Quantitative reconstruction reveals fluvial-aeolian interactions in the Poyang Lake sandy lands in subtropical China

The middle–lower Yangtze River region hosts extensive aeolian deposits, among which the Poyang Lake sandy land (PYSL) constitutes a prominent and geomorphologically distinctive example. However, the relative contributions and synergistic interactions between aeolian and fluvial processes in shaping these landscapes remain insufficiently quantified, primarily due to methodological limitations and spatially fragmented research efforts. This knowledge gap impedes both robust paleoenvironmental reconstructions and the development of effective strategies for mitigating sand-related hazards. Here, an integrated provenance study of the PYSLs was conducted, combining detrital zircon U Pb geochronology, heavy mineral analysis, and grain-size distribution. The multidimensional scaling (MDS) diagrams and inverse Monte Carlo models (IMCM) of detrital zircon ages indicate major provenance areas are the eastern Cathaysia Block (mainly the south and central Jiangxi ranges; 16.2–85.5%) and the Jiangnan Orogenic Belt (primarily the Jiuling Mountains; 14.5–83.8%). The results demonstrate pronounced spatial heterogeneity in sediment direct sources. The central PYSLs are primarily supplied by the Ganjiang and Xiushui rivers, whereas the northern PYSL is dominated by the Yangtze and Ganjiang rivers, and the southern PYSL derives sediment mainly from the Jinjiang river. Obviously, wind plays a subordinate role in large-scale sediment reworking, as evidenced by the marked compositional heterogeneity between the northern and southern PYSL. Nevertheless, aeolian processes remain dynamically active in the local redistribution of sediments within the central PYSLs. These findings collectively emphasize that topographic factors must be carefully considered in paleoenvironmental studies of aeolian deposits. However, surface samples provide only a limited view into longer-term landscape evolution.