Indagini archeometallurgiche su reperti preistorici dalla Val di Chiana: lo sfruttamento dei giacimenti toscani nelle prime fasi delle età dei metalli

An archaeometallurgical study was realised on a dagger of Guardistallo type and a halberd of Calvatone type found in a burial at San Cristoforo delle Vertighe, near Monte San Savino in Val di Chiana. The elementary analyses conducted by means of ICP mass on the finds revealed that they both were realized in arsenical copper, although with different arsenic percentages. The dagger and the halberd show smaller amounts of elements like silver, lead and iron, and high percentages of antimony. These data suggest, for the high levels of impurities, that the objects were produced from the smelting of Fahlertz type copper ores. In central Europe Fahlertz ores characterize the beginnings of the Early Bronze Age. Moreover, data suggest the use of slagging smelting processes, a developed smelting technology. Lead isotope analyses show that the two finds were made with the same copper ore; the ore deposit has to be located most probably in Tuscany. At present it is not possible to localize with precision such deposit, but it seems however not to be in the Colline Metallifere.