8th Experimental Archaeology Conference abstract – Schenck and Groom

Experiments with aceramic birch bark tar extraction

Tine Schenck & Peter Groom

University of Exeter, UK

Birch bark tar has been a widely used product in prehistory. From adhesive purposes to waterproofing, it is a versatile agent which also proves to have medicinal properties and may have been used as such. Finds of birch bark tar date as far back as 50 000 BP, in other words the Middle Palaeolithic (see for instance Mazza et al., 2006), but has been in consistent use from the Mesolithic onwards.

The production of birch bark tar takes place in a dry-distillation process, which demands strict control over temperature, oxygen exclusion and moisture levels. From the Neolithic onwards, ceramic containers seem to be the preferred mode of production (e.g. Ottaway, 1992), and understandably so as they provide a heat conducting, airtight medium. However, it is clear that birch bark tar was also produced before ceramics entered the material record, amongst others in the shape of numerous lumps with teeth imprints from the Scandinavian Mesolithic (Aveling and Heron, 1999). How this tar was produced is still unclear, and our experiments target the technology behind aceramic production methods of birch bark tar.

One set of exploratory experiments were undertaken in 2009 (Groom et al., 2013), during which we attempted pit firings with little success. However, these experiments led to further questions, and a set of experiments with raised features were conducted in 2013. In this talk, we present the results and discuss their relevance for the prehistoric dry-distillation of birch bark tar.

AVELING, E. M. & HERON, C. 1999. Chewing tar in the early Holocene. Antiquity, 73, 579-584.

GROOM, P., SCHENCK, T. & PEDERSEN, G. M. 2013. Experimental explorations into the aceramic dry distillation of Betula pubescens (downy birch) bark tar. Archaeological and Anthropological Science, 5.

MAZZA, P. P. A., MARTINI, F., SALA, B., MAGI, M., COLOMBINI, M. P., GIACHI, G., LANDUCCI, F., LEMORINI, C., MODUGNO, F. & RIBECHINI, E.
2006. A new Palaeolithic discovery: tar-hafted stone tools in a European Mid-Pleistocene bone-bearing bed. Journal of Archaeological Science, 33, 1310-1318.

OTTAWAY, B. S. 1992. The Fischergasse: a wetland site in Lower Bavaria. Antiquity, 66, 689-701.

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