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| Iron and magnesium isotopic compositions of subduction-zone fluids and implications for arc volcanism | |
| Huang, Jian1,2; Guo, Shun3; Jin, Qi-Zhen1; Huang, Fang1,2 | |
| 2020-06-01 | |
| Source Publication | GEOCHIMICA ET COSMOCHIMICA ACTA
 |
| ISSN | 0016-7037 |
| Volume | 278Pages:376-391 |
| Abstract | High-pressure (HP) metamorphic veins in eclogites provide insights into the composition and evolution of fluids in subduction zones. We here present the first Fe-Mg isotope data for three types of HP veins, eclogites and their mineral separates from the Dabie Orogen to constrain the Fe-Mg isotopic compositions of subduction-zone fluids and the Fe-Mg isotope behaviors during fluid-rock interaction and fluid evolution. The HP veins include omphacite-epidote (Omp-Ep), epidotequartz (Ep-Qtz), and kyanite-epidote-quartz (Ky-Ep-Qtz) veins. The Omp-Ep veins first crystallized from eclogite-derived, solute-rich vein-forming fluids with the Ep-Qtz and Ky-Ep-Qtz veins successively crystallizing from the residual fluids after the formation of the Omp-Ep veins. The early Omp-Ep veins have much heavier Fe-Mg isotopic compositions compared to the host eclogites, indicating Fe-Mg isotope fractionation during fluid-rock interaction due to preferential dissolution of isotopically heavy Omp and Ep from the eclogites into the vein-forming fluids. The delta Fe-56 and delta Mg-26 values of the Omp-Ep, Ep-Qtz, and Ky-Ep-Qtz veins gradually decrease and positively correlate with the Eu/Eu * values of whole rock and epidote. This indicates that Fe-Mg isotope fractionation during fluid evolution results from continuous crystallization of isotopically heavy Omp and Ep from the vein-forming fluids. Our results thus demonstrate that Fe-Mg isotopes can significantly fractionate during the dissolution-precipitation processes of minerals in subduction zones. The high delta Fe-56 (0.04-0.21 parts per thousand) and delta Mg-26 (-0.08 to 0.15 parts per thousand) values of fluid-related HP veins within mafic eclogites indicate that fluids derived from subducted altered oceanic crust (AOC) probably have Fe-Mg isotopic compositions similar to or higher than those of mid-ocean ridge basalts (MORBs). Thus, contribution from AOC-derived fluids is unlikely to explain the light Fe and heavy Mg isotopic compositions of arc lavas. We propose that the light Fe and heavy Mg isotopic compositions of arc lavas may result from a combination of prior melt depletion and addition of serpentinite-derived Fe-54 -Mg-26 rich fluids into the overlying mantle wedge. (C) 2019 Elsevier Ltd. All rights reserved. |
| Keyword | Fe-Mg isotope fractionation Metamorphic veins Fluid-rock interaction Fluid evolution Arc volcanism |
| DOI | 10.1016/j.gca.2019.06.020 |
| Funding Organization | Chinese Ministry of Science and Technology ; Chinese Ministry of Science and Technology ; National Key R&D Program of China ; National Key R&D Program of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; CAS Youth Innovation Promotion Association ; CAS Youth Innovation Promotion Association ; Chinese Ministry of Science and Technology ; Chinese Ministry of Science and Technology ; National Key R&D Program of China ; National Key R&D Program of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; CAS Youth Innovation Promotion Association ; CAS Youth Innovation Promotion Association ; Chinese Ministry of Science and Technology ; Chinese Ministry of Science and Technology ; National Key R&D Program of China ; National Key R&D Program of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; CAS Youth Innovation Promotion Association ; CAS Youth Innovation Promotion Association ; Chinese Ministry of Science and Technology ; Chinese Ministry of Science and Technology ; National Key R&D Program of China ; National Key R&D Program of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; CAS Youth Innovation Promotion Association ; CAS Youth Innovation Promotion Association |
| WOS Keyword | TRACE-ELEMENT MOBILIZATION ; HIGH-PRESSURE ; DABIE-SHAN ; ROCK INTERACTION ; OCEANIC-CRUST ; CONTINENTAL-CRUST ; METAMORPHIC ROCKS ; WESTERN ALPS ; MANTLE ; ECLOGITE |
| Language | 英语 |
| Funding Project | Chinese Ministry of Science and Technology[2015CB856102] ; National Key R&D Program of China[2016YFC0600404] ; National Natural Science Foundation of China[41773002] ; National Natural Science Foundation of China[41573018] ; National Natural Science Foundation of China[41630206] ; CAS Youth Innovation Promotion Association[2019449] |
| Funding Organization | Chinese Ministry of Science and Technology ; Chinese Ministry of Science and Technology ; National Key R&D Program of China ; National Key R&D Program of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; CAS Youth Innovation Promotion Association ; CAS Youth Innovation Promotion Association ; Chinese Ministry of Science and Technology ; Chinese Ministry of Science and Technology ; National Key R&D Program of China ; National Key R&D Program of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; CAS Youth Innovation Promotion Association ; CAS Youth Innovation Promotion Association ; Chinese Ministry of Science and Technology ; Chinese Ministry of Science and Technology ; National Key R&D Program of China ; National Key R&D Program of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; CAS Youth Innovation Promotion Association ; CAS Youth Innovation Promotion Association ; Chinese Ministry of Science and Technology ; Chinese Ministry of Science and Technology ; National Key R&D Program of China ; National Key R&D Program of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; CAS Youth Innovation Promotion Association ; CAS Youth Innovation Promotion Association |
| WOS Research Area | Geochemistry & Geophysics |
| WOS Subject | Geochemistry & Geophysics |
| WOS ID | WOS:000536445700011 |
| Publisher | PERGAMON-ELSEVIER SCIENCE LTD |
| Citation statistics | |
| Document Type | 期刊论文 |
| Identifier | http://ir.iggcas.ac.cn/handle/132A11/96685 |
| Collection | 岩石圈演化国家重点实验室 |
| Corresponding Author | Huang, Jian |
| Affiliation | 1.Univ Sci & Technol China, Sch Earth & Space Sci, CAS Key Lab Crust Mantle Mat & Environm, Hefei 230026, Peoples R China 2.CAS Ctr Excellence Comparat Planetol, Hefei, Peoples R China 3.Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, POB 9825, Beijing 100029, Peoples R China |
| Recommended Citation GB/T 7714 | Huang, Jian,Guo, Shun,Jin, Qi-Zhen,et al. Iron and magnesium isotopic compositions of subduction-zone fluids and implications for arc volcanism[J]. GEOCHIMICA ET COSMOCHIMICA ACTA,2020,278:376-391. |
| APA | Huang, Jian,Guo, Shun,Jin, Qi-Zhen,&Huang, Fang.(2020).Iron and magnesium isotopic compositions of subduction-zone fluids and implications for arc volcanism.GEOCHIMICA ET COSMOCHIMICA ACTA,278,376-391. |
| MLA | Huang, Jian,et al."Iron and magnesium isotopic compositions of subduction-zone fluids and implications for arc volcanism".GEOCHIMICA ET COSMOCHIMICA ACTA 278(2020):376-391. |
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