ISOTOPE COMPOSITION OF MEDIEVAL LEAD GLASSES REFLECTING EARLY SILVER PRODUCTION IN CENTRAL-EUROPE

The lead isotope composition of 32 lead glasses excavated from strata of the twelfth to early fifteenth century in six countries of NW Europ e made the predominance of the Hart Mountains in this period of the Me dieval European lead and silver production highly probable. Post-Varis can vein type galena, Devonian syngenetic hydrothermal ore (Rammelsber g) and blended ore from both deposits in the Hart were used. Our evalu ation of 200 mining sites in Germany, Britain and Ireland also demonst rated that minor lead sources for lead glass were located in Bavaria/ Bohemia and England. Lead ores from the Rhenohercynian orogenic belt i n Germany are derived from rock sources close to the upper continental crust composition in U-238/(204)pb of about 10 and Th/U of about 4. T he ores in Central England originated from rocks with U-238/(204)pb of about 11.