The probable industrial origin of archaeological daub at an Iron Age site in Northeast Thailand

Determining probable firing temperatures of daub recovered from archaeological sites provides opportunities to interpret the design and/or function of prehistoric structures. This paper critiques some of the methods for determining firing temperatures of daub, and presents a case study using samples from a secure depositional context at the Iron Age archaeological site of Noen U-Loke, in northeast Thailand. Adopting a multimethod approach, the paper examines relationships between color, micro- and macro-inclusions, elemental and mineralogical composition, physical form, and temperature, through the application of ICP-MS, XRD analysis, magnetic susceptibility, and light microscopy. The important methodological point here is that the combined interpretation of independent measures provides a better estimate of the original firing temperatures of the archaeological material than has hitherto been possible. Initial examination implied that our samples were fired, in antiquity, at low temperatures, and concluded a nonindustrial source for the daub. We suggest that determining maximum temperatures for this original firing will provide the clearest discrimination between possible types of features (e.g., housing, kiln/furnace) from which the daub originally came. The results of our study indicate that the archaeological daub samples have been exposed to a range of temperatures from 200°C to 1000°C. It seems highly likely, therefore, that the daub was derived from a spatially complex structure, such as an industrial kiln or furnace, which has experienced a range of firing temperatures