Mineralogical investigation of modern sediments and source analysis of different grain-size fractions in the middle and lower Yellow River

The Yellow River has the highest suspended sediment load among the Earth's big rivers. High sediment supply and rapid sediment accumulation caused numerous flood disasters such as channel breaches and diversions through history. Understanding sediment characteristics and relative contributions from potential source areas is important for recognizing the formation of hyperconcentrated flows and implementing water and sediment regulation projects. We here combine mineral analyses (clay minerals and heavy minerals) of 52 samples of modern riverbed sediments from the middle and lower reaches of the Yellow River and its tributaries, the Haihe River Basin, and the Huaihe River Basin to explore sediment-transport processes in the Huang-Huai-Hai Plain. Frequency models are used to calculate the relative contributions of each potential source area to the sediments of different grain-size in the lower Yellow River. Our results show that clay-sized sediments originate mainly from the Weihe Basin and the southern Loess Plateau, whereas coarser sediments (> 30 μm) are primarily supplied by the Jinshaan Gorge (the mainstream) and its western tributaries. This study underscores the heterogeneity of sediment sources of sediments with different grain-size in the lower Yellow River. It will shed new light on further research on the mechanisms of the formation of hyperconcentrated flows. Our findings contribute to the formulation of strategies for water and soil conservation and water-sediment regulation in the middle Yellow River; and they provide fundamental provenance analysis data for future studies of the connectivity of the Yuxi Gorge, and sedimentary and geomorphological research related to the diversion of the Yellow River to the Huaihe River Basin.