Small marginal sea basins are often short-lived and typically not older than several to tens of million years, but they play critical roles in global plate tectonic cycles. This paper highlights some recent achievements in answering a range of geodynamic questions stemming from scientific ocean drilling by International Ocean Discovery Program Expeditions 349, 367, 368, and 368X in the South China Sea. Together, results from these expeditions provide new insights into continental breakup in terms of the opening style and time of spreading cessation, magmatism, and sedimentation during the formation of this marginal basin. The outcomes of these expeditions have revealed new challenges and spawned new hypotheses in mantle dynamics and crustal accretion that need to be addressed by future drilling on carefully identified drill targets in the tectonically active western Pacific.

Li, C.-F., P.D. Clift, Z. Sun, and H.C. Larsen. 2019. Starting a new ocean and stopping it. Oceanography 32(1):153–156, https://doi.org/10.5670/oceanog.2019.138.

Briais, A., P. Patriat, and P. Tapponnier. 1993. Updated interpretation of magnetic anomalies and seafloor spreading stages in the South China Sea: Implications for the tertiary tectonics of Southeast Asia. Journal of Geophysical Research 98:6,299–6,328, https://doi.org/​10.1029/92JB02280.

Clift, P.D., J. Lin, and ODP Leg 184 Scientific Party. 2001. Patterns of extension and magmatism along the continent-ocean boundary, South China margin. Pp. 489–510 in Non-volcanic Rifting of Continental Margins: A Comparison of Evidence from Land and Sea. R.C.L. Wilson, R.B. Whitmarsh, B. Taylor, and N. Froitzheim, eds, Geological Society London.

Clift, P.D. 2017. A revised budget for Cenozoic sedimentary carbon subduction. Reviews of Geophysics 55:97–125, https://doi.org/​10.1002/​2016RG000531.

Fan, W., and M. Menzies. 1992. Destruction of aged lower lithosphere and accretion of asthenosphere mantle beneath eastern China. Geotectonica et Metallogenia 16:171–180.

Flower, M.F.J., R.M. Russo, K. Tamaki, and N. Hoang. 2001. Mantle contamination and the Izu-Bonin-Mariana (IBM) “high-tide mark”: Evidence for mantle extrusion caused by Tethyan closure. Tectonophysics 333(1–2):9–34, https://doi.org/​10.1016/S0040-1951(00)00264-X.

Franke, D., U. Barckhausen, N. Baristeas, M. Engels, S. Ladage, R. Lutz, J. Montano, N. Pellejera, E.G. Ramos, and M. Schnabel. 2011. The continent-​ocean transition at the southeastern margin of the South China Sea. Marine and Petroleum Geology 28:1,187–1,204, https://doi.org/10.1016/​j.marpetgeo.2011.01.004.

Hall, C.E., M. Gurnis, M. Sdrolias, L.L. Lavier, and R.D. Müller. 2003. Catastrophic initiation of subduction following forced convergence across fracture zones. Earth and Planetary Science Letters 212:15–30, https://doi.org/10.1016/S0012-821X(03)00242-5.

Hayes, D.E., and S.D. Lewis. 1985. Structure and tectonics of the Manila trench system, Western Luzon, Philippines. Energy 10:263–279, https://doi.org/​10.1016/0360-5442(85)90046-5.

Holloway, N.H. 1982. North Palawan Block, Philippines—Its relation to the Asian mainland and role in evolution of South China Sea. American Association of Petroleum Geologists Bulletin 66:1,355–1,383.

Hutchison, C.S. 2004. Marginal basin evolution: The southern South China Sea. Marine and Petroleum Geology 21(9):1,129–1,148, https://doi.org/10.1016/​j.marpetgeo.2004.07.002.

Larsen, H.C., G. Mohn, M. Nirrengarten, Z. Sun, J. Stock, Z. Jian, A. Klaus, C.A. Alvarez-Zarikian, J. Boaga, S.A. Bowden, and others. 2018. Rapid transition from continental breakup to igneous oceanic crust in the South China Sea. Nature Geoscience 11:782–789, https://doi.org/10.1038/s41561-018-0198-1.

Li, J., X. Jin, A. Ruan, S. Wu, Z. Wu, and J. Liu. 2004. Indentation tectonics in the accretionary wedge of middle Manila Trench. Chinese Science Bulletin 49:1,279–1,288, https://doi.org/​10.1360/03wd0412.

Li, C., and R.D. van der Hilst. 2010. Structure of the upper mantle and transition zone beneath Southeast Asia from traveltime tomography. Journal of Geophysical Research: Solid Earth 115, B07308, https://doi.org/10.1029/2009JB006882.

Li, C.-F., Z. Zhou, J. Li, B. Chen, and J. Geng. 2008. Magnetic zoning and seismic structure of the South China Sea ocean basin. Marine Geophysical Researches 29:223–238, https://doi.org/10.1007/s11001-008-9059-4.

Li, C.-F., X. Xu, J. Lin, Z. Sun, J. Zhu, Y. Yao, X. Zhao, Q. Liu, D.K. Kulhanek, J. Wang, and others. 2014. Ages and magnetic structures of the South China Sea constrained by deep tow magnetic surveys and IODP Expedition 349. Geochemistry, Geophysics, Geosystems 15(12):4,958–4,983, https://doi.org/10.1002/2014GC005567.

Li, C.-F., J. Lin, D.K. Kulhanek, T. Williams, R. Bao, A. Briais, E.A., Brown, Y. Chen, P.D. Clift, F.S. Colwell, and others. 2015. Site U1433. In Proceedings of the International Ocean Discovery Program, 349: South China Sea Tectonics, College Station, TX, https://doi.org/10.14379/iodp.proc.349.105.2015.

