Geochemistry of subducted metabasites exhumed from the Mariana forearc: Implications for Pacific seamount subduction
Geochemistry of subducted metabasites exhumed from the Mariana forearc: Implications for Pacific seamount subduction
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从马里亚纳弧前挖出的俯冲变基岩的地球化学：对太平洋海山俯冲的影响
DOI：
10.1016/j.gsf.2020.12.002
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发表时间：
2021-05
影响因子：
8.9
通讯作者：
Sun Weidong
中科院分区：
文献类型：
--
作者：
Deng Jianghong;Zhang Lipeng;Liu He;Liu Haiyang;Liao Renqiang;Mastoi A. S.;Yang Xiaoyong;Sun Weidong
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 Fantangisña 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 Fantangisña 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 Fantangisña 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.
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DOI：
10.1186/bf03353114
发表时间：
2008-06
期刊：
Earth, Planets and Space
影响因子：
--
作者：
Y. Matsumoto;T. Ishikawa;M. Fujita;Mariko Sato;H. Saito;M. Mochizuki;T. Yabuki;A. Asada
通讯作者：
Y. Matsumoto;T. Ishikawa;M. Fujita;Mariko Sato;H. Saito;M. Mochizuki;T. Yabuki;A. Asada
DOI：
10.1002/9781118666180.ch14
发表时间：
2013-03
期刊：
Geophysical monograph
影响因子：
--
作者：
R. Hickey‐Vargas;I. Savov;M. Bizimis;T. Ishii;K. Fujioka
通讯作者：
R. Hickey‐Vargas;I. Savov;M. Bizimis;T. Ishii;K. Fujioka
影响因子：
3.9
作者：
Guoliang Zhang;Ji Zhang;Shuai Wang;Jian-xin Zhao
通讯作者：
Guoliang Zhang;Ji Zhang;Shuai Wang;Jian-xin Zhao
影响因子：
--
作者：
A. Davis;M. Pringle;L. G. Pickthorn;D. Clague;W. C. Schwab
通讯作者：
A. Davis;M. Pringle;L. G. Pickthorn;D. Clague;W. C. Schwab
影响因子：
64.8
作者：
B. Hanan;J. Blichert‐Toft;D. Pyle;D. Christie
通讯作者：
B. Hanan;J. Blichert‐Toft;D. Pyle;D. Christie