Chemical and lead isotope composition of silver jewels from ancient Thrace (Bulgaria)

Ilian Iliev1,
Ivelin Kuleff2,
1TU-Bergakademie Freiberg, Freiberg, Germany
2Faculty of Chemistry, University of Sofia, Bulgaria

In this study 9 silver jewels (earrings, fibulas and ornaments) were analyzed. The finds were discovered during archaeological excavations on Thracian sites dated 6-th c. BC to 1-st c. AD in South-West Bulgaria. Using ED-XRF the concentration of 13 elements (Ag, As, Au, Bi, Co, Cu, Fe, Ni, Pb, Sb, Se, Sn and Zn) in the investigated silver finds was determined. In addition, after electrochemical separation of lead by anode oxidation [1], using an ICP-MS the isotope ratios of lead was determined. As a result of the present investigation of the chemical and isotope composition of the silver objects, the technology of production and localization of the ore sources were revealed.

The metal for the 4 earrings was produced from Rhodopes ore sources. Since the earrings are very similar in chemical and isotopic composition it may be presumed with high probability that the ore for the metal production was obtained from the same ore body at the same time. The two fibulas, one pin and one axe also have similar chemical and isotopic composition and localization - the Rhodopes, but they originate from a different ore body.

The fibula with a pin is of certain interest, since its body was made from metal originating from the Rhodopes while the metal for the pin comes from the Sredna Gora mountain. Probably the fibula was repaired with a metal different from the original.

The object found in Pazardzhik district was produced from metal originating from Greece - Chalkidiki or Thasos.

From historical point of view the localization of the ore sources for production of silver finds is very interesting. Since the silver is obtained from lead via cupellation. In addition there are many data for import of metals and especially of lead from ancient Greek metallurgical centers such as Lavrion, Chalkidiki, and Thasos. Thus the localization of silver find from Pazardzhik is expected. The localization of the ore sources for the other finds shows significant development of metallurgy and metal treatment in ancient Thrace. This confirms the studies of other authors indicating extremely intense development of metallurgy and precious metals production in different Thrace regions during these ages.

[1] I.Iliev et al., Analytica Chimica Acta, 497, 227-233 (2003)