Comprehensive Analysis of the Surface Decoration Layer of Buddha Statues from Dazu Rock Carvings in China

Abstract

The surface decoration layers of Samantabhadra Bodhisattva and Thousand Hand Guanyin from Dazu Rock Carvings were examined using digital microscopy, energy-dispersive spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and pyrolysis—gas chromatography/mass spectrometry using thermally assisted hydrolysis and methylation. Gypsum was present in the preparation layer, while the painted layer included lacquer sap (urushiol). The presence of heat-bodied tung oil and resin (benzoin resin) was also detected in some painted layers. Mineral pigments were found in the painted layers, including cinnabar, lead red, orpiment, litharge, and carbon. In addition, there was a layer of gold foil on the surface of the Thousand Hand Guanyin sample. The mass percentage of gold was 96.70%. The gold foil contained gold, silver, copper, and iron as a solid solution. This study provides a reference for the study and protection of cultural relic samples from grottoes.

Keywords:

• Dazu Rock carvings
• energy-dispersive spectrometry
• Fourier transform infrared spectroscopy
• heat-bodied tung oil
• pyrolysis-gas chromatography/mass spectrometry
• urushiol
• X-ray diffraction

Conflicts of interest

The authors declare that they have no conflicts of interest.