Physicochemical characterization and provenance of colouring materials from Akrotiri-Thera in relation to their archaeological context and application

Summarization: An assemblage of approximately 500 colouring materials and objects related to their use, found in different contexts and forms at Akrotiri, Thera, was recently investigated. The items date to the Early, Middle and Late Cycladic Bronze Age (c. 3000–1600 bc) and include materials or pigments found in their natural state, in specifically made forms or inside vessels. Some of the contexts do not provide any indication of the pigments’ use, storage, trade or application. Among the investigated materials, which include red and yellow ochres and blue riebeckite, are those that can be associated with pigments that were widely used in the past in wall paintings or to decorate pottery. There is also evidence for the selective use of purple pigments, which were derived from shellfish, in wall paintings. However, there are other raw colouring materials, such as lead pigments that have not been previously known to have been used in wall paintings or in any other applications during the prehistoric period in the Aegean. A thorough macro- and microscopic visual examination of the quality and morphology of these items enabled the identification of physical features (colour, homogeneity, grain size and shape) that indicate their nature or degree of processing. To identify the mineral composition of the pigments and to investigate their provenance from a geological perspective, quantitative X-ray diffraction (XRD) analysis was conducted. For those samples requiring additional information on their composition and for the refining or confirming of the XRD data, scanning electron microscopy combined with energy dispersive X-ray spectroscopy (SEM-EDX), micro-Raman and Fourier transform infrared (FT-IR) spectroscopies were performed. This work is part of a larger project, supported by Institute for Aegean Prehistory, that aims to clarify major archaeological queries that are not restricted to the identification of the nature, composition and provenance of the colouring materials but extend to aspects of their selection, preparation and application techniques used during the Early to the Late Bronze Age.Presented on: Archaeological and Anthropological Science