Abstract: The tectonic evolution of the South China Sea (SCS) is intricately linked to the subduction-collision systems of Southeast Asia. However, the termination of the collision between the Dangerous Grounds terrane and the Sabah-Palawan margin remains debated due to insufficient age constraints at the southern SCS margin. A deep well drilled on Meiji Atoll, penetrating Cenozoic carbonate strata in the central Dangerous Grounds, provides robust Sr-isotope and LA-ICP-MS U-Pb ages that critically constrain the Cenozoic evolution of the southern SCS. A middle-Miocene hiatus spanning nine million years is identified on Meiji Atoll, interpreted as primarily resulting from tectonic uplift in the central Dangerous Grounds. This uplift phase was synchronous with under-thrusting beneath the southern Palawan margin and orogenic uplift in northern Borneo, indicating an active mid-Miocene collision in the southern SCS. The resumption of carbonate deposition above the hiatus at ~11 Ma dates the end of this collision event, postdating the cessation of seafloor spreading in the SCS (~15 Ma).

Key words: South China Sea, NK1, Meiji, tectonic evolution, Sr-isotope