Evolution of eastern Asia river systems reconstructed by the mineralogy and detrital-zircon geochronology of modern Red River and coastal Vietnam river sand

Abstract

The Cenozoic rise of the Tibetan Plateau has caused a thorough reorganization of the eastern Asia river network. Unravelling the still unclear evolution of the Red River, formerly a larger paleoriver system, represents one essential step towards a better understanding of the interaction between climate and mountain building in this extremely tectonically active region of the Earth. We here present original and compiled petrographic, heavy-mineral, Sr and Nd isotope, and UPb detrital-zircon geochronological data from Red River sediments, upper reaches of modern rivers sourced in Tibet, stratigraphic successions of inland basins, and cores drilled in offshore basins in the South China Sea, to provide new light on the Cenozoic drainage evolution across southeast Asia. The south-flowing transcontinental paleoriver that flowed through the Sichuan, Chuxiong, Simao and Khorat basins in the latest Cretaceous was disrupted in the Paleogene in response to regional uplift. The Pearl paleoriver then began to develop as the joint Bei and Dong paleorivers and started to incise westward to eventually reach the margin of the southeastern Tibetan Plateau in the Neogene. The Red paleoriver also progressively evolved into a larger catchment through the Paleogene, incorporating the Jinsha paleoriver and a tributary draining the western Yangtze block. In the early-middle Miocene, the Red paleoriver eventually lost its Tibetan headwaters when the Jinsha River was captured by the Yangtze River at the First Bend. The present drainage configuration of the Red and Pearl rivers started to develop in the mid-Miocene.