Geochemical and isotopic characteristics of volcanic rocks from the northern East China Sea shelf margin and the Okinawa Trough

doi:10.1007/s13131-010-0050-y

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	Geochemical and isotopic characteristics of volcanic rocks from the northern East China Sea shelf margin and the Okinawa Trough
	Zeng Zhigang 1; Yu Shaoxiong 1,2; Wang Xiaoyuan 1,2; Fu Yongtao 1; Yin Xuebo 1; Zhang Guoliang 1,2; Wang Xiaomei 1,2; Chen Shuai 1,2
刊名	ACTA OCEANOLOGICA SINICA
	2010-07-01
卷号	29 期号:4 页码:48-61
关键词	Volcanic Rocks Geochemical Characteristics Northern East China Sea Shelf Margin Okinawa Trough
ISSN号	0253-505X
DOI	10.1007/s13131-010-0050-y
文献子类	Article
英文摘要	Volcanic rocks both from the northern East China Sea (NECS) shelf margin and the northern Okinawa Trough are subalkaline less aluminous, and lower in High Field Strength Elements (HFSE). These rocks are higher in Large Ion Lithophile Elements (LILE), thorium and uranium contents, positive lead anomalies, negative Nb-Ta anomalies, and enrichment in Light Rare Earth Elements (LREE). Basalts from the NECS shelf margin are akin to Indian Ocean Mid-Ocean Ridge Basalt (MORB), and rhyolites from the northern Okinawa Trough have the highest (207)Pb/(208)Pb and (208)Pb/(204)Pb ratios. The NECS shelf margin basalts have lower (87)Sr/(86)Sr ratios, epsilon(Nd) and sigma(18)O than the northern Okinawa Trough silicic rocks. According to (40)K-(40)Ar isotopic ages of basalts from the NECS shelf margin, rifting of the Okinawa Trough may have been active since at least 3.65-3.86 Ma. The origin of the NECS shelf margin basalt can be explained by the interaction of melt derived from Indian Ocean MORB-like mantle with enriched subcontinental lithosphere. The basalts from both sides of the Okinawa Trough may have a similar origin during the initial rifting of the Okinawa Trough, and the formation of basaltic magmas closely relates to the thinning of continental crust. The source of the formation of the northern Okinawa Trough silicic rocks was different from that of the middle Okinawa Trough, which could have been generated by the interaction of basaltic melt with an enriched crustal component. From the Ryukyu island arc to East China, the Cenozoic basalts have apparently increasing trends of MgO contents and ratios of LREE to Heavy Rare Earth Elements (HREE), suggesting that the trace element variabilities of basalts may have been influenced by the subduction of the Philippine Sea plate, and that the effects of subduction of the Philippine Sea plate on the chemical composition of basaltic melts have had a decreasing effect from the Ryukyu island arc to East China.; Volcanic rocks both from the northern East China Sea (NECS) shelf margin and the northern Okinawa Trough are subalkaline less aluminous, and lower in High Field Strength Elements (HFSE). These rocks are higher in Large Ion Lithophile Elements (LILE), thorium and uranium contents, positive lead anomalies, negative Nb-Ta anomalies, and enrichment in Light Rare Earth Elements (LREE). Basalts from the NECS shelf margin are akin to Indian Ocean Mid-Ocean Ridge Basalt (MORB), and rhyolites from the northern Okinawa Trough have the highest Pb-207/Pb-208 and Pb-208/Pb-204 ratios. The NECS shelf margin basalts have lower Sr-87/Sr-86 ratios, epsilon(Nd) and sigma O-18 than the northern Okinawa Trough silicic rocks. According to K-40-Ar-40 isotopic ages of basalts from the NECS shelf margin, rifting of the Okinawa Trough may have been active since at least 3.65-3.86 Ma. The origin of the NECS shelf margin basalt can be explained by the interaction of melt derived from Indian Ocean MORB-like mantle with enriched subcontinental lithosphere. The basalts from both sides of the Okinawa Trough may have a similar origin during the initial rifting of the Okinawa Trough, and the formation of basaltic magmas closely relates to the thinning of continental crust. The source of the formation of the northern Okinawa Trough silicic rocks was different from that of the middle Okinawa Trough, which could have been generated by the interaction of basaltic melt with an enriched crustal component. From the Ryukyu island arc to East China, the Cenozoic basalts have apparently increasing trends of MgO contents and ratios of LREE to Heavy Rare Earth Elements (HREE), suggesting that the trace element variabilities of basalts may have been influenced by the subduction of the Philippine Sea plate, and that the effects of subduction of the Philippine Sea plate on the chemical composition of basaltic melts have had a decreasing effect from the Ryukyu island arc to East China.
学科主题	Oceanography
URL标识	查看原文
语种	英语
WOS记录号	WOS:000282285900007
公开日期	2010-12-24
内容类型	期刊论文
源URL	[http://ir.qdio.ac.cn/handle/337002/5115]
专题	海洋研究所_海洋地质与环境重点实验室
作者单位	1.Chinese Acad Sci, Inst Oceanol, Seafloor Hydrothermal Activ Lab, Key Lab Marine Geol & Environm, Qingdao 266071, Peoples R China 2.Chinese Acad Sci, Grad Sch, Beijing 100049, Peoples R China
推荐引用方式 GB/T 7714	Zeng Zhigang,Yu Shaoxiong,Wang Xiaoyuan,et al. Geochemical and isotopic characteristics of volcanic rocks from the northern East China Sea shelf margin and the Okinawa Trough[J]. ACTA OCEANOLOGICA SINICA,2010,29(4):48-61.
APA	Zeng Zhigang.,Yu Shaoxiong.,Wang Xiaoyuan.,Fu Yongtao.,Yin Xuebo.,...&Chen Shuai.(2010).Geochemical and isotopic characteristics of volcanic rocks from the northern East China Sea shelf margin and the Okinawa Trough.ACTA OCEANOLOGICA SINICA,29(4),48-61.
MLA	Zeng Zhigang,et al."Geochemical and isotopic characteristics of volcanic rocks from the northern East China Sea shelf margin and the Okinawa Trough".ACTA OCEANOLOGICA SINICA 29.4(2010):48-61.