Reconstructing the late Quaternary soil erosion and dust deposition dynamics in the southern Loess Plateau: Insights from Lake Luyanghu sedimentary records

Abstract

Investigating the history of wind-dust deposition and soil erosion is crucial for understanding the relationship between geomorphologic formation, monsoon evolution and the current state of soil erosion on the Loess Plateau. This study utilizes a 50-m sedimentary record from Lake Luyanghu (LYH) in the southern Loess Plateau. We developed a chronological framework using optically stimulated luminescence (OSL) dating and stratigraphic comparisons. By applying end-member modeling of grain size, we identified various sediment sources and quantitatively reconstructed the dust deposition fluxes and soil erosion modulus during the late Quaternary. Additionally, we examined the patterns of sediment source evolution with environmental changes at LYH. Our findings reveal that dust constitutes an average of 32.3% of the lake sediments, with an average deposition rate of 40.2 g/cm²/ka. Notably, after the Last Glacial period, dust deposition became the dominant component of the lake sediment. During the Marine Isotope Stages (MIS) 5b, 5d, 4 and 2, enhanced dry climatic conditions, decreased vegetation cover and composition, leading to significant soil erosion. Based on the results of this research, future studies should aim to reconstruct the watershed's erosion and deposition processes throughout geological periods by integrating aspects of lake evolution, such as water levels and developmental stages.