Geochemistry of subducted metabasites exhumed from the Mariana forearc: Implications for Pacific seamount subduction

doi:10.1016/j.gsf.2020.12.002

	Geochemistry of subducted metabasites exhumed from the Mariana forearc: Implications for Pacific seamount subduction
	Deng, Jianghong 1,2,3; Zhang, Lipeng 1,2; Liu, He 1,2; Liu, Haiyang 1,2; Liao, Renqiang1,2,4 ; Mastoi, Abdul Shakoor 3,5; Yang, Xiaoyong 3; Sun, Weidong1,2,4
	2021-05-01
发表期刊	GEOSCIENCE FRONTIERS
ISSN	1674-9871
卷号	12 期号:3 页码:12
通讯作者	Liu, He([email protected])
摘要	Seamounts on the drifting oceanic crust are inevitably carried by plate motions and eventually accreted or subducted. However, the geochemical signatures of the subducted seamounts and the significance of seamount subduction are not well constrained. Hundreds of seamounts have subducted beneath the Philippine Sea Plate following the westward subduction of the Pacific Plate since the Eocene (similar to 52 Ma). The subducted oceanic crust and seamount materials can be exhumed from the mantle depth to the seafloor in the Mariana forearc region by serpentinite mud volcanoes, providing exceptional opportunities to directly study the subducted oceanic crust and seamounts. The International Ocean Discovery Program (IODP) expedition 366 has recovered a few metamorphosed mafic clasts exhumed from the Mariana forearc serpentinite mud volcanoes, e.g., the Fantangisna and Asut Tesoru seamounts. These mafic clasts have tholeiitic to alkaline affinities with distinct trace elements and Nd-Hf isotopes characteristics, suggesting different provenances and mantle sources. The tholeiites from the Fantangisna Seamount have trace element characteristics typical of mid-ocean ridge basalt. The Pacific-type Hf-Nd isotopic compositions, combined with the greenschist metamorphism of these tholeiites further suggest that they came from the subducted Pacific oceanic crust. The alkali basalts-dolerites from the Fantangisna and Asut Tesoru seamounts show ocean island basalt (OIB)-like geochemical characteristics. The OIB-like geochemical signatures and the low-grade metamorphism of these alkali basalts-dolerites suggest they came from subducted seamounts that originally formed in an intraplate setting on the Pacific Plate. The Pacific Plate origin of these metabasites suggests they were formed in the Early Cretaceous or earlier. Two types of OIBs have been recognized from alkali metabasites, one of which is geochemically similar to the HIMU-EMI-type OIBs from the West Pacific Seamount Province, and another is similar to the EMII-type OIBs from the Samoa Island in southern Pacific, with negative Nb-Ta-Ti anomalies and enriched Nd-Hf isotopes. Generally, these alkali metabasites are sourced from the heterogeneous mantle sources that are similar to the present South Pacific Isotopic and Thermal Anomaly. This study provides direct evidence for seamount subduction in the Mariana convergent margins. We suggest seamount subduction is significant to element cycling, mantle heterogeneity, and mantle oxidation in subduction zones. (c) 2021 China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V.
关键词	IODP 366 Mariana convergent margin Forearc Seamount subduction OIB
DOI	10.1016/j.gsf.2020.12.002
收录类别	SCI
语种	英语
资助项目	Strategic Priority Research Program of the Chinese Academy of Sciences[XDA22050103]; Strategic Priority Research Program of the Chinese Academy of Sciences[XDB420 20303]; Strategic Priority Research Program of the Chinese Academy of Sciences[XDB18020102]; National Natural Science Foundation of China[41803002]; China Postdoctoral Science Foundation[2018 M642708]; Qingdao National Laboratory for Marine Science and Technology[2017ASKJ02]; Taishan Scholar Foundation of Shandong Province[ts201712075]
WOS研究方向	Geology
WOS类目	Geosciences, Multidisciplinary
WOS记录号	WOS:000636463500031
出版者	CHINA UNIV GEOSCIENCES, BEIJING
引用统计	被引频次：15[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/170538
专题	深海极端环境与生命过程研究中心
通讯作者	Liu, He
作者单位	1.Chinese Acad Sci, Ctr Deep Sea Res, Ctr Ocean Megasci, Inst Oceanol, Qingdao 266071, Peoples R China 2.Qingdao Natl Lab Marine Sci & Technol, Lab Marine Mineral Resources, Qingdao 266237, Peoples R China 3.Univ Sci & Technol China, CAS Key Lab Crust Mantle Mat & Environm, Hefei 230026, Peoples R China 4.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 5.Univ Sindh, Ctr Pure & Appl Geol, Jamshoro 76080, Pakistan
第一作者单位	中国科学院海洋大科学研究中心
通讯作者单位	中国科学院海洋大科学研究中心
推荐引用方式 GB/T 7714	Deng, Jianghong,Zhang, Lipeng,Liu, He,et al. Geochemistry of subducted metabasites exhumed from the Mariana forearc: Implications for Pacific seamount subduction[J]. GEOSCIENCE FRONTIERS,2021,12(3):12.
APA	Deng, Jianghong.,Zhang, Lipeng.,Liu, He.,Liu, Haiyang.,Liao, Renqiang.,...&Sun, Weidong.(2021).Geochemistry of subducted metabasites exhumed from the Mariana forearc: Implications for Pacific seamount subduction.GEOSCIENCE FRONTIERS,12(3),12.
MLA	Deng, Jianghong,et al."Geochemistry of subducted metabasites exhumed from the Mariana forearc: Implications for Pacific seamount subduction".GEOSCIENCE FRONTIERS 12.3(2021):12.

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