气候变化领域集成服务门户(CCPortal): Tectono-magmatic evolution of Late Jurassic to Early Cretaceous granitoids in the west central Lhasa subterrane, Tibet

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DOI	10.1016/j.gr.2016.01.006
	Tectono-magmatic evolution of Late Jurassic to Early Cretaceous granitoids in the west central Lhasa subterrane, Tibet
	Cao, MingJian; Qin, KeZhang; Li, GuangMing; Li, JinXiang; Zhao, JunXing; Evans, Noreen J.; Hollings, Pete
通讯作者	Qin, KZ (通讯作者)
发表日期	2016
ISSN	1342-937X
EISSN	1878-0571
起始页码	386
结束页码	400
卷号	39
英文摘要	There is ongoing debate as to the subduction direction of the Bangong-Nujiang Ocean during the Mesozoic (northward, southward or bidirectional subduction). Arc-related intermediate to felsic intrusions could mark the location of the subduction zone and, more importantly, elucidate the dominant geodynamic processes. We report whole rock geochemical and zircon U-Pb and Hf isotopic data for granitoids from the west central Lhasa subterrane (E80 degrees to E86 degrees). All rocks show metaluminous to peraluminous, calc-alkaline signatures, with strong depletion of Nb, Ta and Ti, enrichment of large ion lithophile elements (e.g., Cs, Rb, K), a negative correlation between SiO2 and P2O5, and a positive correlation between Rb and Th. All these features are indicative of I-type arc magmatism. New zircon U-Pb results, together with data from the literature, indicate continuous magmatism from the Late Jurassic to the Early Cretaceous (160 to 130 Ma). Zircon U-Pb ages for samples from the northern part of the west central Lhasa subterrane (E80 degrees to E82 degrees 30') yielded formation ages of 165 to 150 Ma, whereas ages of 142 to 130 Ma were obtained on samples from the south. This suggests flat or low-angle subduction of the Bangong-Nujiang Ocean, consistent with a slight southward decrease in zircon epsilon Hf(t) values for Late Jurassic rocks. Considering the crustal shortening, the distance from the Bangong-Nujiang suture zone, and a typical subduction zone melting depth of similar to 100 km, the subduction angle was less than 14 degrees for Late Jurassic magmatism in the central Lhasa interior, consistent with flat or low-angle subduction. Compared with Late Jurassic rocks (main eHf(t) values of -16 to -7), Early Cretaceous rocks (145 to 130 Ma) show markedly higher eHf(t) values (mainly-8 to 0), possibly indicating slab roll-back, likely caused by slab foundering or break-off. Combined with previously published works on arc magmatism in the central Lhasa and west part of the southern Qiangtang subterranes, our results support the bidirectional subduction of the Bangong-Nujiang Ocean along the Bangong-Nujiang Suture Zone, and indicates flat or low-angle southward subduction (165 to 145Ma) followed by slab roll-back (145 to 130 Ma). (C) 2016 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.
关键词	U-PB GEOCHRONOLOGY HF ISOTOPIC CONSTRAINTS PORPHYRY COPPER-DEPOSIT TERTIARY IGNEOUS ROCKS A-TYPE GRANITES LU-HF TRACE-ELEMENT FLAT SUBDUCTION VOLCANIC-ROCKS TECTONIC EVOLUTION
英文关键词	Arc magmatism; Zircon U-Pb-Hf isotopes; Flat or low-angle subduction; Central Lhasa subterrane; Tibet
语种	英语
WOS研究方向	Geology
WOS类目	Geosciences, Multidisciplinary
WOS记录号	WOS:000397872900022
来源期刊	GONDWANA RESEARCH
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/258775
推荐引用方式 GB/T 7714	Cao, MingJian,Qin, KeZhang,Li, GuangMing,et al. Tectono-magmatic evolution of Late Jurassic to Early Cretaceous granitoids in the west central Lhasa subterrane, Tibet[J]. 中国科学院青藏高原研究所,2016,39.
APA	Cao, MingJian.,Qin, KeZhang.,Li, GuangMing.,Li, JinXiang.,Zhao, JunXing.,...&Hollings, Pete.(2016).Tectono-magmatic evolution of Late Jurassic to Early Cretaceous granitoids in the west central Lhasa subterrane, Tibet.GONDWANA RESEARCH,39.
MLA	Cao, MingJian,et al."Tectono-magmatic evolution of Late Jurassic to Early Cretaceous granitoids in the west central Lhasa subterrane, Tibet".GONDWANA RESEARCH 39(2016).