Abstract: Complex geomorphological evolution in the lower reaches of the Yangtze River during the Holocene has been jointly driven by frequent human activities and hydrological changes, which affected the continuity of sedimentary processes
and complicated accurate understanding of the relationship between the origin and development of prehistoric cultures and environmental evolution in the region. In this study, we collected sedimentary samples from the Xingang site in the lower reaches of the Yangtze River and established a chronological framework for natural sedimentary strata based on archaeological stratigraphy and AMS14C dating of natural cores. Multiple proxy indices-including magnetic susceptibility, Mn/Ti, Fe/Mn, and grain-size parameters were analyzed to reconstruct regional environmental evolution and its linkage to cultural development. The results show a shift from an aquatic to a terrestrial sedimentary environment near the site around 7 ka BP. Together with sedimentary hiatuses identified in multiple cores across the region, this suggests the contemporary formation of the Yangtze River Delta. The emergence of the delta provided new habitats and agricultural space for prehistoric settlements. The drier climate after 7 ka BP led to further expanded arable land. This coupled geomorphic-climatic effect enhanced land productivity and supported substantial population growth, thereby laying the spatial foundation for the development of the Majiabang-Songze archaeological cultures and ultimately contributing to the rise of early state societies in the region.

Key words: Mid Holocene, Yangtze River Delta Plain, Landscape evolution, Majiabang culture, Songze culture