Human dispersal and interaction during the spread of microblade industries in East Asia

Abstract Analyses of microblade industries shed light on the human dispersal and technological diffusion in the terminal Upper Paleolithic of East Asia. From ca. 27–17 ka, with the advances of the Last Glacial Maximum (LGM), the Mammoth Steppe and its associated mammoth fauna shifted southward. In the wake of these changes, human groups with the Northern Microblade Industries (NMI) also migrated southward to Northeast China. NMI did not appear in North China, so it is presumed that those migrating human groups did not extend their activity areas beyond NE China. Meanwhile, the human groups with small flake tool industries in North China appear to have interacted with those groups with NMI at the ecological border area between NE. China and N. China, and obtained the microblade technology of pressure flaking, wedge-shaped micro-cores, transverse burins with marginal retouch and other elements of NMI, leading to the formation of the microblade industries that are unique to N. China. Technological elements of the NMI that appeared in N. China are regarded as the result of external expansion diffusion. Among the distinct features of the microblade industries in N. China is the microblade technology based on pyramidal micro-cores. This technology was transferred to Southwest Japan. This transfer of microblade technology and its spread across SW Japan was carried out through the materials and information exchange network that had connected N. China and SW Japan since the pre-stage of microblade industry. This diffusion of microblade technology is also regard as an example of external expansion diffusion. From ca. 17–9 ka, human groups that were migrating with NMI through NE China were able to enter N. China because of their flexible “collector” subsistence strategy and high level of adaptability to the environment. The appearance of NMI in N. China is regard as the result of external relocation diffusion. The technological transfer also occurred between the migrating human groups and the indigenous groups. The indigenous ones in turn adopted the technology of NMI, invented small bifacial points. This process is an example of expansion diffusion.