LUMINESCENCE DATING OF BRICK FROM NAKHON KALONG CITY ARCHAEOLOGICAL SITE IN NORTHEASTERN THAILAND

Abstract

Nakhon Kalong, located in Ban Khon Sawan, Khon Sawan District, Chaiyaphum Province, Northeastern Thailand, is an archaeological site associated with the Dvaravati period (12th-16th Buddhist centuries). The site features distinctive characteristics of Dvaravati culture, including a moated settlement, earthen ramparts, laterite structures, sandstone sema markers (bai sema), and a large sandstone Buddha image. The bricks used in construction at the site were subjected to a heating process prior to use, which makes them suitable for luminescence dating. In this study, brick samples obtained as rubble from excavation sites in Ban Khon Sawan were analyzed to determine their age. The accumulated dose was measured using Optically Stimulated Luminescence (OSL) dating, while the annual dose was determined by Laser Ablation-Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). The annual dose was measured at 2.80±0.67 mGy per year, and the accumulated dose was found to be 2.92±0.24 Gy. These values yield an estimated luminescence age of 1,042±263 years. The dating results are consistent with historical records, confirming the occupation of Nakhon Kalong during the Dvaravati period.