Light iron isotopes in high-silica granites record fluid evolution in magmatic-hydrothermal systems
文献类型：期刊论文
| 作者 | Li, Qi-Wei6,7; Wang, Qiang5,7; Ma, Lin7; Kerr, Andrew C.4; Fan, Jing-Jing7; Zhao, Jun-Hong3,6; Gu, Hai-Ou2; Wang, Wei6; Su, Zhi-Kun1 |
| 刊名 | GEOCHIMICA ET COSMOCHIMICA ACTA
 |
| 出版日期 | 2025-02-15 |
| 卷号 | 391页码:277-290 |
| 关键词 | High-silica granites Fe-Mg isotopes Fractional crystallization Fluid exsolution Melt-fluid interaction |
| ISSN号 | 0016-7037 |
| DOI | 10.1016/j.gca.2024.12.034 |
| 英文摘要 | High-silica (SiO2 > 70 wt%) granites in continental collisional zones are crucial for understanding formation and evolution of the upper continental crust. Fluids released from felsic magmas can help drive the transition from magmatic to magmatic-hydrothermal systems in shallow magma chambers. However, the influence of these fluids on compositional variations and Fe isotope fractionation during the later stages of evolution of felsic magmas are unclear. In this contribution, we report stable Fe-Mg isotope compositions for the Paleocene Zhengga leucogranite pluton, part of the Gangdese batholith in southern Tibet. The pluton consists of both biotite granite and garnet-bearing two-mica granite, the latter of which contains zoned plagioclase and patchy K-feldspar that show fluid-mediated partial replacement textures, recording complicated magmatic and hydrothermal processes. Compared to high-silica granites worldwide (delta Fe-57 = +0.10 parts per thousand to +0.74 parts per thousand), all rocks from the Zhengga leucogranite pluton have light and variable delta Fe-57 values (+0.03 parts per thousand to +0.28 parts per thousand relative to IRMM-014), which display wave-shaped variations with progressive magmatic differentiation. However, their delta Mg-26 values (relative to DSM-3) decrease from -0.12 parts per thousand to -0.72 parts per thousand with increasing SiO2. The variable Fe and Mg isotope signatures of the Zhengga pluton can be best explained by a three-stage process, comprising initial fractional crystallization of biotite and magnetite, followed by deuteric fluid exsolution with decreasing temperatures and pressures, and final interaction between trapped fluids and residual melts in the highly crystalline magma mush. In combination with previously published Sr-Nd-Mo isotopes on the same samples, our new results suggest that fluid exsolution is required to elevate the delta Fe-57 of the felsic melts by up to 0.15 permil, but subsequent fluid-melt reaction reduces the Fe isotopes and leads to similar light-Fe isotope compositions of final residual melts to their primary magma. Therefore, the high-silica granites can be enriched in light Fe isotopes due to the effects of magmatic fluids, which make a significant contribution to the formation and evolution of upper continental crust. |
| WOS研究方向 | Geochemistry & Geophysics |
| 语种 | 英语 |
| WOS记录号 | WOS:001421764500001 |
| 源URL | [http://ir.gig.ac.cn/handle/344008/82648]  |
| 专题 | 同位素地球化学国家重点实验室 |
| 通讯作者 | Wang, Qiang |
| 作者单位 | 1.China Univ Geosci, Sch Earth Resources, Wuhan 430074, Peoples R China 2.Hefei Univ Technol, Ore Deposit & Explorat Ctr ODEC, Hefei 230009, Peoples R China 3.Chinese Acad Sci, State Key Lab Ore Deposit Geochem, Inst Geochem, Guiyang 550081, Peoples R China 4.Cardiff Univ, Sch Earth & Environm Sci, Cardiff CF10 3AT, Wales 5.Univ Chinese Acad Sci, Coll Earth & Planetary Sci, Beijing 100049, Peoples R China 6.China Univ Geosci, Sch Earth Sci, Wuhan 430074, Peoples R China 7.Chinese Acad Sci, State Key Lab Isotope Geochem, Guangzhou Inst Geochem, Guangzhou 510640, Peoples R China |
| 推荐引用方式 GB/T 7714 | Li, Qi-Wei,Wang, Qiang,Ma, Lin,et al. Light iron isotopes in high-silica granites record fluid evolution in magmatic-hydrothermal systems[J]. GEOCHIMICA ET COSMOCHIMICA ACTA,2025,391:277-290. |
| APA | Li, Qi-Wei.,Wang, Qiang.,Ma, Lin.,Kerr, Andrew C..,Fan, Jing-Jing.,...&Su, Zhi-Kun.(2025).Light iron isotopes in high-silica granites record fluid evolution in magmatic-hydrothermal systems.GEOCHIMICA ET COSMOCHIMICA ACTA,391,277-290. |
| MLA | Li, Qi-Wei,et al."Light iron isotopes in high-silica granites record fluid evolution in magmatic-hydrothermal systems".GEOCHIMICA ET COSMOCHIMICA ACTA 391(2025):277-290. |
入库方式： OAI收割
来源：广州地球化学研究所
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。