Source lithology and crustal assimilation recorded in low delta O-18 olivine from Okinawa Trough, back-arc basin

doi:10.1016/j.lithos.2020.105444

CORC > 海洋研究所 > 中国科学院海洋研究所 > 海洋地质与环境重点实验室

	Source lithology and crustal assimilation recorded in low delta O-18 olivine from Okinawa Trough, back-arc basin
	Li, Xiaohui 1,2,3; Zeng, Zhigang 1,2,3,7; Dan, Wei 6; Yang, Huixin 3; Wang, Xiaoyuan 1,2,3; Fang, Bowen 5; Li, Qiuli 4
刊名	LITHOS
	2020-05-01
卷号	360 页码:12
关键词	Olivine Low delta O-18 magma Peridothe source Okinawa Trough Back-arc basins
ISSN号	0024-4937
DOI	10.1016/j.lithos.2020.105444
通讯作者	Li, Xiaohui(lixiaohui@qdio.ac.cn) ; Zeng, Zhigang(zgzeng@qdio.ac.cn)
英文摘要	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.
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
语种	英语
出版者	ELSEVIER
WOS记录号	WOS:000528205200018
内容类型	期刊论文
源URL	[http://ir.qdio.ac.cn/handle/337002/167301]
专题	海洋研究所_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, Ctr Ocean Megasci, 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, Inst Oceanol, Key Lab Marine Geol & Environm, Qingdao 266071, Peoples R China 4.Chinese Acad Sci, State Key Lab Lithospher Evolut, Inst Geol & Geophys, Beijing 100029, Peoples R China 5.Australian Natl Univ, Res Sch Earth Sci, Canberra, ACT 2601, Australia 6.Chinese Acad Sci, Guangzhou Inst Geochem, State Key Lab Isotope Geochem, Guangzhou 510640, Peoples R China 7.Univ Chinese Acad Sci, Beijing 100049, Peoples R China
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.