Luminescence dating of archaeometallurgical slag from Buriram Province, northeastern Thailand

Abstract

In this study, the possibility of directly dating archaeometallurgical slags is assessed. The enormous slag heaps distributed in the Ban Kruat district, Buriram Province, Thailand, have been interpreted as one of the most prominent archaeometallurgical sites in Mainland Southeast Asia. Therefore, five slag samples were collected from the topmost level of two heaps. The X-ray diffraction measurement of each slag revealed the existence of quartz minerals, which is conceptually useful to luminescence dating. Based on optically stimulated luminescence (OSL) measurements, two of the five samples showed a weak luminescence signal, which was not suitable for OSL dating, and may reflect the lack of quartz minerals. However, the other three quartz-rich slag samples clearly expressed an OSL signal. Therefore, 40 or 96 aliquots of a single aliquot regenerative measurement were employed to date them.With the combination of the activated dose rate obtained from environmental radioactive elements (U, Th, and K), two timespans of iron-smelting activity were defined, as approximately 140 y ago and 470-710 y ago. Compared with the radiocarbon dates of the adjacent slag heap in Buriram (560 ± 280 y BP), the 140-y-old slag heap dated in this study is younger and represents the latest (most recently) datable iron-smelting industry in the Angkor highland (Thailand). Meanwhile, the radiocarbon dates (140 ± 20 y BP) of the slag heap in the Angkor lowland (Cambodia) conformed to the date obtained in this study. Therefore, it is concluded that OSL dating is effective for direct dating of the slag-bearing quartz.

Remote sensing and luminescence dating of archaeological sites in Buriram province, northeastern Thailand

“…The OSL dating of these technical ceramics yielded an approximate age of the 17 th century. This result aligns well with the age of the slag sample found in the same heap (Khamsiri et al, 2022). Therefore, by combining the dating results of both the slag samples and the technical ceramics, it can be concluded that this site represents a long-lasting ancient production site that existed from the Iron Age through the Angkorian Period and into the post-Angkorian Period.…”