Mantle dynamics and generation of a geochemical mantle boundary along the East Pacific Rise - Pacific/Antarctic ridge

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	Mantle dynamics and generation of a geochemical mantle boundary along the East Pacific Rise - Pacific/Antarctic ridge
	Zhang, Guo-Liang 1; Chen, Li-Hui 2; Li, Shi-Zhen 3
刊名	EARTH AND PLANETARY SCIENCE LETTERS
	2013-12-01
卷号	383 页码:153-163
关键词	mantle boundary mantle dynamics mid-oceanic ridge basalts HIMU asthenosphere consumption Pacific mantle sub-domain
ISSN号	0012-821X
通讯作者	Zhang, GL
中文摘要	A large-scale mantle compositional discontinuity was identified along the East Pacific Rise (EPR) and the Pacific-Antarctic Ridge (PAR) with an inferred transition located at the EPR 23 degrees S-32 degrees S. Because of the EPR-Easter hotspot interactions in this area, the nature of this geochemical discontinuity remains unclear. IODP Sites U1367 and 1J1368 drilled into the ocean crust that was accreted at similar to 33.5 Ma and similar to 13.5 Ma, respectively, between 28 degrees S and 30 degrees S on the EPR. We use lavas from Sites U1367 and U1368 to track this mantle discontinuity away from the EPR. The mantle sources for basalts at Sites U1367 and U1368 represent, respectively, northern and southern Pacific mantle sub-domains in terms of Sr-Nd-Pb-Hf isotopes. The significant isotopic differences between the two IODP sites are consistent with addition of ancient subduction-processed ocean crust to the south Pacific mantle sub-domain. Our modeling result shows that a trace element pattern similar to that of U1368 E-MORB can be formed by melting a subduction-processed typical N-MORB. The trace element and isotope compositions for Site U1368 MORBs can be formed by mixing a HIMU mantle end-member with Site U1367 MORBs. Comparison of our data with those from the EPR-PAR shows a geochemical mantle boundary near the Easter microplate that separates the Pacific upper mantle into northern and southern sub-domains. On the basis of reconstruction of initial locations of the ocean crust at the two sites, we find that the mantle boundary has moved northward to the Easter microplate since before 33.5 Ma. A model, in which along-axis asthenospheric flow to where asthenosphere consumption is strongest, explains the movement of the apparent mantle boundary. Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved.
英文摘要	A large-scale mantle compositional discontinuity was identified along the East Pacific Rise (EPR) and the Pacific-Antarctic Ridge (PAR) with an inferred transition located at the EPR 23 degrees S-32 degrees S. Because of the EPR-Easter hotspot interactions in this area, the nature of this geochemical discontinuity remains unclear. IODP Sites U1367 and 1J1368 drilled into the ocean crust that was accreted at similar to 33.5 Ma and similar to 13.5 Ma, respectively, between 28 degrees S and 30 degrees S on the EPR. We use lavas from Sites U1367 and U1368 to track this mantle discontinuity away from the EPR. The mantle sources for basalts at Sites U1367 and U1368 represent, respectively, northern and southern Pacific mantle sub-domains in terms of Sr-Nd-Pb-Hf isotopes. The significant isotopic differences between the two IODP sites are consistent with addition of ancient subduction-processed ocean crust to the south Pacific mantle sub-domain. Our modeling result shows that a trace element pattern similar to that of U1368 E-MORB can be formed by melting a subduction-processed typical N-MORB. The trace element and isotope compositions for Site U1368 MORBs can be formed by mixing a HIMU mantle end-member with Site U1367 MORBs. Comparison of our data with those from the EPR-PAR shows a geochemical mantle boundary near the Easter microplate that separates the Pacific upper mantle into northern and southern sub-domains. On the basis of reconstruction of initial locations of the ocean crust at the two sites, we find that the mantle boundary has moved northward to the Easter microplate since before 33.5 Ma. A model, in which along-axis asthenospheric flow to where asthenosphere consumption is strongest, explains the movement of the apparent mantle boundary. Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved.
学科主题	Geochemistry & Geophysics
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Geochemistry & Geophysics
研究领域[WOS]	Geochemistry & Geophysics
关键词[WOS]	SUBDUCTED OCEANIC-CRUST ; AUSTRALIAN-ANTARCTIC DISCORDANCE ; SOUTH-PACIFIC ; ISLAND BASALTS ; INTRAPLATE VOLCANISM ; SEDIMENTARY SYSTEM ; CONVECTION PLUMES ; SEAMOUNT CHAIN ; MAGMA SOURCES ; DARWIN RISE
收录类别	SCI
原文出处	10.1016/j.epsl.2013.09.045
语种	英语
WOS记录号	WOS:000328593500016
公开日期	2014-07-17
内容类型	期刊论文
源URL	[http://ir.qdio.ac.cn/handle/337002/16307]
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, Key Lab Marine Geol & Environm, Qingdao 266071, Peoples R China 2.Nanjing Univ, Sch Earth Sci & Engn, State Key Lab Mineral Deposits Res, Nanjing 210093, Jiangsu, Peoples R China 3.Chinese Acad Geol Sci, Inst Geol, Beijing 100037, Peoples R China
推荐引用方式 GB/T 7714	Zhang, Guo-Liang,Chen, Li-Hui,Li, Shi-Zhen. Mantle dynamics and generation of a geochemical mantle boundary along the East Pacific Rise - Pacific/Antarctic ridge[J]. EARTH AND PLANETARY SCIENCE LETTERS,2013,383:153-163.
APA	Zhang, Guo-Liang,Chen, Li-Hui,&Li, Shi-Zhen.(2013).Mantle dynamics and generation of a geochemical mantle boundary along the East Pacific Rise - Pacific/Antarctic ridge.EARTH AND PLANETARY SCIENCE LETTERS,383,153-163.
MLA	Zhang, Guo-Liang,et al."Mantle dynamics and generation of a geochemical mantle boundary along the East Pacific Rise - Pacific/Antarctic ridge".EARTH AND PLANETARY SCIENCE LETTERS 383(2013):153-163.