Environmental reconstruction and dating of Shixiakou Locality 1 on China’s West Loess Plateau: implications for human adaptive changes apparent during the Last Glacial Maximum (LGM) and post-LGM periods

The Last Glacial Maximum (LGM; ca. 24–18 ka), the most recent widespread cold event of the later Pleistocene epoch, is thought to have had profound impacts on human evolution and behavior in many ways, including the reduction of population density of prehistoric hunter-gatherers. Although data are limited, decreasing numbers of sites on the West Loess Plateau (WLP) in northern China are considered evidence of depopulation of that area. More occupations dating to the LGM have been reported recently, and new discoveries provide additional information for understanding the demographic history of the West Loess Plateau and northern China. Here, we report new dating results, examine lithic technology, and provide a paleoenvironmental reconstruction based on pollen recovered at Shixiakou Locality 1. Two archaeological layers at the site dating to 20–16.5 ka add new late LGM occupations to a previously reported post-LGM occurrence at Shixiakou. Reconstruction of the paleoenvironment reveals a cold and dry temperate steppe or steppe-desert environment during the LGM, generally in accord with the regional environmental framework. Lithic technology and raw material use were similar during the LGM and post-LGM periods, but great energetic investments, such as the use of beads, were discovered in post-LGM occupation contexts. This might indicate relatively sophisticated social behavior, such as building group identity, although more data are required. A review of known LGM occupations in northern China demonstrates that hunter-gatherers were then distributed widely from the West Loess Plateau to the Nihewan Basin and to Northeast China. Occupation density during the post-LGM period varied greatly in different parts of northern China. This scenario implies that demographic dynamics during the LGM and post-LGM periods in northern China were complex. The Shixiakou case study demonstrates that understanding the adaptations of ancient hunter-gatherers has been enhanced by exploring material culture changes against a background of local and regional paleoenvironmental records.