Chronology of the Youfang site and its implications for the emergence of microblade technology in North China

The Youfang Paleolithic site, located in the eastern Nihewan Basin, Hebei Province, China, was discovered in 1984. However, the microblade assemblages which were excavated from the site lacked reliable chronological data. In this study, an optical dating technique was applied to nine samples from Late Pleistocene eolian sequences at the site. The ages of three samples from artifact-bearing deposits were in the range of ca. 26-29ka with depths between 2.1m and 2.9m obtained with medium-grained quartz, corresponding to Marine Isotope Stage 3 (MIS3). These displayed evidence of a longer-term climate trend, in which the climate became gradually warmer and more humid. The sample from the upper culture layer was dated to 26.4±2.1ka. Five samples taken from the lower culture layer yielded ages between ca. 28ka and 43ka. The results suggest that human occupation at the Youfang site ranged from ca. 26ka to 29ka. Indeed, the Nihewan Basin yields the oldest microblade site in northern high latitudes (40°N), and offers a unique opportunity to study the emergence and characteristics of microblade technologies in northeast Asia. Nevertheless, extensive archeological field surveys and excavations are still needed to understand further the developmental process of microblade technologies in the region.