检索结果-南通市图书馆

Genetic Mechanism of mineral inclusions in Zircons from the Khondalite Series, Southeastern Inner Mongolia

Acta Geologica Sinica(English Edition) 2003年第1期77卷 28-35页

作者： LIU Fulai and SHEN Qihan Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037 Chinese Acad Geol Sci Inst Geol Beijing 100037 Peoples R China

The early Precambrian khondalite series is widely distributed in theJining-Zhuozi-Fengzhen-Liangcheng area, southeastern Inner Mongolia. The khondalite series mainlyconsists of sillimanite garnet potash feldspar (or two-feldspar) gneiss and garnet biotiteplagioclase gneiss. These gneissic rocks have commonly experienced granulite-facies metamorphism. Inzircons separated from sillimanite garnet potash feldspar gneisses, many mineral inclusions,including Sil, Grt, Ky, Kfs, Qtz and Ap, have been identified by the Laser Raman ***, prograde metamorphic mineral inclusion assemblages such as Ky + Kfs + Qtz + Ap and Ky +Grt + Kfs + Qtz are preserved in the core of zircon, while peak granulite-facies metamorphicminerals including Sil + Grt + Kfs + Qtz and Sil + Gif + Kfs + Qtz + Ap are identified in the mantleand rim of the same zircon. However, in some zircons are only preserved the peak metamorphicminerals such as Sil + Grt + Kfs + Qtz and Sil + Grt + Kfs + Qtz + Ap from core to rim, and inothers are inherited the primary cores with minor mineral inclusions of Kfs + Qtz, with peakmetamorphic mineral inclusions around the inherited cores. These data indicate that the mineralassemblage evolution of sillimanite garnet potash feldspar gneisses in the study are did experiencea polymorphic transformation of kyanite to sillimanite. In garnet biotite plagioclase gneisses,secondary electron microscopic images reveal that most zircons display distinct zoning textures,which comprise cores and rims, each with distinctive inclusion assemblages. The inherited mineralinclusions, mainly consisting of Kfs + Pl + Qtz, Kfs + Qtz and Kfs + Qtz + Ap, are preserved in theprimary cores, while peak granulite-facies mineral asemblages, including Grt + Bt + Pl + Qtz + Ap,Grt + Bt + Pl + Qtz and Grt + Bt + Pl + Qtz + Rt, are identified on the rims. The occurrence of peakmetamorphic mineral inclusions in zircons indicates that these gneissic rocks, includingsillimanite garnet potas

关键词： mineral inclusion zircon Laser Raman secondary electron microscopy genetic mechanism khondalite series Inner Mongolia

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A new model for chromitite formation in ophiolites: Fluid immiscibility

引用

Science China Earth Sciences 2021年第2期64卷 220-230页

作者： Benxun SU Xia LIU Chen CHEN Paul TROBINSON Yan XIAO Meifu ZHOU Yang BAI Ibrahim UYSAL Pengfei ZHANG Key Laboratory of mineral Resources Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Innovation Academy for Earth Science Chinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China Department of Earth Sciences the University of Hong KongHong Kong 999077China Department of Geological Engineering Karadeniz Technical UniversityTrabzon 61080Turkey

Although the involvement of hydrous fluids has been widely invoked in formation of podiform chromitites in ophiolites, there is lack of natural evidence to signify the role and mechanism of fluids. In this study, a new model for the genesis of podiform chromitite is proposed on basis of revisits of comprehensive petrological, mineralogical and geochemical results of the well-preserved K?z?lda? ophiolite and the well-characterized Luobusa chromite deposit. In this model, ascending magmas intruding oceanic lithospheric mantle would presumably form a series of small magma chambers continuously connected by conduits. Tiny chromite nuclei would collect fluids dispersed in such magmas to form nascent droplets. They tend to float upward in the magma chamber and would be easily transported upward by flowing magmas. Chromite-rich droplets would be enlarged via coalescence of dispersed droplets during mingling and circulation in the magma chamber and/or transport in magma conduits. Crystallization of the chromite-rich liquid droplets would proceed from the margin of the droplet inward, leaving liquid entrapped within grains as precursor of mineral inclusions. With preferential upward transportation, immiscible chromite-rich liquids would coalesce to a large pool in a magma chamber. Large volumes of chromite would crystallize in situ, forming podiform chromitite and resulting in fluid enrichment in the chamber. The fluids would penetrate and compositionally modify ambient dunite and harzburgite, leading to significant fractionations of elemental and isotopic compositions between melts and fluids from which dunite and chromitite respectively formed. Therefore, fluid immiscibility during basaltic magma ascent plays a vital role in chromitite formation.

