Impact of landscape changes on obsidian exploitation since the Palaeolithic in the central highland of Japan

We have reconstructed landscape changes at a known obsidian source area in the central highland, Japan, using well dated pollen and micro-charcoal records, in order to better understand the difference in obsidian procurement between gathering in the Palaeolithic period (>30-16 ka cal BP) and mining in the Jomon period (16-2.9 ka cal BP). The pollen record at the site shows that alpine vegetation, such as patches of Pinus pumila (dwarf Siberian pine) and alpine meadows with rocky areas surrounded the area during the period 30-17 ka cal BP. The reconstructed Palaeolithic landscape implies that there was a favourable situation for gathering obsidian on the ground surface in the area. Subsequently, growth of woodland started at 17 ka cal BP due to a rise of the tree line elevation corresponding to the deglacial warming. The pollen record at the site shows that mixed woodland consisting of Betula (birch) and boreal conifers covered the area during the period 17-11.2 ka cal BP, and dense mixed oak woodlands flourished during the period 11.2-2.9 ka cal BP. From 17 ka cal BP, local conditions were unfavourable for gathering obsidian, and this probably caused the Jomon people to develop obsidian mining. We can suggest that the landscape changes between the Palaeolithic and Jomon periods strongly influenced the prehistoric exploitation of obsidian in the area.