Deterioration mechanisms of Siberian mammoth tusks: insights from natural versus disturbed states

Amid the global ban on elephant ivory and the urgent need to conserve archeological ivory, including those recovered at the Sanxingdui site in Sichuan, China, this study uses geologically preserved, legally accessible mammoth ivory to investigate degradation mechanisms relevant to heritage conservation. Siberian mammoth ivories representing different deterioration states were characterized by stereomicroscopy, scanning electron microscopy, infrared spectroscopy, X-ray diffraction, X-ray fluorescence spectroscopy, and mechanical testing to evaluate their structural, chemical, and mechanical properties. The results show that degradation is controlled by burial microenvironments, ranging from physical weathering under stable conditions to active hydrogeochemical cycling in disturbed settings. Severe deterioration involves collagen hydrolysis, hydroxyapatite dissolution, secondary mineral reprecipitation, and exogenous element infiltration, leading to structural weakening and, in extreme cases, powdery calcification. These findings clarify the pathways and drivers of ivory degradation in complex burial environments and provide a scientific basis for developing targeted conservation strategies for archeological ivory artifacts.