The metal behind the myths: iron metallurgy in the south-eastern Black Sea region

The south-eastern Black Sea area is a key region for understanding the history of iron metallurgy. While Classical texts mention the people living in this area as producers, and perhaps even inventors, of iron, material evidence has been lacking. Recent archaeological survey and scientific analyses now make it possible to investigate iron technologies in the region during the mid to late first millennium BC and the medieval period, providing new insights into the metallurgical tradition that inspired such admiration in the Graeco-Roman world. These results have implications for the smelting of iron in liquid state, although it remains unclear where and when this technology first appeared in Western Eurasia

The ebb and flow of copper and iron smelting in the South Caucasus

The Eastern Black Sea region of the South Caucasus contains an extremely rich record of metallurgical remains that is poorly known outside of the former Soviet Union. Large numbers of relatively small smelting sites dot the foothill regions, forming a dispersed, yet large-scale metallurgical landscape. New fieldwork in the region has followed up on earlier Soviet period research, relocating and reanalyzing previously known sites and identifying new ones. This paper presents a series of 33 radiocarbon (14C) dates from copper and iron smelting sites in this region. Dates from copper smelting sites suggest that copper smelting occurred over a shorter and more intense period than previously thought, between about 1300 and 800 BC. Dates from newly discovered iron smelting sites place these activities in two episodes during the Classical-Hellenistic period (ca. 500–200 BC) and the High Medieval period (ca. AD 1050–1400). The dramatic expansion in bronze production immediately prior to the adoption of iron mirrors patterns in other regions of Europe and the Near East, and has implications for understanding the economic contexts in which iron emerged. While the new dates from iron smelting sites provide only an initial outline of the iron production chronology in the region, they represent an important step for resolving outstanding issues from previous investigations

Copper production landscapes of the South Caucasus

Studies of metal production frequently show a correlation between scale and organizational complexity. The remarkably rich landscapes of metal-producing sites of late 2nd-early 1st millennium BC Colchis provide an unprecedented opportunity to reexamine this apparent correlation. Investigations of copper smelting sites show that industries with a large aggregate output can be the result of numerous small groups of metalworkers acting independently. Spatial data on site distributions, estimates of productive output, and archaeometric data on ore procurement patterns were integrated to reconstruct the organization of production. Judicious use of a portable X-ray fluorescence spectrometer (pXRF) showed that not only were smelting sites highly dispersed, but also that metalworkers at different sites were using ores from geologically distinct deposits. This innovative approach helped to reconstruct the organization of production in a distinctive metal production landscape, bridging an enduring divide between landscape-scale and microscopic investigations of craft production

Crucible technologies in the Late Bronze–Early Iron Age South Caucasus: copper processing, tin bronze production, and the possibility of local tin ores

The South Caucasus was a major center of metal production in the Late Bronze and Early Iron Ages. Nowhere is this more clear than in the hills and mountains in the southeastern Black Sea region (ancient Colchis), where exceptionally large numbers of metal production sites have been found. Chemical and microscopic analysis of slagged technical ceramics at these sites illuminates several aspects of both raw copper and tin bronze alloy production. Copper ores were smelted in a complex multi-stage process designed to extract metal from sulfide ores. Technical ceramics served as containers for a range of different reactions, from the first phase of smelting, in which the copper sulfides were likely consolidated into a matte, though later stages of matte processing and metal copper production in smaller crucibles. In addition, a single crucible fragment, recovered from a late 2nd millennium BC slag heap, demonstrates that tin bronze was created by the direct addition of cassiterite tin ore, probably of alluvial origin, to metallic copper. The crucible's context, the use of cassiterite ore rather than tin metal, and a review of local geology suggests that the tin used in this crucible came from nearby, with the most likely source being the Vakijvari and Bzhuzhi gorges roughly 10–15 km away. While a single fragment does not speak to the regularity of this practice, at the very least it raises the possibility that the Colchian bronze industry was based on local rather than imported tin

The ebb and flow of copper and iron smelting in the South Caucasus

The Eastern Black Sea region of the South Caucasus contains an extremely rich record of metallurgical remains that is poorly known outside of the former Soviet Union. Large numbers of relatively small smelting sites dot the foothill regions, forming a dispersed, yet large-scale metallurgical landscape. New fieldwork in the region has followed up on earlier Soviet period research, relocating and reanalyzing previously known sites and identifying new ones. This paper presents a series of 33 radiocarbon (14C) dates from copper and iron smelting sites in this region. Dates from copper smelting sites suggest that copper smelting occurred over a shorter and more intense period than previously thought, between about 1300 and 800 BC. Dates from newly discovered iron smelting sites place these activities in two episodes during the Classical-Hellenistic period (ca. 500–200 BC) and the High Medieval period (ca. AD 1050–1400). The dramatic expansion in bronze production immediately prior to the adoption of iron mirrors patterns in other regions of Europe and the Near East, and has implications for understanding the economic contexts in which iron emerged. While the new dates from iron smelting sites provide only an initial outline of the iron production chronology in the region, they represent an important step for resolving outstanding issues from previous investigations

