Stability conditions and compositional variations of deerite in high-pressure meta-ironstone during subduction-exhumation processes (SW Tianshan, China)
文献类型：期刊论文
| 作者 | Li, Ji-Lei2,4; Klemd, Reiner1; Hoefer, Heidi E.3; Gao, Jun2,4,5 |
| 刊名 | LITHOS
 |
| 出版日期 | 2021-10-01 |
| 卷号 | 398页码:18 |
| 关键词 | Subduction zone Eclogite Deerite P-T evolution Oxygen fugacity Tianshan |
| ISSN号 | 0024-4937 |
| DOI | 10.1016/j.lithos.2021.106245 |
| 英文摘要 | Index minerals in metamorphic rocks, such as coesite, glaucophane, or lawsonite, are of great importance to understand high-pressure (HP) to ultrahigh-pressure (UHP) metamorphism, the thermal gradient, and the geodynamics of subduction zones. Deerite is thought to be diagnostic for blueschist-facies metamorphism in cold subduction environments and a sensitive indicator of the oxygen fugacity (fO(2)) in Fe-rich rocks. However, little is known concerning its stability and compositional variation during subduction and exhumation cycles. In this study, we provide the first detailed investigation of deerite in eclogite-facies meta-ironstones (deerite-garnet riebeckitite) from the Southwestern Tianshan (U)HP metamorphic belt. Petrological observation and textural evidence suggest that the meta-ironstones -enclosing eclogite blocks- form part of an initially coherent volcano-sedimentary sequence that underwent a common tectono-metamorphic evolution, including HP metamorphism and subsequent exhumation. Two types of deerite, which display a different texture (inclusion vs. matrix) and composition (TiO2 content), occur in the deerite-garnet riebeckitite. Dee_1 and aegirine-augite appear exclusively as fine-grained inclusions in garnet, and together with garnet, riebeckite, quartz and magnetite form the peak metamorphic mineral assemblages at P-T conditions of similar to 510 degrees C and 2.6 GPa. Matrix deerite (Dee_2), on the other hand, mainly occurs as coarse-grained rods and acicular needle-like grains in quartz, and rarely as inclusions in riebeckite and garnet intimately in the riebeckitite, representing the blueschist-facies retrogression of the meta-ironstones during exhumation. The garnet-clinopyroxene oxybarometer and thermodynamic calculations show that the fO(2) of the deerite-garnet riebeckitite increases from Delta FMQ-0.64 at the peak eclogite-facies stage to Delta FMQ+1.5 at the blueschist-facies retrogression. This fO(2) variation corresponds to the chemical variation of deerite, whereby the TiO2 content increases gradually from <0.1 wt% in the Dee_1 in garnet to about 5 wt% in the matrix Dee_2. Our study reveals the detailed metamorphic P-T-fO(2) evolution of the prograde eclogite-and retrograde blueschist-facies deerite-bearing meta-ironstones during subduction-exhumation processes. This study further emphasizes the potential of deerite to reveal the P-T-fO(2) evolution of subduction-related high-pressure rocks. (C) 2021 Elsevier B.V. All rights reserved. |
| WOS关键词 | FLUID-ROCK INTERACTION ; CONSISTENT THERMODYNAMIC DATA ; OXIDATION-STATE ; OXYGEN FUGACITY ; HYDROTHERMAL ALTERATION ; LAWSONITE ECLOGITE ; METAMORPHIC ROCKS ; PHASE-EQUILIBRIA ; OXIDE MINERALS ; NW-CHINA |
| 资助项目 | National Natural Science Foundation of China[41772056] ; National Natural Science Foundation of China[41972060] ; National Key Research and Development Program of China[2018YFA0702701] ; Youth Innovation Promotion Association CAS[2018090] |
| WOS研究方向 | Geochemistry & Geophysics ; Mineralogy |
| 语种 | 英语 |
| WOS记录号 | WOS:000687294400001 |
| 出版者 | ELSEVIER |
| 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 Key Research and Development Program of China ; National Key Research and Development Program of China ; National Key Research and Development Program of China ; National Key Research and Development Program of China ; Youth Innovation Promotion Association CAS ; Youth Innovation Promotion Association CAS ; Youth Innovation Promotion Association CAS ; Youth Innovation Promotion Association CAS ; 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 Key Research and Development Program of China ; National Key Research and Development Program of China ; National Key Research and Development Program of China ; National Key Research and Development Program of China ; Youth Innovation Promotion Association CAS ; Youth Innovation Promotion Association CAS ; Youth Innovation Promotion Association CAS ; Youth Innovation Promotion Association CAS ; 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 Key Research and Development Program of China ; National Key Research and Development Program of China ; National Key Research and Development Program of China ; National Key Research and Development Program of China ; Youth Innovation Promotion Association CAS ; Youth Innovation Promotion Association CAS ; Youth Innovation Promotion Association CAS ; Youth Innovation Promotion Association CAS ; 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 Key Research and Development Program of China ; National Key Research and Development Program of China ; National Key Research and Development Program of China ; National Key Research and Development Program of China ; Youth Innovation Promotion Association CAS ; Youth Innovation Promotion Association CAS ; Youth Innovation Promotion Association CAS ; Youth Innovation Promotion Association CAS |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/102609]  |
| 专题 | 地质与地球物理研究所_中国科学院矿产资源研究重点实验室 |
| 通讯作者 | Li, Ji-Lei |
| 作者单位 | 1.Univ ErlangenNurnberg, GeoZentrum Nordbayern, Schlossgarten 5a, D-91054 Erlangen, Germany 2.Chinese Acad Sci, Innovat Acad Earth Sci, Beijing 100029, Peoples R China 3.Goethe Univ Frankfurt Main, Inst Geowissensch, Altenhoferallee 1, D-60438 Frankfurt, Germany 4.Chinese Acad Sci, Inst Geol & Geophys, Key Lab Mineral Resources, POB 9825, Beijing 100029, Peoples R China 5.Univ Chinese Acad Sci, Coll Earth & Planetary Sci, Beijing 100049, Peoples R China |
| 推荐引用方式 GB/T 7714 | Li, Ji-Lei,Klemd, Reiner,Hoefer, Heidi E.,et al. Stability conditions and compositional variations of deerite in high-pressure meta-ironstone during subduction-exhumation processes (SW Tianshan, China)[J]. LITHOS,2021,398:18. |
| APA | Li, Ji-Lei,Klemd, Reiner,Hoefer, Heidi E.,&Gao, Jun.(2021).Stability conditions and compositional variations of deerite in high-pressure meta-ironstone during subduction-exhumation processes (SW Tianshan, China).LITHOS,398,18. |
| MLA | Li, Ji-Lei,et al."Stability conditions and compositional variations of deerite in high-pressure meta-ironstone during subduction-exhumation processes (SW Tianshan, China)".LITHOS 398(2021):18. |
入库方式： OAI收割
来源：地质与地球物理研究所
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