Middle Triassic volcanic rocks in the Northern Qiangtang (Central Tibet): Geochronology, petrogenesis, and tectonic implications

doi:10.1016/j.tecto.2015.10.017

	Middle Triassic volcanic rocks in the Northern Qiangtang (Central Tibet): Geochronology, petrogenesis, and tectonic implications
	Chen, SS (Chen, Sheng-Sheng)1,4; Shi, RD (Shi, Ren-Deng)2,4; Yi, GD (Yi, Guo-Ding)1,4; Zou, HB (Zou, Hai-Bo)3; Chen, SS
刊名	TECTONOPHYSICS
	2016
卷号	666 期号:0 页码:90-102
关键词	U-pb Geochronology Nb-enriched Basalts Paleo-tethys Ocean Island-arc Basalts Strength Element Enrichment Hf Isotopic Characteristics Slab Melts Geological Significance Mindanao Philippines Continental-crust
DOI	10.1016/j.tecto.2015.10.017
文献子类	Article
英文摘要	Although voluminous magmatism occurred during the Triassic in the Qiangtang terrane, the petrogenesis of the volcanic rocks and the associated tectonic scenarios remain mysterious. This study focuses on new identified primitive volcanic rocks from the Yanshiping area, Northern Qiangtang subterrane. The whole-rock major trace elemental, Sr-Nd isotopic data, and zircon U-Pb age of volcanic rocks are reported in this paper in order to understand their petrogenesis and tectonic setting. The studied volcanic rocks can be grouped into two types, i.e., Nb-enriched basalts and basaltic andesites (NEBs) in the low sequence and arc basalts in the upper sequence. Zircon U-Pb dating using LA-ICP-MS techniques yields the concordant age with a weighted mean (206)pb/U-238 age of ca. 242-241 Ma for the NEBs and ca. 240 Ma for the arc basalts. The distinct geochemical and isotopic characteristics of whole-rock and varying Th-U-REE components of zircon grains from the volcanic rocks suggest that the NEBs were derived from partial melting of relatively enriched mantle wedge that have been metasomatised by slab-related melts and that the arc basalts originated from partial melting of mixing of mantle wedge and depleted asthenospheric mantle in response to the slab breakoff. Our new geochemical and geochronological results, in combination with regional studies, imply that the Middle Triassic magmatism was generated in the tectonic setting of northward subduction of the Paleo-Tethys or Bangong-Nujiang Ocean. Subduction-related processes that include melting of the slab and the slab breakoff during the Permian-Middle Triassic made an important contribution to crustal growth in the Qiangtang terrane, whereas vertical crustal growth associated with collision-related setting during the Late Triassic is nonsignificant. (C) 2015 Elsevier B.V. All rights reserved.
学科主题	地质学
语种	英语
WOS记录号	WOS:000375731600008
内容类型	期刊论文
源URL	[http://ir.itpcas.ac.cn/handle/131C11/7780]
专题	青藏高原研究所_图书馆
通讯作者	Chen, SS
作者单位	1.Chinese Acad Sci, Grad Univ, Beijing 100049, Peoples R China 2.Chinese Acad Sci, Ctr Excellence Tibetan Plateau Earth Sci, Beijing 100101, Peoples R China 3.Auburn Univ, Dept Geosci, Auburn, AL 36849 USA 4.Chinese Acad Sci, Inst Tibetan Plateau Res, Key Lab Continental Collis & Plateau Uplift, Beijing 100101, Peoples R China
推荐引用方式 GB/T 7714	Chen, SS ,Shi, RD ,Yi, GD ,et al. Middle Triassic volcanic rocks in the Northern Qiangtang (Central Tibet): Geochronology, petrogenesis, and tectonic implications[J]. TECTONOPHYSICS,2016,666(0):90-102.
APA	Chen, SS ,Shi, RD ,Yi, GD ,Zou, HB ,&Chen, SS.(2016).Middle Triassic volcanic rocks in the Northern Qiangtang (Central Tibet): Geochronology, petrogenesis, and tectonic implications.TECTONOPHYSICS,666(0),90-102.
MLA	Chen, SS ,et al."Middle Triassic volcanic rocks in the Northern Qiangtang (Central Tibet): Geochronology, petrogenesis, and tectonic implications".TECTONOPHYSICS 666.0(2016):90-102.