Provenance variations of aeolian sand deposition along the coast of northeastern China in response to regional sea-level changes during glacial-interglacial cycles, as revealed by quartz grain microtextures

Aeolian sand deposits, formed at the boundary between marine and terrestrial settings, are capable of providing valuable insight into sea-level variations and coastal environmental dynamics. However, the factors controlling aeolian sand deposition and the variations in sediment provenance of aeolian deposits during stadial and interstadial periods remain poorly understood. Accordingly, a comprehensive investigation of aeolian sand deposits was conducted by integrating scanning electron microscopy (SEM) with optically stimulated luminescence (OSL) dating, complemented by multiple proxies. The objective of this study was to examine the sedimentary dynamics, identify the controlling factors influencing sedimentary processes, and elucidate changes in sediment provenance. The microtextures of quartz grains exhibit significant spatial variability from the coast to the inland areas, reflecting a shift in sedimentary dynamics from wave-aeolian interaction to aeolian-dominated transport. OSL dating results reveal episodic accumulation during marine isotope stage (MIS) 3 (41–49 ka), MIS 4 (∼67 ka), and MIS 5 (78–96 ka). During interglacial periods, rising sea levels trigger coastal erosion, transporting large amounts of sediment through wave action and longshore drift, thereby promoting the formation of aeolian deposits. The shortened distance to the shoreline, combined with a higher sediment supply, facilitates the accumulation of aeolian sand further inland. Conversely, during periods of low sea level, the subaerial exposure of the continental shelf was eroded by intense aeolian deflation, resulting in the formation of large volumes of sand fractions that were blown landward by onshore winds. Aeolian sand accumulation predominantly occurs in coastal zones, attributed to the extension of the coastline and post-depositional aeolian reworking. Our findings suggest that sediment supply, modulated by sea-level fluctuations, and monsoon intensity are the primary mechanisms driving aeolian accumulation across different climatic intervals.