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Discovery and Significance of Diamonds and Moissanites in Chromitite within the Skenderbeu Massif of the Mirdita Zone Ophiolite,West Albania

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Acta Geologica Sinica(English Edition) 2017年第3期91卷 882-897页

作者： WU Weiwei YANG Jingsui MA Changqian MILUSHI Ibrahim LIAN Dongyang tian yazhou CARMA State Key Laboratory for Continental Tectonics and DynamicsInstitute of GeologyChinese Academy of Geological Sciences School of Earth Sciences China University of Geosciences(Wuhan) Department of Geoscience & Geoenvironment EnergyWater & EnvironmentPolytechnic University of Tirana College of Resources and Environmental Engineering Guizhou University

In recent years diamonds and other unusual minerals （carbides, nitrides, metal alloys and native elements） have been recovered from mantle peridotites and chromitites （both high-Cr chromitites and high-Al chromitites） from a number of ophiolites of different ages and tectonic settings. Here we report a similar assemblage of minerals from the Skenderbeu massif of the Mirdita zone ophiolite, west Albania. So far, more than 20 grains of microdiamonds and 30 grains of moissanites （SIC） have been separated from the podiform chromitite. The diamonds are mostly light yellow, transparent, euhedral crystals, 200-300μm across, with a range of morphologies; some are octahedral and cuboctahedron and others are elongate and irregular. Secondary electron images show that some grains have well-developed striations. All the diamond grains have been analyzed and yielded typical Raman spectra with a shift at -1325 cm^-1. The moissanite grains recovered from the Skenderben chromitites are mainly light blue to dark blue, but some are yellow to light yellow. All the analyzed grains have typical Raman spectra with shifts at 766 cm^-1, 787 cm^-1, and 967 cm^-1. The energy spectrums of the moissanites confirm that the grains are composed entirely of silicon and carbon. This investigation expands the occurrence of diamonds and moissanites to Mesozoic ophiolites in the Neo-Tethys. Our new findings suggest that diamonds and moissanites are present, and probably ubiquitous in the oceanic mantle and can provide new perspectives and avenues for research on the origin of ophiolites and podiform chromitites.

关键词： diamond moissanite high-Cr chromitite Mirdita zone ophiolite Albania

Diamond Discovered in High-Al Chromitites of the Sartohay Ophiolite,Xinjiang Province,China

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Acta Geologica Sinica(English Edition) 2015年第2期89卷 332-340页

作者： tian yazhou YANG Jingsui Paul T.ROBINSON XIONG Fahui LI Yuan ZHANG Zhongming LIU Zhao LIU Fei NIU Xiaolu CARMA State Key Laboratory for Continental Tectonics and DynamicsInstitute of GeologyChinese Academy of Geological Sciences Institute of Mineral Resources Chinese Academy of Geological Sciences

In recent years diamonds and other exotic minerals have been recovered from mantle peridotites and high-Cr chromitites of a number of ophiolites of different age and different tectonic environments. Here we report a similar collection of minerals from the Sartohay ophiolite of Xinjiang Province, western China, which is characterized by having high-Al chromitites. Several samples of massive podiform chromitite with an aggregate weight of nearly 900 kg yielded diamonds, moissanite and other highly reduced minerals, as well as common crustal minerals. Thus far, more than 20 grains each of diamond and moissanite have been recovered from heavy mineral separates of the chromitites. The diamonds are all 100-200 μm in size and range in color from pale yellow to reddish-orange to colorless. Most of the grains are anhedral to subhedral octahedra, commonly with elongate forms exhibiting well-developed striations. They all display characteristic Raman spectra with shifts between 1325 cm^-1 and 1333 cm^-1, mostly 1331.51 cm^-1 or 1326.96 cm^-1. The moissanite grains are light blue to dark blue, broken crystals, 50-150 μm across, commonly occurring as small flakes or fragments. Their typical Raman spectra have shifts at 762 cm^-1, 785 cm^-1, and 966 cm^-1. This investigation extends the occurrence of diamonds and moissanite to a Paleozoic ophiolite in the Central Asian Orogenic Belt and demonstrates that these minerals can also occur in high-Al chromitites. We conclude that diamonds and moissanite are likely to be ubiquitous in ophiolitic mantle peridotites and chromitites.

