气候变化领域集成服务门户(CCPortal): A late Eocene lamprophyre-carbonatite association in the SE Tibetan Plateau: Rapid basalt-induced H2O-saturated partial melting of the upper crust

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DOI	10.1130/GES02639.1
	A late Eocene lamprophyre-carbonatite association in the SE Tibetan Plateau: Rapid basalt-induced H2O-saturated partial melting of the upper crust
	Yang, Tiannan; Xin, Di; Xue, Chuandong; Dong, Mengmeng; Jiang, Lili
发表日期	2024
ISSN	1553-040X
起始页码	74
结束页码	104
卷号	20 期号:1
英文摘要	The processes by which lamprophyres and associated carbonatites are generated remain subject to debate. The Wase Basin on the SE Tibetan Plateau contains trachytes, rhyolites, and minor carbonatites that were emplaced at 37-36 Ma. Coeval lamprophyre dikes are widespread in the adjacent regions. Geochemically and petrographically, both the extrusive trachytes and dikes can be classified as lamprophyre. The numerous millimeter-sized SiO2-rich and calcite-rich ocelli that occur within the trachytes and dikes are solidified pseudomorphs of felsic and calcic melt drops, respectively. These ocelli combined with inherited granitic zircons suggest magma mixing between the calcic melt or felsic melt and basaltic melt. Petrographic evidence, mineral compositions, and zircon textures and U-Pb ages (827-682 Ma) suggest that the felsic melt and the calcic melt were generated by rapid H2O-saturated partial melting of Neoproterozoic granite and limestone, respectively, at >800 degrees C and <2 kbar, according to available experimental data. These melts were separated from each other and were stored at upper crustal depths, forming a zone of transient magma lenses or parcels. Melts mixed when an ascending basaltic magma intersected this zone. Reaction between the basaltic melt and the calcic melt occurred when they mixed, which formed clinopyroxene of predominantly diopside-hedenbergite solid solution. The observed heterogeneity of the upper crust combined with the variable degrees of magma mixing account for the great chemical diversity of the lamprophyres of SE Tibet. This model sheds new light on the petrogenesis of other lamprophyre-carbonatite associations elsewhere.
英文关键词	ZIRCON U-PB; SANJIANG OROGENIC BELT; WESTERN YUNNAN; LIQUID IMMISCIBILITY; SEGREGATION VESICLES; SEISMIC ANISOTROPY; ARCHEAN VARIOLITES; TRACE-ELEMENTS; EASTERN TIBET; SW CHINA
WOS研究方向	Geosciences, Multidisciplinary
WOS记录号	WOS:001145902800001
来源期刊	GEOSPHERE
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/283642
作者单位	China Geological Survey; Institute of Geology, Chinese Academy of Geological Sciences; Chinese Academy of Geological Sciences; Kunming University of Science & Technology; Peking University
推荐引用方式 GB/T 7714	Yang, Tiannan,Xin, Di,Xue, Chuandong,et al. A late Eocene lamprophyre-carbonatite association in the SE Tibetan Plateau: Rapid basalt-induced H2O-saturated partial melting of the upper crust[J],2024,20(1).
APA	Yang, Tiannan,Xin, Di,Xue, Chuandong,Dong, Mengmeng,&Jiang, Lili.(2024).A late Eocene lamprophyre-carbonatite association in the SE Tibetan Plateau: Rapid basalt-induced H2O-saturated partial melting of the upper crust.GEOSPHERE,20(1).
MLA	Yang, Tiannan,et al."A late Eocene lamprophyre-carbonatite association in the SE Tibetan Plateau: Rapid basalt-induced H2O-saturated partial melting of the upper crust".GEOSPHERE 20.1(2024).