Detecting the waves of southward culture diffusion along the eastern margin of Tibetan Plateau during the Neolithic and Bronze Age: a sarcophagus burial perspective

The trajectory for the southward diffusion of cultural elements originated from north China, such as millet crops, painted pottery, and sarcophagus burial, along the eastern margin of the Tibetan Plateau (EMTP) during the Neolithic and Bronze Age, is a hot issue across multiple disciplines. Painted pottery and millet had spread into the southeast margin of the Tibetan Plateau during the early fifth millennium BP, while sarcophagus burials emerged in the same area before ~ 3000 BP. However, the timeline for the southward diffusion of sarcophagus burial remains unclear due to the absence of reliable dates of sarcophagus burials in the northeast Tibetan Plateau (NETP). To solve this problem, we investigated prehistoric sites in the Bailong River valley of NETP and sampled bones from a site and five sarcophagus burials for radiocarbon dating. Most dates span between ~ 4500–3500 BP, which are the earliest direct dates of sarcophagus burials distributed along the EMTP. In comparison to updated results of archaeological studies and radiocarbon dating, we argue that the southward diffusion of sarcophagus burials along the EMTP occurred between ~ 4500–3000 BP, much later than the southward dispersal of painted pottery. This provides a new perspective to understand multiple waves of southward culture diffusion along the EMTP before the dawn of the Imperial Age in China.