Subducted Mg-rich carbonates into the deep mantle wedge
文献类型：期刊论文
| 作者 | Shen, Ji1; Li, Shu-Guang1,2; Wang, Shui-Jiong2; Teng, Fang-Zhen3; Li, Qiu-Li4; Liu, Yong-Sheng5 |
| 刊名 | EARTH AND PLANETARY SCIENCE LETTERS
 |
| 出版日期 | 2018-12-01 |
| 卷号 | 503页码:118-130 |
| 关键词 | subducted carbonates mantle wedge metasomatism Mg isotope O isotope supercritical liquid |
| ISSN号 | 0012-821X |
| DOI | 10.1016/j.epsl.2018.09.011 |
| 英文摘要 | Recent studies have concluded that subducted calcium (Ca-) rich carbonates could be dissolved in slab derived aqueous fluids and transported upwards into the shallow mantle wedge (75-120 km), while magnesium (Mg-) rich carbonates could be delivered to a greater depth (i.e., the mantle transition zone, similar to 410 km), melted, and recycled into the convective upper mantle. However, it remains unknown whether or not Mg-rich carbonates can be transferred to the deep mantle wedge (>similar to 120 km) by subduction-zone fluids, which, if true, is important for tracing deep carbon. In this paper, we report a comprehensive mineralogical, geochemical, stable (Mg and O) and radiogenic isotopic (zircon U-Pb) study of garnet clinopyroxenites from the Maowu ultra-mafic massif (a slice of the mantle wedge) in the Dabie orogeny, Central China. Whole-rock and mineral trace elemental features and zircon U-Pb ages reveal evidence of mantle wedge metasomatism by a slab-derived melt or supercritical fluid from the subducted rutile-bearing eclogitic Paleo-Tethys oceanic crust, in addition to subsequent metamorphism occurring during the Triassic collision between the South and North China blocks. Combined with the results of previous works, the high Th/U ratios of both whole rocks and metasomatized zircons with no oscillatory zoning lead us to infer that a supercritical liquid rather than a melt was the metasomatic agent during oceanic subduction at peak conditions (5.3-6.3 GPa and similar to 800 degrees C, 160-190 km). Abundant carbonate mineral inclusions (including calcite, dolomite and magnesite) and the high delta O-18(VSMOW) values of the metasomatized zircons (up to 12.2 parts per thousand) indicate that sedimentary carbonates were leached by the supercritical fluid. Furthermore, whole-rock delta Mg-26 values (-0.99 parts per thousand to -0.65 parts per thousand) that are lower than normal mantle values (-0.25 +/- 0.07 parts per thousand) imply that the incorporated carbonates contain not only calcites but also a certain amount of dolomites (approximately 1-10 wt.% of the metasomatic supercritical liquid). The dissolved Mg-rich carbonates in the slab-derived supercritical liquid could effectively modify the Mg isotope composition of the deep mantle wedge. Our study represents a critical step towards achieving a broad understanding of the behaviours of recycled carbonate during slab subduction. (C) 2018 Elsevier B.V. All rights reserved. |
| WOS关键词 | MAGNESIUM ISOTOPIC HETEROGENEITY ; TRACE-ELEMENT SIGNATURE ; ZIRCON U-PB ; EASTERN CHINA ; SILICATE MELTS ; NORTH CHINA ; CONTINENTAL SUBDUCTION ; PYROXENITE XENOLITHS ; THERMAL-DIFFUSION ; OXYGEN ISOTOPES |
| 资助项目 | National Key R&D Program of China[2016YFC0600404] ; Chinese Ministry of Science and Technology[2015CB856102] ; National Science Foundation[41730214] ; National Science Foundation[41230209] ; National Science Foundation[41090372] ; National Science Foundation[EAR-1340160] ; National Natural Science Foundation of China[41403001] ; National Natural Science Foundation of China[41673006] ; Chinese Academy of Science[XDPB11] |
| WOS研究方向 | Geochemistry & Geophysics |
| 语种 | 英语 |
| WOS记录号 | WOS:000449246100013 |
| 出版者 | ELSEVIER SCIENCE BV |
| 资助机构 | National Key R&D Program of China ; National Key R&D Program of China ; Chinese Ministry of Science and Technology ; Chinese Ministry of Science and Technology ; National Science Foundation ; National Science Foundation ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; Chinese Academy of Science ; Chinese Academy of Science ; National Key R&D Program of China ; National Key R&D Program of China ; Chinese Ministry of Science and Technology ; Chinese Ministry of Science and Technology ; National Science Foundation ; National Science Foundation ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; Chinese Academy of Science ; Chinese Academy of Science ; National Key R&D Program of China ; National Key R&D Program of China ; Chinese Ministry of Science and Technology ; Chinese Ministry of Science and Technology ; National Science Foundation ; National Science Foundation ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; Chinese Academy of Science ; Chinese Academy of Science ; National Key R&D Program of China ; National Key R&D Program of China ; Chinese Ministry of Science and Technology ; Chinese Ministry of Science and Technology ; National Science Foundation ; National Science Foundation ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; Chinese Academy of Science ; Chinese Academy of Science |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/89434]  |
| 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 | Shen, Ji; Li, Shu-Guang |
| 作者单位 | 1.Univ Sci & Technol China, Sch Earth & Space Sci, CAS Key Lab Crust Mantle Mat & Environm, Hefei 230026, Anhui, Peoples R China 2.Univ Geosci, State Key Lab Geol Proc & Mineral Resources, Beijing 100083, Peoples R China 3.Univ Washington, Dept Earth & Space Sci, Isotope Lab, Seattle, WA 98195 USA 4.Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing 100029, Peoples R China 5.China Univ Geosci, Fac Earth Sci, State Key Lab Geol Proc & Mineral Resources, Wuhan 430074, Hubei, Peoples R China |
| 推荐引用方式 GB/T 7714 | Shen, Ji,Li, Shu-Guang,Wang, Shui-Jiong,et al. Subducted Mg-rich carbonates into the deep mantle wedge[J]. EARTH AND PLANETARY SCIENCE LETTERS,2018,503:118-130. |
| APA | Shen, Ji,Li, Shu-Guang,Wang, Shui-Jiong,Teng, Fang-Zhen,Li, Qiu-Li,&Liu, Yong-Sheng.(2018).Subducted Mg-rich carbonates into the deep mantle wedge.EARTH AND PLANETARY SCIENCE LETTERS,503,118-130. |
| MLA | Shen, Ji,et al."Subducted Mg-rich carbonates into the deep mantle wedge".EARTH AND PLANETARY SCIENCE LETTERS 503(2018):118-130. |
入库方式： OAI收割
来源：地质与地球物理研究所
浏览0
下载0
收藏0
其他版本
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。