气候变化领域集成服务门户(CCPortal): Pyroxenite-harzburgite sequences in the Dazhuqu ophiolite (Southern Tibet) formed through hydrous melt infiltration and melt-peridotite reaction

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DOI	10.1007/s00410-023-02076-y
	Pyroxenite-harzburgite sequences in the Dazhuqu ophiolite (Southern Tibet) formed through hydrous melt infiltration and melt-peridotite reaction
	Zhang, Zhen-Yu; Liu, Chuan-Zhou; Liang, Yan; Liu, Tong; Zhang, Chang; Liu, Bo-Da; Lin, Yin-Zheng; Zhang, Wei-Qi; Ji, Wen-Bin
发表日期	2023
ISSN	0010-7999
EISSN	1432-0967
卷号	178 期号:12
英文摘要	Pyroxenite veins are commonly observed in the mantle section of ophiolites, reflecting a variety of melts that percolate through the mantle, react, and finally crystallize in the lithosphere. To better understand the formation mechanism of the pyroxenite veins and associated peridotites, we conducted an integrated petrological and geochemical study of a suite of orthopyroxenite, websterite, and composite clinopyroxenite-orthopyroxenite veins in residual peridotites from the Dazhuqu ophiolite (Southern Tibet, China). Both orthopyroxene and clinopyroxene in pyroxenites are characterized by high Mg#, low Al2O3 concentrations, and depleted patterns of incompatible trace elements. This suggests that parental melts of the pyroxenites could be formed by re-melting of a previously depleted mantle source. We observed systematic variations in the major and trace element compositions of clinopyroxene and orthopyroxene across the pyroxenite-harzburgite sequences. Through trace element modeling, we have established a model for the formation of pyroxenite veins and associated harzburgites. According to this model, hydrous and aggregated melts were expelled from the tip of the dunite channels and subsequently injected into the lithosphere via fractures. The infiltrating melts then underwent diffusional loss of water into the residual harzburgites within the asthenosphere, which in turn promoting partial melting of the harzburgite. The pyroxenite veins were formed by mixing the infiltrating channel melt and matrix melt derived from partially molten harzburgite. This formation model can be applied to explain the pyroxenite-harzburgite and dunite-pyroxenite-harzburgite sequences in the Yarlung-Tsangbo ophiolite and other ophiolites around the world.
关键词	Pyroxenite Melt-rock reaction Hydrous melt infiltration The Yarlung-Tsangbo ophiolites Concentration gradient
英文关键词	SUPRA-SUBDUCTION ZONE; EARTH-ELEMENT DIFFUSION; ZANGBO SUTURE ZONE; LOW-CA PYROXENE; TRACE-ELEMENT; CLOSURE TEMPERATURE; LUOBUSA OPHIOLITE; MANTLE PERIDOTITE; XIGAZE OPHIOLITE; ROCK REACTION
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
WOS记录号	WOS:001104861700001
来源期刊	CONTRIBUTIONS TO MINERALOGY AND PETROLOGY
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/283234
作者单位	Chinese Academy of Sciences; Institute of Geology & Geophysics, CAS; Chinese Academy of Sciences; University of Chinese Academy of Sciences, CAS; Brown University; Northwest University Xi'an
推荐引用方式 GB/T 7714	Zhang, Zhen-Yu,Liu, Chuan-Zhou,Liang, Yan,et al. Pyroxenite-harzburgite sequences in the Dazhuqu ophiolite (Southern Tibet) formed through hydrous melt infiltration and melt-peridotite reaction[J],2023,178(12).
APA	Zhang, Zhen-Yu.,Liu, Chuan-Zhou.,Liang, Yan.,Liu, Tong.,Zhang, Chang.,...&Ji, Wen-Bin.(2023).Pyroxenite-harzburgite sequences in the Dazhuqu ophiolite (Southern Tibet) formed through hydrous melt infiltration and melt-peridotite reaction.CONTRIBUTIONS TO MINERALOGY AND PETROLOGY,178(12).
MLA	Zhang, Zhen-Yu,et al."Pyroxenite-harzburgite sequences in the Dazhuqu ophiolite (Southern Tibet) formed through hydrous melt infiltration and melt-peridotite reaction".CONTRIBUTIONS TO MINERALOGY AND PETROLOGY 178.12(2023).