Geochemical constraints on a mixed pyroxenite-peridotite source for East Pacific Rise basalts

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	Geochemical constraints on a mixed pyroxenite-peridotite source for East Pacific Rise basalts
	Zhang, Guo-Liang 1; Zong, Chun-Lei 2; Yin, Xue-Bo 1; Li, He 3
刊名	CHEMICAL GEOLOGY
	2012-11-10
卷号	330 页码:176-187
关键词	Mid-ocean ridge basalt Major element heterogeneity Recycled oceanic crust Pyroxenite East Pacific Rise
ISSN号	0009-2541
通讯作者	Zhang, GL (reprint author), Chinese Acad Sci, Inst Oceanol, Key Lab Marine Geol & Environm, Qingdao 266071, Peoples R China.
英文摘要	The extent to which the lithological heterogeneity of the mantle source controls mid-oceanic ridge basalt (MORB) compositions remains largely debated. The recycling of oceanic crust into the mantle is widely considered to be an important cause of mantle source heterogeneity. We provide data for major and trace elements and Sr-Nd-Pb isotopes of thirteen mid-ocean ridge basalt (MORB) samples from the East Pacific Rise (EPR) to investigate the mantle source heterogeneity introduced by recycled oceanic crust (ROC). Relationships of Sr-Nd-Pb isotopes and incompatible trace element ratios, such as Sm/Yb and Hf/Zr, and ratios Zn/Fe, Co/Fe and (Pb/Pb*)(N) indicate a geochemically and lithologically heterogeneous mantle source. Mixing between components from depleted mantle (DMM) and enriched ROC-derived pyroxenite is required to explain these relationships. The relatively high Sm/Yb and the good correlation of Sr-87/Sr-86 vs. Sr/Nd are in concert with variable contributions from a pyroxenite component derived from recycled plagioclase-fractionated E-MORB. The narrow range of MgO contents (7.49 wt.% to 8.58 wt.%) and the correlations of major contents with Sr-87/Sr-86 and Zn/Fe ratios indicate the control of a mixed pyroxenite-peridotite source on the major element compositions of these lavas. To further investigate the major element contribution from the lithologically heterogeneous mantle source (peridotite/pyroxenite), major element compositions were corrected for fractional crystallization both to a given MgO wt.% and a given liquidus temperature. After correction for fractional crystallization, the Fear and Na2O increase and CaO decreases with increasing melt proportion from the enriched end-member. Based on the observations of this study and the results from partial melting experiments on pyroxenite and peridotite, a melting model, in which magma forms by mixing a deep and enriched melt (pyroxenite melt) with a shallow and depleted DMM melt (peridotite melt), provides a likely mechanism that can produce the major element systematics. (C) 2012 Elsevier B.V. All rights reserved.
学科主题	Geochemistry & Geophysics
收录类别	SCI
原文出处	10.1016/j.chemgeo.2012.08.033
语种	英语
WOS记录号	WOS:000311241000014
公开日期	2013-09-24
内容类型	期刊论文
源URL	[http://ir.qdio.ac.cn/handle/337002/12503]
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.Western Univ, State Key Lab Continental Dynam, Xian 710069, Peoples R China 3.Chinese Acad Sci, Inst Geol & Geophys, Beijing 100029, Peoples R China
推荐引用方式 GB/T 7714	Zhang, Guo-Liang,Zong, Chun-Lei,Yin, Xue-Bo,et al. Geochemical constraints on a mixed pyroxenite-peridotite source for East Pacific Rise basalts[J]. CHEMICAL GEOLOGY,2012,330:176-187.
APA	Zhang, Guo-Liang,Zong, Chun-Lei,Yin, Xue-Bo,&Li, He.(2012).Geochemical constraints on a mixed pyroxenite-peridotite source for East Pacific Rise basalts.CHEMICAL GEOLOGY,330,176-187.
MLA	Zhang, Guo-Liang,et al."Geochemical constraints on a mixed pyroxenite-peridotite source for East Pacific Rise basalts".CHEMICAL GEOLOGY 330(2012):176-187.