气候变化领域集成服务门户(CCPortal): Middle Triassic volcanic rocks in the Northern Qiangtang (Central Tibet): Geochronology, petrogenesis, and tectonic implications

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DOI	10.1016/j.tecto.2015.10.017
	Middle Triassic volcanic rocks in the Northern Qiangtang (Central Tibet): Geochronology, petrogenesis, and tectonic implications
	Chen, Sheng-Sheng; Shi, Ren-Deng; Yi, Guo-Ding; Zou, Hai-Bo
通讯作者	Chen, SS (通讯作者)
发表日期	2016
ISSN	0040-1951
EISSN	1879-3266
起始页码	90
结束页码	102
卷号	666
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.
关键词	U-PB GEOCHRONOLOGY NB-ENRICHED BASALTS STRENGTH ELEMENT ENRICHMENT ISLAND-ARC BASALTS PALEO-TETHYS ISOTOPIC CHARACTERISTICS GEOLOGICAL SIGNIFICANCE CONTINENTAL-CRUST NUJIANG SUTURE IGNEOUS ZIRCON
英文关键词	Magmatism; Triassic; Crust growth; Qiangtang; Tibetan Plateau
语种	英语
WOS研究方向	Geochemistry & Geophysics
WOS类目	Geochemistry & Geophysics
WOS记录号	WOS:000375731600008
来源期刊	TECTONOPHYSICS
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/258723
推荐引用方式 GB/T 7714	Chen, Sheng-Sheng,Shi, Ren-Deng,Yi, Guo-Ding,et al. Middle Triassic volcanic rocks in the Northern Qiangtang (Central Tibet): Geochronology, petrogenesis, and tectonic implications[J]. 中国科学院青藏高原研究所,2016,666.
APA	Chen, Sheng-Sheng,Shi, Ren-Deng,Yi, Guo-Ding,&Zou, Hai-Bo.(2016).Middle Triassic volcanic rocks in the Northern Qiangtang (Central Tibet): Geochronology, petrogenesis, and tectonic implications.TECTONOPHYSICS,666.
MLA	Chen, Sheng-Sheng,et al."Middle Triassic volcanic rocks in the Northern Qiangtang (Central Tibet): Geochronology, petrogenesis, and tectonic implications".TECTONOPHYSICS 666(2016).