| 冲绳海槽中部伊平屋脊火山岩地球化学和Sr-Nd-Pb同位素组成：对岩石成因和地幔源区的指示 |
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| 引用本文： | 李晓辉,曾志刚,陈帅,马瑶,张玉祥,陈祖兴.冲绳海槽中部伊平屋脊火山岩地球化学和Sr-Nd-Pb同位素组成：对岩石成因和地幔源区的指示[J].海洋学报(英文版),2018,37(1):73-88. |
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| 作者姓名： | 李晓辉 曾志刚 陈帅 马瑶 张玉祥 陈祖兴 |
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| 作者单位： | 中国科学院海洋研究所, 海洋地质与环境重点实验室, 青岛, 266071;青岛海洋科学与技术国家实验室, 海洋矿产资源评价与探测技术功能实验室, 青岛, 266071,中国科学院海洋研究所, 海洋地质与环境重点实验室, 青岛, 266071;中国科学院大学, 北京, 100049,中国科学院海洋研究所, 海洋地质与环境重点实验室, 青岛, 266071,中国科学院海洋研究所, 海洋地质与环境重点实验室, 青岛, 266071,中国科学院海洋研究所, 海洋地质与环境重点实验室, 青岛, 266071,中国科学院海洋研究所, 海洋地质与环境重点实验室, 青岛, 266071;青岛海洋科学与技术国家实验室, 海洋矿产资源评价与探测技术功能实验室, 青岛, 266071 |
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| 摘 要： | As an active back-arc basin, the Okinawa Trough is located in the southeastern region of the East China Sea shelf and is strongly influenced by the subduction of the Philippine Sea Plate. Major element, trace element and Sr-NdPb isotopic composition data are presented for volcanic rocks from the Iheya Ridge(IR), the middle Okinawa Trough. The IR rocks record large variations in major elements and range from basalts to rhyolites. Similar trace element distribution characteristics together with small variations in ~(87)Sr/~(86)Sr(0.703 862–0.704 884), ~(144)Nd/~(143)Nd(0.512 763–0.512 880) and Pb isotopic ratios, demonstrate that the IR rocks are derived from a similar magma source. The fractional crystallization of olivine, clinopyroxene, plagioclase, and amphibole, as well as accessory minerals, can reasonably explain the compositional variations of these IR rocks. The simulations suggest that approximately 60% and 75% fractionation of an evolved basaltic magma can produce trace element compositions similar to those of the intermediate rocks and acid rocks, respectively. The analysis of their Sr-Nd-Pb isotopic content ratios suggest that the source of the rocks from the IR is close to the depleted mantle(DM) but extends to the enriched mantle(EMII), indicating that the mantle source of these rocks is a mixture between the DM and EMII end members. The simulations show that the source of the IR volcanic rocks can be best interpreted as the result of the mixing of approximately 0.8%–2.0% subduction sediment components and 98.0%–99.2% mantlederived melts.
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| 关 键 词： | 基性到中酸性岩 分离结晶 俯冲沉积组分 伊平屋脊 冲绳海槽 |
| 收稿时间： | 2017/6/19 0:00:00 |
Geochemical and Sr-Nd-Pb isotopic compositions of volcanic rocks from the Iheya Ridge, the middle Okinawa Trough: implications for petrogenesis and a mantle source |
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| LI Xiaohui,ZENG Zhigang,CHEN Shuai,MA Yao,YANG Huixin and ZHANG Yuxiang.Geochemical and Sr-Nd-Pb isotopic compositions of volcanic rocks from the Iheya Ridge, the middle Okinawa Trough: implications for petrogenesis and a mantle source[J].Acta Oceanologica Sinica,2018,37(1):73-88. |
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| Authors: | LI Xiaohui ZENG Zhigang CHEN Shuai MA Yao YANG Huixin and ZHANG Yuxiang |
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| Institution: | Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China;University of Chinese Academy of Sciences, Beijing 100049, China,Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China;Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China,Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China,Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China,Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China and Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China;University of Chinese Academy of Sciences, Beijing 100049, China |
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| Abstract: | As an active back-arc basin, the Okinawa Trough is located in the southeastern region of the East China Sea shelf and is strongly influenced by the subduction of the Philippine Sea Plate. Major element, trace element and Sr-Nd-Pb isotopic composition data are presented for volcanic rocks from the Iheya Ridge (IR), the middle Okinawa Trough. The IR rocks record large variations in major elements and range from basalts to rhyolites. Similar trace element distribution characteristics together with small variations in 87Sr/86Sr (0.703 862-0.704 884), 144Nd/143Nd (0.512 763-0.512 880) and Pb isotopic ratios, demonstrate that the IR rocks are derived from a similar magma source. The fractional crystallization of olivine, clinopyroxene, plagioclase, and amphibole, as well as accessory minerals, can reasonably explain the compositional variations of these IR rocks. The simulations suggest that approximately 60% and 75% fractionation of an evolved basaltic magma can produce trace element compositions similar to those of the intermediate rocks and acid rocks, respectively. The analysis of their Sr-Nd-Pb isotopic content ratios suggest that the source of the rocks from the IR is close to the depleted mantle (DM) but extends to the enriched mantle (EMII), indicating that the mantle source of these rocks is a mixture between the DM and EMII end members. The simulations show that the source of the IR volcanic rocks can be best interpreted as the result of the mixing of approximately 0.8%-2.0% subduction sediment components and 98.0%-99.2% mantle-derived melts. |
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| Keywords: | basic to intermediate-acid rocks fractional crystallization subduction sediment components Iheya Ridge Okinawa Trough |
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