Study on the influence of weathering process on the chemical composition of ancient glass based on CLR

Abstract

The aim of this study was to investigate the effects of weathering processes on the chemical composition of high-potassium and lead-barium glass. First, correlation and difference analyses were performed on the surface weathering of glass artifacts in relation to their glass type, ornaments, and color, all of which showed that glass type had a significant effect on surface weathering, and that lead-barium glass was more susceptible to weathering than high-potassium glass. Then, the complex and difficult compositional data of glass artifacts were transformed into simple and easy to handle CLR data by central logarithmic ratio transformation (CLR), and independent sample t-tests or Satterthwaite approximate t-tests were performed for each chemical composition content of high-potassium glass and lead-barium glass before and after weathering, respectively, to identify the influence of weathering process on the chemical composition content of the two glasses. Finally, the chemical composition content of the weathered glass artifacts before weathering was predicted from their chemical composition content after weathering by distribution matching method and transformed back to the compositional data by CLR inversion.