Late Cretaceous transition from subduction to collision along the Bangong-Nujiang Tethys: New volcanic constraints from central Tibet

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, DL (Liu, De-Liang)1,2; Shi, RD (Shi, Ren-Deng)2; Ding, L (Ding, Lin)2; Zou, HB (Zou, Hai-Bo)3
刊名	LITHOS
	2018
卷号	296 期号:0 页码:452-470
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
ISSN号	0024-4937
DOI	10.1016/j.lithos.2017.11.012
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.
学科主题	地质学
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000423890600029
内容类型	期刊论文
源URL	[http://ir.itpcas.ac.cn/handle/131C11/8781]
专题	青藏高原研究所_图书馆
通讯作者	Liu, DL (Liu, De-Liang)
作者单位	1.China Univ Geosci, Fac Earth Resource, Collaborat Innovat Ctr Explorat Strateg Mineral R, Wuhan 430074, Hubei, Peoples R China; 2.Chinese Acad Sci, Inst Tibetan Plateau Res, Key Lab Continental Collis & Plateau Uplift, Beijing 100101, Peoples R China; 3.Auburn Univ, Dept Geosci, Auburn, AL 36849 USA.
推荐引用方式 GB/T 7714	Liu, DL ,Shi, RD ,Ding, L ,et al. Late Cretaceous transition from subduction to collision along the Bangong-Nujiang Tethys: New volcanic constraints from central Tibet[J]. LITHOS,2018,296(0):452-470.
APA	Liu, DL ,Shi, RD ,Ding, L ,&Zou, HB .(2018).Late Cretaceous transition from subduction to collision along the Bangong-Nujiang Tethys: New volcanic constraints from central Tibet.LITHOS,296(0),452-470.
MLA	Liu, DL ,et al."Late Cretaceous transition from subduction to collision along the Bangong-Nujiang Tethys: New volcanic constraints from central Tibet".LITHOS 296.0(2018):452-470.