Theories about ancient trade and agriculture built on traces of olive oil in archaeological pottery are facing serious scrutiny. An interdisciplinary team led by Cornell University has found that the calcareous, alkaline soils of the Mediterranean alter plant oil residues preserved in ceramics. According to the study, published in the Journal of Archaeological Science, many ancient residues previously identified as olive oil may in fact come from other vegetable oils or from animal fats.
The Hidden Impact of Mediterranean Soils
In archaeology, organic residue analysis has long been used to reconstruct past dietary and trade practices by examining microscopic molecules trapped in the pores of ancient vessels. However, the researchers realized that in Eastern Mediterranean soils these chemical analyses had not been experimentally tested in sufficient detail. To address this gap, they brought soils from Cyprus into the laboratory for controlled experiments.
Clay ceramic pellets were immersed in olive oil, then buried in alkaline soil from Cyprus and, for comparison, in mildly acidic soil from New York. They were kept at 50 degrees Celsius for one year to accelerate the kind of degradation that would normally occur over thousands of years. The results were striking: molecular markers of olive oil in the ceramics buried in Cypriot calcareous soil disappeared rapidly. As the olive oil molecules broke down, their chemical signature gradually shifted to resemble that of animal fats.
Challenging Assumptions about Diet and Economy
The researchers suggest that archaeologists, motivated by the expectation that olive oil played a central role in the ancient Mediterranean economy, may have been prone to interpret chemically altered residues of other fats as olive oil. This could mean that some long-standing historical assumptions, particularly about periods such as the Late Bronze Age when Mediterranean trade networks were especially dense, need to be revisited [1].
Other large-scale studies on the evolution of human diets are already challenging familiar narratives in a similar way. For example, a comprehensive study by Tel Aviv University on Stone Age dietary practices argued that humans functioned for roughly two million years primarily as meat-eating apex predators [2]. According to that research, a significant shift toward plant-based diets occurred only toward the end of the Stone Age, as large mammal species became extinct [3]. This new methodological insight into lipid residues in pottery is expected to help refine our understanding of how human societies moved from hunting to settled farming communities and, eventually, to systematic olive cultivation and oil production.
Sources and further reading
- [1] Humans were apex predators for two million years, study finds
- [2] Ancient Humans Were Apex Predators For 2 Million Years, Study ...
- [3] Humans revealed to have been apex predators for two million years
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