Crust-Mantle Interaction in a Continental Subduction Channel: Evidence from Orogenic Peridotites in North Qaidam, Northern Tibet

doi:10.1093/petrology/egx011

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

	Crust-Mantle Interaction in a Continental Subduction Channel: Evidence from Orogenic Peridotites in North Qaidam, Northern Tibet
	Chen, Ren-Xu 1; Li, Hai-Yong 1; Zheng, Yong-Fei 1; Zhang, Long 1; Gong, Bing 1; Hu, Zhaochu 2; Yang, Yueheng 3
刊名	JOURNAL OF PETROLOGY
	2017-02-01
卷号	58 期号:2 页码:191-226
关键词	continental collision subduction zone metamorphic geochemistry slab-mantle interaction orogenic peridotite garnet pyroxenite metasomatic zircon
ISSN号	0022-3530
DOI	10.1093/petrology/egx011
文献子类	Article
英文摘要	A combined study of rock-forming mineral and O isotope compositions, zircon U-Pb ages, trace element compositions, mineral inclusions and Hf-O isotopes was made on orogenic peridotites from North Qaidam in northern Tibet to provide insights into crustal metasomatism at the slab-mantle interface in a continental subduction channel. Rock-forming mineral O isotope analyses yield olivine delta O-18 values of 5.0-5.6 parts per thousand for lherzolites and 3.5-5.3 parts per thousand for dunites; orthopyroxene has delta O-18 values of 4.5-5.3 parts per thousand for lherzolites, 4.5-5.3 parts per thousand for dunites, and 7.8 parts per thousand for pyroxenites. It appears that the protolith of these ultramafic rocks underwent high-temperature metasomatism by both low-and high-delta O-18 fluids. The occurrence of zircon in thin section and the presence of olivine inclusions in zircon from these rocks explicitly indicates the growth of metasomatic zircon during continental subduction zone processes. Two distinct groups of zircon domains are distinguished. Intermediate-to high-luminescent zircon domains have U-Pb ages of 417 +/- 4 to 426 +/- 3Ma, variable Th/U ratios, low rare earth element (REE) contents, flat heavy REE (HREE) patterns with a relative lack of negative Eu anomalies, and inclusions of olivine, clinopyroxene, orthopyroxene and graphite. These features are interpreted as zircon growth through metasomatic reaction by addition of fluids in the early exhumation stage of deeply subducted continental crust. The Hf-O isotope compositions of these zircon domains suggest the same origin for these fluids. In contrast, low-luminescent zircon rims mostly exhibit younger U-Pb ages of 404 +/- 3 to 405 +/- 8Ma, low Th/U ratios <0.1, high REE contents, and steep HREE patterns with negative Eu anomalies, and contain calcite inclusions as well as multiphase solid inclusions of Cal+Kfs and Qtz+Kfs+Pl. Such observations indicate their growth through metasomatic reaction by infiltration of hydrous silicate melts during the late exhumation stage. All the zircon domains have variable Hf isotope compositions with a large difference between samples, but a narrow delta O-18 range from 5.4 to 6.6 parts per thousand. Their Hf-O isotope compositions are similar to those of UHP metamorphic rocks in North Qaidam, suggesting that the metasomatic fluids originated from deeply subducted continental crust. Whereas the high-delta O-18 fluids originated from deeply subducted continental crust, the low-delta O-18 fluids were derived from dehydration of the subducting oceanic crust that preceded the subduction of continental crust. The orogenic peridotites thus record the metasomatic reaction of mantle wedge peridotite with fluids of different origins.
WOS关键词	OXYGEN-ISOTOPE FRACTIONATION ; PRESSURE METAMORPHIC ROCKS ; U-PB AGES ; MULTIPHASE SOLID INCLUSIONS ; WESTERN GNEISS REGION ; SULU UHP TERRANE ; IN-SITU ANALYSIS ; LU-HF ISOTOPE ; LA-ICP-MS ; GARNET-PERIDOTITE
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	OXFORD UNIV PRESS
WOS记录号	WOS:000404122800001
资助机构	Chinese Ministry of Science and Technology(2015CB856106) ; Natural Science Foundation of China(41590620 ; Youth Innovation Promotion Association CAS(2013283) ; Fundamental Research Funds for the Central Universities(WK 3410000009) ; Foundation for the Author of National Excellent Doctoral Dissertation of PR China(201229) ; 41422301 ; 41372073) ; Chinese Ministry of Science and Technology(2015CB856106) ; Natural Science Foundation of China(41590620 ; Youth Innovation Promotion Association CAS(2013283) ; Fundamental Research Funds for the Central Universities(WK 3410000009) ; Foundation for the Author of National Excellent Doctoral Dissertation of PR China(201229) ; 41422301 ; 41372073) ; Chinese Ministry of Science and Technology(2015CB856106) ; Natural Science Foundation of China(41590620 ; Youth Innovation Promotion Association CAS(2013283) ; Fundamental Research Funds for the Central Universities(WK 3410000009) ; Foundation for the Author of National Excellent Doctoral Dissertation of PR China(201229) ; 41422301 ; 41372073) ; Chinese Ministry of Science and Technology(2015CB856106) ; Natural Science Foundation of China(41590620 ; Youth Innovation Promotion Association CAS(2013283) ; Fundamental Research Funds for the Central Universities(WK 3410000009) ; Foundation for the Author of National Excellent Doctoral Dissertation of PR China(201229) ; 41422301 ; 41372073)
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/51795]
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	Chen, Ren-Xu
作者单位	1.Univ Sci & Technol China, Sch Earth & Space Sci, CAS Key Lab Crust Mantle Mat & Environm, Hefei 230026, Peoples R China 2.China Univ Geosci, State Key Lab Geol Proc & Mat Resources, Fac Earth Sci, Wuhan 430074, Peoples R China 3.Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing 100029, Peoples R China
推荐引用方式 GB/T 7714	Chen, Ren-Xu,Li, Hai-Yong,Zheng, Yong-Fei,et al. Crust-Mantle Interaction in a Continental Subduction Channel: Evidence from Orogenic Peridotites in North Qaidam, Northern Tibet[J]. JOURNAL OF PETROLOGY,2017,58(2):191-226.
APA	Chen, Ren-Xu.,Li, Hai-Yong.,Zheng, Yong-Fei.,Zhang, Long.,Gong, Bing.,...&Yang, Yueheng.(2017).Crust-Mantle Interaction in a Continental Subduction Channel: Evidence from Orogenic Peridotites in North Qaidam, Northern Tibet.JOURNAL OF PETROLOGY,58(2),191-226.
MLA	Chen, Ren-Xu,et al."Crust-Mantle Interaction in a Continental Subduction Channel: Evidence from Orogenic Peridotites in North Qaidam, Northern Tibet".JOURNAL OF PETROLOGY 58.2(2017):191-226.