Holocene coastal environmental evolution and human adaptation in the Yaojiang-Ningfeng plain, eastern China, revealed by reanalysis of the radiocarbon dates

The Yaojiang-Ningfeng coastal plain attracted widespread attention since this region is the core area of the flourishing Neolithic Hemudu Culture and rice domestication. However, the availability of accurate deposited ages of sediments from this region are always difficult due to dating anomalies. One of the possible reasons is that previous studies mainly used the radiocarbon (14C) dates from one to several cores which might be biased by the complex coastal environment. However, the implications of the anomalous 14C dates from a regional size remain to be investigated. Therefore, we collected 424 published radiocarbon dates and reanalyzed ages with different dating materials through the age-depth distributions, the summed probability distributions (SPD) and the Bacon model. The results show that radiocarbon dates with organic matter and pollen residues are significantly older than these with plants, charred materials, peat, shells and other dating materials. Excluding the pollen residues and organic matter results, the average sediment accumulation rates (SARs) generated by the Bacon models are shown two sudden drops in 7.8–7.7 cal kyr BP and 6.4–6.3 cal kyr BP, which correspond to the decline of the Jingtoushan archaeological site and the interruption of the Hemudu Culture. Our study indicates that environmental evolution can be explored through the regional radiocarbon dates and that is related to ancient human activity.