Organic residue analysis in pottery vessels from Drakaina Cave

Organic residue analysis in pottery vessels from Drakaina Cave

Physicochemical analyses in archaeological pottery were introduced since the second half of the 20th century AD to promote understanding of important archaeological questions, such as the correlations between materials and society. Identification of organic residues present in pottery can provide information regarding vessel content and use. Organic residue analysis in pottery vessels can also provide evidence contributing to broader issues of palaeodiet and subsistence, such as food preparation, consumption and storage, transportation of goods and trade, the processing of natural material and the utilisation of natural substances as adhesives and sealants (Heron et al. 1994; Evershed et al. 2002; Kimpe et al. 2002; Regert 2004; Mirabaud et al. 2007; Craig et al. 2007). Both visible and absorbed residues surviving in pottery vessels are altered due to degradation processes taking place during burial, excavation and post-excavation treatments. Therefore it is difficult to assign them to a particular source (Evershed et al. 1992). Fortunately, the development of analytical techniques that can provide adequate separation and detection of these residues has enhanced analyses of organic remains in archaeological material.

Figure 1

The neolithic deposits of Drakaina include a variety of artefacts, pottery artefacts being the most abundant amongst them. Analysis of organic residues in pottery from Drakaina seeks to explore the possibility of organic remains to have been preserved in a variety of vessels (pithoid vessels, decorated and burnished vessels). Our aim was to investigate issues related to the function of the ceramics and contribute to archaeological dialogue regarding the function of the cave. To this end it was endeavoured to define the nature of residues preserved using Gas Chromatography-Mass Spectrometry (GC-MS).

The results obtained show the preservation of wide range of compounds, with fatty acids, acylglycerols, alkanes, alcohols and wax esters being the most characteristic amongst them. Four main categories could be observed:

(a) Residue consisting of fatty acids and acylglycerols, indicating plant or animal lipids found mostly in burnished and pithoid vessels,

(b) Residue consisting of alkanes and wax esters, indicating the use of beeswax, possibly as a sealant, found mainly in pithoid and decorated vessels,

(c) Residue consisting of aliphatic compounds and also fatty acids and acylglycerols (Figure 1), indicating the use of beeswax and plant and/or animal lipids in the same vessel, and

(d) Residue consisting of diterpenoids in one pithoid vessels along with beeswax residue, indicating the use of pine resin. It is worth noting that the detection of diterpenic resins is not often encountered in neolithic pottery (Regert 2004).

 

Figures

Figure 1. Partial total ion chromatogram of sample DC08A (bichrome vessel). The peak identities are: Fx:y are fatty acids, where x is the carbon chain length and y the degree of unsaturation; ALx are alcohols, where x is the carbon chain length; Ax are alkanes, where x is the carbon chain length; Wx:y are wax esters, where x is the carbon chain length and y the degree of unsaturation; Mx:y are monoacylglycerols, where x is the acyl carbon chain length and y the degree of unsaturation; Dx:y are diacylglycerols, where x is the acyl carbon chain length and y the degree of unsaturation; Tx:y are triacylglycerols where x is the acyl carbon chain length and y the degree of unsaturation; 12-OH-F18:0 stands for 12-hydroxy-octadecanoic acid; P stands for plasticiser; C stands for contamination and IS for the internal standard.

 

References

Craig, O. E., Forster, M., Andersen, S. H., Koch, E., Crombe, P., Milner, N. J., Stern, B., Bailey, G. N. & Heron, C. P. 2007. Molecular and isotopic demonstration of the processing of aquatic products in northern European prehistoric pottery, Archaeometry 49, 135-152.

Evershed, R. P., Heron, C., Charters, S. & Goad, L. J. 1992. The survival of food residues: new methods of analysis, interpretation and application, in A. M. Pollard (ed.), New developments in archaeological science: a joint symposium of the Royal Society and the British Academy, 187-208. Oxford: Oxford University Press.

Evershed, R. P., Dudd, S. N.Copley, M., Berstan, R., Stott, A., Mottram, H., Buckley, S. A. & Crossman, Z. 2002. Chemistry of archaeological animal fats, Accounts of Chemical Research 35, 660-668.

Heron, C., Nemcek, N., Bonfield, K. M., Dixon, D. & Ottaway, B. S. 1994. The chemistry of Neolithic beeswax, Naturwissenschaften 81, 266-296.

Kimpe, K., Jacobs, P. A. & Waelkens, M. 2002. Mass spectrometric methods prove the use of beeswax and ruminant fat in late Roman cooking pots, Journal of Chromatography A, 968, 151-160

Mirabaud, S., Rolando, C., & Regert, M. 2007. Molecular criteria for discriminating adipose fat and milk from different species by NanoESI MS and MS/MS of their triacylglycerols: application to archaeological remains, Analytical Chemistry 79, 6182-6192.

Regert, M. 2004. Investigating the history of prehistoric glues by gas chromatography-mass spectrometry, Journal of Separation Science 27, 244-254.

 

June 2009
Dr. Maria Roumpou
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