In situ Sr isotopic analyses of epidote: tracing the sources of multi-stage fluids in ultrahigh-pressure eclogite (Ganghe, Dabie terrane)

doi:10.1007/s00410-014-0975

	In situ Sr isotopic analyses of epidote: tracing the sources of multi-stage fluids in ultrahigh-pressure eclogite (Ganghe, Dabie terrane)
	Guo, Shun; Ye, Kai; Yang, Yueheng; Chen, Yi; Zhang, Lingmin; Liu, Jingbo; Mao, Qian; Ma, Yuguang
刊名	CONTRIBUTIONS TO MINERALOGY AND PETROLOGY
	2014-02-01
卷号	167 期号:2
关键词	In situ Sr isotope Epidote UHP eclogite Vein Multi-stage fluids Dabie
ISSN号	0010-7999
DOI	10.1007/s00410-014-0975
文献子类	Article
英文摘要	This study presents in situ strontium (Sr) isotope and Sr content data on multi-stage epidote crystals from ultrahigh-pressure (UHP) eclogites and omphacite-epidote veins therein at Ganghe (Dabie terrane, China), determined using LA-MC-ICP-MS. The Ganghe eclogites occur as lenses in mainly leucocratic UHP gneisses, and therefore, our data provide insights into the origin, composition, and transport scale of the discrete multi-stage fluids in UHP eclogites during the subduction and exhumation of a continental crust. Four textural types of epidote that record compositional and isotopic signatures of fluid at various metamorphic P-T conditions have been distinguished based on petrographic observations and compositional analyses. They are (1) fine-grained high-pressure (HP) epidote inclusions (Ep-In) in omphacite that define the earliest stage of epidote formation in the eclogite; (2) coarse-grained UHP epidote porphyroblasts (Ep-P) that contain omphacite with Ep-In inclusions in the eclogite; (3) fine-grained HP epidote in omphacite-epidote veins (Ep-V) as well as (4) the lateststage epidote in disseminated amphibolite-facies veinlets (Ep-A), which crosscut the Ep-P or matrix minerals in the eclogite and HP vein. Both Ep-P and Ep-V crystals exhibit significant and complex chemical zonations with respect to the XFe (= Fe/(Fe + Al)) ratio and Sr content. In contrast to the varying Sr contents, Ep-In, Ep-P, and Ep-V have similar and narrow ranges of initial Sr-87/(86) Sr ratios (from 0.70692 to 0.70720 for Ep-In, from 0.70698 to 0.70721 for Ep-P, and from 0.70668 to 0.70723 for Ep-V), which are significantly different from those in Ep-A (from 0.70894 to 0.71172). The initial Sr-87/(86) Sr ratio of Ep-A is closer in value to the initial Sr isotopic composition of the gneisses (from 0.710790 to 0.712069) which enclose the UHP eclogite. These data indicate different sources of the eclogite-facies fluids and retrograde amphibolite-facies fluid in the Ganghe eclogites. The HP-UHP fluids responsible for the large amounts of hydrous minerals in the eclogites were internally derived and buffered. The omphacite-epidote veins were precipitated from the channelized solute-rich HP-UHP fluids released from the host eclogite. However, hydrated amphibolite-facies metamorphism during exhumation was mainly initiated by the low-Sr and high-Sr-87/(86) Sr external fluid, which infiltrated into the eclogite from the surrounding gneisses. The eclogite-facies fluids in the Ganghe eclogites were locally derived, whereas the infiltration of the retrograde amphibolite-facies fluid from the gneisses required a long transport, most likely longer than 80 m. This study highlights that the in situ Sr isotopic analysis of multi-stage epidote can be employed as a powerful geochemical tracer to provide key information regarding the origin and behavior of various-stage subduction-zone metamorphic fluids.
WOS关键词	SUBDUCTED CONTINENTAL-CRUST ; MC-ICP-MS ; COESITE-BEARING ECLOGITE ; NORTH CHINA CRATON ; ROCKS SESIA ZONE ; U-PB AGE ; METAMORPHIC ROCKS ; EASTERN CHINA ; WESTERN ALPS ; ELEMENT MOBILITY
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
语种	英语
出版者	SPRINGER
WOS记录号	WOS:000332584800012
资助机构	National Basic Research Program of China (973 Program)(2009CB825001) ; National Basic Research Program of China (973 Program)(2009CB825001) ; National Basic Research Program of China (973 Program)(2009CB825001) ; National Basic Research Program of China (973 Program)(2009CB825001) ; National Science Foundation of China(41102034 ; National Science Foundation of China(41102034 ; National Science Foundation of China(41102034 ; National Science Foundation of China(41102034 ; 41372079 ; 41372079 ; 41372079 ; 41372079 ; 41090371) ; 41090371) ; 41090371) ; 41090371) ; National Basic Research Program of China (973 Program)(2009CB825001) ; National Basic Research Program of China (973 Program)(2009CB825001) ; National Basic Research Program of China (973 Program)(2009CB825001) ; National Basic Research Program of China (973 Program)(2009CB825001) ; National Science Foundation of China(41102034 ; National Science Foundation of China(41102034 ; National Science Foundation of China(41102034 ; National Science Foundation of China(41102034 ; 41372079 ; 41372079 ; 41372079 ; 41372079 ; 41090371) ; 41090371) ; 41090371) ; 41090371) ; National Basic Research Program of China (973 Program)(2009CB825001) ; National Basic Research Program of China (973 Program)(2009CB825001) ; National Basic Research Program of China (973 Program)(2009CB825001) ; National Basic Research Program of China (973 Program)(2009CB825001) ; National Science Foundation of China(41102034 ; National Science Foundation of China(41102034 ; National Science Foundation of China(41102034 ; National Science Foundation of China(41102034 ; 41372079 ; 41372079 ; 41372079 ; 41372079 ; 41090371) ; 41090371) ; 41090371) ; 41090371) ; National Basic Research Program of China (973 Program)(2009CB825001) ; National Basic Research Program of China (973 Program)(2009CB825001) ; National Basic Research Program of China (973 Program)(2009CB825001) ; National Basic Research Program of China (973 Program)(2009CB825001) ; National Science Foundation of China(41102034 ; National Science Foundation of China(41102034 ; National Science Foundation of China(41102034 ; National Science Foundation of China(41102034 ; 41372079 ; 41372079 ; 41372079 ; 41372079 ; 41090371) ; 41090371) ; 41090371) ; 41090371)
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/84874]
专题	中国科学院地质与地球物理研究所
通讯作者	Guo, Shun
作者单位	Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing 100029, Peoples R China
推荐引用方式 GB/T 7714	Guo, Shun,Ye, Kai,Yang, Yueheng,et al. In situ Sr isotopic analyses of epidote: tracing the sources of multi-stage fluids in ultrahigh-pressure eclogite (Ganghe, Dabie terrane)[J]. CONTRIBUTIONS TO MINERALOGY AND PETROLOGY,2014,167(2).
APA	Guo, Shun.,Ye, Kai.,Yang, Yueheng.,Chen, Yi.,Zhang, Lingmin.,...&Ma, Yuguang.(2014).In situ Sr isotopic analyses of epidote: tracing the sources of multi-stage fluids in ultrahigh-pressure eclogite (Ganghe, Dabie terrane).CONTRIBUTIONS TO MINERALOGY AND PETROLOGY,167(2).
MLA	Guo, Shun,et al."In situ Sr isotopic analyses of epidote: tracing the sources of multi-stage fluids in ultrahigh-pressure eclogite (Ganghe, Dabie terrane)".CONTRIBUTIONS TO MINERALOGY AND PETROLOGY 167.2(2014).