关键词： diamond moissanite high-Al chromitite Sartohay Xinjiang

Mineralogical and Geochemical Constraints on the Origin of the Ultramafic Rocks from Wuwamen Ophiolite at the Southern Margin of Middle tianshan, Xinjiang

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Acta Geologica Sinica(English Edition) 2015年第A02期89卷 70-71页

作者： NIU Xiaolu YANG Jingsui LIU Fei FENG Guangying .tian yazhou ZHANG Lan GAO Jian ZHAO Yijue CARMA State Key Laboratory of Continental Tectonics and Dynamics Institute of Geology Chinese Academy ofGeological Sciences Beijing 100037 School of Earth Sciences and Mineral Resources China University of Geosciences Beijing 100083

Wuwamen ophiolite is located at the southern margin of Middle tianshan, Xinjiang Province. In this paper, petrology, mineralogy and geochemistry of the ultramafic rocks from Wuwamen ophiolite were studied to constrain their origin and tectonic setting. The studies will be helpful in interpreting the evolution process of the South tianshan Ocean.

关键词： RESEARCH Petrology Mineralogy Geochemistry Ultrabasic rocks Ophiolites

Petrogenesis of Peridotites from the Purang Ophiolite in Western Part of Yarlung-Zangbo Suture Zone, Southern Tibet

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Acta Geologica Sinica(English Edition) 2015年第A02期89卷 125-126页

作者： ZHOU Wenda YANG Jingsui ZHAO Junhong MA Changqian XIONG Fahui XU Xiangzhen CHEN Yanhong tian yazhou Institute of Geology and Mining China Nonferrous Metals (Guilin) Geology and Mining Co. Ltd Guilin 541004 CARMA State Key Laboratory of Continental Tectonics and Dynamics Institute of Geology Chinese Academy ofGeological Sciences Beijing 100037 Faculty of Earth Sciences China University of Geosciences Wuhan 430074 College of Resource and Environmental Engineering Guizhou University Guiyang 550025

Peridotites are an important part of ophiolites： they not only record plate tectonic settings and events, but also offer help to interpret the composition of the mantle and the effect of the deep mantle. The Yarlung-... 详细信息

关键词： RESEARCH Ophiolites Suture zones (Structural geology) Geochemistry Mid-ocean ridges Petrogenesis Peridotite

Inclusions in Sartohay Chromitites and Implication

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Acta Geologica Sinica(English Edition) 2016年第S1期90卷 241-页

作者： tian yazhou CARMA College of Resources and Environmental Engineering Guizhou University CARMA State Key Laboratory for Continental Tectonics and Dynamics Institute of Geology Chinese Academy of Geological Sciences

It is significant for recognizing the origin of chromitites to research the primary mineral inclusions in chromitites.A large number of primary mineral inclusions including CPXs,OPXs,olivines,aspidolites,Na-Cr pargasi... 详细信息

关键词： Cr Inclusions in Sartohay Chromitites and Implication high

新疆西准噶尔阿克巴斯套蛇绿混杂岩中辉绿岩地球化学、年代学及构造意义

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地质学报 2019年第9期93卷 2209-2225页

作者：杨华燊田亚洲杨经绥田云雷贵州大学资源与环境工程学院贵阳550025 地幔研究中心国土资源部深地动力学重点实验室中国地质科学院地质研究所北京100037

本文以阿克巴斯套蛇绿混杂岩中辉绿岩为研究对象,进行了详细的野外地质调查、LA-ICP-MS锆石U-Pb年代学、岩石地球化学研究,旨在探究其岩石成因、成岩时代及构造背景,以便为探讨西准噶尔地区构造演化提供新的数据支持。岩石地球化学特征... 详细信息

