Investigating the Late Pleistocene to Present-Day Deposition Processes of Paleofloods in the Yellow River-Huangshui River Valley through End-Member Modeling

Abstract

Detailed field investigations in the Yellow River-Huangshui River Valley(YHV) uncover stratigraphic sections of soil sediments intercalated with multiple layers of slack water deposit(SWD). In-depth analysis of palaeoflood sediment sections in the YHV: Combination of detailed observational measurements, stratigraphic delineation, sampling, optical stimulated luminescence(OSL) dating, grain size analysis, and End-Member(EM) analysis. Non-Parametric method resolves 7 EMs components with distinct source and depositional dynamics from the palaeoflood sediment sequence in 3 sections. Analysis of soil sediment stratigraphic units in the YHV reveals mixed superposition of multiple EM components. Macroscopic characteristics, physical and chemical properties indicate occurrence of paleofloods in 28.9 ka-18.4 ka phases, with SWD formed from long-distance transport of surface sediment carried by river floods and sandy sediment from river diffuse beaches under hydrodynamic action. EM analysis of full sample size reflects diverse sediment dynamics of the YHV. Findings hold significant implications for disaster prevention and mitigation in the region.