气候变化领域集成服务门户(CCPortal): A greenstone belt in southeast Tibet: An accreted middle-late Permian oceanic plateau

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DOI	10.1016/j.gsf.2023.101534
	A greenstone belt in southeast Tibet: An accreted middle-late Permian oceanic plateau
	Wang, Bin; Xie, Chao-Ming; Yakymchuk, Chris; Dong, Yong-sheng; Song, Yu-hang; Duan, Meng-long
发表日期	2023
ISSN	1674-9871
卷号	14 期号:3
英文摘要	Studies of accreted oceanic plateau sections provide crucial information on their structures, composi-tions, and origins. We investigate the petrogenesis of ultramafic-mafic rocks in the Tangjia-Sumdo greenstone belt of southeast Tibet using petrography, whole-rock geochemistry, and U-Pb zircon geochronology. These rocks are divided into four groups based on geochemical characteristics that include depleted and tholeiitic mafic rocks, transitional mafic rocks, enriched and alkaline mafic rocks, and picritic ultramafic rocks. Depleted and tholeiitic mafic rocks have the oldest crystallization ages (-272 Ma), followed by picritic ultramafic rocks (-270 Ma), transitional mafic rocks (267-254 Ma), and enriched and alkaline mafic rocks (252-250 Ma). Hafnium and neodymium isotope ratios of depleted and tholeiitic mafic rocks (eHf(t) = +13.1-+16.9; eNd(t) = +6.9-+7.1), transitional mafic rocks (eHf(t) = +1.8- +16.9; eNd(t) = +0.8-+5.5), enriched and alkaline mafic rocks (eHf(t) = +0.5-+5.4; eNd(t) =-1.5 to +1.9) and picritic ultramafic rocks (eHf(t) = +14.9-+17.2; eNd(t) = +7.8-+9.0) are similar to those of N-MORB, E-MORB, OIB and depleted-type picritic mafic rocks in other oceanic plateaus, respectively. The geochem-ical characteristics of the depleted and tholeiitic mafic rocks suggest that they formed by partial melting of depleted spinel lherzolite in a mid-ocean ridge setting, whereas the picritic ultramafic rocks suggest a high degree of partial melting of depleted lherzolite in a hot mantle plume head. The transitional mafic rocks formed by partial melting of moderately enriched garnet lherzolite. The youngest rocks (enriched and alkaline mafic rocks) formed by partial melting of a more enriched garnet lherzolite (compared to transitional mafic rocks) at relatively low temperatures. We propose that the depleted and tholeiitic mafic rocks represent normal oceanic crust of the Sumdo Paleo-Tethys Ocean and the transitional mafic rocks, enriched and alkaline mafic rocks and picritic ultramafic rocks are the fragments of the oceanic pla-teau, which were related to middle-late Permian mantle plume activity in the Sumdo Paleo-Tethys Ocean. We further suggest that the majority of the Tangjia-Sumdo greenstone belt represents a mid-dle-late Permian oceanic plateau that reflects a previously unrecognized middle-late Permian mantle plume.(c) 2023 China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).
关键词	Oceanic plateau Mantle plume Paleo-Tethys Tibet Greenstone belts
英文关键词	LARGE IGNEOUS PROVINCES; MINO-TAMBA BELT; LHASA TERRANE; GEOCHEMICAL EVIDENCE; SUBDUCTION INITIATION; CONTINENTAL-CRUST; OROGENIC BELT; FLOOD BASALTS; MAFIC ROCKS; U-PB
WOS研究方向	Geosciences, Multidisciplinary
WOS记录号	WOS:000923089500001
来源期刊	GEOSCIENCE FRONTIERS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/282776
作者单位	Jilin University; Ministry of Natural Resources of the People's Republic of China; Jilin University; University of Waterloo
推荐引用方式 GB/T 7714	Wang, Bin,Xie, Chao-Ming,Yakymchuk, Chris,et al. A greenstone belt in southeast Tibet: An accreted middle-late Permian oceanic plateau[J],2023,14(3).
APA	Wang, Bin,Xie, Chao-Ming,Yakymchuk, Chris,Dong, Yong-sheng,Song, Yu-hang,&Duan, Meng-long.(2023).A greenstone belt in southeast Tibet: An accreted middle-late Permian oceanic plateau.GEOSCIENCE FRONTIERS,14(3).
MLA	Wang, Bin,et al."A greenstone belt in southeast Tibet: An accreted middle-late Permian oceanic plateau".GEOSCIENCE FRONTIERS 14.3(2023).