本文以阿克巴斯套蛇绿混杂岩中辉绿岩为研究对象,进行了详细的野外地质调查、LA-ICP-MS锆石U-Pb年代学、岩石地球化学研究,旨在探究其岩石成因、成岩时代及构造背景,以便为探讨西准噶尔地区构造演化提供新的数据支持。岩石地球化学特征显示:辉绿岩SiO2(51.15%~54.34%)、Na2O (4.95%~6.36%)、TiO2(1.79%~2.08%)含量高,而MgO(3.90%~5.15%)、K2O (0.13%~0.80%)含量低,且Na2O>K2O,具富钠贫钾的特征。∑REE=117.52×10^-6~143.12×10^-6, LREE/HREE=1.79~2.04,(La/Yb)N=1.04~1.22,轻重稀土分异不明显,δEu平均值为0.93,富集大离子亲石元素(K、Rb、Sr),明显亏损高场强元素(Th、Nb、Ti),表明辉绿岩具有N-MORB与岛弧玄武岩相似的特征。辉绿岩锆石样品176Hf/177Hf比值范围为0.282783~0.282993,平均值为0.282926,εHf(t)值为+8.0^+15.2,平均值为+12.8。根据地球化学特征研究表明,该辉绿岩源区为俯冲流体交代亏损地幔尖晶石二辉橄榄岩经25%~30%部分熔融形成,同时,岩浆在演化过程中经历了一定程度的结晶分异作用。锆石U-Pb年代学研究显示阿克巴斯套蛇绿混杂岩中辉绿岩年龄为357.6±2.4 Ma(n=24, MSWD=5.3),形成于早石炭世,该年龄佐证了西准噶尔地区洋盆演化一直延续到石炭世早期,为新疆西准噶尔晚古生代残余洋盆消亡的时代提供了依据。结合成岩年龄及区域地质背景,认为阿克巴斯套蛇绿混杂岩形成于石炭世早期与俯冲作用相关的弧后盆地构造环境。

关键词：西准噶尔辉绿岩锆石U-Pb定年 Hf同位素弧后盆地

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新疆萨尔托海铬铁矿中铂族矿物及硫化物特征

地质学报 2019年第10期93卷 2639-2655页

作者：田亚洲杨经绥杨华燊田云雷贵州大学资源与环境工程学院贵阳550025 地幔研究中心自然资源部深地动力学重点实验室中国地质科学院地质研究所北京100037

新疆萨尔托海高Al型铬铁矿中几乎不含原生的铂族矿物(PGM)和贱金属硫化物(BMS)包体,显示出成矿岩浆贫硫的特征。BMS多产于铬铁矿铬粒间裂隙、基质及蚀变环带中,主要以赫硫镍矿和针镍矿为主,其次为辉铜矿、砷镍矿、硫砷镍矿、毒砂等。PG... 详细信息

新疆萨尔托海高Al型铬铁矿中几乎不含原生的铂族矿物(PGM)和贱金属硫化物(BMS)包体,显示出成矿岩浆贫硫的特征。BMS多产于铬铁矿铬粒间裂隙、基质及蚀变环带中,主要以赫硫镍矿和针镍矿为主,其次为辉铜矿、砷镍矿、硫砷镍矿、毒砂等。PGM以包体产于BMS或铬铁矿粒间缝隙中,以硫钌矿(RuS2)为主,还包括硫锇矿(OsS2)、硫镍锇矿[(Os,Ni)S2]、硫钌锇矿[(Ru,Os)S2],锑钯矿(Pd5Sb2)和少量Cu、Pt、Au的硫化物。铬铁矿全岩ΣPGE含量50.64×10^-9~92.00×10^-9,较世界范围内蛇绿岩型铬铁矿低,且具有IPGE较PPGE富集的特点,PdN/IrN在0.1~0.9之间,具有Os相对Ir富集的特点。铬铁矿主量元素和原位微量元素显示出与菲律宾阿科杰高Al型铬铁矿以及MORB中尖晶石相似的地球化学特征。根据萨尔托海铬铁矿中PGM及BMS的种类、产出特征,结合铬铁矿全岩PGE及单矿物微量元素地球化学特征,认为铬铁矿的形成与贫硫的拉斑玄武质岩浆与地幔橄榄岩的熔体岩石反应有关。铬铁矿形成后的晚期岩浆阶段使得自形程度较高的PGM(如硫锇矿)和BMS(如赫硫镍矿)形成,随后向热液阶段转变的过程中,由于温压条件改变、热液蚀变,形成了萨尔托海铬铁矿中Fe-Ni-As-S和PGM矿物组合。

