Time constraints for the Yellow River traversing the Sanmen Gorge

The Yellow River is the second longest river in China, a total course of 5464 km. The Yellow River traverses 30 gorges within its main course and the last one is the Sanmen Gorge. The timing of cut through the Sanmen Gorge indicates the final integration of the Yellow River. Previous geological surveys identify a paleolake in the Weihe Basin located west of the Sanmen Gorge; the lake was drained when the gorge was cut through. Using cosmogenic nuclide burial dating, we obtain ages of transition from lake to fluvial environments in the Weihe Basin and formation of fluvial terraces within the Sanmen Gorge. The timing of cut through the Sanmen Gorge is constrained to 1.3-1.5 Ma. Zircon U-Pb age distributions further suggest that the Weihe, the largest tributary of the Yellow River running from west to east along the northern section of the Qinling Mountains, primarily flowed over the Sanmen Gorge, followed by the upper and middle Yellow River traversing 1.3-1.4 Ma ago. It appears that formation and integration of the Yellow River occurred in a short duration in the early Pleistocene, probably related to global climate changes.