Direct evidence for the co-manufacturing of early iron and copper-alloy artifacts in the Caucasus

Abstract

Models for iron innovation in Eurasia are predicated on understanding the relationship between the bronze and iron industries. In eastern Anatolia, South Caucasus, and Iran, the absence of scientific analyses of metallurgical debris has obscured the relative chronology, spatial organization, and economic context of early iron and contemporary copper-alloy industries.Excavation and surface survey at Mtsvane Gora, a fortified hilltop site close to major polymetallic ore sources in the Lesser Caucasus range, recovered metallurgical debris dating to the 8th-6th centuries BC. Optical microscopy, scanning electron microscopy, and energy and wavelength dispersive spectrometry revealed evidence for both iron and copper-alloy metallurgy, including smithing and alloying. Metal particles trapped within clear iron smithing slags were contaminated with copper, arsenic, and tin, suggesting that iron and copper-alloy working took place in the same hearths. The discovery of a small fragment of unprocessed material consisting of pyrite and jarosite, minerals typical of major nearby polymetallic ore deposits, links the secondary smithing and alloying at Mtsvane Gora with nearby mining activities, though the nature of those connections remains unclear. While the earliest iron in the region probably predates the Mtsvane Gora assemblage, the remains date to a period when iron use was still expanding, and they are at present the earliest analytically confirmed, radiocarbon-dated iron metallurgical debris in the Caucasus. The remains are therefore significant for understanding the spread of iron innovation eastward from Anatolia and the Levant. When considered in light of evidence from other Near Eastern sites, the results support a model for innovation in which early iron manufacturing was at least partially integrated with the copper-alloy metallurgical economy.

Spatial investigation of technological choice and recycling in copper‐base metallurgy of the South Caucasus

“…Arsenical copper could have been manufactured through mixing copper with iron arsenide (speiss), as this method has been suggested in Cu‐As alloying elsewhere in the South Caucasus (Erb‐Satullo et al . 2020) and Iran (Thornton et al . 2009; Rehren et al .…”

Tradition and Innovation in Aegean Iron Technologies: A View From Early Iron Age Ionia

“…The observations on cross-craft interaction certainly apply in the EIA technological setting, as reflected by the lively debates on the link between bronze and early iron technology in the eastern Mediterranean (Fig. 4; Erb-Satullo et al 2020; Liss, Levy and Day 2020). As for the Aegean, the rather deterministic idea that the knowledge gained from copper and tin bronze metallurgy was crucial for the mastering of iron – based on a linear understanding of technological development – has not yet been dismissed in favour of a more complex investigation of a set of practices and behaviours in production techniques (both smelting and melting).…”

“…The recent studies on the longstanding metallurgical tradition on Thasos from as early as the EBA have demonstrated the utility of multipronged research to technological trajectories (Nerantzis, Bassiakos and Papadopoulos 2016; Sanidas et al 2016; Bassiakos, Nerantzis and Papadopoulos 2019). A similar shift in the analytical scope can also benefit the examination of manufacturing techniques (alloying, casting, refining and smithing) within the chaîne opératoire , as the recent evidence from the Levant suggests a strong correlation between the bronze working and iron production at the beginning of the EIA (Yahalom-Mack and Eliyahu-Behar 2015; Erb-Satullo et al 2020). Given the relative scarcity of easily available iron ore deposits of high or at least sufficient quality around the Aegean (Muhly 2006) and the continuing supra-regional movement of raw or semi-finished material in the region (Kiderlen et al 2016), the possibility of an early adoption of new iron technologies by Aegean bronzesmiths remains intriguing, namely in terms of locally specific modes of adoption.…”

Micro‐Raman spectroscopy and complementary techniques applied for the study of copper and iron wastes from Motya (Italy)

“…In addiction, evidence of speiss as an intermediary product for the manufacture of copper-alloys has been reported in the Near East. [14,42,73] On the other hand, samples MM.16.6, MM.16.23, and MM.16.24 excavated from the industrial area of the City Walls-that was built after the destruction of Motya in 397/6 BC-belong to the more recent metallurgical activities of refining of copper and iron to produce artifacts.…”