Scanning electron microscopy and micro-Raman spectroscopy of slip layers of Hellenistic ceramic wares from Dorylaion/Turkey

Anatolia (Asia Minor) was inhibitated by several civilizations during the history. Dorylaion at Eskişehir/Turkey, an ancient site, is on the crossroads of many ancient civilizations. Artifacts belonging to different historical periods and cultures have been uncovered during the excavations carried out there since 1989. One of the two important groups of ceramic findings uncovered in these excavation works is the moldmade bowls, familiarly known as the Megarian bowls and the other is the West Slope wares. Both types of wares were probably the fashion cups around the east Mediterranean basin of the Hellenistic period. In this study, an attempt was made to enlighten the technological parameters and production technology of selected Megarian bowls and West Slope wares by characterizing their slip layers. Scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDX) were performed for microstructural and microchemical characterization. Micro-Raman spectroscopy was further applied for assessing the mineralogical components. The slip layers of both wares have similar elemental diversity, apart from the fact that the West Slope wares have more iron content than the Megarian bowls. The iron rich composition of the slip layers in different colors showed that hematite (α-Fe2O3), maghemite (γ-Fe2O3) and magnetite (Fe3O4) are the principal coloring agents for the slip layers of the investigated Hellenistic ceramic wares. However, firing conditions affecting the formation and the abundance of these minerals were probably adjusted in order to obtain the desired color.