The middle reach of the Yangtze River experienced significant drainage reorganization during the Mesozoic to Cenozoic tectonic evolution of South China. A continental-scale, westward-flowing axial river, or paleo–Middle Yangtze, formed following the Mesozoic collision between the North China and South China blocks. The river later flowed to the east as a result of the Cenozoic uplift of the Tibetan Plateau, but its reversal history remains largely unknown. Changes in detrital zircon U-Pb ages of Mesozoic to Cenozoic strata in the Three Gorges region identify a vital provenance shift in the sediments of the paleo–Middle Yangtze. Combined with paleocurrent measurements and petrography, our results indicate that the paleo–Middle Yangtze initially reversed during the late Cretaceous, followed by progressive westward capturing in the Eocene. This conclusion provides a paleogeographic explanation for the limited exposures of Upper Cretaceous to Cenozoic rocks in the Sichuan Basin and refutes the “drainage divide” hypothesis for the Three Gorges.
Late Cretaceous drainage reorganization of the Middle Yangtze River
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