Ancient metalworking at Yodhawewa site, Sri Lanka: tracing the archaeological and geochemical relationship by analyzing soil and slags

Abstract

The Yodhawewa archaeometallurgical site was the latest discovery in Sri Lanka in 2018. This study aimed to trace the archaeological and geochemical relationship by analyzing the soil and slags of the site dating back to the c. 1st to 8th centuries AD. The analysis was mainly based on the X-ray fluorescence (XRF) method. The soil chemistry resulted in some clues to special metal processing zones in the excavation-1 area. The cultural layers of that area (profiles 1 and 2) showed relatively high copper composition (max. 470ppm), and crucible fragments containing copper particles were also detected in the same layers. The vertical distribution of soil elements and their correlations with TiO2 suggested that long-term metal activity may have affected changes in environmental soil chemistry. Relatively high phosphorus was indicated in the soil-related furnace wall, suggesting the artificial addition of organic matter to the clay body during the furnace wall construction to withstand the high temperatures. High iron slag (HIS) varies from 12.96 to 49.63 wt% of Fe2O3 and shows high MnO, P2O5, and V. Lightweight amorphous/glassy slags (LIS) associated with secondary refining have low iron content and a high CaO and Sr composition.