On the origin of natural bitumen at Yasnoye-8 (Sakhalin island)

In this study, we analyze samples of a black substance that was used for restoring a Tym-type vessel at Yasnoye-8, Central Sakhalin. On the basis of similar finds from the Japanese archipelago, it was initially assumed to be natural bitumen. However, science-based methods have not been previously used to test this assumption. In addition to the identification of natural bitumen, we sought to identify its source. The study was carried out independently at two laboratories, using geochemical and petrographic methods, so the results can be considered reliable. For the first time in Russia, the method of pyrolysis gas chromatography - mass spectrometry was used, along with elemental and petrographic analysis, to identify hydrocarbon from an archaeological site. The results confirm the use of natural bitumen during the Early Iron Age. It can be procured in sufficient amounts on Sakhalin Island. Identification of specific sources is complicated by the virtually complete lack of geological data (bitumen is not mined for industrial purposes). Available materials suggest that bitumen found at Yasnoye-8 originates from the northern Sakhalin petroleum zone or from adjacent areas. No relationship to bitumen deposits in northeastern Honshu was found. Nor is it likely that the sample is related to superficial hydrocarbons of Hokkaido.