Exploitation of lydite and jasper by Epipaleolithic foragers in the Northeastern Tibetan Plateau and surrounding regions

Lithic raw material analysis is the key to understanding prehistoric foragers’ resource exploitation strategies, mobility patterns, cultural interactions and exchange networks. Previous geochemical study of obsidian artifacts from Paleolithic and Epipaleolithic sites on the Tibetan Plateau revealed possible human interactions in the Chang Tang and southern Tibet. However, obsidian is rare in sites on the Northeastern Tibetan Plateau (NETP) and adjacent low elevation regions. To understand the lithic raw material economy and related human interactions on the NETP and the surrounding regions, here we analyze lithic raw materials from these regions through macroscopic rock type identification, Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analysis. We found that at least four varieties of lydite (a type of basaltic rock, Lydite A, B, C, and D) and three varieties of red jasper (Jasper A, B, and C) were used in these sites. The Northern Tibet volcanic belt in the central Tibetan Plateau and Alashan Gobi Desert may be the sources of the two most dominant materials, Lydite A and Jasper A. The maximum, “as the crow flies,” transportation distances are more than 900 km for Lydite A and 580 km for Jasper A among archaeological sites, indicating Epipaleolithic foragers in NETP and adjacent low elevation regions were either highly mobile or formed vast exchange networks. Long distance exploitation of lydite resources might have encouraged human occupation of the high central Tibetan Plateau in the early Holocene. In addition, the spatial distribution of Epipaleolithic sites sharing the same varieties of lydite and red jasper in the study area suggests that the river valleys connecting the Qilian Mountains, the Hexi Corridor and the Tengger Desert oases were important channels for human movements during Epipaleolithic period. Therefore, lithic raw material analysis here provides important information for resource exploitation and mobility strategies of Epipaleolithic foragers in NETP and surrounding regions.