气候变化领域集成服务门户(CCPortal): Ultrapotassic enclaves in the Miocene adakitic granitoids, southern Tibet: Direct evidence for collision-related crust-mantle interaction and its implications

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DOI	10.1016/j.lithos.2023.107052
	Ultrapotassic enclaves in the Miocene adakitic granitoids, southern Tibet: Direct evidence for collision-related crust-mantle interaction and its implications
	Wu, Chang-Da; Zheng, Yuan-Chuan; Xu, Bo; Hou, Zeng-Qian; Chai, Peng; Li, Xin; Zhang, Lin-Yuan; Wang, Zi-Xuan; Wang, Lu; Shen, Yang
发表日期	2023
ISSN	0024-4937
EISSN	1872-6143
卷号	442
英文摘要	Crust-mantle interaction is essential to the evolution of continental crust, but its type and mechanism remain controversial in continental collision zones. Post-collisional ultrapotassic and adakitic rocks in southern Tibet can provide important constraints on this issue. Here, we newly identify the Miocene ultrapotassic enclaves hosted within the coeval Renduo adakitic granitoids (17-16 Ma), an excellent target to decipher the origin of two types of magmatism and their genetic relationship. The petrographic observations, together with elemental and iso- topic features, argue for a magma mixing process. In addition, the ultrapotassic enclaves are not only enriched in incompatible trace elements and radiogenic isotopes, but also characterized by Nd-Hf isotopic decoupling and sub-chondritic Hf/Sm ratios, indicating that their lithospheric mantle source was metasomatized by previous Neo-Tethyan oceanic components rather than by Indian continental materials. The adakitic host granitoids have relatively low MgO and compatible trace element contents, as well as low but variable whole-rock epsilon Nd(t) and zircon epsilon Hf(t) values. This suggests that they were generated by partial melting of thickened ancient lower crust, with varying degrees of involvement of ultrapotassic melts and asthenosphere-derived juvenile components. In combination with previously published results, we propose that relative to the metasomatism of subcontinental lithospheric mantle by subducted Indian crustal materials, the interaction between mantle-derived melts and overlying Lhasa continental crust was much more significant during the collisional orogeny, and played an important role in the crustal growth and reworking of southern Tibet; besides, the extensive post-collisional magmatism was likely triggered by the tearing of subducted Indian slab.
关键词	Ultrapotassic enclaves Adakitic rocks Crust-mantle interaction Himalayan-Tibetan orogen
英文关键词	EAST-WEST EXTENSION; LHASA TERRANE; MICROGRANULAR ENCLAVES; ISOTOPIC CONSTRAINTS; LITHOSPHERIC MANTLE; CONTINENTAL-CRUST; MAFIC MAGMATISM; VOLCANIC-ROCKS; K-RICH; SLAB
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
WOS记录号	WOS:000990635900001
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/283137
作者单位	China Geological Survey; Institute of Geology, Chinese Academy of Geological Sciences; Chinese Academy of Geological Sciences; China University of Geosciences - Beijing; China University of Geosciences - Beijing; China Geological Survey; Chinese Academy of Geological Sciences; China University of Geosciences - Beijing
推荐引用方式 GB/T 7714	Wu, Chang-Da,Zheng, Yuan-Chuan,Xu, Bo,et al. Ultrapotassic enclaves in the Miocene adakitic granitoids, southern Tibet: Direct evidence for collision-related crust-mantle interaction and its implications[J],2023,442.
APA	Wu, Chang-Da.,Zheng, Yuan-Chuan.,Xu, Bo.,Hou, Zeng-Qian.,Chai, Peng.,...&Shen, Yang.(2023).Ultrapotassic enclaves in the Miocene adakitic granitoids, southern Tibet: Direct evidence for collision-related crust-mantle interaction and its implications.LITHOS,442.
MLA	Wu, Chang-Da,et al."Ultrapotassic enclaves in the Miocene adakitic granitoids, southern Tibet: Direct evidence for collision-related crust-mantle interaction and its implications".LITHOS 442(2023).