Optically Stimulated Luminescence Chronology of the Huangqiyu Site of the Lower Min River

Prehistoric human cultural sites along the eastern coast of Fujian Province are important records for studying the origin and spread of the Austronesian civilization. The Huangqiyu site is the first Tanshishan culture site to be unearthed in the Min River estuary area and was excavated by scientific archeology. It has great significance for further research of the Tanshishan culture and the coupled relationship between prehistoric human activities and environmental changes in the Fujian coastal region. The chronology of archeological sites is an important foundation for prehistoric archeology. In this study, the burial age of the Huangqiyu site in Lianjiang County was analyzed using the Optically Stimulated Luminescence (OSL) dating technique on the basis of Accelerator Mass Spectrometry (AMS) 14C dating. In the field, the T2 section of the Huangqiyu site was selected for sampling, and the single-aliquot regeneration dose method of medium-grained quartz was used to assess OSL chronology in the laboratory. The results showed that the OSL burial age of the Huangqiyu site ranges from approximately 8.5 ± 0.5 to 4.4 ± 0.2 ka, corresponding to the sedimentary/cultural strata of the early Middle Holocene. The OSL age of sample 2019118, which was consistent with the AMS 14C age, was 4.4 ± 0.2 ka, corresponding roughly to the Tanshishan culture. The age of sample 2019117 was 5.4 ± 0.3 ka, which may be an overestimation because the equivalent dose of this sample showed a weakly skewed distribution with a tail at the high value end, indicating that there was a small amount of sundry particles and that the drying was insufficient. This problem may have led to a bias in the measured equivalent dose and, in turn, to overestimation of the age of the sample. The age of sample 2019119, which was affected by the sampling environment, was 8.5 ± 0.5 ka, possibly indicating the maximum age of the bottom boundary of the site. Archeological studies have found that the age indicated by the pottery features excavated from the cultural layer at the bottom of the Huangqiyu site is most likely earlier than the Tanshishan culture, or possibly that of the lower strata of the Tanshishan culture. Overall, the ages of samples 2019117 and 2019119 are different from the AMS 14C ages, but these are consistent with the archeological characteristics of the site. By comparing the geomorphological and environmental evolution process of the Fuzhou Basin, where the Huangqiyu site is located, with the regional prehistoric human activities, it was found that the site corresponds to the warm climate of 6 500-4 000 a B P and relatively a high sea level period. Many prehistoric remains were developed in the Fuzhou Basin during this period, and the prosperous Tanshishan culture and the lower Tanshishan culture emerged in the region. At the end of the Neolithic age, the abrupt cold event of 4.2-4.0 ka, the drastic change of climate and environment in the tropical and subtropical regions on both sides of the Pacific Ocean at 4 000-3 000 a B P, and the invasion of the northern Wu-Yue culture may explain the disappearance of the follow-up culture. Because of the limited precision of the regional sea-level change curve, it is insufficient to discuss sea-land change and the coupled relationship with human activities. Relevant studies need to strengthen these aspects in the future.