Hubei Provincial Museum

Abstract The formation mechanism of type-I patina and the existence state of Cu on the surface of ancient bronze are not clear. This study compared the surface patina of ancient bronze with pure SnO2 nanoparticles prepared by hydrothermal method. The main crystalline component of the patina was ~ 5 nm SnO2 nanoparticles, which are very similar to those of pure SnO2, indicating their comparability. Cu element was found in patina, but it did not form crystals. The XRD diffraction peak of the patina shifted, indicating that Cu entered the SnO2 lattice and caused crystallinity decreased. Compared to pure SnO2, new peaks appeared in the XPS spectra of Cu and O in the patina, which are speculated to be Cu-O-Sn binding which is the key character of type-I patina. It indicates that type-I patina is mainly composed of crystalline SnO2 nanoparticles with some Cu dissolves in its lattice structure. The concentration of Cu in SnO2 crystal cells is limited, and mainly copper forms amorphous Cu2O with Sn. Sn can increase the structural stability of Cu2O, making it easy to enter it which hinders the crystallization of Cu2O. When the Sn content is insufficient, sufficient Cu-O-Sn amorphous cannot be formed, and Cu2O may crystallize.

Microbial communities in tomb soil change during archaeological excavation, and these changes can accelerate the deterioration of buried heritage. In this study, a high-throughput sequencing method was used to analyze the soil microbial diversity of tomb M88 from the Sujialong Cultural Property after careful excavation in the laboratory. The phylum of Proteobacteria, Acidobacteria and Ascomycota predominated in the tomb soil, and the dominant genera, Pseudarthrobacter, Penicillium, and Cladosporium, showed the potential to degrade residual relics in the tomb soil. These findings will help to explore the process of microbial degradation in buried heritage during long-term archaeological excavation and improve careful excavation procedures in the laboratory for further conservation. Additionally, numerous plant species were identified in the tomb soil, and most of the plants belonged to the native vegetation species. However, the identified dominant species, Glycine, Angelica, and Hippophae, should be from residual heritage rather than native species, which may provide clues for the study of funeral customs and cultural exchange in the Zeng State.