The present-day Yangtze River was established in the late Miocene: Evidence from detrital zircon ages

Abstract

Abstract The Yangtze River originates in the Tibetan Plateau and supplies tremendous sediments to the East China Sea. To date, when and how the Yangtze River was formed is still highly debated. This paper presents systematic detrital zircon U-Pb ages (3575 grain ages from a total of 29 samples) from the Cenozoic sediments of offshore basins in East China. The zircon age spectra vary significantly in the South Yellow Sea Basin, but are relatively stable in the East China Sea Shelf Basin (ECB) and significantly different from those of present-day Yangtze River (PYR) before the late Miocene. Comparisons of zircon ages with potential source terranes suggest that the ECB has received detrital sediments that PYR features since the late Miocene, whereas before that time, the sediment provenances show a North China and Korea affinity. Considering the overwhelming sediment input from the eastern Tibetan Plateau, the first occurrence of the PYR-featured sediments in the ECB in the late Miocene suggests that the Yangtze River with approximately present erosion patterns was established at that time. This agrees well with the exhumation history of the eastern Tibetan Plateau. The unique zircon ages in the Eocene to mid-Miocene sediments imply that the Yangtze River with headwaters in eastern Tibet might not exist before the late Miocene. This study provides new insights into the Yangtze River evolution although more lines of evidence are required, which is mainly because of the complex river sediment source-to-sink processes and tectonic and climatic forcings in the large catchment.