气候变化领域集成服务门户(CCPortal): Late Cretaceous transition from subduction to collision along the Bangong-Nujiang Tethys: New volcanic constraints from central Tibet

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DOI	10.1016/j.lithos.2017.11.012
	Late Cretaceous transition from subduction to collision along the Bangong-Nujiang Tethys: New volcanic constraints from central Tibet
	Liu, De-Liang; Shi, Ren-Deng; Ding, Lin; Zou, Hai-Bo
通讯作者	Liu, DL (通讯作者)
发表日期	2018
ISSN	0024-4937
EISSN	1872-6143
起始页码	452
结束页码	470
卷号	296
英文摘要	This study deals with arc-type and subsequent bimodal volcanic rocks interbedded with (late) Cretaceous sedimentary formations near Gaize, central Tibet that shed new light on the Tethyan evolution along the Bangong-Nujiang suture. Unit I consists of trachyandesites interbedded with fine-grained sandstone, slate, and limestone. Zircon dating on a trachyandesite sample yields a Pb-206/U-238 age of 99 +/- 1 Ma. The trachyandesites are characterized by strong enrichment in LILE but depletion in HFSE, low zircon saturation temperatures (T-Zr = 642-727 degrees C), and high oxygen fugacity (Delta FMQ = 0.67-0.73), indicating their arc affinities. Unit II comprises a bimodal basalt-rhyolite suite interbedded with coarse-grained sandstone and conglomerate. Zircon dating on two rhyolitic samples yield Pb-206/U-238 ages of 97.1-87.0 Ma. In contrast with Unit I trachyandesites, Unit II basalts and rhyolites exhibit OIB-like trace element patterns, high temperatures (T=1298-1379 degrees C for basalts, T-Zr = 855-930 degrees C for rhyolites), and low oxygen fugacity (AFMQ = 3.37 similar to - 0.43), suggesting that Unit II bimodal volcanic rocks probably formed in an extensional setting. The Sr-Nd isotopes of both Unit I (Sr-87/Sr-86; = 0.7052-0.7074, epsilon Nd(t) = -2.21-1.02) and Unit II (Sr-87/Sr-86(i) = 0.7057-0.7098, epsilon Nd(t) = 3.22-0.88) rocks are similar to mantle-wedge-derived volcanic rocks within the southern Qiangtang block. The parental magma of Unit I trachyandesites was formed by fluid induced melting of the mantle wedge above the subducted Bangong-Nujiang Tethyan slab, and contaminated by crustal materials during MASH process within a deep crustal hot zone; and Unit II bimodal volcanic rocks were derived by melting of upwelling asthenosphere and a mildly metasomatized mantle wedge during the Lhasa-Qiangtang collision. We propose that the transition from the Bangong-Nujiang Tethyan subduction to the Lhasa-Qiangtang collision occurred during the Late Cretaceous in central Tibet. (C) 2017 Elsevier B.V. All rights reserved.
关键词	TRACK THERMOCHRONOLOGY EVIDENCE U-PB GEOCHRONOLOGY A-TYPE GRANITES SOUTHERN QIANGTANG LHASA TERRANE TECTONIC EVOLUTION INTRUSIVE ROCKS CRUSTAL GROWTH GEOCHEMICAL CHARACTERISTICS OCEANIC LITHOSPHERE
英文关键词	Volcanic rocks; Subduction; Collision; Bangong-Nujiang Tethys; Qiangtang; Tibet
语种	英语
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
WOS类目	Geochemistry & Geophysics ; Mineralogy
WOS记录号	WOS:000423890600029
来源期刊	LITHOS
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/259227
推荐引用方式 GB/T 7714	Liu, De-Liang,Shi, Ren-Deng,Ding, Lin,et al. Late Cretaceous transition from subduction to collision along the Bangong-Nujiang Tethys: New volcanic constraints from central Tibet[J]. 中国科学院青藏高原研究所,2018,296.
APA	Liu, De-Liang,Shi, Ren-Deng,Ding, Lin,&Zou, Hai-Bo.(2018).Late Cretaceous transition from subduction to collision along the Bangong-Nujiang Tethys: New volcanic constraints from central Tibet.LITHOS,296.
MLA	Liu, De-Liang,et al."Late Cretaceous transition from subduction to collision along the Bangong-Nujiang Tethys: New volcanic constraints from central Tibet".LITHOS 296(2018).