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Rare earth element enrichment in sedimentary phosphorites formed during the Precambrian-Cambrian transition,Southwest China

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Geoscience Frontiers 2024年第2期15卷 334-348页

作者： Jieqi Xing Yuhang Jiang Haiyang Xian Wubin Yang Yiping Yang hecai niu Hongping He Jianxi Zhu CAS Key Laboratory of Mineralogy and Metallogeny Guangdong Provincial Key Laboratory of Mineral Physics and MaterialsGuangzhou Institute of GeochemistryChinese Academy of Sciences(CAS)Guangzhou 510640China CAS Center for Excellence in Deep Earth Science Guangzhou 510640China University of Chinese Academy of Sciences Beijing 100049China

Numerous sedimentary phosphorites in Southwest China were formed around the Precambrian–Cambrian transition(PC–C),including the upper Ediacaran Doushantuo Formation and lower Cambrian Gezhongwu *** Gezhongwu phosphorites in Zhijin exhibit marked rare earth element(REE)enrichment(>1000 ppm),and may represent new REE *** the main characteristics of the Gezhongwu phosphorites have been well constrained,the REE enrichment mechanisms remain *** undertook a comparative study of three typical sedimentary phosphorites with variable REE contents formed at the PC–C transition in central Guizhou Province,Southwest *** include sections A and B of the Doushantuo phosphorites(560±8 Ma)from the Weng’an area(i.e.,WA-A and WA-B),and the Gezhongwu phosphorites(527±24 Ma)from the Zhijin area(ZJ).The phosphorites were investigated with state-of-the-art macroscale to nanoscale analytical *** contrast to the extraordinary REE enrichment in the ZJ phosphorites(average RREE=1157 ppm),the phosphorites in WA-A(average RREE=234 ppm)and WA-B(average RREE=114 ppm)are *** mapping by laser ablation–inductively coupled plasma–mass spectrometry,along with transmission electron microscopy analyses,showed the REEs in the studied phosphorites are hosted in nanoscale *** 87Sr/86Sr and Y/Ho ratios of the francolite grains indicate that greater terrigenous input may have led to more REE enrichment in the WA-A than WA-B phosphorites,but this cannot explain the extraordinary REE enrichment in the ZJ *** F/P_(2)O_(5)values of the francolite grains in the ZJ phosphorites(~0.097)are higher than those in the WA-A(~0.084)and WA-B(~0.084)phosphorites,and the grain size of the francolite in the ZJ phosphorites(~89.9 nm)is larger than those in the WA-A(~56.6 nm)and WA-B(~57.4 nm)phosphorites,indicative of more intense reworking of the ZJ than WA phosphorites during early diagenesis.A plot of Nd concentration versus Ce/Ce^(*)r

关键词： REE enrichment Francolite,phosphorites Sedimentary reworking Rate of sedimentary

Discovery of super-silicic and super-titanic garnets in garnet-pyroxenite in Zhaheba and its geological significance

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Chinese Science Bulletin 2008年第14期53卷 2186-2191页

作者： niu hecai ZHANG HaiXiang SHAN Qiang YU XueYuan Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China

Super-silicic garnet which exists stably at more than 5 GPa is a typical ultra-high pressure mineral. The super-silicic garnet and super-titanic garnet were discovered for the first time in garnet-pyroxenite of early Paleozoic Zhaheba-Aermantai orogenic belt in north Xinjiang. Our study indicates that these su- per-silicic garnets as well as super-titanic garnets were formed at a depth of at least 300 km. Their host rock―― garnet-pyroxenite is one kind of ultra-pressure metamorphic rocks which is related to the ul- tra-deep subduction of the oceanic crust. Thus, the early Paleozoic Zhaheba-Aermantai orogenic belt is related to the ultra-deep subduction of the Paleo-Asian oceanic crust.

关键词：蛇纹石辉岩石榴石变质作用

Discovery of Mg-righ volcanic rock series in western Altay area, Xinjiang and its geologic significance

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Chinese Science Bulletin 1999年第18期44卷 1685-1688页

作者： hecai niu Jifeng Xu Xueyuan Yu Fanrong Chen Zouping Zheng Chinese Acad Sci Guangzhou Inst Geochem Canton 510640 Peoples R China

A series of Mg-rich volcanic rocks, including rare Mg-rich dacites in the Asherle copper mine, western Altay Area, has been found. This suite of Mg-rich volcanic rocks is characterized by high SiO2, MgO and low Ti contents. Compared with the island arc tholeiite and MORB, these rocks are depleted in HFSE and are therefore similar to boninite. The dacites show V-shaped distribution REE patterns whereas the basalts display flat or

关键词： Mg-rich volcanic rock Middle Devonian Altay Xinjiang.

