Phytolith analysis of olive oil and wine sediments for possible identification in archaeology

Abstract

Phytoliths are microscopic, amorphous silica or crystalline, inclusions of plant origin that can be of diagnostic value in an archaeological context. This study demonstrated that distinct phytoliths can be extracted from two major extant and ancient crop species: olive (Olea europaea L.) and grape (Vitis vinifera L.). Nonacid digestion of leaves and fruits of two Greek olive cultivars (Megareitiki and Kothreiki) and a Greek grape cultivar (Agiorgitiko) showed that olive and grape contained distinctly different calcium phytoliths and that olive fruit flesh and stone contained sclereids. Olive oil sediment from traditionally produced oil from Greece and Turkey and barrel sediment from traditional Greek red wine were found to contain phytoliths and (or) sclereids corresponding to their fruit of origin. Olive oil could therefore be distinguished from wine, making the nonacid phytolith extraction method a potentially useful alternative to chemical analysis of ancient storage jar residues. Key words: calcium and silica phytoliths, olive, grape, sediment analysis.