中国科学院机构知识库网格
Chinese Academy of Sciences Institutional Repositories Grid
首页 机构 成果 学者
  
  1. CAS IR Grid
  2. 地质与地球物理研究所
  3. 中国科学院地质与地球物理研究所
  4. 中国科学院矿产资源研究重点实验室
The Critical Role of Fluid-Mediated Diffusion in Anomalous Fe-Mg-O Isotope Fractionations in Ultramafic Rocks of Ophiolites

文献类型：期刊论文

作者Su, Ben-Xun3,4,5; Chen, Chen3,5; Xiao, Yan2,5; Robinson, Paul T.3; Liu, Xia3,4,5; Wang, Jing3,4,5; Uysal, Ibrahim1; Bai, Yang3,4,5; Sun, Yang2,5
刊名JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
出版日期2021-04-01
卷号126期号:4页码:20
关键词Chromite Fe-Mg-O isotopes fluid immiscibility olivine ophiolite
ISSN号2169-9313
DOI10.1029/2020JB020632
英文摘要A number of bulk-rock and mineral Fe and Mg isotope data have been increasingly reported from ophiolitic rocks, but their anomalous fractionations are still not well addressed. This study presents new Fe, Mg, and O isotopes and published Li isotope data of olivine and/or chromite in chromitite, dunite, and harzburgite from the Pozanti-Karsanti ophiolite (southern Turkey) to reveal the mechanisms of inter- and intra-mineral isotope fractionation during chromitite formation. In the studied samples, both olivine and chromite have highly variable delta Fe-56 ranging from -0.125 parts per thousand to 0.101 parts per thousand and -0.261 parts per thousand to 0.191 parts per thousand, respectively, but with heavier olivine than coexisting chromite in most samples. In contrast, olivine records homogeneous Mg isotopic compositions with delta Mg-26 values of -0.36 parts per thousand to -0.26 parts per thousand, whereas chromite grains have variable but relatively high delta Mg-26 values ranging from -0.02 parts per thousand to 0.45 parts per thousand. The delta O-18 values of olivine range from 4.65 parts per thousand to 5.86 parts per thousand and co-vary with delta Li-7 (-5.43 parts per thousand to 16.65 parts per thousand), delta Fe-56, and delta Mg-26, particularly at lithological scale. These isotopic features cannot be explained solely by subsolidus diffusion between olivine and chromite, or by partial melting and fractional crystallization. Instead, they require fluids as a diffusive medium for high efficient element exchange between chromite and olivine. The fluids were likely the hydrous fluids that were collected on chromite grain surfaces during crystallization and released later from chromite piles during precipitation. The fluid-olivine reaction preferentially transferred light Fe from olivine grains resulting in elevated delta Fe-56, but caused small O and Mg isotopic variations in the olivine. The Li diffusion depends on Li concentration gradient between olivine and fluid and olivine/fluid ratio, which can account for large delta Li-7 variations in olivine between different rock types. As these reactions proceeded, they induced elemental and isotopic variations in the fluids. These fluids could continuously penetrate the harzburgites through the dunite envelopes around the chromitites, producing some of the observed anomalous geochemical features of the harzburgites. Thus, we conclude that the hydrous fluids acted as critical media for ion exchange between chromite and olivine and for significant modification of the host harzburgites.
WOS关键词POZANTI-KARSANTI OPHIOLITE ; GEOLOGICAL REFERENCE MATERIALS ; PODIFORM CHROMITE DEPOSITS ; SOUTHERN TURKEY ; SUBDUCTION INITIATION ; PERIDOTITE XENOLITHS ; OCEANIC LITHOSPHERE ; KIZILDAG OPHIOLITE ; LUOBUSA OPHIOLITE ; PARENTAL MAGMAS
资助项目National Natural Science Foundation of China[91755205] ; National Natural Science Foundation of China[41772055] ; Second Tibetan Plateau Scientific Expedition and Research Program (STEP)[2019QZKK0801] ; Youth Innovation Promotion Association, Chinese Academy of Sciences
WOS研究方向Geochemistry & Geophysics
语种英语
WOS记录号WOS:000644658600048
出版者AMER GEOPHYSICAL UNION
