Post-rifting magmatism at the northern margin of the South China Sea: Evidenced by an ocean bottom seismometer experimentKey points
Magmatism at continental margins is of great significance in understanding the continental rifting. We present a two-dimensional P-wave velocity model derived from an ocean bottom seismometer experiment, conducted across the middle northern continental margin of the South China Sea (SCS). The detail...
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KeAi Communications Co., Ltd.
2025-02-01
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S1674451924000570 |
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| author | Lu Zhang Chen Cai Rui Gao |
| author_facet | Lu Zhang Chen Cai Rui Gao |
| author_sort | Lu Zhang |
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| description | Magmatism at continental margins is of great significance in understanding the continental rifting. We present a two-dimensional P-wave velocity model derived from an ocean bottom seismometer experiment, conducted across the middle northern continental margin of the South China Sea (SCS). The detailed velocity structures reveal significant heterogeneities extending from the continental shelf to the continent-ocean transition zone. The crust exhibits its greatest thickness below the continental shelf, measuring ∼23 km and gradually thins to ∼13 km at the distal margin. Furthermore, a narrow and distinct continent-ocean transition with only 40-km width is revealed. We also observe a high-velocity layer within the transition zone, reaching thickness of up to 4 km, characterized by P-wave velocities ranging from 7.0 km/s to 7.6 km/s in the lower crust. Based on the syn-rift melt generation using decompression melting model, we ascertain that syn-rift magmatism cannot fully account for the observed thick high-velocity layer. By integrating findings from previous geophysical and geochemical studies presenting extensive volcanic edifice on the seafloor at the northern margin, as well as ocean-island-basalt-type magmatic samples in the SCS area, we propose that post-rifting magmatism associated with the Hainan Plume may have influenced the formation of the high-velocity lower crust within the transition zone and the northern margin of the SCS can thus be recognized as magma-poor type margin. |
| format | Article |
| id | doaj-art-92dfe8de9d894665b2f2aaf085e376d1 |
| institution | Kabale University |
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| language | English |
| publishDate | 2025-02-01 |
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| spelling | doaj-art-92dfe8de9d894665b2f2aaf085e376d12024-12-19T10:53:01ZengKeAi Communications Co., Ltd.Earthquake Science1867-87772025-02-01381116Post-rifting magmatism at the northern margin of the South China Sea: Evidenced by an ocean bottom seismometer experimentKey pointsLu Zhang0Chen Cai1Rui Gao2School of Earth Sciences and Engineering, Sun Yat-sen University, Guangzhou 510275, China; School of Geophysics and Geomatics, China University of Geosciences, Wuhan 430074, China; Corresponding author.School of Earth Sciences and Engineering, Sun Yat-sen University, Guangzhou 510275, China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519000, China; Guangdong Provincial Key Lab of Geodynamics and Geohazards, Guangzhou 510275, China; Corresponding author.School of Earth Sciences and Engineering, Sun Yat-sen University, Guangzhou 510275, China; Guangdong Deep Earth Exploration and Geological Process Technology Research Center, Guangzhou 510275, China; Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China; Corresponding author.Magmatism at continental margins is of great significance in understanding the continental rifting. We present a two-dimensional P-wave velocity model derived from an ocean bottom seismometer experiment, conducted across the middle northern continental margin of the South China Sea (SCS). The detailed velocity structures reveal significant heterogeneities extending from the continental shelf to the continent-ocean transition zone. The crust exhibits its greatest thickness below the continental shelf, measuring ∼23 km and gradually thins to ∼13 km at the distal margin. Furthermore, a narrow and distinct continent-ocean transition with only 40-km width is revealed. We also observe a high-velocity layer within the transition zone, reaching thickness of up to 4 km, characterized by P-wave velocities ranging from 7.0 km/s to 7.6 km/s in the lower crust. Based on the syn-rift melt generation using decompression melting model, we ascertain that syn-rift magmatism cannot fully account for the observed thick high-velocity layer. By integrating findings from previous geophysical and geochemical studies presenting extensive volcanic edifice on the seafloor at the northern margin, as well as ocean-island-basalt-type magmatic samples in the SCS area, we propose that post-rifting magmatism associated with the Hainan Plume may have influenced the formation of the high-velocity lower crust within the transition zone and the northern margin of the SCS can thus be recognized as magma-poor type margin.http://www.sciencedirect.com/science/article/pii/S1674451924000570South China Seacontinental marginseismic refractionpost-rift magmatism |
| spellingShingle | Lu Zhang Chen Cai Rui Gao Post-rifting magmatism at the northern margin of the South China Sea: Evidenced by an ocean bottom seismometer experimentKey points Earthquake Science South China Sea continental margin seismic refraction post-rift magmatism |
| title | Post-rifting magmatism at the northern margin of the South China Sea: Evidenced by an ocean bottom seismometer experimentKey points |
| title_full | Post-rifting magmatism at the northern margin of the South China Sea: Evidenced by an ocean bottom seismometer experimentKey points |
| title_fullStr | Post-rifting magmatism at the northern margin of the South China Sea: Evidenced by an ocean bottom seismometer experimentKey points |
| title_full_unstemmed | Post-rifting magmatism at the northern margin of the South China Sea: Evidenced by an ocean bottom seismometer experimentKey points |
| title_short | Post-rifting magmatism at the northern margin of the South China Sea: Evidenced by an ocean bottom seismometer experimentKey points |
| title_sort | post rifting magmatism at the northern margin of the south china sea evidenced by an ocean bottom seismometer experimentkey points |
| topic | South China Sea continental margin seismic refraction post-rift magmatism |
| url | http://www.sciencedirect.com/science/article/pii/S1674451924000570 |
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