The casting core composition and provenance of the Goljamata Kosmatka (Bulgaria) bronze head

The composition of casting core residues from the interior of a 4th century BC bronze head, unearthed in a Thracian tomb of central Bulgaria, was studied by means of petrographic, SEM, chemical and XRD analyses. Results indicated that the sand–clay mixture is dominantly rich in rock and mineral fragments, mostly derived from metamorphic and plutonic silica-rich rocks. No significant compositional differences were noted between the five analysed samples, except for content of bronze impurities and oxidation products. On the basis of geological studies and of chemical comparison with potteries of various ages, speculations were made about the location of the bronze foundry. The results are compatible with a derivation of the casting core from northeast Greece and the southern areas of F.Y.R.O. Macedonia and Bulgaria have terrains compatible with the casting core composition