Metasomatism of the crust-mantle boundary by melts derived from subducted sedimentary carbonates and silicates

doi:10.1016/j.gca.2019.06.033

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

	Metasomatism of the crust-mantle boundary by melts derived from subducted sedimentary carbonates and silicates
	Hu, Jun 1,2; Jiang, Neng 1,2; Carlson, Richard W.3; Guo, Jinghui 1,2; Fan, Wenbo 4; Huang, Fang 5; Zhang, Shuangquan 6; Zong, Keqing 7; Li, Tiejun 1; Yu, Huimin 5
刊名	GEOCHIMICA ET COSMOCHIMICA ACTA
	2019-09-01
卷号	260 页码:311-328
关键词	Subduction Metasomatism Sediment-derived melts Pyroxenite xenoliths North China craton
ISSN号	0016-7037
DOI	10.1016/j.gca.2019.06.033
英文摘要	Substantial quantities of sediments are known to enter the deep lithosphere at subduction zones, but the extent to which sediments melt and the process involved in sediment contribution to the deep lithosphere are inadequately understood. Vigorous debate continues about whether the subducted sediment component is terrigenous or pelagic and transported as a hydrous melt, an aqueous fluid, or bulk sediment. In this contribution, we conduct an integrated study on a variety of deep-seated xenoliths in the Neogene Hannuoba basalts from the northern margin of the North China Craton. Among these xenoliths, clinopyroxenite xenoliths are compositionally and isotopically distinct. Mineral chemistry shows that the clinopyroxenite xenoliths come from a depth near the MOHO, rather than from the mantle as suggested previously. The clinopyroxenite xenoliths have extremely evolved Sr-Nd-Hf isotopic compositions and are interpreted to have a late Archean protolith age. The extremely low contents of Cr and Ni for the clinopyroxenite xenoliths preclude a magmatic origin. Instead, a metasomatic origin is suggested, which is strongly supported for the clinopyroxenites by the occurrence of hydrous minerals and high contents of large-ion-lithophile elements (K, Rb, Ba, Th and Sr) and light rare earth elements, as well as elevated delta O-18 (9.9-11.3 parts per thousand) and light delta Mg-26 (-1.04 parts per thousand to 1.42 parts per thousand) isotopic compositions. Furthermore, their high high-field-strength element (Nb, Ta, Zr and Hf) contents indicate that the metasomatic agent is a hydrous melt, rather than an aqueous fluid. The metasomatic melts are considered to be derived from a mixed source of sedimentary carbonates and ancient, felsic continental materials. A combination of zircon ages and oxygen isotope data for the clinopyroxenite xenoliths further restricts the timing of metasomatism to the late Paleozoic. Considering the regional tectonic setting, the sediments most likely came from the subducted Paleo-Asian oceanic slab. Thus the Hannuoba clinopyroxenite xenoliths provide direct evidence for melting of the subducted Paleo-Asian oceanic slab sediment and its interaction with the deep lithosphere. The data show that melting of subducted sediments can take place at a much shallower depth than commonly thought and place an independent constraint on future models of slab geotherms. (C) 2019 Elsevier Ltd. All rights reserved.
资助项目	National Natural Science Foundation of China[41573032]
WOS关键词	OXYGEN-ISOTOPE EVIDENCE ; NORTH CHINA CRATON ; FIELD-STRENGTH ELEMENTS ; VOLCANIC-ROCKS ; EASTERN CHINA ; OCEANIC-CRUST ; HF ; ND ; ASSIMILATION ; XENOLITHS
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	PERGAMON-ELSEVIER SCIENCE LTD
WOS记录号	WOS:000475938300019
资助机构	National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/92956]
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	Jiang, Neng
作者单位	1.Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing 100029, Peoples R China 2.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 3.Carnegie Inst Sci, Dept Terr Magnetism, 5241 Broad Branch Rd NW, Washington, DC 20015 USA 4.Northwest Univ, State Key Lab Continental Dynam, Xian 710069, Shaanxi, Peoples R China 5.Univ Sci & Technol China, Sch Earth & Space Sci, CAS Key Lab Crust Mantle Mat & Environm, Hefei 230026, Anhui, Peoples R China 6.Carleton Univ, Dept Earth Sci, Ottawa, ON, Canada 7.China Univ Geosci, State Key Lab Geol Proc & Mineral Resources, Wuhan 430074, Hubei, Peoples R China
推荐引用方式 GB/T 7714	Hu, Jun,Jiang, Neng,Carlson, Richard W.,et al. Metasomatism of the crust-mantle boundary by melts derived from subducted sedimentary carbonates and silicates[J]. GEOCHIMICA ET COSMOCHIMICA ACTA,2019,260:311-328.
APA	Hu, Jun.,Jiang, Neng.,Carlson, Richard W..,Guo, Jinghui.,Fan, Wenbo.,...&Yu, Huimin.(2019).Metasomatism of the crust-mantle boundary by melts derived from subducted sedimentary carbonates and silicates.GEOCHIMICA ET COSMOCHIMICA ACTA,260,311-328.
MLA	Hu, Jun,et al."Metasomatism of the crust-mantle boundary by melts derived from subducted sedimentary carbonates and silicates".GEOCHIMICA ET COSMOCHIMICA ACTA 260(2019):311-328.