Residue Analysis on Terracotta Vessels from Owo, Ondo State: Functional Interpretation

The functional interpretation of archaeological ceramics has been transformed in recent decades by the application of organic residue analysis, which can identify absorbed lipid, protein, and carbohydrate compounds preserved within ceramic matrices long after visible traces of contents have disappeared. This study applies organic residue analysis to terracotta vessels from the Owo site assemblage in Ondo State, using gas chromatography-mass spectrometry (GC-MS) to identify lipid biomarkers preserved within vessel walls. The analytical programme targets thirty-five vessels selected to represent the morphological range of the Owo assemblage, spanning large storage and cooking vessels, small bowls, and ritual vessel forms, with the aim of linking vessel morphology to documented functional uses through residue comparison. GC-MS results identify degraded lipid profiles in twenty-two of thirty-five analysed vessels, with identifiable components including plant wax markers consistent with oil palm products in larger vessels, animal fat markers in medium-sized bowls, and a distinctive plant sterol profile in two ritual vessel forms not detected in any utilitarian category. The presence of palm oil markers in large vessels is consistent with ethnographic and historical accounts of palm oil storage and trade as central to the Owo economy, while the distinctive sterol profile in ritual vessels suggests the use of plant-derived offerings or libation substances not documented in written sources. The study contributes to the functional interpretation of the Owo ceramic assemblage and provides a reference dataset for comparative organic residue research in the Yoruba-Benin zone. Keywords: organic residue analysis, terracotta vessels, Owo, functional interpretation, GC-MS.