Late Bronze and Early Iron Age copper smelting technologies in the South Caucasus: the view from ancient Colchis c. 1500–600 BC

Many of the arguments for how and why people began to use iron in Southwest Asia rely on assumptions about the technology and relative organization of copper and iron smelting. However, research on the technological transformations of the Late Bronze Age and Early Iron Age suffers from a lack of investigation of primary metal production contexts, especially in regions outside the Levant. The current research examines metal production debris from a large number of smelting sites in western Georgia, and addresses questions of technology and resource utilization through detailed examination of few select sites. Through the chemical and mineralogical analysis of slag samples, we demonstrate the existence of an extensive copper-production industry and reconstruct several key aspects of the smelting technology during the Late Bronze Age and Early Iron Age. Combining a statistical analysis of slag mineralogy with other lines of evidence, we argue that copper was extracted from sulfide ores through a process of roasting and smelting in deep pit furnaces. The data also suggest that metalworkers at different sites exploited different ore sources within the same ore body. These results form a fundamental basis for further examination of spatial and chronological patterns of technological variation, with implications for models of Near Eastern copper production in this crucial period. Intriguing evidence of bloomery iron smelting, though currently undated, reinforces the region's potential to provide data on a key technological transformation

Late Bronze and Early Iron Age copper smelting technologies in the South Caucasus: the view from ancient Colchis c. 1500–600 BC

Many of the arguments for how and why people began to use iron in Southwest Asia rely on assumptions about the technology and relative organization of copper and iron smelting. However, research on the technological transformations of the Late Bronze Age and Early Iron Age suffers from a lack of investigation of primary metal production contexts, especially in regions outside the Levant. The current research examines metal production debris from a large number of smelting sites in western Georgia, and addresses questions of technology and resource utilization through detailed examination of few select sites. Through the chemical and mineralogical analysis of slag samples, we demonstrate the existence of an extensive copper-production industry and reconstruct several key aspects of the smelting technology during the Late Bronze Age and Early Iron Age. Combining a statistical analysis of slag mineralogy with other lines of evidence, we argue that copper was extracted from sulfide ores through a process of roasting and smelting in deep pit furnaces. The data also suggest that metalworkers at different sites exploited different ore sources within the same ore body. These results form a fundamental basis for further examination of spatial and chronological patterns of technological variation, with implications for models of Near Eastern copper production in this crucial period. Intriguing evidence of bloomery iron smelting, though currently undated, reinforces the region's potential to provide data on a key technological transformation

Copper production landscapes of the South Caucasus

Studies of metal production frequently show a correlation between scale and organizational complexity. The remarkably rich landscapes of metal-producing sites of late 2nd-early 1st millennium BC Colchis provide an unprecedented opportunity to reexamine this apparent correlation. Investigations of copper smelting sites show that industries with a large aggregate output can be the result of numerous small groups of metalworkers acting independently. Spatial data on site distributions, estimates of productive output, and archaeometric data on ore procurement patterns were integrated to reconstruct the organization of production. Judicious use of a portable X-ray fluorescence spectrometer (pXRF) showed that not only were smelting sites highly dispersed, but also that metalworkers at different sites were using ores from geologically distinct deposits. This innovative approach helped to reconstruct the organization of production in a distinctive metal production landscape, bridging an enduring divide between landscape-scale and microscopic investigations of craft production

Crucible technologies in the Late Bronze–Early Iron Age South Caucasus: copper processing, tin bronze production, and the possibility of local tin ores

The South Caucasus was a major center of metal production in the Late Bronze and Early Iron Ages. Nowhere is this more clear than in the hills and mountains in the southeastern Black Sea region (ancient Colchis), where exceptionally large numbers of metal production sites have been found. Chemical and microscopic analysis of slagged technical ceramics at these sites illuminates several aspects of both raw copper and tin bronze alloy production. Copper ores were smelted in a complex multi-stage process designed to extract metal from sulfide ores. Technical ceramics served as containers for a range of different reactions, from the first phase of smelting, in which the copper sulfides were likely consolidated into a matte, though later stages of matte processing and metal copper production in smaller crucibles. In addition, a single crucible fragment, recovered from a late 2nd millennium BC slag heap, demonstrates that tin bronze was created by the direct addition of cassiterite tin ore, probably of alluvial origin, to metallic copper. The crucible's context, the use of cassiterite ore rather than tin metal, and a review of local geology suggests that the tin used in this crucible came from nearby, with the most likely source being the Vakijvari and Bzhuzhi gorges roughly 10–15 km away. While a single fragment does not speak to the regularity of this practice, at the very least it raises the possibility that the Colchian bronze industry was based on local rather than imported tin