Period: Stone Age – The mesolithic (80.000 BC – 4000 BC)
Projekt titel: Akeramisk fremstilling af tjære
Researcher: Tine Schenck, Grete Moéll Pedersen & Peter Groom, Norway and England.
In 80.000 BC, before modern man had settled in Europe, Neanderthals had invented the production of a super-chemical which was to become essential throughout prehistory. The chemical is wood tar, which can be used for a variety of purposes depending on the consistency. The nomadic hunter-gatherers of the time had good use for the tar for, sealing surfaces, waterproofing and gluing.
The mystery is, that wood tar is produced by distilling the juices in birch bark by heating it in an airtight container. 80.000 years ago airtight containers which were able to withstand heat, like ceramic had not been invented. It is therefore difficult to imagine how the Neanderthals could create the conditions for an airtight and heated distillation of tar. But Tine Schenck, Grete Pedersen and Peter Groom are ready to take up the challenge an will try to produce birch bark tar without a container, using only, soil, sand and bark.
The Researcher's Conclusions:
Sixteen attempts were made to produce birch bark tar without the use of ceramic containers. The starting point for the experiments were the finds of ancient birch bark tar lumps, evidently made intentionally as observed through flint implement imprints on 80 000 year old tar lumps from Königsaue in Germany and chew marks on several Scandinavian Mesolithic specimens. All these lumps with imprints are found in environments that have not yet incorporated ceramics. A variety of structures were dug and built to try and replicate the procurement of birch bark tar without pottery or kiln structures.
All experiments were performed in paired structures to observe similar variables simultaneously. A number of structures were pits with and without outlet channels, piled with dried birch bark and sealed with sand and turf, before a fire was lit on top. However, as the temperature seemed to not reach the 400oC necessary for tar distillation, the piles were eventually put above ground and surrounded by fire.
None of the experiments resulted in proper tar. However, two showed certain signs of the beginning stages of tarring, whereas a number of others also produced charred birch bark tar with what seemed to be a tar sheen. Experiments will continue on the aspect of temperature, as achieving high enough temperatures was our main obstacle. On the positive side, airtightness was quickly mastered, as most experiments produced the remains of the bark that would otherwise have burnt.
Reference number HAFF 12/09