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Nb-Ta fractionation by partial melting at the titanite-rutile transition

文献类型：期刊论文

作者John, Timm1; Klemd, Reiner2; Klemme, Stephan1; Pfaender, Joerg A.3; Hoffmann, J. Elis4,5; Gao, Jun6
刊名CONTRIBUTIONS TO MINERALOGY AND PETROLOGY
出版日期2011
卷号161期号:1页码:35-45
关键词Crustal evolution Nb-Ta Partial melting Rutile Titanite Subduction zone Eclogite
ISSN号0010-7999
DOI10.1007/s00410-010-0520-4
文献子类Article
英文摘要During the evolution of the Earth, distinct geochemical reservoirs with different Nb/Ta ratios have developed. Archean granitoids of the tonalite-trondhjemite-granodiorite (TTG) suite, which represent the Earth's early continental crust, show larger Nb/Ta variations than any other Earth reservoir. This implies that significant Nb-Ta fractionation must have occurred during early crust formation, while the underlying mechanism behind is still unclear. Here, we present a new model on how Nb may be fractionated from Ta during partial melting of subducted oceanic crust. Our data show that Nb/Ta ratios in melts derived from rutile- and titanite-bearing eclogite are largely controlled by the modal relative abundances of rutile and titanite in the source. High modal ratios of titanite over rutile generate melts with very high Nb/Ta (> 60), whereas low modal titanite/rutile produces melts with much lower Nb/Ta (a parts per thousand currency sign30). Very low Nb/Ta (< 16) occur when all Ti-phases are consumed at very high degrees of melting. As the modal ratio of titanite to rutile is a function of pressure, the Nb/Ta of melts is a function of melting depth. Our new model helps to explain the extreme variation of Nb/Ta observed in many TTGs and thus how Nb and Ta were fractionated during the early evolution of the Earth. Furthermore, the model also indicates that simple one-stage melting models for mafic crust are not sufficient to explain the formation of TTGs.
WOS关键词EARLY CONTINENTAL-CRUST ; FLUID-ROCK INTERACTION ; ACCESSORY PHASE SATURATION ; TRACE-ELEMENT MOBILIZATION ; WESTERN TIANSHAN OROGEN ; HP-LT ROCKS ; NW-CHINA ; SUBDUCTION ZONES ; EXPERIMENTAL CONSTRAINTS ; HIGH-PRESSURE
WOS研究方向Geochemistry & Geophysics ; Mineralogy
语种英语
WOS记录号WOS:000285787900003
出版者SPRINGER
资助机构DFG(KL 692/17-2) ; DFG(KL 692/17-2) ; DFG(KL 692/17-2) ; DFG(KL 692/17-2) ; DFG(KL 692/17-2) ; DFG(KL 692/17-2) ; DFG(KL 692/17-2) ; DFG(KL 692/17-2)
源URL[http://ir.iggcas.ac.cn/handle/132A11/74228]  
专题中国科学院地质与地球物理研究所
通讯作者John, Timm
作者单位1.Univ Munster, Inst Mineral, D-48149 Munster, Germany
2.Univ Erlangen Nurnberg, GeoZentrum Nordbayern, D-91054 Erlangen, Germany
3.Tech Univ Bergakad Freiberg, Inst Geol, D-09599 Freiberg, Germany
4.Univ Bonn, Steinmann Inst, D-53115 Bonn, Germany
5.Univ Bonn, D-50674 Cologne, Germany
6.Chinese Acad Sci, Key Lab Mineral Resources, Inst Geol & Geophys, Beijing 100029, Peoples R China
推荐引用方式
GB/T 7714		 John, Timm,Klemd, Reiner,Klemme, Stephan,et al. Nb-Ta fractionation by partial melting at the titanite-rutile transition[J]. CONTRIBUTIONS TO MINERALOGY AND PETROLOGY,2011,161(1):35-45.
APA John, Timm,Klemd, Reiner,Klemme, Stephan,Pfaender, Joerg A.,Hoffmann, J. Elis,&Gao, Jun.(2011).Nb-Ta fractionation by partial melting at the titanite-rutile transition.CONTRIBUTIONS TO MINERALOGY AND PETROLOGY,161(1),35-45.
MLA John, Timm,et al."Nb-Ta fractionation by partial melting at the titanite-rutile transition".CONTRIBUTIONS TO MINERALOGY AND PETROLOGY 161.1(2011):35-45.

入库方式： OAI收割

来源：地质与地球物理研究所

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