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Li X, Ishizuka O, Stern RJ, Li S, Lai Z, Somerville I, Suo Y, Chen L, Yu H. A HIMU-like component in Mariana Convergent Margin magma sources during initial arc rifting revealed by melt inclusions. Nat Commun 2024; 15:4088. [PMID: 38744830 PMCID: PMC11094193 DOI: 10.1038/s41467-024-48308-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Accepted: 04/26/2024] [Indexed: 05/16/2024] Open
Abstract
Compositions of island arc and back-arc basin basalts are often used to trace the recycling of subducted materials. However, the contribution of subducted components to the mantle source during initial arc rifting before back-arc basin spreading is not yet well constrained. The northernmost Mariana arc is ideal for studying this because the transition from rifting to back-arc spreading is happening here. Here we report major and trace element and Pb isotopic compositions of olivine-hosted melt inclusions from lavas erupted during initial rifting at 24°N (NSP-24) and compare them with those in active arc front at 21°N and mature back-arc basin at 18°N. NSP-24 high-K melt inclusions have highly radiogenic Pb compositions and are close to those of the HIMU end-member, suggesting the presence of this component in the magma source. The HIMU-like component may be stored in the over-riding plate and released into arc magma with rifting. HIMU-type seamounts may be subducted elsewhere beneath the Mariana arc, but obvious HIMU-type components appear only in the initial stages of arc rifting due to the low melting degree and being consumed during the process of back-arc spreading.
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Affiliation(s)
- Xiaohui Li
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, Key Lab of Submarine Geosciences and Prospecting Techniques, MOE and College of Marine Geosciences, Ocean University of China, Qingdao, 266100, China
- Laboratory for Marine Mineral Resources, Qingdao Marine Science and Technology Center, Qingdao, 266237, China
- Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
| | - Osamu Ishizuka
- Institute of Geology and Geoinformation, Geological Survey of Japan/AIST, Central 7, 1-1-1, Higashi, Tsukuba, Ibaraki, 305-8567, Japan
- Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima, Yokosuka, Kanagawa, 237-0061, Japan
| | - Robert J Stern
- Department of Sustainable Earth Systems Science, University of Texas at Dallas, Richardson, TX, 75080, USA
| | - Sanzhong Li
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, Key Lab of Submarine Geosciences and Prospecting Techniques, MOE and College of Marine Geosciences, Ocean University of China, Qingdao, 266100, China.
- Laboratory for Marine Mineral Resources, Qingdao Marine Science and Technology Center, Qingdao, 266237, China.
| | - Zhiqing Lai
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, Key Lab of Submarine Geosciences and Prospecting Techniques, MOE and College of Marine Geosciences, Ocean University of China, Qingdao, 266100, China
| | - Ian Somerville
- UCD School of Earth Sciences, University College Dublin, Belfield, Dublin, 4, Ireland
| | - Yanhui Suo
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, Key Lab of Submarine Geosciences and Prospecting Techniques, MOE and College of Marine Geosciences, Ocean University of China, Qingdao, 266100, China
- Laboratory for Marine Mineral Resources, Qingdao Marine Science and Technology Center, Qingdao, 266237, China
| | - Long Chen
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, Key Lab of Submarine Geosciences and Prospecting Techniques, MOE and College of Marine Geosciences, Ocean University of China, Qingdao, 266100, China
- Laboratory for Marine Mineral Resources, Qingdao Marine Science and Technology Center, Qingdao, 266237, China
| | - Hongxia Yu
- Guangxi Key Laboratory of Hidden Metallic Ore Deposits Exploration, Guilin University of Technology, Guilin, 541006, China
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Geochemical Variation of Miocene Basalts within Shikoku Basin: Magma Source Compositions and Geodynamic Implications. MINERALS 2020. [DOI: 10.3390/min11010025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Shikoku Basin is unique as being located within a trench-ridge-trench triple junction. Here, we report mineral compositions, major, trace-element, and Sr-Nd-Pb isotopic compositions of bulk-rocks from Sites C0012 (>18.9 Ma) and 1173 (13–15 Ma) of the Shikoku Basin. Samples from Sites C0012 and 1173 are tholeiitic in composition and display relative depletion in light rare earth elements (REEs) and enrichment in heavy REEs, generally similar to normal mid-ocean ridge basalts (N-MORB). Specifically, Site C0012 samples display more pronounced positive anomalies in Rb, Ba, K, Pb and Sr, and negative anomalies in Th, U, Nb, and Ta, as well as negative Nb relative to La and Th. Site 1173 basalts have relatively uniform Sr-Nd-Pb isotopic compositions, close to the end member of depleted mantle, while Site C0012 samples show slightly enriched Sr-Nd-Pb isotopic signature, indicating a possible involvement of enriched mantle 1 (EM1) and EM2 sources, which could be attributed to the metasomatism of the fluids released from the dehydrated subduction slab, but with the little involvement of subducted slab-derived sedimentary component. Additionally, the Shikoku Basin record the formation of the back-arc basin was a mantle conversion process from an island arc to a typical MORB. The formation of the Shikoku Basin is different from that of the adjacent Japan Sea and Parece Vela Basin, mainly in terms of the metasomatized subduction-related components, the nature of mantle source, and partial melting processes.
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