气候变化领域集成服务门户(CCPortal): Melting a melt-metasomatized subcontinental lithospheric mantle: Evidence from Oligocene lamproites within the Gangdese batholith, southern Tibet

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DOI	10.1016/j.lithos.2023.107163
	Melting a melt-metasomatized subcontinental lithospheric mantle: Evidence from Oligocene lamproites within the Gangdese batholith, southern Tibet
	Tian, Yihong; Zeng, Lingsen; Shen, Yu; Yan, Lilong; Zhao, Linghao; Xu, Qian; Li, Guangxu; Di, Yinglong
发表日期	2023
ISSN	0024-4937
EISSN	1872-6143
卷号	448
英文摘要	Lamproite represents one of the most exotic mantle-derived magmas and provides insights into geochemical properties of subcontinental lithospheric mantle (SCLM). Zircon U-Pb ages and whole-rock element and Sr-Nd-Pb isotopic data on four lamproite dikes within the Qulin complex, Gangdese batholith, southern Tibet demonstrate that these dikes formed at-30 Ma,-4 myr earlier than those potassic to ultrapotassic rocks occurred along the N-S trending rift zones. The Nyemo lamproites have low SiO2 and Al2O3, but high K2O, MgO, and CaO. They also have high Sr and Ba concentrations, enriched in light rare earth element (LREE) but strong depleted in heavy rare earth element (HREE) with (La/Yb)N = 43.9-136, and enriched in LILE, as well as negative anomalies in Nb, Ta and Ti. The Nyemo lamproites have unradiogenic epsilon Nd(t) values ranging from-9.0 to-15.6, and 206Pb/204Pb(t) = 18.64-18.83, 207Pb/204Pb(t) = 15.77-15.81 and 208Pb/204Pb(t) = 39.53-39.83. They were derived from low-degree partial melting of SCLM which had been metasomatized by silicic melt and minor carbonated melt. Elevated Nb/Ta and Th/U ratios might be resulted from element transfer and meta-somatism by silicic melt from the subducting sediments during the prolonged and episodic subduction of the Tethyan oceanic lithosphere followed by the Indian continental lithosphere. High Ba and Sr concentrations and super-chondritic Zr/Hf ratios are related to a carbonate metasomatism. The contribution from the melt-modified SCLM in the Nyemo lamproites is much higher than in the other Tethyan Realm Lamproites (TRL). Both the age and geochemical differences of the Nyemo lamproites from the other potassic to ultrapotassic rocks in southern Tibet could be explained by the preferential melting of fertile and enriched components in the SCLM due to melt metasomatism during the initial opening of the Southern Tibet Rift System (STRS). Some of high Sr/Y and high Ba rocks might be derived from partial melting of thickened mafic lower crust modified by various degrees of infiltration of lamproitic magma. Most importantly, the Nyemo lamproite dikes within the Yadong-Gulu Rift suggest the initiation of the N-S trending STRS could be as early as-30 Ma.
关键词	Lamproites Melt-metasomatized SCLM Potassic to ultrapotassic rocks High Sr Y rocks Southern Tibet Rift System
英文关键词	CONTINENTAL COLLISION ZONE; EASTERN DHARWAR CRATON; U-PB GEOCHRONOLOGY; TRACE-ELEMENTS; MESOPROTEROZOIC LAMPROITES; ULTRAPOTASSIC MAGMATISM; ISOTOPIC CONSTRAINTS; TECTONIC EVOLUTION; HIGH-PRESSURE; SW TIBET
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
WOS记录号	WOS:000975940000001
来源期刊	LITHOS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/282687
作者单位	China Geological Survey; Institute of Geology, Chinese Academy of Geological Sciences; Chinese Academy of Geological Sciences; China Geological Survey; Chinese Academy of Geological Sciences; National Research Center for Geoanalysis, Chinese Academy of Geological Sciences
推荐引用方式 GB/T 7714	Tian, Yihong,Zeng, Lingsen,Shen, Yu,et al. Melting a melt-metasomatized subcontinental lithospheric mantle: Evidence from Oligocene lamproites within the Gangdese batholith, southern Tibet[J],2023,448.
APA	Tian, Yihong.,Zeng, Lingsen.,Shen, Yu.,Yan, Lilong.,Zhao, Linghao.,...&Di, Yinglong.(2023).Melting a melt-metasomatized subcontinental lithospheric mantle: Evidence from Oligocene lamproites within the Gangdese batholith, southern Tibet.LITHOS,448.
MLA	Tian, Yihong,et al."Melting a melt-metasomatized subcontinental lithospheric mantle: Evidence from Oligocene lamproites within the Gangdese batholith, southern Tibet".LITHOS 448(2023).