Ancient bronze technology and nomadic communities of the Middle Gobi Desert, Mongolia

The Xiongnu period of Mongolian prehistory (ca. 3rd century BC–AD 2nd century) is notable for the emergence of an expansive nomadic state and major changes in metallurgical and ceramic technologies. A number of Xiongnu period and pre-Xiongnu period bronze and bronze-related artifacts from the site at Baga Gazaryn Chuluu in the Middle Gobi province of Mongolia were examined for their chemical compositions and microstructures. They include finished objects, leftovers from casting, and pieces of slag from copper smelting and the assemblage likely represents a combination of local and regional production as well as long-distance exchange items. Results show that the entire bronze manufacturing process, from smelting to fabrication, is represented at BGC sites and bronze working may have been technologically self-sufficient, though ore sources are still uncertain. Our evidence suggests that this bronze assemblage was the result of two different technological traditions characterized by either the dominant use of arsenic, enforced apparently by restriction in tin supply, or the profuse use of both tin and lead. The arsenic-based tradition was observed in the majority of pre-Xiongnu period objects while the tin and lead recipes were verified in most objects dating to the Xiongnu period. This shift in bronze tradition may reflect changes in inter-regional interaction with frontier groups beyond the Gobi Desert and with the early state societies of China.

Research highlights
► Bronzes of the Xiongnu and earlier period from Mongolian Gobi were examined.
► They consist of objects representing the entire bronze manufacturing process.
► Shift in major alloying elements from As to Sn and Pb was observed with time.
► This shift in bronze tradition may reflect changes in inter-regional interaction.