Unusual replacement of Fe-Ti oxides by rutile during retrogression in amphibolite-hosted veins (Dabie UHP terrane): A mineralogical record of fluid-induced oxidation processes in exhumed UHP slabs

doi:10.2138/am-2017-6120

CORC > 地质与地球物理研究所 > 中国科学院地质与地球物理研究所 > 岩石圈演化国家重点实验室

	Unusual replacement of Fe-Ti oxides by rutile during retrogression in amphibolite-hosted veins (Dabie UHP terrane): A mineralogical record of fluid-induced oxidation processes in exhumed UHP slabs
	Guo, Shun 1,2; Tang, Pan 1,3; Su, Bin 1,3; Chen, Yi 1,2; Ye, Kai 1; Zhang, Lingmin 4; Gao, Yijie 1,3; Liu, Jingbo 1; Yang, Yueheng 1
刊名	AMERICAN MINERALOGIST
	2017-11-01
卷号	102 期号:11 页码:2268-2283
关键词	Rutile Fe-ti Oxides Replacement Reaction Fluid Oxygen Fugacity Exhumation Dabie Uhp Terrane
ISSN号	0003-004X
DOI	10.2138/am-2017-6120
文献子类	Article
英文摘要	The replacement of rutile by Fe-Ti oxides is a common phenomenon during the retrogression of eclogites. Here, we report an unusual case regarding the replacement of Fe-Ti oxides by rutile during greenschist-facies metamorphic overprinting of veins in amphibolites (retrograded eclogites) from the Dabie ultrahigh-pressure (UHP) terrane, eastern China. The veins mainly consist of plagioclase, Fe-Ti oxides, and quartz, which crystallized from a Ti-rich amphibolite-facies fluid that formed during exhumation of the eclogites. Two types of textures involving the replacement of Fe-Ti oxides by rutile are recognized in the veins: (1) the first type is characterized by the development of rutile coronas (Rt-C) and other silicates (high-Fe epidote, muscovite, and chlorite) around the external boundaries of the Fe-Ti oxide grains, and (2) the second type is characterized by the formation of symplectitic intergrowths of rutile (Rt-S) and magnetite after exsolved hemo-ilmenite (H-Ilm) lamellae in the Fe-Ti oxides. The micro-textures, mineral assemblages, and Zr-in-rutile thermometry indicate that both replacement reactions involved mineral re-equilibration processes in the presence of an infiltrating fluid phase at similar to 476-515 degrees C, taking place by an interface-coupled dissolution-precipitation mechanism. Thermodynamic modeling reveals that both replacement reactions occurred during oxidation processes under relatively high-oxygen fugacity (f(O2)) conditions, approximately 2.5-4.5 logf(O2) units higher than the fayalite-magnetite-quartz (FMQ) reference buffer. In situ Sr isotopic analyses of epidote (Ep-C) coexisting with the Rt-C suggest that the infiltrating fluid involved in the greenschist-facies replacement reactions was externally derived from the surrounding granitic gneisses (the wall rocks of the amphibolites). Compared with the rutile in the UHP eclogites (Rt-E) and amphibolites (Rt-A), the Rt-C is characterized by distinctly lower contents of Nb (<10 ppm) and Ta (<2 ppm) and Nb/Ta ratios (<10) and higher contents of Cr (>340 ppm) and V (>1580 ppm). These results provide a geochemical fingerprint for distinguishing the low-pressure (LP) rutile from relic high-grade phases in retrograded HP-UHP rocks.
WOS关键词	ULTRAHIGH-PRESSURE ECLOGITE ; U-PB AGE ; SUBDUCTION ZONES ; EASTERN CHINA ; METAMORPHIC RUTILE ; CONTINENTAL-CRUST ; COOLING HISTORY ; OXYGEN FUGACITY ; PETROLOGICAL INTEREST ; GRADE METAMORPHISM
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
语种	英语
出版者	MINERALOGICAL SOC AMER
WOS记录号	WOS:000414669300012
资助机构	National Basic Research Program of China (973 Program)(2015CB856103) ; National Basic Research Program of China (973 Program)(2015CB856103) ; National Science Foundation of China(41672059 ; National Science Foundation of China(41672059 ; Youth Innovation Promotion Association CAS(2017090) ; Youth Innovation Promotion Association CAS(2017090) ; 41372079 ; 41372079 ; 41525012) ; 41525012) ; National Basic Research Program of China (973 Program)(2015CB856103) ; National Basic Research Program of China (973 Program)(2015CB856103) ; National Science Foundation of China(41672059 ; National Science Foundation of China(41672059 ; Youth Innovation Promotion Association CAS(2017090) ; Youth Innovation Promotion Association CAS(2017090) ; 41372079 ; 41372079 ; 41525012) ; 41525012) ; National Basic Research Program of China (973 Program)(2015CB856103) ; National Basic Research Program of China (973 Program)(2015CB856103) ; National Science Foundation of China(41672059 ; National Science Foundation of China(41672059 ; Youth Innovation Promotion Association CAS(2017090) ; Youth Innovation Promotion Association CAS(2017090) ; 41372079 ; 41372079 ; 41525012) ; 41525012) ; National Basic Research Program of China (973 Program)(2015CB856103) ; National Basic Research Program of China (973 Program)(2015CB856103) ; National Science Foundation of China(41672059 ; National Science Foundation of China(41672059 ; Youth Innovation Promotion Association CAS(2017090) ; Youth Innovation Promotion Association CAS(2017090) ; 41372079 ; 41372079 ; 41525012) ; 41525012)
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/62476]
专题	地质与地球物理研究所_岩石圈演化国家重点实验室
通讯作者	Guo, Shun
作者单位	1.Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, POB 9825, Beijing 100029, Peoples R China 2.CAS Ctr Excellence Tibetan Plateau Earth Sci, Beijing 100101, Peoples R China 3.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 4.Tongji Univ, State Key Lab Marine Geol, Shanghai 200092, Peoples R China
推荐引用方式 GB/T 7714	Guo, Shun,Tang, Pan,Su, Bin,et al. Unusual replacement of Fe-Ti oxides by rutile during retrogression in amphibolite-hosted veins (Dabie UHP terrane): A mineralogical record of fluid-induced oxidation processes in exhumed UHP slabs[J]. AMERICAN MINERALOGIST,2017,102(11):2268-2283.
APA	Guo, Shun.,Tang, Pan.,Su, Bin.,Chen, Yi.,Ye, Kai.,...&Yang, Yueheng.(2017).Unusual replacement of Fe-Ti oxides by rutile during retrogression in amphibolite-hosted veins (Dabie UHP terrane): A mineralogical record of fluid-induced oxidation processes in exhumed UHP slabs.AMERICAN MINERALOGIST,102(11),2268-2283.
MLA	Guo, Shun,et al."Unusual replacement of Fe-Ti oxides by rutile during retrogression in amphibolite-hosted veins (Dabie UHP terrane): A mineralogical record of fluid-induced oxidation processes in exhumed UHP slabs".AMERICAN MINERALOGIST 102.11(2017):2268-2283.