Protection of excavated ivory from Sanxingdui Ruins sees new progress

The waterlogged ivory unearthed at the Sanxingdui Ruins site Photo: Courtesy of Henan Provincial Institute of Cultural Heritage and Archaeology

Researchers have yielded significant results in dehydrating and reinforcing waterlogged ivory unearthed at the Sanxingdui Ruins site in Sichuan, Chen Jiachang, deputy director of the Henan Provincial Institute of Cultural Heritage and Archaeology, told the Global Times on Thursday.

"We have successfully protected nine deteriorated ivory fragments and one complete ivory carving unearthed from the Sanxingdui Ruins site, achieving a breakthrough in rescuing waterlogged and deteriorated ivory," Chen said.  

According to Chen, from 2020 to 2021, more than 400 ivory fragments were excavated from sacrificial areas K3 to K8 at the Sanxingdui Ruins site. 

Underground burials, particularly in the presence of groundwater, soluble salts, and various unfavorable factors, can cause the decomposition of organic components crucial for keeping ivory together. 

Without protective intervention, these ivory pieces, once excavated, would quickly crack, peel, and eventually disintegrate into powder after drying out, a huge loss for historical research. 

"It is crucial to find a dehydrating reinforcement material with high permeability, good compatibility, strong reinforcement, and high environmental adaptability," said Zhang Liangshuai, an archaeologist from Henan Provincial Institute of Cultural Heritage and Archaeology, China News Service reported on Wednesday.

Through CT scans of the waterlogged ivory and analysis of the burial environment, researchers clarified the causes of the damage, which comes down to a loss of organic collagen fibers, making minerals connections fragile. Keeping the items moist was identified as crucial for maintaining the ivory pieces' current form, as the shrinkage caused from moisture loss was the primary cause of their disintegration.

After extensive research efforts, the Henan research team successfully developed protective materials and related techniques for preserving the waterlogged ivory artifacts. 

Chen highlighted the scarcity of research on the protection of ivory and ivory artifacts worldwide. Existing reports indicate that countries such as Canada, the US, Italy, and Japan have successfully protected ivory fossils that have been buried for tens of thousands of years and have undergone mineralization. However, there have been no successful cases of protecting waterlogged deteriorated ivory.

"Our team has now established a comprehensive technical system for dehydrating and reinforcing the protection of waterlogged deteriorated ivory unearthed in archaeological excavations, providing a 'Chinese solution' for the preservation of such artifacts," said Chen.