气候变化领域集成服务门户(CCPortal): An early Eocene magmatic event in southern Tibet triggered by oceanic slab break-off: evidence from ocean island basalt-like mafic rocks

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DOI	10.1007/s00410-022-01987-6
	An early Eocene magmatic event in southern Tibet triggered by oceanic slab break-off: evidence from ocean island basalt-like mafic rocks
	Lei, Ming; Chen, Jianlin; Wang, Dan; Luo, Ying; Liu, Yixin
发表日期	2023
ISSN	0010-7999
EISSN	1432-0967
卷号	178 期号:1
英文摘要	The timing and origins of the Early Cenozoic magmatic flare-up in southern Tibet remain controversial, mainly because of the lack of available data for the rare, small-volume, ocean island basalt (OIB)-like mafic rocks that can shed insights into this geological event. We have confirmed that Early Cenozoic OIB-like basalts in the Zhongba area, southern Tibet, were closely related to this magmatic flare-up, which occurred in response to deep mantle geodynamics. In this study, we present detailed geochronological and geochemical data for the Zhongba basalts. These Eocene (ca. 52 Ma) OIB-like basalts have negative K, Zr, Hf, and Ti anomalies, low Fe/Mn and high Fe/Zn ratios, and uniform and enriched Sr-Nd-Hf and HIMU-like Pb isotopic compositions (Sr-87/Sr-86((i)) = 0.7052-0.7053; epsilon Nd-(t) = - 1.7 to - 1.3; epsilon Hf-(t) = - 1.1 to - 0.3; Pb-206/Pb-204 = 19.83-19.87), indicative of derivation from carbonated peridotite. Based on the regional tectonic evolution, we propose that the carbonated peridotite source of the Zhongba basalts was generated by the reaction between depleted mid-ocean ridge basalt-like mantle peridotite and melts from subducted Neo-Tethys carbonate-bearing oceanic crust. This carbonated peridotite was possibly preserved at the thermal boundary between the lithosphere and asthenosphere and underwent partial melting to produce the Zhongba basalts in response to slab break-off of the Neo-Tethys oceanic lithosphere at ca. 52 Ma. The slab break-off triggered the magmatic flare-up and other geological processes (e.g., a decrease in the velocity of the Indian Plate) in southern Tibet during the Eocene.
关键词	Eocene Zhongba basalts Carbonated peridotite Carbonate-bearing oceanic crust Slab break-off Southern Tibet
英文关键词	INTRAPLATE ALKALI BASALTS; U-PB AGES; NEOTETHYAN SLAB; CONTINENTAL COLLISION; TECTONIC EVOLUTION; GANGDESE BATHOLITH; STEEP SUBDUCTION; PERIDOTITE KLB-1; VOLCANIC-ROCKS; MANTLE PLUMES
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
WOS记录号	WOS:000906702600001
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/282762
作者单位	Chinese Academy of Sciences; Guangzhou Institute of Geochemistry, CAS
推荐引用方式 GB/T 7714	Lei, Ming,Chen, Jianlin,Wang, Dan,et al. An early Eocene magmatic event in southern Tibet triggered by oceanic slab break-off: evidence from ocean island basalt-like mafic rocks[J],2023,178(1).
APA	Lei, Ming,Chen, Jianlin,Wang, Dan,Luo, Ying,&Liu, Yixin.(2023).An early Eocene magmatic event in southern Tibet triggered by oceanic slab break-off: evidence from ocean island basalt-like mafic rocks.CONTRIBUTIONS TO MINERALOGY AND PETROLOGY,178(1).
MLA	Lei, Ming,et al."An early Eocene magmatic event in southern Tibet triggered by oceanic slab break-off: evidence from ocean island basalt-like mafic rocks".CONTRIBUTIONS TO MINERALOGY AND PETROLOGY 178.1(2023).