Liu, C., P.D. Clift, A. Carter, P. Böning, Z. Hu, Z. Sun, and K. Pahnke. 2017. Controls on modern erosion and the development of the Pearl River drainage in the late Paleogene. Marine Geology 394:52–68, https://doi.org/10.1016/j.margeo.2017.07.011.

Liu, W.-N., C.-F. Li, J. Li, D. Fairhead, and Z. Zhou. 2014. Deep structures of the Palawan and Sulu Sea and their implications for opening of the South China Sea. Marine and Petroleum Geology 58:721–735, https://doi.org/10.1016/​j.marpetgeo.2014.06.005.

McKenzie, D.P., and M.J. Bickle. 1988. The volume and composition of melt generated by extension of the lithosphere. Journal of Petrology 29:625–679, https://doi.org/10.1093/petrology/29.3.625.

Metcalfe, I. 2013. Gondwana dispersion and Asian accretion: Tectonic and palaeogeographic evolution of eastern Tethys. Journal of Asian Earth Sciences 66:1–33, https://doi.org/10.1016/​j.jseaes.2012.12.020.

Schellart, W., M.W. Jessell, and G.S. Lister. 2003. Asymmetric deformation in the backarc region of the Kuril arc, northwest Pacific: New insights from analogue modeling. Tectonics 22(5):1047, https://doi.org/10.1029/2002TC001473.

Song, T., and C.-F. Li. 2015. Rifting to drifting transition of the southwest subbasin of the South China Sea. Marine Geophysical Research 36:167–185, https://doi.org/10.1007/s11001-015-9253-0.

Song, X., C.-F. Li, Y. Yao, and H. Shi. 2017. Magmatism in the evolution of the South China Sea: Geophysical characterization. Marine Geology 394:4–15, https://doi.org/10.1016/​j.margeo.2017.07.021.

Sun, Z., J. Stock, Z. Jian, K. McIntosh, C.A. Alvarez-Zarikian, and A. Klaus. 2016. Expedition 367/368 Scientific Prospectus: South China Sea Rifted Margin. International Ocean Discovery Program. https://doi.org/10.14379/iodp.sp.367368.2016.

Sun, Z., Z. Jian, J.M. Stock, H.C. Larsen, A. Klaus, C.A. Alvarez Zarikian, and the Expedition 367/368 Scientists. 2018. South China Sea rifted margin. In Proceedings of the International Ocean Discovery Program, 367/368, College Station, TX, https://doi.org/10.14379/iodp.proc.367368.2018.

Tapponnier, P., G. Peltzer, A.Y. Le Dain, R. Armijo, and P. Cobbold. 1982. Propagating extrusion tectonics in Asia: New insights from simple experiments with plasticine. Geology 7:611–616, https://doi.org/10.1130/0091-7613(1982)10​<611:PETIAN>2.0.CO;2.

Wheeler, P., and N. White. 2000. Quest for dynamic topography: Observations from Southeast Asia. Geology 28(11):963–966, https://doi.org/10.1130/​0091-7613(2000)28<963:QFDTOF>2.0.CO;2.

Xie, X., R.D. Müller, S. Li, Z. Gong, and B. Steinberger. 2006. Origin of anomalous subsidence along the Northern South China Sea margin and its relationship to dynamic topography. Marine and Petroleum Geology 23:745–765, https://doi.org/10.1016/​j.marpetgeo.2006.03.004.

Xu, Y., J. Wei, H. Qiu, H. Zhang, and X. Huang. 2012. Opening and evolution of the South China Sea constrained by studies on volcanic rocks: Preliminary results and a research design. Chinese Science Bulletin 57(24):3,150–3,164, https://doi.org/​10.1007/s11434-011-4921-1.

Yu, M., Y. Yan, C.-Y. Huang, X. Zhang, Z. Tian, W.-H. Chen, and M. Santosh. 2018. Opening of the South China Sea and upwelling of the Hainan plume. Geophysical Research Letters 45(6):2,600–2,609, https://doi.org/​10.1002/2017GL076872.

Zhang, G.L., L.H. Chen, M.G. Jackson, and A.W. Hofmann. 2017. Evolution of carbonated melt to alkali basalt in the South China Sea. Nature Geoscience 10(3):229–235, https://doi.org/10.1038/ngeo2877.

Zhong, L.-F., G.-Q. Cai, A.A.P. Koppers, Y.-G. Xu, H.-H. Xu, H.-F. Gao, and B. Xia. 2018. ⁴⁰Ar/³⁹Ar dating of oceanic plagiogranite: Constraints on the initiation of seafloor spreading in the South China Sea. Lithos 302–303:421–426, https://doi.org​/10.1016/j.lithos.2018.01.018.

Zhu, M., S. Graham, and T. McHargue. 2009. The Red River Fault zone in the Yinggehai Basin, South China Sea. Tectonophysics 476:397–417, https://doi.org/10.1016/j.tecto.2009.06.015.

This is an open access article made available under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/), which permits use, sharing, adaptation, distribution, and reproduction in any medium or format as long as users cite the materials appropriately, provide a link to the Creative Commons license, and indicate the changes that were made to the original content. Images, animations, videos, or other third-party material used in articles are included in the Creative Commons license unless indicated otherwise in a credit line to the material. If the material is not included in the article’s Creative Commons license, users will need to obtain permission directly from the license holder to reproduce the material.