“TOROUD”, THE LATE MOTION FOR As-Sb BEARING Cu PRODUCTION FROM 2ND MILLENNIUM BC IN IRAN: AN ARCHAEOMETALLURGICAL APPROACH

Abstract

The interest in arsenic copper and its use in antiquity is on a speedy rise. The potential values of such commodity have drawn significant attention. According to many literatures that will be presented throughout this paper, there is great evidence. that real tin bronze replaced arsenic bronze during 2350-2200 B.C. in the central plateau of Iran. "Chah-Messi" copper mine could be a key point of such investigations. Indeed, multimelange metallic outcrops made this region to a great metallogenic zone. Archaeometallurgical investigations based on geological survey in “Chah-Messi” copper mine in northern part of the central Iranian desert indicate that during the 2nd millennium BC ancient mining and metallurgy were carried out because of outcropping of hydrothermal copper mineralization. The main point of this work focuses on the characterization of the extractive slags with respect to the Cu-As-Sb bearing minerals. Mineralogical-petrochemical studies have been carried out via reflected- and transmitted light microscopy including electron probe microanalyser (EPMA) to perform the analysis of the chemical composition of phases. Based on the results, the material proved to have high amount of Cu, CaO and iron oxide and low in MgO, MnO. Furthermore the result of this study indicated that the Chalcosite and covellite were the processed ore. Lauzonite (Cu-As-Sb) and domeykite (Cu-As) were the dominant Cu-As-Sb bearing minerals which could have the primary influence on the smelting processes and composition of extracted metal. Such characteristics are the hall mark of this region.