OSL chronology of stratified iron-smelting slag from the Don up Mung site, northeastern Thailand

Abstract

Iron-smelting slag from the Don Up Mung archaeological site, Nong Bua Lamphu Province, northeastern Thailand, was investigated to evaluate the applicability of Optically Stimulated Luminescence (OSL) dating for archaeometallurgical materials. Slag samples recovered from stratified deposits between the surface and 100–110 cm depth were dated using the quartz inclusion method with the Single Aliquot Regeneration (SAR) protocol. Environmental dose rates were quantified by laser ablation–inductively coupled plasma mass spectrometry (LA-ICP-MS) through in situ determination of uranium (U), thorium (Th), and potassium (K) concentrations, minimizing spatial heterogeneity effects commonly associated with bulk measurements. The obtained OSL ages range from 1426 ± 162 year to 2539 ± 223 year, indicating consistent burial histories across stratigraphic levels. Independent Accelerator Mass Spectrometry (AMS) radiocarbon ages of charcoal and human bone (1700–2600 year) show good agreement with the OSL results, supporting the reliability of the luminescence-derived chronology. These results demonstrate that OSL dating of iron-smelting slag, when combined with high-resolution dose rate assessment, provides robust chronological constraints and represents a valuable radiation-based approach for reconstructing metallurgical activity sequences in Southeast Asia.