Zircon SHRIMP U-Pb dating on plagiogranite from Kuerti ophiolite in Altay,North Xinjiang

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Chinese Science Bulletin 2003年第20期48卷 2231-2235页

作者： ZHANG Haixiang niu hecai Kentaro Terada YU Xueyuan Hiroaki Sato Jun抜chi Ito Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China Graduate School of Science Hiroshima University Higashi-Hiroshima 739-8526 Japan Graduate School of Science and Technology Kobe University Kobe 657-8501 Japan

Field observation, petrological and geochemical characteristics of plagiogranite from Kuerti ophiolite indicate a similar origin to those in shearing zones. It isderived from partial melting of amphibolite that is developed from gabbro within the ocean layer 3 shear zone by the low-angle shearing deformation during the oceanic crustmigrating process. Zircon SHRIMP age of 372±19 Ma for the plagioganite from Kuerti ophiolite indicates that thisophiolite formed in the Devonian period and it alsorepresented the time of extension of the Kuerti backarc basin that is relevant to the northwards subduction of thePaleo-Asian oceanic crust. Therefore, the northwardssubduction of the Paleo-Asian Ocean beneath the Siberian Plate began in the early stage of the Late Paleozoic era.

关键词：新疆北部斜长花岗岩蛇绿岩锆石U-Pb测年古生代

Adakite-type sodium-rich rocks in Awulale Mountain of west Tianshan:Significance for the vertical growth of continental crust

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Chinese Science Bulletin 2001年第10期46卷 811-817页

作者： XIONG Xiaolin ZHAO Zhenhua BAI Zhenghua MEI Houjun WANG Yixian WANG Qiang XU Jifeng niu hecai BAO Zhiwei Guangzhou Institute of Geochemistry Chinese Academy of SciencesGuangzhou 510640China State Key Laboratory of Mineral Deposit Research of Nanjing University Nanjing 210093China

The sodium-rich dacites and albite porphyries of Permian in the Awulale Mountain of west Tianshan have unique chemical and trace element signatures identical to adakite. These intermediate-acidic igneous rocks are characterized by high Na2O, Al2O3 and Sr contents and high Sr/Y and La/Y ratios (>40 and >20, respectively), and low Y and Yb contents, and strong depletion in HREE, and positive Eu anomaly. The (143Nd/144Nd)i is in the range from0.51236 to 0.51248 and the εNd(t) is positive value (+0.79-+3.11); the (87Sr/86Sr)i is in the range from 0.7052 to 0.7054. These Nd and Sr isotopic composition features indicate that the source rocks of these adakite-type rocks are from a weakly depleted mantle, or a depleted mantle, but was contaminated by the crustal materials. These adakite-type rocks were most likely derived from the partial melting of new underplated basaltic rocks under the conditions of amphibo-lite to eclogite transition in the postcollisional environment of North Xinjiang during the Permian

关键词： Awulale adakite-type rocks underplating vertical growth of continental crust.

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Chinese Science Bulletin 2001年第15期46卷 1312-1316页

作者： Jifeng Xu Houjun Mei Xueyuan Yu Zhenghua Bai hecai niu Fanrong Chen Zuoping Zhen Qiang Wang Chinese Acad Sci Guangzhou Inst Geochem Guangzhou 510640 Peoples R China

Volcanic rocks with adakitic compositional signature have been recognized in the northern margin of ancient Junggar island arc for the Late Paleozoic. These adakites for the early Devonian from the Tuoranggekudouke Group (D1t) are characteristic of high Sr, Sr/Y and (La/Yb)N but low Y, Yb and HREE. Their compositional characteristics are much similar to those of the typical adakites in the world but distinct from those of the normal arc volcanic rocks from the same Group. We conclude that these adakitic volcanic rocks were produced by slab melting during the early period of Paleoasia-ocean lithosphere subduction. This infers that the Paleoasia Ocean in the north Junggar area began a new subduction process in the early Devonian.

关键词： adakite volcanic rocks Paleoasia Ocean subduction Junggar Xinjiang.

扫描电镜-能谱在单个包裹体物质组成研究中的应用

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岩石学报 2000年第4期16卷 711-714页

作者：单强牛贺才中国科学院广州地球化学研究所广州510640

利用扫描电镜 -能谱对四川冕宁稀土矿床早期萤石的单个流体 -熔融包裹体中的成分进行了分析 ,发现包裹体内流体相阳离子以 Na、Ca、K、Ba为主 ,阴离子以 SO4、F、Cl为主 ,有意义的是在包裹体中发现了 L a、Ce、Nd等稀土元素 ,其中矿化... 详细信息

利用扫描电镜 -能谱对四川冕宁稀土矿床早期萤石的单个流体 -熔融包裹体中的成分进行了分析 ,发现包裹体内流体相阳离子以 Na、Ca、K、Ba为主 ,阴离子以 SO4、F、Cl为主 ,有意义的是在包裹体中发现了 L a、Ce、Nd等稀土元素 ,其中矿化元素铈的含量最高。

