Tectonic Topography Changes in Cenozoic East Asia: A Landscape Erosion-Sediment Archive in the South China Sea

The mode and tempo of Cenozoic fluvial input into the South China Sea by Asian rivers were strongly controlled by tectonically induced topographic changes and landscape development that resulted in repeated river captures and reversals. New Nd isotope and U-Pb detrital zircon data from clastic sedimentary sequences in the northern South China Sea display secular variations reflecting significant changes in the compositions of fluvial sediment as well as changes in source rocks. The oldest, Eocene-Oligocene (before similar to 25 Ma) clastic rocks of the South China Sea contain sediments with epsilon(Nd) values of 25 to -7.5 and detrital zircons of Cretaceous, Jurassic, and Permo-Triassic, all derived from southern Cathaysia. The Oligocene-Middle Miocene (similar to 25-11 Ma) sediments in the South China Sea strata display epsilon(Nd) values of 212 to 214 and Archean, Proterozoic, and Paleozoic detrital zircons, suggesting northern Cathaysia and/or the Yangtze Blocks as their provenance. The headward expansion of the Pearl River and reversal of the Middle Yangtze River correlates with the opening of the South China Sea and growth of the eastern Tibetan Plateau at similar to 25 Ma. Further uplift of the eastern Tibetan Plateau and the Wuyi-Nanling Mountains in SE China around 11 Ma reshaped the landscape and caused another phase of erosion-pattern adjustment and drainage-divide migration in East Asia, leading to the establishment of the modern fluvial systems of the Pearl, Minjiang, and Lower Yangtze Rivers. Plain Language Summary The mode and tempo of Cenozoic fluvial input into the South China Sea by Asian rivers were strongly controlled by tectonically induced topographic changes and landscape development that resulted in repeated river captures and reversals. This study reconstructs tectonic topography changes and drainage development over 30 million years using Nd isotope and single grain zircon U-Pb data from the South China Sea. Our study shows that tectonic topography and river systems in East Tibet experienced two major reorganization events, reflecting the protracted and episodic growth of eastern Tibet, East Asia marginal seas, and Asian monsoonal climate. Our findings shed light on how tectonic, climate, and river drainage processes have interacted in this part of the world during the latter part of the Cenozoic. We believe our work is international interest and contributed to unravel the history of tectonic topographic evolution and drainage development through time in eastern Tibet