Article Abstract
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.