关键词：扫描电镜-能谱流体-熔融包裹体稀土矿床地质

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小秦岭草滩碳酸岩型铁矿床形成机制

岩石学报 2023年第11期39卷 3491-3505页

作者：赵晓晨严爽牛贺才赵旭中国科学院广州地球化学研究所矿物学与成矿学重点实验室广州510640 中国科学院大学北京100049 中国科学院深地科学卓越创新中心广州510640

草滩碳酸岩体出露于小秦岭北端,与黄龙铺碳酸岩体直线距离约18km,但二者矿化特征显著不同,前者以铁矿化为主,后者则以钼-稀土多金属矿化为特征。已有的研究认为,草滩碳酸岩是富集地幔部分熔融的产物,它不但含方解石碳酸岩,还含有早期结... 详细信息

草滩碳酸岩体出露于小秦岭北端,与黄龙铺碳酸岩体直线距离约18km,但二者矿化特征显著不同,前者以铁矿化为主,后者则以钼-稀土多金属矿化为特征。已有的研究认为,草滩碳酸岩是富集地幔部分熔融的产物,它不但含方解石碳酸岩,还含有早期结晶的白云石碳酸岩,但有关铁矿化机制的研究则鲜有报道。本文对草滩碳酸岩和铁矿石进行了元素地球化学和Sr-Nd-Pb同位素组成研究,并对两类样品中磁铁矿和磷灰石进行了原位微量元素组成分析,旨在约束碳酸岩型铁矿床的形成机制。通过岩相学和地球化学的综合研究,本文在草滩碳酸岩体中厘定出了磁铁橄磷岩,它也是母岩浆早期结晶的产物,这表明该碳酸岩体实际上是一个由方解石碳酸岩、白云石碳酸岩、磁铁橄磷岩和铁矿体组成的碳酸岩杂岩体。铁矿石的Sr-Nd-Pb同位素组成与磁铁橄磷岩相近,暗示铁矿化是富铁碳酸质岩浆自身演化的产物。草滩磁铁橄磷岩与铁矿石中磁铁矿和磷灰石的微量元素地球化学特征显示,铁矿化发生在岩浆阶段;但与磁橄磷岩相比,铁矿石的母岩浆演化程度更高,不但明显富集挥发分,且体系氧逸度也明显增加。

关键词：草滩碳酸岩磁铁橄磷岩铁矿化岩浆演化氧逸度

新疆北部阿尔泰南缘晚古生代高钾高硅熔结凝灰岩的地球化学、岩浆成因及构造背景

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岩石学报 2007年第7期23卷 1721-1729页

作者：单强牛贺才于学元曾乔松中国科学院广州地球化学研究所成矿动力学重点实验室广州510640

新疆北部阿尔泰南缘分布着一条晚古生代的火山岩带。通过岩石学和地球化学的研究,我们从克朗和麦兹火山-沉积盆地的下泥盆统康布铁堡组地层的火山岩中,厘定出一种高钾高硅熔结凝灰岩(Ignimbrite),前人称之为钾质流纹岩。高钾高硅熔结凝... 详细信息

新疆北部阿尔泰南缘分布着一条晚古生代的火山岩带。通过岩石学和地球化学的研究,我们从克朗和麦兹火山-沉积盆地的下泥盆统康布铁堡组地层的火山岩中,厘定出一种高钾高硅熔结凝灰岩(Ignimbrite),前人称之为钾质流纹岩。高钾高硅熔结凝灰岩主要由钾长石(微斜长石)、石英和黑云母,以及少量白云母组成。其岩石化学成分的特征为过铝质的(A/CNK=1.01～1.36)、高硅(SiO_2=69%～80%)、高钾(K_2O=5%～11%)、高钾钠比值,并富集大离子亲石元素(Rb,Ba,K,La),亏损高场强元素(Nb,Ta,Ti,P)和低的 Nb/Y 比值,以及富 LREE 和亏损 Eu 的 REE 分布模式。以上这些特征体现它们继承了形成硅质岩浆的大陆地壳源区特点。微量元素的构造环境判别图解显示,本区高钾高硅熔结凝灰岩形成于活动大陆边缘的岛弧构造环境。综合岩石学和地球化学研究的结果,作者提出高钾高硅熔结凝灰岩岩浆的二阶段成因模型:1)地幔楔二辉橄榄岩部分熔融产生的大体积玄武岩岩浆侵入导致其上部地壳发生部分熔融形成了高硅的熔结凝灰岩岩浆;2)高硅岩浆经富钠斜长石的分离结晶作用最终形成高钾高硅的熔结凝灰岩浆。

关键词：高钾高硅熔结凝灰岩阿尔泰南缘晚古生代火山作用分离结晶作用