气候变化领域集成服务门户(CCPortal): Oceanic plateau subduction during closure of the Bangong-Nujiang Tethyan Ocean: Insights from central Tibetan volcanic rocks

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DOI	10.1130/B32045.1
	Oceanic plateau subduction during closure of the Bangong-Nujiang Tethyan Ocean: Insights from central Tibetan volcanic rocks
	Hao L.-L.; Wang Q.; Zhang C.; Ou Q.; Yang J.-H.; Dan W.; Jiang Z.-Q.
发表日期	2019
ISSN	167606
起始页码	864
结束页码	880
卷号	131 期号:2021-05-06
英文摘要	Identification of arc magmatic rock associations in a subduction zone has important implications for specifically revealing the geodynamic evolution of the subduction system. The closure time of the Bangong-Nujiang Tethyan Ocean and the detailed subduction processes have been hotly debated, hindering our understanding of the tectonic evolution of central Tibet. Here, we investigated the ca. 110-104 Ma Gerze lavas (basalts, basaltic andesites, andesites, dacites, and rhyolites) in southern Qiangtang. Fusion of slab fluid-metasomatized mantle wedge could yield the basalts, and such basaltic magmas, if contaminated with ancient basement orthogneisses, could have formed the andesites. The basaltic andesites with high Nb and Nb/La are similar to the Nb-enriched arc basalts and probably originated from slab melt-metasomatized mantle. The dacites were generated by fractional crystallization of the subducted mélange-derived intermediate magmas. The rhyolites have geochemical characteristics (high SiO2 and La/Yb; low MgO and Sr/Y) similar to those of Jamaican-type adakites and were possibly sourced from the subducted oceanic plateau at low pressures. The Gerze Jamaican-type adakites and Nb-enriched basalt association could imply intense slab-mantle interactions. The Gerze lava suites show clear arc affinities, indicating that oceanic subduction may have lasted until 100 Ma. Based on previous studies and a noticeable ca. 145-125 Ma magmatic lull in southern Qiangtang, we suggest that the Bangong-Nujiang oceanic subduction geodynamics involved normal subduction (170-145 Ma), flat subduction (145-125 Ma), and slab roll-back (125-101 Ma). Moreover, the flat subduction was most likely caused by subduction of the oceanic plateau. Therefore, we propose, for the first time, that Tethyan oceanic plateau subduction during the Early Cretaceous could explain the tectonic evolution of the Bangong-Nujiang Ocean and distinctive magmatism in southern Qiangtang, central Tibet. © 2018 Geological Society of America.
语种	英语
来源期刊	Bulletin of the Geological Society of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/184926
作者单位	State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China; University of Chinese Academy of Sciences, Beijing, 10069, China; Chinese Academy of Science Center for Excellence in Tibetan Plateau Earth Sciences, Beijing, 100101, China; Department of Geosciences, Fort Hays State University, Hays, KA 67601-4099, United States; Institute of Geology and Geophysics, Chinese Academy of Science, Beijing, 100029, China; School of Earth Science, Guilin University of Technology, Guilin, 541004, China
推荐引用方式 GB/T 7714	Hao L.-L.,Wang Q.,Zhang C.,et al. Oceanic plateau subduction during closure of the Bangong-Nujiang Tethyan Ocean: Insights from central Tibetan volcanic rocks[J],2019,131(2021-05-06).
APA	Hao L.-L..,Wang Q..,Zhang C..,Ou Q..,Yang J.-H..,...&Jiang Z.-Q..(2019).Oceanic plateau subduction during closure of the Bangong-Nujiang Tethyan Ocean: Insights from central Tibetan volcanic rocks.Bulletin of the Geological Society of America,131(2021-05-06).
MLA	Hao L.-L.,et al."Oceanic plateau subduction during closure of the Bangong-Nujiang Tethyan Ocean: Insights from central Tibetan volcanic rocks".Bulletin of the Geological Society of America 131.2021-05-06(2019).