdenite skarn Indosinian Jingren deposit Qimantage metallogenic belt

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内蒙古白云鄂博矿床发现两种铌、钪新矿物:鄂博铌矿和翟钪闪石

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地质科学 2024年第5期59卷 1466-1469页

作者：佘海东刘双良范宏瑞谷湘平李晓春杨奎锋王其伟中国科学院地质与地球物理研究所矿产资源研究重点实验室中国科学院大学地球与行星科学学院白云鄂博稀土资源研究与综合利用全国重点实验室中南大学地球科学与信息物理学院

稀土元素和铌元素具有独特的磁—光—电物理特性及高熔点等优点,且能与其它元素组成性能各异、品种繁多的新型材料,大幅提高低碳能源材料的质量和性能,是发展低碳绿色新能源产业的关键矿产资源。内蒙古白云鄂博矿床是全球最大的稀土矿床... 详细信息

稀土元素和铌元素具有独特的磁—光—电物理特性及高熔点等优点,且能与其它元素组成性能各异、品种繁多的新型材料,大幅提高低碳能源材料的质量和性能,是发展低碳绿色新能源产业的关键矿产资源。内蒙古白云鄂博矿床是全球最大的稀土矿床,同时也伴生有大量的铁、铌、钪、钍及萤石等矿产资源,且具有非常复杂的矿物组成和共生组合。据统计,在该矿床已发现的矿物达200余种,其中新矿物20种。鄂博铌矿和翟钪闪石是近期在该矿床发现的两种新矿物。其中,鄂博铌矿,呈黄褐色至褐色,板状,自形至半自形,粒度约为20～100 μm,该矿物是一种结构简单的镁—铌氧化物类矿物,理想化学式Mg4Nb2O9,铌氧化物平均含量为58.0%,属于三方晶系,空间群P■c1（#165）。翟钪闪石,呈淡黄色或淡蓝色,长柱状,自形—半自形,粒度可达350 μm,该矿物是一种含钪的角闪石族矿物,理想化学式为NaNa2（Mg4Sc）(Si8O22)F2,钪氧化物平均含量为6.4%,属于单斜晶系,空间群C2/m（#12）。两个新矿物的发现,不仅增加了白云鄂博可用铌、钪金属选冶矿物种类,进而助力资源高效利用,而且也是人类不断了解、认识大自然,并利用自然界物质的重要过程。

关键词：新矿物鄂博铌矿翟钪闪石白云鄂博

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Growth Pattern and Its Indication of Spheroidal Nano-Micro Crystal Aggregates of Pyrite in the Baiyunpu Pb-Zn Polymetallic Deposit, Central Hunan

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Acta Geologica Sinica(English Edition) 2014年第6期88卷 1770-1783页

作者： GAO Shang HUANG Fei gu xiangping LI Xiangyou MENG Lin LIU Rui SUN Li GAO Wenyuan YU Huantao College of Resources and Civil Engineering Northeastern University School of Geosciences and Info-Physics Institute Central South University Yunxiang Mining Limited Company

The Baiyunpu deposit lies in the southwest plunging Dachengshan anticline in central Hunan, which is a large Pb-Zn polymetallic deposit. The orebodies were surrounded by the Qiziqiao Formation limestone in the Middle Devonian, and its geological occurrence is consistent with the wall rocks. A large number of spheroidal pyrite aggregates are found unevenly distributed in the ores. The spheroidal aggregates are made up of kernels and concentric rings. The kernels are composed of approximately epigranular pyrite nanocrystals, while the rings are composed of accumulated pyrite microcrystals growing along the radial direction. The spheroidal pyrite aggregate and its outer zones can be divided into five areas（A–E）. The results of electron probe micro analysis（EPMA） show that from the zone A1 to B, Co/Ni 〈1, the sum of Co and Ni is 0.08%–0.26%, S/Fe increases from 2.06 to 2.15. While from the zone C to E, Ni cannot be detected and S/Fe decreases from 2.22 to 2.08. Powder X-ray diffraction（XRD） analysis in the micro zone shows obvious crystalline characteristics in the aggregates. Moving from the inside outwards, the maximum diffraction peak intensity of the（111） and（220） crystal planes of pyrite increases, and the crystallinity improves. The degree of change in the（111） plane is the most prominent. Considering the theory of crystal growth along with the geologic features of the depositional environment where the spheroidal pyrite aggregates developed, we confirm that the spheroidal aggregates are the result of nano-micro crystalline gathering and growth occurring by the following sequence of processes：nano-crystalline nucleation and growth, gathering into a ball, oriented growth of microcrystals, continuous accumulation, and adjustment of grain boundaries. The formation of the spheroidal pyrite aggregates in the late Qiziqiao Formation of the Middle Devonian occurred in a neutral to weak alkaline and reductive sedimentary environment in the normal oxygen-rich shallowwater

关键词： Baiyunpu Pb-Zn polymetallic deposit pyrite nano-micro crystal spheroidal aggregates growth pattern indication significance

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