关键词：铂族矿物硫化物铬铁矿萨尔托海新疆

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含有连续分布时滞偶阶微分方程的振动性

应用数学学报 2013年第6期36卷 1080-1093页

作者：田亚州蔡远利孟凡伟西安交通大学电子与信息工程学院西安710049 曲阜师范大学数学科学学院曲阜273165

本文研究了一类含有连续分布时滞偶数阶中立型微分方程的振动性,利用推广的Riccati变换和平均值技巧得到了该方程所有解均为振动的若干新的振动准则,推广和改进了已有文献中的主要结果,最后给出了几个例子说明结果优越性.

关键词：振动性中立微分方程偶数阶

Diamonds, Super-Reduced and Crustal Minerals in Chromitites of the Hegenshan and Sartohay Ophiolites, Central Asian Orogenic Belt, China

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Acta Geologica Sinica(English Edition) 2017年第S1期91卷 32-页

作者： Paul T.ROBINSON YANG Jingsui tian yazhou ZHU Huang CARMA State Key Laboratory of Continental Tectonics and DynamicsInstitute of GeologyChinese Academy of Geological SciencesBeijing 100037China

The Central Asian Orogenic Belt(CAOB)is a huge tectonic mélange that lies between the North China Craton and the Siberian *** is composed of multiple orogenic belts,continental fragments,magmatic and metamorphic rocks,suture zones and discontinuous ophiolite *** the Hegenshan and Sartohay ophiolites are separated by nearly 3000 km and lie in completely different parts of the CAOB,they are remarkably similar in many *** are composed mainly of serpentinized peridotite and dunite,with minor gabbro and sparse *** both host significant podiform chromitites that consist of high-Al,refractory magnesiochromite with Cr#s[100Cr/(Cr+Al)]averaging<*** Sartohay ophiolite has a zircon U-Pb age of ca.300 Ma and has been intruded by granitic plutons of similar age,resulting in intense hydrothermal activity and the formation of gold-bearing *** age of the Hegenshan is not firmly established but is thought to have formed in the *** many other ophiolites that we have investigated in other orogenic belts,the chromitites in these two bodieshave abundant diamonds,as well as numerous super-reduced and crustal *** diamonds are mostly,colorless to pale yellow,200-300μm across and have euhedral to anhedral *** all have low carbon isotopes(δ14C=-18 to-29)and some have visible *** are accompanied by numerous super-reduced minerals such as moissanite,native elements(Fe,Cr,Si,Al,Mn),and alloys(e.g.,Ni-Mn-Fe,Ni-Fe-Al,Ni-Mn-Co,Cr-Ni-Fe,Cr-Fe,Cr-Fe-Mn),as well as a wide range of oxides,sulfides and *** of zircon are abundant in the chromitites of both ophiolites and range in age from Precambrian to Cretaceous,reflecting both incorporation of old zircons and modification of grains by hydrothermal *** investigation confirms that high-Al,refractory chromitites in these two ophiolites have the same range of exotic minerals as high-Cr metallurgical chromitites such as those in the Luobus

关键词： Cr China Diamonds Super-Reduced and Crustal Minerals in Chromitites of the Hegenshan and Sartohay Ophiolites Central Asian Orogenic Belt