Metamorphic garnet pyroxenite from the 540-600 m main borehole of the Chinese Continental Scientific Drilling (CCSD) project

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	Metamorphic garnet pyroxenite from the 540-600 m main borehole of the Chinese Continental Scientific Drilling (CCSD) project
	Zeng, LS (Zeng, Lingsen); Liang, FH (Liang, Fenghua); Chen, ZY (Chen, Zhenyu); Liu, FL (Liu, Fulai); Xu, ZQ (Xu, Zhiqin)
刊名	TECTONOPHYSICS
	2009
卷号	475 期号:2 页码:396-412
关键词	Sulu-Dabie UHP belt Eclogite Garnet pyroxenite CCSD Nb/Ta-Zr/Hf systematics
ISSN号	0040-1951
英文摘要	Compared to other mafic and ultramafic rocks from the CCSD main borehole as well as from the outcrops, rocks from the 540-600 m section is extraordinary in terms of its geophysical as well as geochemical properties. It consists of >70% hematite-ilmenite garnet pyroxenite (HI-GPX) and <30% intercalated rutile garnet pyroxenite (R-GPX). Whole-rock geochemical data show that HI-GPXs have (1) relatively high V with an average of 606 ppm, but lower Nb and Ta; (2) highest TFeO, Fe(2)O(3)/FeO ratio, and highly variable but strong positive Eu anomalies with Eu/Eu* up to 2.9; (3) anomalously high V/Sc ratios ranging from 8.39 to 43.23, average 15.03; and (4) high amounts of hematite-ilmenite solid solutions with a very fine intergrowth structure down to nanometer scale. V/Sc ratios in the CCSD garnet pyroxenites are correlated negatively with MgO, but positively with Fe(2)O(3)/FeO ratios. Both suites of pyroxenites have similar rare earth elements and high field strength elements geochemistry. These features demonstrate that these pyroxenites were formed from metamorphism of high-Fe and/or-Ti gabbroic cumulates. This can account not only for low high field strength elements (HFSE) and rare earth elements (REE) but also low Nb/Ta and Zr/Hf ratios in these rocks. Seemingly negative correlation between Nb/Ta and Zr/Hf in the CCSD metabasites, not significantly affected by UHP metamorphism, is also consistent with the silicate differentiation trend in a basaltic magma chamber. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.
学科主题	变质岩岩石学
WOS关键词	ULTRAHIGH-PRESSURE METAMORPHISM ; TRACE-ELEMENT COMPOSITION ; CRUST-MANTLE SYSTEM ; EASTERN CHINA ; REMANENT MAGNETIZATION ; SKAERGAARD INTRUSION ; XENOLITHIC ECLOGITES ; ULTRAMAFIC ROCKS ; DEPLETED MANTLE ; WAVE VELOCITIES
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000271331800015
内容类型	期刊论文
源URL	[http://119.78.100.197/handle/2HKVOGP0/38942]
专题	中国地质调查局
作者单位	Chinese Acad Geol Sci, Inst Mineral & Resources, Beijing 100037, Peoples R China
推荐引用方式 GB/T 7714	Zeng, LS ,Liang, FH ,Chen, ZY ,et al. Metamorphic garnet pyroxenite from the 540-600 m main borehole of the Chinese Continental Scientific Drilling (CCSD) project[J]. TECTONOPHYSICS,2009,475(2):396-412.
APA	Zeng, LS ,Liang, FH ,Chen, ZY ,Liu, FL ,&Xu, ZQ .(2009).Metamorphic garnet pyroxenite from the 540-600 m main borehole of the Chinese Continental Scientific Drilling (CCSD) project.TECTONOPHYSICS,475(2),396-412.
MLA	Zeng, LS ,et al."Metamorphic garnet pyroxenite from the 540-600 m main borehole of the Chinese Continental Scientific Drilling (CCSD) project".TECTONOPHYSICS 475.2(2009):396-412.