| Source lithology and crustal assimilation recorded in low delta O-18 olivine from Okinawa Trough, back-arc basin | |
| Li, Xiaohui1,2,3; Zeng, Zhigang1,2,3,4; Dan, Wei5; Yang, Huixin1; Wang, Xiaoyuan1,2,3; Fang, Bowen6; Li, Qiuli7 | |
| 2020-05-01 | |
| 发表期刊 | LITHOS
 |
| ISSN | 0024-4937 |
| 卷号 | 360页码:12 |
| 通讯作者 | Li, Xiaohui(lixiaohui@qdio.ac.cn) ; Zeng, Zhigang(zgzeng@qdio.ac.cn) |
| 摘要 | Low delta O-18 magmas (with delta O-18 values of <5 parts per thousand) are significantly volumetrically smaller than the abundant high delta O-18 magmas in diverse tectonic settings. We report, for the first time, low delta O-18 olivines within the Okinawa Trough, a nascent epicontinental back-arc basin. An integrated element and oxygen isotope study of olivines gives direct evidence for the source I ithologies and the magmatic evolution of volcanic rocks in the Okinawa Trough. In general, olivines show lower Ni contents (149-1644 ppm) and Fe/Mn ratios (44-76) but higher Mn contents (1720-3339 ppm) and Mn/Zn ratios (13-19) than olivines crystallized from partial melts of pyroxenite, suggesting that the volcanic rocks were derived from a peridotite source. Olivines from middle Okinawa Trough basalts have homogeneous delta O-18 values of 5.25 +/- 0.55 parts per thousand (2SD), which are similar to the primitive mantle values Olivines from middle Okinawa Trough andesites can be divided into two groups. The first group exhibits Fo>78, with element compositions and delta O-18 values (4.87 +/- 0.38 parts per thousand, 2SD) to similar those of the olivine in basalts. The other group of olivines exhibits Fo <78 and lower delta O-18 values (4.13 +/- 0.45 parts per thousand, 2SD). These features imply that high 10 olivines may be derived from the same magma chamber as the basalts, while low Fo olivines are generated by some shallow magmatic process. The olivines in basaltic andesites from the southern Okinawa Trough have delta O-18 values of 4.13 +/- 0.42 parts per thousand (2SD), all of which are lower than those of the primitive mantle. We suggest that the olivines in basalts were crystalized from an unaltered deep magma source, whereas the low delta O-18 olivines in andesites and basaltic andesites originated from assimilated high-temperature hydrothermally altered low delta O-18 continental crust rather than from altered lower oceanic crust. Moreover, all the whole rocks in the Okinawa Trough have high delta O-18 values (> 6 parts per thousand), indicating that later magmatic evolution of low delta O-18 magma toward high delta O-18 values was probably a result of the leaching of high delta O-18 fluid from the upper continental crust. Our study of olivines provide vital information for systematic understanding of magmatism in epicontinental back-arc basins compared to that in infra-oceanic settings. (C) 2020 Elsevier B.V. All rights reserved. |
| 关键词 | Olivine Low delta O-18 magma Peridothe source Okinawa Trough Back-arc basins |
| DOI | 10.1016/j.lithos.2020.105444 |
| 收录类别 | SCI |
| 语种 | 英语 |
| 资助项目 | National Natural Science Foundation of China[91958213] ; National Programme on Global Change and Air-Sea Interaction[GASI-GEOGE-02] ; Open Fund of the Key Laboratory of Marine Geology and Environment, Chinese Academy of Sciences[MGE2019KG07] ; International Partnership Program of Chinese Academy of Sciences[133137KYSB20170003] ; National Special Fund for the 13th Five Year Plan of COMRA[DY135-G2-1-02] ; Special Fund for the Taishan Scholar Program of Shandong Province[ts201511061] ; Qingdao Postdoctoral Applied Research Project ; National Basic Research Program of China[2013CB429700] |
| WOS研究方向 | Geochemistry & Geophysics ; Mineralogy |
| WOS类目 | Geochemistry & Geophysics ; Mineralogy |
| WOS记录号 | WOS:000528205200018 |
| 出版者 | ELSEVIER |
| 引用统计 | |
| 文献类型 | 期刊论文 |
| 条目标识符 | http://ir.qdio.ac.cn/handle/337002/167302 |
| 专题 | 海洋地质与环境重点实验室 |
| 通讯作者 | Li, Xiaohui; Zeng, Zhigang |
| 作者单位 | 1.Chinese Acad Sci, Inst Oceanol, Key Lab Marine Geol & Environm, Qingdao 266071, Peoples R China 2.Qingdao Natl Lab Marine Sci & Technol, Lab Marine Mineral Resources, Qingdao 266061, Peoples R China 3.Chinese Acad Sci, Ctr Ocean Megasci, Qingdao 266071, Peoples R China 4.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 5.Chinese Acad Sci, Guangzhou Inst Geochem, State Key Lab Isotope Geochem, Guangzhou 510640, Peoples R China 6.Australian Natl Univ, Res Sch Earth Sci, Canberra, ACT 2601, Australia 7.Chinese Acad Sci, State Key Lab Lithospher Evolut, Inst Geol & Geophys, Beijing 100029, Peoples R China |
| 第一作者单位 | 中国科学院海洋研究所; 中国科学院海洋大科学研究中心 |
| 通讯作者单位 | 中国科学院海洋研究所; 中国科学院海洋大科学研究中心 |
| 推荐引用方式 GB/T 7714 | Li, Xiaohui,Zeng, Zhigang,Dan, Wei,et al. Source lithology and crustal assimilation recorded in low delta O-18 olivine from Okinawa Trough, back-arc basin[J]. LITHOS,2020,360:12. |
| APA | Li, Xiaohui.,Zeng, Zhigang.,Dan, Wei.,Yang, Huixin.,Wang, Xiaoyuan.,...&Li, Qiuli.(2020).Source lithology and crustal assimilation recorded in low delta O-18 olivine from Okinawa Trough, back-arc basin.LITHOS,360,12. |
| MLA | Li, Xiaohui,et al."Source lithology and crustal assimilation recorded in low delta O-18 olivine from Okinawa Trough, back-arc basin".LITHOS 360(2020):12. |
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