Response of modern fluvial sediments to regional tectonic activity along the upper Min River, eastern Tibet

Abstract. The deposition of fluvial sediments in tectonically active areas is mainly controlled by tectonics, climate, and associated Earth surface processes; consequently, can provide a valuable record changes regional climate tectonic activity. In this study, we conducted detailed analysis the grain-size distribution modern from upper Min River, eastern Tibet. These data, combined with information on vegetation, hydrology, geomorphology, lithology, fault slip rate, indicate that activity along River be divided into three segments. Specifically, Minjiangyuan–Diexi segment are dominated silts (< 63 µm, 70.2 %), agreeing low runoff, rainfall, high vegetation cover revealing windblown origin influenced arid windy climate. observations consistent hillslope angle relief, all indicating weak Minjiang Fault. coarse-grained fraction (> 250 µm) Diexi–Wenchuan Wenchuan–Dujiangyan segments increases stepwise downstream, although runoff rainfall do not change significantly. patterns correlate well both relief angles. Together, these imply Maoxian–Wenchuan Fault becomes more pervasive downstream River. occurrence well-sorted well-rounded pebbles Dujiangyan must related to long-time scouring sorting rivers. This study marks first development new research approach characterize collected regions.