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.

The composition and origin of Ghana medicine clays.

The mineral, organic and elemental composition of medicine clays from three shrines in the Tong Hills in northern Ghana (Gbankil, Kusanaab, and Yaane) are assessed to ascertain what additives they might contain and the implications for their recognition, for example in archaeological contexts. These are clays that are widely used for healing purposes being perceived efficacious in curing multiple ailments and which are given a divine provenance, but their collection is ascribed human agency. The Yaane clay is also supplied as part of the process of obtaining the right to operate the shrine elsewhere making it widely dispersed. Organic geochemical analyses revealed a predominance of plant-derived material with a substantial contribution of microbial origin. Based on these (supported by elemental and mineral analyses), no unnatural organic material could be detected, making an exogenous contribution to these clays unlikely. The implications are that these are wholly natural medicinal substances with no anthropogenic input into their preparation, as the traditions suggest. The very similar mineralogy of all the clays, including a non-medicine clay sampled, suggests that, unless the geology radically differed, differentiating between them analytically in an archaeological contexts would be doubtful.