Remnants of oceanic lower crust in the subcontinental lithospheric mantle: Trace element and Sr-Nd-O isotope evidence from aluminous garnet pyroxenite xenoliths from Jiaohe, Northeast China

	Remnants of oceanic lower crust in the subcontinental lithospheric mantle: Trace element and Sr-Nd-O isotope evidence from aluminous garnet pyroxenite xenoliths from Jiaohe, Northeast China
	Song-Yue Yu; Yi-Gang Xu; Jin-Long Ma; Yong-Fei Zheng; Yong-Sheng Kuang; Lu-Bing Hong; Wen-Chun Ge; Lai-Xi Tong
	2010
发表期刊	Earth and Planetary Science Letters
卷号	297 期号:3-4 页码:413-422
摘要	Pyroxenite xenoliths entrained in alkali basalts are usually interpreted to be high pressure cumulates from mantle-derived melts. However, those from Jiaohe, Northeast China may have originated from subducted oceanic crust. Their high bulk Al(2)O(3) contents (12.2-17.4%) and Mg# (up to 0.88) resemble those of olivine-bearing cumulative gabbros. A crustal origin for the Jiaohe pyroxenites from plagioclase-bearing protoliths is further supported by positive Eu and Sr anomalies in both whole rock and in garnet and clinopyroxene analyses, low HREE abundances in garnet and low delta(18)O (4.9-5.1 parts per thousand) relative to typical mantle values (5.5 parts per thousand). Compared with average values for the corresponding mantle minerals, the delta(18)O values of the Jiaohe clinopyroxene (4.5-5.4 parts per thousand) are lower, the delta(18)O values of garnet (5.1-5.6 parts per thousand) are similar, whereas those of spinet are higher (5.2 parts per thousand). In particular, there are disequilibrium O isotopic fractionations between garnet/spinet and clinopyroxene, resembling those of plagioclase/clinopyroxene pairs in seawater-altered oceanic crust. This is attributed to spinet and garnet inheriting their O isotope characteristics from plagioclase prior to transformation to these minerals during subduction metamorphism of altered oceanic gabbros, without isotopic re-equilibration at mantle conditions. Identification of remnants of subducted oceanic crust in the subcontinental lithospheric mantle is important to understanding mantle heterogeneity and genesis of intraplate magmatism.
关键词	Pyroxenite Xenoliths Eu Anomaly o Isotope Inheritance Mineralogical Transformation Subducted Gabbroic Oceanic Crust Subcontinental Lithospheric Mantle Northeast China
学科领域	矿床地球化学
收录类别	SCI
语种	英语
文献类型	期刊论文
条目标识符	http://ir.gyig.ac.cn/handle/352002/4959
专题	矿床地球化学国家重点实验室_矿床地球化学国家重点实验室_期刊论文
推荐引用方式 GB/T 7714	Song-Yue Yu,Yi-Gang Xu,Jin-Long Ma,et al. Remnants of oceanic lower crust in the subcontinental lithospheric mantle: Trace element and Sr-Nd-O isotope evidence from aluminous garnet pyroxenite xenoliths from Jiaohe, Northeast China[J]. Earth and Planetary Science Letters,2010,297(3-4):413-422.
APA	Song-Yue Yu.,Yi-Gang Xu.,Jin-Long Ma.,Yong-Fei Zheng.,Yong-Sheng Kuang.,...&Lai-Xi Tong.(2010).Remnants of oceanic lower crust in the subcontinental lithospheric mantle: Trace element and Sr-Nd-O isotope evidence from aluminous garnet pyroxenite xenoliths from Jiaohe, Northeast China.Earth and Planetary Science Letters,297(3-4),413-422.
MLA	Song-Yue Yu,et al."Remnants of oceanic lower crust in the subcontinental lithospheric mantle: Trace element and Sr-Nd-O isotope evidence from aluminous garnet pyroxenite xenoliths from Jiaohe, Northeast China".Earth and Planetary Science Letters 297.3-4(2010):413-422.

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