Extreme Mg and Zn isotope fractionation recorded in the Himalayan leucogranites
文献类型：期刊论文
| 作者 | Wang, Ze-Zhou2; Liu, Sheng-Ao2; Liu, Zhi-Chao3; Zheng, Yuan-Chuan2; Wu, Fu-Yuan1 |
| 刊名 | GEOCHIMICA ET COSMOCHIMICA ACTA
 |
| 出版日期 | 2020-06-01 |
| 卷号 | 278页码:305-321 |
| 关键词 | High-silica granite Mg isotopes Zn isotopes Himalayan leucogranite Granite differentiation |
| ISSN号 | 0016-7037 |
| DOI | 10.1016/j.gca.2019.09.026 |
| 英文摘要 | High-silica granites (typically > 70 wt.% SiO2) represent the products of extreme crustal differentiation, but whether their distinctive chemical compositions reflect source lithology or are produced via magmatic differentiation is commonly difficult to discriminate. To provide new insights into this issue, here we present high-precision Mg and Zn isotope data for high-silica, peraluminous leucogranites from the Himalayan orogen. The samples are subdivided into two-mica leucogranite, tourmaline leucogranite and garnet-bearing leucogranite based on their mineral assemblages. The two-mica leucogranites, representing the least evolved Himalayan leucogranites, have similar delta Zn-66(JMC 3-0749L) (mean = 0.31 +/- 0.06 parts per thousand) but heavier delta Mg-26(DSM-3) values (mean = -0.01 +/- 0.12 parts per thousand) relative to more mafic igneous rocks. This indicates that they were formed by anatexis of weathered silicates, consistent with the well-acknowledged metasedimentary source of the Himalayan leucogranites. In contrast, the more evolved tourmaline leucogranites and garnet-bearing leucogranites have lower delta Mg-26 and higher delta Zn-66 values compared with the two-mica leucogranites. The extremely low delta Mg-26 (-1.32 parts per thousand to -0.54 parts per thousand) and high delta Zn-66 values (0.35-0.69 parts per thousand) of garnet-bearing leucogranites vary systematically with indices of granitic differentiation (e.g., Zr/Hf, K/Rb, Eu/Eu*, 1/TiO2). Although exsolution of chlorine-rich fluid may result in elevated delta Zn-66 values, it is unlikely to explain the low delta Mg-26 signatures of the same samples. Analysis of major Mg-bearing minerals suggests that substantial segregation of tourmaline and/or Fe-Ti oxide could have driven the differentiated leucogranites towards very low delta Mg-26 values. In this regard, the slightly lower delta Mg-26 values (mean = -0.17 +/- 0.06 parts per thousand) of tourmaline leucogranites relative to the two-mica leucogranites may also reflect that the former were more differentiated than the latter. Thus, although source heterogeneity may be responsible for the Mg isotopic variations observed in some high-silica granites, our study implies that high-silica granites could be remarkably heterogeneous in terms of Mg isotopes primarily as a result of prolonged fractional crystallization at the late stage of melt evolution. The anomalously light Mg and heavy Zn isotopic signatures of garnet-bearing leucogranites highlight that Mg and Zn isotopes may be treated as important makers of highly fractionated granites in future studies. (C) 2019 Elsevier Ltd. All rights reserved. |
| WOS关键词 | S-TYPE GRANITES ; TECTONIC EVOLUTION ; TETHYAN HIMALAYA ; MAGMATIC DIFFERENTIATION ; FLUID INCLUSION ; BLACK-HILLS ; I-TYPE ; ZR-HF ; MAGNESIUM ; ZINC |
| 资助项目 | National Natural Science Foundation of China[41622303] ; National Natural Science Foundation of China[41730214] ; "Strategic Priority Research Program"of the Chinese Academy of Sciences[XDB18000000] ; National Key R&D Program of China[2016YFC0600310] |
| WOS研究方向 | Geochemistry & Geophysics |
| 语种 | 英语 |
| WOS记录号 | WOS:000536445700006 |
| 出版者 | PERGAMON-ELSEVIER SCIENCE LTD |
| 资助机构 | National Natural Science Foundation of China ; National Natural Science Foundation of China ; "Strategic Priority Research Program"of the Chinese Academy of Sciences ; "Strategic Priority Research Program"of the Chinese Academy of Sciences ; 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 ; "Strategic Priority Research Program"of the Chinese Academy of Sciences ; "Strategic Priority Research Program"of the Chinese Academy of Sciences ; 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 ; "Strategic Priority Research Program"of the Chinese Academy of Sciences ; "Strategic Priority Research Program"of the Chinese Academy of Sciences ; 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 ; "Strategic Priority Research Program"of the Chinese Academy of Sciences ; "Strategic Priority Research Program"of the Chinese Academy of Sciences ; National Key R&D Program of China ; National Key R&D Program of China |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/96701]  |
| 专题 | 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 | Liu, Sheng-Ao |
| 作者单位 | 1.Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing 100029, Peoples R China 2.China Univ Geosci, State Key Lab Geol Proc & Mineral Resources, Beijing 100083, Peoples R China 3.Sun Yat Sen Univ, Sch Earth Sci & Engn, Guangdong Prov Key Lab Geodynam & Geohazards, Guangzhou 510275, Peoples R China |
| 推荐引用方式 GB/T 7714 | Wang, Ze-Zhou,Liu, Sheng-Ao,Liu, Zhi-Chao,et al. Extreme Mg and Zn isotope fractionation recorded in the Himalayan leucogranites[J]. GEOCHIMICA ET COSMOCHIMICA ACTA,2020,278:305-321. |
| APA | Wang, Ze-Zhou,Liu, Sheng-Ao,Liu, Zhi-Chao,Zheng, Yuan-Chuan,&Wu, Fu-Yuan.(2020).Extreme Mg and Zn isotope fractionation recorded in the Himalayan leucogranites.GEOCHIMICA ET COSMOCHIMICA ACTA,278,305-321. |
| MLA | Wang, Ze-Zhou,et al."Extreme Mg and Zn isotope fractionation recorded in the Himalayan leucogranites".GEOCHIMICA ET COSMOCHIMICA ACTA 278(2020):305-321. |
入库方式： OAI收割
来源：地质与地球物理研究所
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