Tar production in the medieval Bohemia tracked trough gas chromatography and radiocarbon dating

0568913 - ÚJF 2023 CH eng A - Abstract
Brychová, Veronika - Krofta, Tomáš - Světlík, Ivo - Pachnerová Brabcová, Kateřina - Petrová, Markéta
Tar production in the medieval Bohemia tracked trough gas chromatography and radiocarbon dating.
24th Radiocarbon Conference. 10th 14C & Archaeology Conference. Zurich, 11-16 September 2022. Book of abstracts. Zurich: ETH Zurich, 2022, č. článku A03_P03. ISBN N.
[Radiocarbon Conference /24./ 14C & Archaeology Conference /10./. 11.09.2022-16.09.2022, Zurich]
R&D Projects: GA MŠMT EF16_019/0000728
Institutional support: RVO:61389005
Keywords : tar * dating * charcoal
OECD category: Physical chemistry
https://radiocarbon24.ethz.ch/wp-content/uploads/2022/09/BookOfAbstracts.pdf

Accurate dating of tar kilns is crucial not only for understanding economic history but also for historical anthropology and environmental history. The historical production of tar in Bohemia is one of the neglected topics, although tar was an indispensable substance with a wide range of applications, and evidence of its production in Bohemia is dated back to the Neolithic. Dry distillation of coniferous wood leads to different types of products. A liquid organic phase, tar, is rich in diterpenic compounds, mostly retene, abietic acid and its derivatives. From the analysis of several archaeological pottery and soil samples, it is known these compounds can survive in a depositional environment over a long time scale.
In this study, we sampled charcoal, pottery, and charred resinous residue from a supposedly medieval tar kiln in Brdy mountains (Central Bohemian region). Samples of pottery and resinous surface residues were subjected to solvent extraction and gas chromatography analysis to scan organic compounds preserved. Samples of charcoal and charred residue were radiocarbon dated. Pottery and charred residues solvent extracts differed in organic compound composition and concentration. Pottery extracts were dominated by long and very long fatty acids with a contribution of diterpenic residues ‐ retene and abietic acid derivatives. Radiocarbon dates of charcoals fall into 12th century AD. Radiocarbon dating of pottery extract or surface residue through a more compound‐specific approach is under further study.
Permanent Link: https://hdl.handle.net/11104/0340191