The composition and provenance of Late Bronze Age vitreous materials from Kefalonia, Greece

In this study, we present the results of the analysis of Late Bronze Age (LBA) vitreous materials from three cemeteries on the island of Kefalonia, Greece (Mazarakata, Metaxata, and Kokkolata-Menegata). A multianalytical approach (EPMA, LA-ICP-MS, MC-ICP-MS [Sr-Nd]) was used to determine the composition and provenance of a group of 14 glass beads, a glass fragment, and a faience bead, all dating to the 14th-11th centuries BCE. Most of the beads were produced using a plant ash alkali with one having a mixed alkali composition. Identification of the colorants revealed that the blue glasses were colored using Cu, Co-Cu, or Co. Cobaltiferous alum from the Western Desert of Egypt imparted the blue color to the cobalt containing glasses. Trace element and isotopic analysis showed that all the relief plaques were made using imported Egyptian glass. The isotopic signature of one relief plaque, a triple rosette motif unique to Kefalonia (K13-4), suggests that there may be greater geological variation among the currently identified LBA Egyptian silica and alkali sources or possibly the use of new raw material sources in the region. Silica and plant ashes from different regions were exploited for the manufacture of two beads of Near Eastern origin. One bead (M18-3) was made from an alkali derived from plants likely growing in river valleys in zones MP-1 (northern Iraq) or MP-3 (southern Iraq) and silica from zone MP-2 (deserts in western Iraq/eastern Syria). The other bead was unique in composition characterized by high chromium, silica from northern Iraq (zone MP-1 N), and plant ash from the desert (zone MP-2). Similarities to raw materials used to produce glass at Alalakh may tentatively suggest a similar origin. A Mycenaean Group B faience bead (Co-Cu blue) included in the study was manufactured with an alkali and a source of cobalt that did not come from the Western Desert. Further identification of the alkali type and the source of the raw materials for this faience bead was not possible but similarities were found to Group B beads from Psara and Mesara in Greece.