Climate‐Dependent Sediment Composition and Transport of Mountainous Rivers in Tectonically Stable, Subtropical East Asia
Xing Jian, Wei Zhang, Shouye Yang, Shuh‐Ji Kao
Abstract
Abstract While mountainous rivers in subtropical East Asia deliver a disproportionately large amount of sediments to the global ocean, the controlling mechanisms for sediment supply and transport remain understudied. Here we target a mesoscale tectonically stable mountainous river, the Minjiang River, in southeast China. We present petrography, heavy minerals, and Sr‐Nd isotopic data from suspended particulate matter (SPM) and riverbed sediments to characterize sediment‐climate feedback processes. Results show Sr‐Nd isotopic compositions of the SPM vary seasonally, corresponding well with the spatiotemporal variations of precipitation. River sands display low compositional and textural maturity and represent first cycle‐dominated and fast‐transported detritus. Provenance analysis suggests prominent contributions of upstream Proterozoic‐Paleozoic rocks to downstream SPM and riverbed sediments. We propose that climate‐induced hydrological variations exert a major control on sediment supply, transport, and compositions. Our study highlights the crucial role of climate in driving physical erosion of mountains in tectonically stable, subtropical East Asia.