Geochemistry of subducted metabasites exhumed from the Mariana forearc: Implications for Pacific seamount subduction
文献类型：CNKI期刊论文
| 作者 | Jianghong Deng; Lipeng Zhang; He Liu; Haiyang Liu; Renqiang Liao ; Abdul Shakoor Mastoi; Xiaoyong Yang; Weidong Sun
|
| 发表日期 | 2021-05-15 |
| 出处 | Geoscience Frontiers
 |
| 关键词 | IODP 366 Mariana convergent margin Forearc Seamount subduction OIB |
| 英文摘要 | 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(～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 Fantangis?a and Asùt 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 Fantangis?a 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 Fantangis?a and Asùt 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. |
| 文献子类 | CNKI期刊论文 |
| 资助机构 | financially supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA22050103, XDB420 20303, XDB18020102) ; the National Natural Science Foundation of China (Grant No.41803002) ; China Postdoctoral Science Foundation (No.2018 M642708) ; the Qingdao National Laboratory for Marine Science and Technology (2017ASKJ02) ; the Taishan Scholar Foundation of Shandong Province (ts201712075) |
| 卷 | v.12期:03页:364-375 |
| 语种 | 英文; |
| 分类号 | P736 |
| ISSN号 | 1674-9871 |
| 源URL | [http://ir.qdio.ac.cn/handle/337002/187764]  |
| 专题 | 中国科学院海洋研究所 |
| 作者单位 | 1.CASKeyLaboratoryofCrust-MantleMaterialsandEnvironments,UniversityofScienceandTechnologyofChina 2.CentreforPureandAppliedGeology,UniversityofSindh 3.CenterofDeepSeaResearch,InstituteofOceanology,CenterforOceanMega-Science,ChineseAcademyofSciences 4.LaboratoryforMarineMineralResources,QingdaoNationalLaboratoryforMarineScienceandTechnology 5.UniversityofChineseAcademyofSciences |
| 推荐引用方式 GB/T 7714 | Jianghong Deng,Lipeng Zhang,He Liu,et al. Geochemistry of subducted metabasites exhumed from the Mariana forearc: Implications for Pacific seamount subduction. 2021. |
入库方式： OAI收割
来源：海洋研究所
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