Inversion of Dadu River Bedrock Channels for the Late Cenozoic Uplift History of the Eastern Tibetan Plateau

The Dadu River in the eastern Tibetan Plateau has the potential to record transient variations of tectonic uplift since the Late Cenozoic. In this study, we extracted bedrock channels of the Dadu River drainage basin from the 30 m ASTER digital elevation model. The longitudinal river profiles were then analyzed, and three generations of knickpoints were recognized via the slope area method. By solving the analytical solution of the linear transient stream power incision model, we determined a Late Cenozoic history of regional tectonic uplift. The results reveal slow pre-middle Miocene uplift rates (<0.1 mm/a) and then increased gradually to 0.33 +/- 0.03 mm/a since 12-15 Ma until present. This increase of uplift rate from bedrock channel inversion is consistent with the regional findings of low-temperature themochronology, emphasizing the potential and significance to utilize channel profiles to infer the tectonic uplift history. Plain Language Summary Recently, numerous thermochronology studies have provided constraints on the timing of rapid denudation along the eastern Tibetan Plateau. However, the rates of denudation/uplift determined by thermochronological profiles are often given as an average since a certain time duration. Thus, it is difficult to quantify the history of the tectonic uplift and whether uplift has been uniform or varied through time. We used the linear simulation method and inverted the longitudinal river profiles to decipher the Late Cenozoic uplift history of the eastern Tibetan Plateau. The results reveal that before the middle Miocene, the uplift rate was slow (<0.1 mm/a), and it increased gradually to 0.33 +/- 0.03 mm/a since 12-15 Ma until present.