气候变化领域集成服务门户(CCPortal): Generation of late cretaceous ji'an basalts through asthenosphere-slab interaction in South China

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DOI	10.1130/B35196.1
	Generation of late cretaceous ji'an basalts through asthenosphere-slab interaction in South China
	Wu Y.; Guo F.; Wang X.-C.; Zhang B.; Zhang X.; Alemayehu M.; Wang G.
发表日期	2020
ISSN	167606
起始页码	1316
结束页码	1332
卷号	132 期号:2021-05-06
英文摘要	Recycled crustal components have been widely identified in the source of continental basalts with geochemical features similar to oceanic island basalts (OIBs). However, the mechanism of how these recycled materials are involved remains highly debatable. Here we conduct comprehensive geochemical analyses (including whole-rock, olivine, and melt inclusion) and numerical modeling on Late Cretaceous Ji'an basalts from South China interior, aiming to investigate the possible role of recycled crustal components in basalt petrogenesis driven by the subducted paleo-Pacific oceanic plate. The Ji'an basalts show geochemical characteristics akin to OIBs and have depleted asthenospheric mantle-like Sr-Nd-Pb-Hf isotopic compositions with moderately radiogenic Os. Their olivine-hosted melt inclusions have low H2O and highly negative δD values and olivine phenocrysts are mainly characterized by depletion of 18O with δ18O values lowering to 3.9‰. These features are consistent with positive Sr and Eu anomalies in some whole-rock samples. The combined geochemical data suggest that the primary magmas were derived from an asthenospheric mantle enriched by melts from an altered gabbroic oceanic crust, which had experienced intensive dehydration. Further numerical modeling shows that melting of the dehydrated oceanic crust can occur along the torn flank of the subducting lithosphere, in the case that the slab is strongly thinned and fractured. The low δ18O preserved in olivine and the estimated slab age (<300 Ma) from the radiogenic whole-rock Os and Pb compositions also require the involvement of a recently recycled slab, probably represented by the subducted paleo-Pacific oceanic plate. Rollback of the subducting paleo-Pacific slab might create a slab window, in which melt from the torn/fractured slab reacted with the upwelling asthenosphere to form an enriched mantle source for the Ji'an basalts and similar counterparts. © 2019 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/184793
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, 100049, China; Research Centre for Earth System Science, Yunnan Key Laboratory of Earth System Science, Yunnan University, Kunming, 650500, China; Radiogenic Isotope Facility, School of Earth and Environment Sciences, University of Queensland, Brisbane, QLD 4072, Australia
推荐引用方式 GB/T 7714	Wu Y.,Guo F.,Wang X.-C.,et al. Generation of late cretaceous ji'an basalts through asthenosphere-slab interaction in South China[J],2020,132(2021-05-06).
APA	Wu Y..,Guo F..,Wang X.-C..,Zhang B..,Zhang X..,...&Wang G..(2020).Generation of late cretaceous ji'an basalts through asthenosphere-slab interaction in South China.Bulletin of the Geological Society of America,132(2021-05-06).
MLA	Wu Y.,et al."Generation of late cretaceous ji'an basalts through asthenosphere-slab interaction in South China".Bulletin of the Geological Society of America 132.2021-05-06(2020).