Genesis of the mega-crystal zircons in the dunite veins of North Qaidam Mountains, northwestern China

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	Genesis of the mega-crystal zircons in the dunite veins of North Qaidam Mountains, northwestern China
	Meng, FC (Meng FanCong); Zhang, JX (Zhang JianXin)
刊名	CHINESE SCIENCE BULLETIN
	2009
卷号	54 期号:24 页码:4688-4696
关键词	mega-crystal zircon baddeleyite srepentinization dunite North Qaidam
ISSN号	1001-6538
英文摘要	A megacrystal zircon occurs in serpentinized dunite veins from North Qaidam, northwestern China. It is red-brown and 3-4 mm long and 2 mm wide in size. BSE imaging shows the presence of micro-grains (30-50 mu m) of zircon between olivine and serpentine, part of them gathering into clusters (100-300 mu m). Thus we infer that these zircon crystals were precipitated from hydrothermal fluid. Inclusions of baddeleyite (white) in the shape of isolated island locally occur in the large zircon (grey), implying that the former formed earlier than the latter. The mirco-baddeleyite (50-100 mu m) aggregate consists of baddeleyite (3-5 mu m) and olivine (<5 mu m), indicating the zircon formation through interaction between baddeleyite and silica-bearing fluid. Therefore, we consider a genetic link between the formation of the large zircon and the serpentinization of dunite. SHIRIMP U-Pb dating of the large zircon gave two groups of concordant ages at 414 +/- 13 Ma and 371 +/- 9 Ma, respectively. This might reflect two episodes of zircon growth in response to two episodes of fluid action.
学科主题	火成岩岩石学
WOS关键词	TRACE-ELEMENT COMPOSITION ; U-PB AGE ; GARNET PERIDOTITE ; HYDROTHERMAL ZIRCON ; MANTLE METASOMATISM ; SUBDUCTION ZONES ; TIBETAN PLATEAU ; ISOTOPE ; GEOCHRONOLOGY ; METAMORPHISM
WOS研究方向	Science & Technology - Other Topics
语种	英语
出版者	SCIENCE PRESS
WOS记录号	WOS:000273155600023
内容类型	期刊论文
源URL	[http://119.78.100.197/handle/2HKVOGP0/39033]
专题	中国地质调查局
作者单位	Chinese Acad Geol Sci, Inst Geol, Beijing 100037, Peoples R China
推荐引用方式 GB/T 7714	Meng, FC ,Zhang, JX . Genesis of the mega-crystal zircons in the dunite veins of North Qaidam Mountains, northwestern China[J]. CHINESE SCIENCE BULLETIN,2009,54(24):4688-4696.
APA	Meng, FC ,&Zhang, JX .(2009).Genesis of the mega-crystal zircons in the dunite veins of North Qaidam Mountains, northwestern China.CHINESE SCIENCE BULLETIN,54(24),4688-4696.
MLA	Meng, FC ,et al."Genesis of the mega-crystal zircons in the dunite veins of North Qaidam Mountains, northwestern China".CHINESE SCIENCE BULLETIN 54.24(2009):4688-4696.