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Evolution of Deep Sea Processes in the South China Sea
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International Ocean Discovery Program expeditions 349, 367 and 368 explore the initiation of the South China Sea
P-SPS6-10
Zhen Guo* , The IODP China Office, Tongji University
Shouting Tuo, The IODP China Office, Tongji University
Tingyu Wen, The IODP China Office, Tongji University
Presenter Email: zhenguo@tongji.edu.cn |
| International Ocean Discovery Program (IODP) is an international collaborative research organization focusing on exploring Earth’s history and dynamics by recovering information recorded in the seafloor sediments and rocks. The IODP, dated from 1968, has made the most significant contribution to understanding the history of the Earth and is still playing an important role in the geoscience research. China jointed the IODP (ocean drilling program, ODP at that time) as the first associate member in 1998 and became an official member of IODP in 2013. The IODP expeditions 349, 367 and 368 were designed mainly by Chinese scientists and conducted in South China Sea (SCS) in 2014, 2017 and 2017 respectively. These expeditions aimed to understand the opening of the SCS and the mechanisms of lithosphere extension during continental breakup at a non-volcanic rifted margin. The magnetic surveys and igneous cores in Expedition 349 suggest that the seafloor spreading started about 33 Ma ago with a full spreading rate between about 20 and 80 km/Myr in the northeastern SCS (Li et al., 2014). The Mid-Ocean Ridge Basalt (MORB) in SCS is composed similarly to that in the Pacific Ocean, suggesting that the magmatism in SCS is tightly related to that in the Pacific Ocean. The MORB cores from Expeditions 367 and 368 and seismic survey in SCS support the existence of hyperextended margin, which is considered as the "missing link" between the magma-rich and magma-poor margins in North Atlantic (Larsen et al., 2018). The model suggests that the seafloor spreading of SCS is forced by magmatism at the thin crust resulting in weakening the mantle lithosphere and massive extrusive activity along the entire rift zone. References: Li, C.-F., et al. (2014), Ages and magnetic structures of the South China Sea constrained by deep tow magnetic surveys and IODP Expedition 349, Geochem. Geophys. Geosyst., 15, 4958-4983, doi:10.1002/2014GC005567. Larsen, H. C., et al. (2018), Rapid transition from continental breakup to igneous oceanic crust in the South China Sea, Nature Geoscience, doi: 10.1038/s41561-018-0198-1. |
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