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DOI	10.1111/1755-6724.14989
	Genesis of Pyroxenite Veins in the Zedang Ophiolite, Southern Tibetan Plateau
	Xu, Xiangzhen; Xiong, Fahui; Zoheir, Basem; Yan, Jinyu; Zhang, Boyang; Gao, Jian; Yang, Jingsui
发表日期	2023
ISSN	1000-9515
EISSN	1755-6724
起始页码	707
结束页码	726
卷号	97 期号:3
英文摘要	Understanding the nature of parental melts for pyroxenite veins in supra-subduction zone (SSZ) ophiolites provides vibrant constraints on melt infiltration processes operating in subduction zones. The Zedang ophiolitic massif in the eastern Yarlung-Zangbo suture zone in Tibet consists of mantle peridotites and a crustal section of gabbro, diabase, and basalt. Veins of two pyroxenite varieties cut the southern part of the Zedang massif. These pyroxenite rocks have different geochemical characteristics, where the first variety (type-I) has relatively higher contents of SiO2 (51.82-53.08 wt%), MgO (20.08-23.23 wt%), and & sigma;PGE (3.42-13.97 ppb), and lower Al2O3 (1.59-2.28 wt%) and & sigma;REE (1.63-2.94 ppm). The second pyroxenite variety (type-II) is characterized by SiO2 (45.44-49.61 wt%), MgO (16.68-19.78 wt%), Al2O3 (4.24-8.77 wt%), & sigma;PGE (14.46-322.06 ppb), and & sigma;REE (5.82-7.44 ppm). Pyroxenite type-I shows N-MORB-like chondrite-normalized REE patterns. Zircon U-Pb ages of pyroxenite type-I (194 & PLUSMN; 10 Ma), associated ophiolitic gabbro (135.3 & PLUSMN; 2.0 Ma), and plagiogranite (124.2 & PLUSMN; 2.3 Ma) evidently imply episodic evolution of the Zedang ophiolites. The mineralogical and geochemical characteristics of the investigated pyroxenites can be explained by subduction-initiated hydrous melting of metasomatized sub-arc mantle, later overprinted by sub-slab mantle melting triggered by upwelling asthenosphere during the Jurassic-Early Cretaceous times. The geochemical variations in pyroxenite vein composition, coupled with age differences amongst the other ophiolite units, may correspond to intermittent emplacement of pyroxenite dikes and isotropic gabbroic intrusions where the geodynamic setting progressed from arc maturation and slab rollback to slab tearing and delamination.
关键词	pyroxenite mineralogy geochemistry forming processes Zedang ophiolite Yarlung-Zangbo suture zone
英文关键词	SUPRA-SUBDUCTION ZONE; TSANGPO SUTURE ZONE; MELT-PERIDOTITE INTERACTIONS; PLATINUM-GROUP ELEMENTS; U-PB GEOCHRONOLOGY; GEOCHEMICAL CONSTRAINTS; SOUTHWESTERN TIBET; UPPER-MANTLE; ISOTOPIC HETEROGENEITIES; LITHOSPHERIC MANTLE
WOS研究方向	Geosciences, Multidisciplinary
WOS记录号	WOS:001025156600002
来源期刊	ACTA GEOLOGICA SINICA-ENGLISH EDITION
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/283655
作者单位	China Geological Survey; Institute of Geology, Chinese Academy of Geological Sciences; Chinese Academy of Geological Sciences; Southern Marine Science & Engineering Guangdong Laboratory; Southern Marine Science & Engineering Guangdong Laboratory (Guangzhou); Egyptian Knowledge Bank (EKB); Benha University; University of Kiel
推荐引用方式 GB/T 7714	Xu, Xiangzhen,Xiong, Fahui,Zoheir, Basem,et al. Genesis of Pyroxenite Veins in the Zedang Ophiolite, Southern Tibetan Plateau[J],2023,97(3).
APA	Xu, Xiangzhen.,Xiong, Fahui.,Zoheir, Basem.,Yan, Jinyu.,Zhang, Boyang.,...&Yang, Jingsui.(2023).Genesis of Pyroxenite Veins in the Zedang Ophiolite, Southern Tibetan Plateau.ACTA GEOLOGICA SINICA-ENGLISH EDITION,97(3).
MLA	Xu, Xiangzhen,et al."Genesis of Pyroxenite Veins in the Zedang Ophiolite, Southern Tibetan Plateau".ACTA GEOLOGICA SINICA-ENGLISH EDITION 97.3(2023).