关键词： Chromitite Fluid immiscibility mineral inclusion Ophiolite

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Metamorphic Evolution of a Tremolite Marble from the Dabie UHP Terrane,China:A Focus on Zircon

引用

Journal of Earth Science 2022年第2期33卷 493-506页

作者： Penglei Liu Zhenmin Jin School of Earth Sciences China University of GeosciencesWuhan 430074China

In this study,a tremolite marble from the Dabie ultrahigh-pressure(UHP)terrane,eastcentral China was investigated for its metamorphic evolution by focusing on *** marble contains an amphibolite-facies assemblage of dolomite,Mg-calcite,tremolite,biotite,and plagioclase,while zircon in the marble witnesses a complex recrystallization and growth history under both amphiboliteand eclogite-facies *** reveals eight characteristic zones for *** indicated by mineral inclusions in zircon,two zones formed no earlier than amphibolite-facies retrogression and are too thin to *** other six zones contain inclusions of dolomite,aragonite,diopside(X_(Na)=Na/(Na+Ca)=0.11-0.14),garnet(X_(Ca)=0.51-0.62,X_(Mg)=0.21-0.23,X_(Fe)=0.17-0.26,X_(Mn)=0.01),phengite and rutile,and formed under eclogite-facies *** equilibria calculations illustrat that the Na-richest diopside formed under UHP *** an accessory eclogite-facies mineral in the marble,the analyzed chemistry of garnet inclusions cannot be reproduced by phase equilibria calculations because solid-solution models for many other minerals don't incorporate *** eclogite-facies zircon zones show low HREE contents and flat MREE-HREE distribution patterns,which are interpreted to have been determined by the low bulk-rock HREE content instead of the presence of accessary garnet in the marble.U-Pb dating yielded a large age dataset ranging from about 250 to 210 Ma for the eclogite-facies zircon ***,the eclogite-facies ages are characterized by a Gaussian distribution with a median peak at 232 *** propose that zircon experienced a“protracted”recrystallization and/or growth history in the tremolite marble during the Triassic subduction and exhumation.

关键词： Dabie UHP marble mineral inclusion recrystallization zoned zircon tectonics

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Single grain pyrite Rb-Sr dating of the Linglong gold deposit,eastern China

Single grain pyrite Rb-Sr dating of the Linglong gold deposi...

引用

中国科学院地质与地球物理研究所2008学术年会

作者： Qiu-Li Li~(a,b),Fukun Chen~(a,b,*),Jin-Hui Yang~a,Hong-Rui Fan~a a Key Laboratory of mineral Resources,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing,100029,People’s Republic of China b Laboratory for Radiogenic Isotope Geochemistry,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing,100029,People’s Republic of China

This study employs the single grain pyrite Rb-Sr technique to date mineralization,using the example of the Linglong lode gold deposit, Jiaodong Peninsula,eastern *** gold deposits in this area are interpreted to have a consistent spatial-temporal relationship with widespread Late Jurassic-Early Cretaceous magmatism in eastern China,likely related to lithospheric thinning around 120 *** of the Linglong gold mine contains different types of mineral inclusions such as sericite and feldspar that cause distinguishable variations in Rb- and Sr contents and Rb/Sr *** pyrite samples from veins of different mineralization stages give an average isochron age of 120.6±0.9 Ma. Analyses of one quartz and two sericite samples yield isochron ages between 122 Ma and 120 *** of mineralization is often hampered by disequilibrium of isotopic systems and/or the lack of suitable minerals for dating ***,the successful attempt of the single grain Rb-Sr technique of pyrite,which occurs as a common mineral phase in orebodies and is genetically related to the mineralization,has great potential for precise geochronology of hydrothermal mineral deposits.

关键词： Pyrite Single grain Rb-Sr dating Gold deposit mineral inclusion

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：