The key role of bangles in the evolution of standardized bronze technology in Indian antiquity

Abstract

Bangles represent one of the few Bronze Age metal objects that survived the bronze-to-iron transition in Indian antiquity. Thirty-six bangles excavated from the megalithic burials at Raipur, India, were examined for their role in the evolution of Indian bronze technology. These objects were all made of binary copper-tin alloys, with the average tin level set at 9.3% based on weight. No lead was added to any of them. They were consistently treated with forging subsequent to casting. Laboratory experiments revealed that plastic deformation with proper thermal treatments could be effective at removing unwanted tin-rich brittle δ particles from the alloys, greatly improving their forgeability. Such high-quality bangles, if used as intermediaries, would inevitably lead to a standardized and optimized bronze tradition dedicated to the manufacture of thin-walled prestige items in a simplified process of forging. As a symbol of wealth and status, therefore, bangles likely stimulated the dissemination of standardized portable bronze technology in keeping with emerging socioeconomic inequality throughout India during the Indus-to-Megalithic transition period.