Organic geochemical analysis of archaeological medicine pots from Northern Ghana. The multi-functionality of pottery

Sherds from pots found layered under a granite boulder in the Tong Hills of the Upper East Region of Northern Ghana seem, based on their deposition context to have been used for the preparation of medicines. Organic geochemical and isotopic analyses of these sherds and a modern day analogue reveal an n-alkanoic acid composition that is consistent with their being used in the preparation of plant derived substances. Isotopic analyses of the modern medicine pot indicate a contribution of n-alkanoic acids derived from plants that use C₄ carbon fixation, most likely maize, sorghum and/or millet suggesting that this pot was used for cooking C₄ based plant substances, perhaps, based on current analogy, staple porridge type food. The modern medicine pot could thus have had a prior use. The absence of C₄ plant residues in the archaeological sherds suggests that either staple foodstuffs differed radically to today, or, more likely, were not prepared in vessels that were to be used for medicinal purposes.