气候变化领域集成服务门户(CCPortal): Recycling of eroded crust by melange diapirs evidenced from the Early Cretaceous arc magmatism in southern Tibet

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DOI	10.1016/j.lithos.2023.107263
	Recycling of eroded crust by melange diapirs evidenced from the Early Cretaceous arc magmatism in southern Tibet
	Mai, Yuan-Jun; Zhu, Li-Dong; Jin, Xin; Yang, Wen-Guang; Tong, Xia; Zhong, Yao
发表日期	2023
ISSN	0024-4937
EISSN	1872-6143
卷号	454
英文摘要	Crustal material recycling in a subduction factory increases the diversity and complexity of arc magma. However, the exact origin and mechanism of its contribution to arc magma are not fully understood. Here, we present new data on the Molang basaltic rocks from the southern Lhasa terrane to gain an in-depth-understanding of the mechanisms of crustal recycling. The zircon U-Pb ages indicate that these rocks were emplaced at 128 Ma. They display characteristics ranging from forearc basalts to tholeiitic arc basalts with depleted mantle isotope compositions (e(Nd)(t) = +4.58 to +4.86) and zircon e(Hf)(t) values (+7.3 to +8.7). The uniform isotopic composition (Sr-Nd) and fractionation of trace elements show that crustal materials could have been added to the magma source in the form of bulk sediment. Therefore, we have proposed an argument supporting the melange diapirs model. The age spectra of the inherited zircons are consistent with those of the detrital zircons from the subduction hanging wall. This implies that the inherited zircons may be unmolten residues of eroded forearc crust that survived erosion and subduction from the slab in well-mixed melange diapirs that passed through a comparatively hot mantle wedge and occur as key evidence for crustal recycling in the arc magma. Based on a synthesis of earlier research, we suggest that the Molang basaltic rocks were derived from the partial melting of the melange diapirs in a steep subduction setting during a new subduction initiation event involving the NeoTethyan oceanic slab.
关键词	Melange diapir Subduction erosion Lhasa terrane Detrital zircon Tholeiitic arc basalt
英文关键词	LINZIZONG VOLCANIC SUCCESSION; CONTINENTAL-CRUST; SUBDUCTION INITIATION; LHASA TERRANE; TRACE-ELEMENT; GANGDESE BELT; ROCKS; GEOCHEMISTRY; PETROGENESIS; OPHIOLITE
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
WOS记录号	WOS:001034743800001
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/283474
作者单位	Chengdu University of Technology; Chinese Academy of Sciences; Institute of Oceanology, CAS; Sichuan University
推荐引用方式 GB/T 7714	Mai, Yuan-Jun,Zhu, Li-Dong,Jin, Xin,et al. Recycling of eroded crust by melange diapirs evidenced from the Early Cretaceous arc magmatism in southern Tibet[J],2023,454.
APA	Mai, Yuan-Jun,Zhu, Li-Dong,Jin, Xin,Yang, Wen-Guang,Tong, Xia,&Zhong, Yao.(2023).Recycling of eroded crust by melange diapirs evidenced from the Early Cretaceous arc magmatism in southern Tibet.LITHOS,454.
MLA	Mai, Yuan-Jun,et al."Recycling of eroded crust by melange diapirs evidenced from the Early Cretaceous arc magmatism in southern Tibet".LITHOS 454(2023).