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DOI	10.1016/j.lithos.2024.107558
	Early Paleocene diorite and bimodal dykes from the Dagze region, southern Lhasa Terrane: Tectonic implications for the late-stage of Neo-Tethyan subduction
	Tang, Yan; Zhao, Zhidan; Li, Xiaowei; Wang, Zhenzhen; Qi, Ningyuan; Liu, Dong; Wang, Qing; Mo, Xuanxue
发表日期	2024
ISSN	0024-4937
EISSN	1872-6143
起始页码	472
卷号	472
英文摘要	The tectonic transition from oceanic subduction to continental collision is a fundamental process during orogenesis. Yet, the nature of this transition and its deep geodynamic processes for the southern Tibetan Plateau remain contentious. This study presents zircon U-Pb-Hf isotopes, whole -rock geochemistry, and Sr-Nd isotopes for a quartz diorite intrusion and bimodal dykes from Dagze, combined with compiled data from the southern Lhasa subterrane, to reveal the geodynamic processes of late -stage of Neo-Tethyan subduction. Most of Dagze samples were emplaced between 66 and 64 Ma, while muscovite granite aplite dykes were emplaced between 64 and 60 Ma. They exhibit relatively uniform, depleted Sr-Nd isotopes, with epsilon Nd(t) values ranging from +2.2 to +4.0, positive zircon epsilon Hf(t) values, and young depleted mantle model ages. Both exhibit compositional characteristics of subduction-related arc magma, marked by the enrichment of large ion lithophile elements and the depletion of high field strength elements. The mafic dykes with relatively low SiO2, high MgO, Cr, Ni, possibly originated from a fluid-metasomatized depleted mantle. The quartz diorite intrusion with low MgO, Cr, and Ni was generated by partial melting of sub -arc lithospheric mantle and experienced subsequent fractional crystallization of amphibole, clinopyroxene and orthopyroxene. The granitic dykes originated from partial melting of Gangdese juvenile crust and experienced fractional crystallization dominated by plagioclase. We suggest that the slab rollback and continental collision conjointly controlled the evolution of the latest Cretaceous to Paleocene Himalayan-Tibetan orogeny. Slab rollback of Neo-Tethys commenced around 70 Ma, triggering the partial melting of depleted mantle and juvenile crust, and this process resulted in the formation of Dagze diorites and bimodal dykes with arc affinity.
英文关键词	Lhasa Terrane; Bimodal dykes; Neo-Tethyan subduction; Slab rollback
语种	英语
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
WOS类目	Geochemistry & Geophysics ; Mineralogy
WOS记录号	WOS:001203752200001
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/303620
作者单位	Shandong University of Science & Technology
推荐引用方式 GB/T 7714	Tang, Yan,Zhao, Zhidan,Li, Xiaowei,et al. Early Paleocene diorite and bimodal dykes from the Dagze region, southern Lhasa Terrane: Tectonic implications for the late-stage of Neo-Tethyan subduction[J],2024,472.
APA	Tang, Yan.,Zhao, Zhidan.,Li, Xiaowei.,Wang, Zhenzhen.,Qi, Ningyuan.,...&Mo, Xuanxue.(2024).Early Paleocene diorite and bimodal dykes from the Dagze region, southern Lhasa Terrane: Tectonic implications for the late-stage of Neo-Tethyan subduction.LITHOS,472.
MLA	Tang, Yan,et al."Early Paleocene diorite and bimodal dykes from the Dagze region, southern Lhasa Terrane: Tectonic implications for the late-stage of Neo-Tethyan subduction".LITHOS 472(2024).