CCPortal
DOI10.1016/j.gca.2018.07.008
Iron isotope fractionation during magmatic-hydrothermal evolution: A case study from the Duolong porphyry Cu-Au deposit, Tibet
Li, Jin-Xiang; Qin, Ke-Zhang; Li, Guang-Ming; Evans, Noreen J.; Huang, Fang; Zhao, Jun-Xing
通讯作者Li, JX (通讯作者)
发表日期2018
ISSN0016-7037
EISSN1872-9533
起始页码1
结束页码15
卷号238
英文摘要Ore-forming fluids ultimately precipitate Fe-bearing sulfides and oxides in hydrothermal ore deposits and the Fe isotopic composition of these minerals can trace magmatic-hydrothermal evolution. Here, we report on the Fe isotopic compositions of a suite of hydrothermal minerals (magnetite, pyrite, and chalcopyrite) and granodiorite porphyry from the giant Duolong porphyry Cu-Au deposit (Bolong and Duobuza section), central Tibet. Most magnetite grains with potassic alteration show only minor delta Fe-57 variation (0.38 +/- 0.07 parts per thousand to 0.52 +/- 0.04 parts per thousand in Bolong and 0.68 +/- 0.02 parts per thousand to 0.77 +/- 0.08 parts per thousand in Duobuza), consistent with the equilibrium fluid delta Fe-57 (similar to-0.3 parts per thousand and similar to-0.1 parts per thousand, respectively) at similar to 550-480 degrees C. The equilibrium fluids have lighter Fe isotope signatures than the Duolong granodiorite porphyry (delta Fe-57 = 0.03 +/- 0.06 parts per thousand to 0.07 +/- 0.02 parts per thousand), corroborating the hypothesis that exsolved fluids should have a lighter Fe isotopic composition relative to parental magmas. Chalcopyrite from the mineralized Bolong and Duobuza porphyries have relatively consistent delta Fe-57 values of -0.60 +/- 0.07 parts per thousand to -0.42 +/- 0.07 parts per thousand and -0.40 +/- 0.08 parts per thousand to -0.30 +/- 0.05 parts per thousand, respectively, with equilibrium fluids at similar to 450-350 degrees C having lighter delta Fe-57 values of similar to-0.7 parts per thousand and similar to-0.6 parts per thousand. The trend of decreasing delta Fe-57 values in evolved fluids likely reflects Rayleigh fractionation of magnetite enriched in heavy Fe isotopes. This supposition is supported by the lighter delta Fe-57 value (0.25 +/- 0.07 parts per thousand) recorded in magnetite that equilibrated with a lighter delta Fe-57 fluid (similar to-0.5 parts per thousand) at similar to 470 degrees C. Compared to chalcopyrite, pyrite from the Bolong and Duobuza sections have heavier delta Fe-57 values of 0.35 +/- 0.06 parts per thousand to 0.71 +/- 0.06 parts per thousand and 0.53 +/- 0.06 parts per thousand to 0.71 +/- 0.07 parts per thousand, respectively. The pyrite values correlate variably with the Fe isotopic composition of ore-forming fluids (delta Fe-57 -0.6 parts per thousand to -0.7 parts per thousand), likely due to variations in the degree of Fe isotope exchange between pyrite and fluid. Moreover, combined with previously published Fe isotopic compositions of hydrothermal minerals from oxidized and reduced ore deposits, the results show that chalcopyrite in oxidized hydrothermal deposits always has a lighter Fe isotopic composition than chalcopyrite from reduced hydrothermal deposits. This is likely controlled by melt composition and precipitation of magnetite/pyrrhotite-bearing mineral assemblages. Therefore, the Fe isotopic composition of chalcopyrite could be a useful diagnostic tool for distinguishing oxidized from reduced fluids in hydrothermal systems. (C) 2018 Elsevier Ltd. All rights reserved.
关键词FE-ISOTOPECOPPER-DEPOSITU-PBQIANGTANG TERRANEHIGH-TEMPERATUREEL-SALVADORRE-OSGOLDMINERALIZATIONGEOCHRONOLOGY
英文关键词Fe isotope; Magmatic-hydrothermal evolution; Porphyry Cu-Au deposit; Duolong; Tibet
语种英语
WOS研究方向Geochemistry & Geophysics
WOS类目Geochemistry & Geophysics
WOS记录号WOS:000441893500001
来源期刊GEOCHIMICA ET COSMOCHIMICA ACTA
来源机构中国科学院青藏高原研究所
文献类型期刊论文
条目标识符http://gcip.llas.ac.cn/handle/2XKMVOVA/259261
推荐引用方式
GB/T 7714
Li, Jin-Xiang,Qin, Ke-Zhang,Li, Guang-Ming,et al. Iron isotope fractionation during magmatic-hydrothermal evolution: A case study from the Duolong porphyry Cu-Au deposit, Tibet[J]. 中国科学院青藏高原研究所,2018,238.
APA Li, Jin-Xiang,Qin, Ke-Zhang,Li, Guang-Ming,Evans, Noreen J.,Huang, Fang,&Zhao, Jun-Xing.(2018).Iron isotope fractionation during magmatic-hydrothermal evolution: A case study from the Duolong porphyry Cu-Au deposit, Tibet.GEOCHIMICA ET COSMOCHIMICA ACTA,238.
MLA Li, Jin-Xiang,et al."Iron isotope fractionation during magmatic-hydrothermal evolution: A case study from the Duolong porphyry Cu-Au deposit, Tibet".GEOCHIMICA ET COSMOCHIMICA ACTA 238(2018).
条目包含的文件
条目无相关文件。
个性服务
推荐该条目
保存到收藏夹
导出为Endnote文件
谷歌学术
谷歌学术中相似的文章
[Li, Jin-Xiang]的文章
[Qin, Ke-Zhang]的文章
[Li, Guang-Ming]的文章
百度学术
百度学术中相似的文章
[Li, Jin-Xiang]的文章
[Qin, Ke-Zhang]的文章
[Li, Guang-Ming]的文章
必应学术
必应学术中相似的文章
[Li, Jin-Xiang]的文章
[Qin, Ke-Zhang]的文章
[Li, Guang-Ming]的文章
相关权益政策
暂无数据
收藏/分享

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。