Estimation of incision and uplift rate based on feldspar OSL dating of river channel sediments; Case study in the Oi River

Ogata, Manabu ; Tsukahara, Yuzuko ; Nishiyama, Nariaki  ; Komatsu, Tetsuya  ; Uchida, Mao; Kawamura, Makoto; Ishihara, Takanori; Nakanishi, Toshimichi*

Terrace to terrace (TT) method is mainly used for estimating uplift rate on mountain areas of Japan on 10-year time scale. However, this method cannot be applied to the area with poor distribution of fluvial terraces. In such area, the method based on the emergence ages of the fluvial landform, e.g., an abandoned river valley around a cutoff spur, and the relative elevation between old and present reiver bed is expected instead of TT method. This method calculates the river-incision rate by dividing the relative elevation by the emergence age. The river-incision rate is equal to the uplift rate if the river is at equilibrium (graded stream). We are investigating the fluvial landform in the Oi River basin for verifying this method. In this presentation, we will present the incision and uplift rate estimated by feldspar OSL dating results.