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 ; Second Tibetan Plateau Scientific Expedition and Research Program (STEP) ; Second Tibetan Plateau Scientific Expedition and Research Program (STEP) ; Second Tibetan Plateau Scientific Expedition and Research Program (STEP) ; Second Tibetan Plateau Scientific Expedition and Research Program (STEP) ; Youth Innovation Promotion Association, Chinese Academy of Sciences ; Youth Innovation Promotion Association, Chinese Academy of Sciences ; Youth Innovation Promotion Association, Chinese Academy of Sciences ; Youth Innovation Promotion Association, Chinese Academy of Sciences ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; Second Tibetan Plateau Scientific Expedition and Research Program (STEP) ; Second Tibetan Plateau Scientific Expedition and Research Program (STEP) ; Second Tibetan Plateau Scientific Expedition and Research Program (STEP) ; Second Tibetan Plateau Scientific Expedition and Research Program (STEP) ; Youth Innovation Promotion Association, Chinese Academy of Sciences ; Youth Innovation Promotion Association, Chinese Academy of Sciences ; Youth Innovation Promotion Association, Chinese Academy of Sciences ; Youth Innovation Promotion Association, Chinese Academy of Sciences ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; Second Tibetan Plateau Scientific Expedition and Research Program (STEP) ; Second Tibetan Plateau Scientific Expedition and Research Program (STEP) ; Second Tibetan Plateau Scientific Expedition and Research Program (STEP) ; Second Tibetan Plateau Scientific Expedition and Research Program (STEP) ; Youth Innovation Promotion Association, Chinese Academy of Sciences ; Youth Innovation Promotion Association, Chinese Academy of Sciences ; Youth Innovation Promotion Association, Chinese Academy of Sciences ; Youth Innovation Promotion Association, Chinese Academy of Sciences ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; Second Tibetan Plateau Scientific Expedition and Research Program (STEP) ; Second Tibetan Plateau Scientific Expedition and Research Program (STEP) ; Second Tibetan Plateau Scientific Expedition and Research Program (STEP) ; Second Tibetan Plateau Scientific Expedition and Research Program (STEP) ; Youth Innovation Promotion Association, Chinese Academy of Sciences ; Youth Innovation Promotion Association, Chinese Academy of Sciences ; Youth Innovation Promotion Association, Chinese Academy of Sciences ; Youth Innovation Promotion Association, Chinese Academy of Sciences
源URL[http://ir.iggcas.ac.cn/handle/132A11/101231]  
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
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Su, Ben-Xun
作者单位1.Karadeniz Tech Univ, Dept Geol Engn, Trabzon, Turkey
2.Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing, Peoples R China
3.Chinese Acad Sci, Inst Geol & Geophys, Key Lab Mineral Resources, Beijing, Peoples R China
4.Univ Chinese Acad Sci, Coll Earth & Planetary Sci, Beijing, Peoples R China
5.Chinese Acad Sci, Innovat Acad Earth Sci, Beijing, Peoples R China
推荐引用方式
GB/T 7714		 Su, Ben-Xun,Chen, Chen,Xiao, Yan,et al. The Critical Role of Fluid-Mediated Diffusion in Anomalous Fe-Mg-O Isotope Fractionations in Ultramafic Rocks of Ophiolites[J]. JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH,2021,126(4):20.
APA Su, Ben-Xun.,Chen, Chen.,Xiao, Yan.,Robinson, Paul T..,Liu, Xia.,...&Sun, Yang.(2021).The Critical Role of Fluid-Mediated Diffusion in Anomalous Fe-Mg-O Isotope Fractionations in Ultramafic Rocks of Ophiolites.JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH,126(4),20.
MLA Su, Ben-Xun,et al."The Critical Role of Fluid-Mediated Diffusion in Anomalous Fe-Mg-O Isotope Fractionations in Ultramafic Rocks of Ophiolites".JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH 126.4(2021):20.

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。