Palynological evidence for Early to Mid-Holocene sea-level fluctuations over the present-day Ningshao Coastal Plain in eastern China

Sea-level fluctuation in a coastal plain setting was crucial for Neolithic human occupations of the Ningshao Coastal Plain in eastern China. In this study, we carry out analyses using detailed palynological records of dinoflagellate cysts (dinocysts), freshwater algae and foraminiferal organic linings from two sediment cores (HMD1501 and HMD1502) at the Tianluoshan archaeological site, Zhejiang Province, eastern China. Brief sea-level fluctuations and environmental changes on the Ningshao Coastal Plain during the Early to Mid-Holocene were recovered by using radiocarbon chronology. The results show the Tianluoshan site underwent marine transgression processes, and experienced warm and humid climatic conditions during the ca. 10, 708-5850 cal. yr BP. After that, there was a relatively cold and dry climate, marine regression processes occurred at the Tianluoshan site during the ca. 5850-5655 cal. yr BP, indicated by an abrupt increase in the cold-water species of dinoflagellates (especially O. centrocarpum), freshwater algae concentration and the ratio of pollen to dinoflagellates (P/D), with an abrupt decrease appeared in foraminifer linings concentration. Marine regression processes provided an opportunity for Hemudu ancestors to enter the Tianluoshan site, which helped create a brilliant Hemudu-Tianluoshan Culture on the Ningshao Coastal Plain.