Smelting Iron from Laterite: Technical Possibility or Ethnographic Aberration?

Abstract

The existing Southeast Asian archaeological literature commonly presupposes that the region’s extensive laterite deposits are rich in iron and have been used as ore sources for the smelting of iron. We summarize what is known about laterite in light of the universal physico-chemical requirements for the bloomery smelting of iron, and suggest that in each instance the interpretation of laterite as an iron ore should be proven and not assumed. We present a case study from the fourteenthto fifteenth-century a.d. site of Ban Kao Din Tai, recently excavated by Thai and Cambodian archaeologists in Buriram Province in northeast Thailand. The proximity of this site to known laterite deposits, along with the recovery of laterite fragments near what are thought to be smelting furnaces, could imply that past metalworkers were exploiting a local source of iron oxides for metal production. Here we discuss the likelihood of this association. If laterite is not a ubiquitous iron source for Southeast Asian iron production, then there is strong research potential to examine iron’s possible role in regional exchange networks. Iron production and consumption evidence may provide an exciting new angle for investigating Southeast Asian social interactions, and we outline some of the analytical techniques that could elucidate them.