Preliminary Elemental Study of Bronze Sacred Sculptures From Sukhothai to Rattanakosin Periods (13th - 19th CE) Using Portable X-Ray Fluorescence Technique

Narongrit Sosa1, Sasiphan Khaweerat1, Alisa Chaiwong1, Surat Lertlum2, Jeerawan Sangpetch3

1Nuclear Technology Research and Development Center, Thailand Institute of Nuclear Technology, Thailand

2Research Center, Chulachomklao Royal Military Academy, Thailand

3Faculty of Fine and Applied Arts, Chulalongkorn University, Thailand

Ancient bronze artifacts play a crucial role in the world’s cultural heritage. Bronze is a metallic mixture between copper and tin with various metal ratios. It possibly contains different trace elements, e.g., lead, zinc, iron, and arsenic depending on ore sources and the smelting process. In Thai cultural history, bronze sacred sculptures from the Sukhothai period (13th - 15th century CE) have been recognized as masterpieces. Due to population growth, regional/trans-continental impacts, and specific artisan techniques, bronze artifacts of the following periods: Ayutthaya and Rattanakosin, demonstrate typical characters through time and space. Nowadays, the past metallurgical processes and bronze composition have been intensively investigated using multidisciplinary protocols. Accordingly, portable X-ray fluorescence (pXRF) becomes a powerful non-destructive technique for semi-quantitative analysis. By the courtesy of the National Museum Bangkok and Wat Benchamabophit Dusitvanaram, several bronze sacred sculptures from Sukhothai to Rattanakosin eras (13th - 19th century CE) were analyzed using pXRF. This preliminary study provides elemental composition data of these sculptures reflecting the smelting technology development, values, and characters of particular artisan schools. Remarkably, the amount of zinc found in some sculptures probably indicates specific ingredients of different artisan schools. The relationship between metallurgical technological development and comparative date determination will be further investigated to better understand the prosperous cultures of Thai ancestors.